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-rw-r--r--frida_mode/src/entry.c1
-rw-r--r--frida_mode/src/instrument/instrument.c11
-rw-r--r--frida_mode/src/js/api.js430
-rw-r--r--frida_mode/src/js/js.c13
-rw-r--r--frida_mode/src/js/js_api.c12
-rw-r--r--frida_mode/src/persistent/persistent.c28
-rw-r--r--frida_mode/src/persistent/persistent_arm64.c399
-rw-r--r--frida_mode/src/persistent/persistent_x64.c174
-rw-r--r--frida_mode/src/persistent/persistent_x86.c111
9 files changed, 561 insertions, 618 deletions
diff --git a/frida_mode/src/entry.c b/frida_mode/src/entry.c
index 186d5098..e95b923b 100644
--- a/frida_mode/src/entry.c
+++ b/frida_mode/src/entry.c
@@ -13,6 +13,7 @@ guint64 entry_point = 0;
 
 static void entry_launch(void) {
 
+  OKF("Entry point reached");
   __afl_manual_init();
 
   /* Child here */
diff --git a/frida_mode/src/instrument/instrument.c b/frida_mode/src/instrument/instrument.c
index d6ae505d..2a217d96 100644
--- a/frida_mode/src/instrument/instrument.c
+++ b/frida_mode/src/instrument/instrument.c
@@ -11,6 +11,7 @@
 #include "entry.h"
 #include "frida_cmplog.h"
 #include "instrument.h"
+#include "js.h"
 #include "persistent.h"
 #include "prefetch.h"
 #include "ranges.h"
@@ -165,8 +166,6 @@ static void instrument_basic_block(GumStalkerIterator *iterator,
 
       }
 
-      begin = FALSE;
-
     }
 
     instrument_debug_instruction(instr->address, instr->size);
@@ -178,7 +177,13 @@ static void instrument_basic_block(GumStalkerIterator *iterator,
 
     }
 
-    gum_stalker_iterator_keep(iterator);
+    if (js_stalker_callback(instr, begin, excluded, output)) {
+
+      gum_stalker_iterator_keep(iterator);
+
+    }
+
+    begin = FALSE;
 
   }
 
diff --git a/frida_mode/src/js/api.js b/frida_mode/src/js/api.js
index 983f1efa..4cb04704 100644
--- a/frida_mode/src/js/api.js
+++ b/frida_mode/src/js/api.js
@@ -1,201 +1,243 @@
-const write = new NativeFunction(
-    Module.getExportByName(null, 'write'),
-    'int',
-    ['int', 'pointer', 'int']
-);
-
-const afl_frida_trace = Process.findModuleByName('afl-frida-trace.so');
-
-function get_api(name, ret, args) {
-    const addr = afl_frida_trace.findExportByName(name);
-    return new NativeFunction(addr, ret, args);
-}
-
-const js_api_done = get_api(
-    'js_api_done',
-    'void',
-    []);
-
-const js_api_error = get_api(
-    'js_api_error',
-    'void',
-    ['pointer']);
-
-const js_api_set_entrypoint = get_api(
-    'js_api_set_entrypoint',
-    'void',
-    ['pointer']);
-
-const js_api_set_persistent_address = get_api(
-    'js_api_set_persistent_address',
-    'void',
-    ['pointer']);
-
-const js_api_set_persistent_return = get_api(
-    'js_api_set_persistent_return',
-    'void',
-    ['pointer']);
-
-const js_api_set_persistent_count = get_api(
-    'js_api_set_persistent_count',
-    'void',
-    ['uint64']);
-
-const js_api_set_persistent_debug = get_api(
-    'js_api_set_persistent_debug',
-    'void',
-    []);
-
-const js_api_set_debug_maps = get_api(
-    'js_api_set_debug_maps',
-    'void',
-    []);
-
-const js_api_add_include_range = get_api(
-    'js_api_add_include_range',
-    'void',
-    ['pointer', 'size_t']);
-
-const js_api_add_exclude_range = get_api(
-    'js_api_add_exclude_range',
-    'void',
-    ['pointer', 'size_t']);
-
-const js_api_set_instrument_libraries = get_api(
-    'js_api_set_instrument_libraries',
-    'void',
-    []);
-
-const js_api_set_instrument_debug_file = get_api(
-    'js_api_set_instrument_debug_file',
-    'void',
-    ['pointer']);
-
-const js_api_set_prefetch_disable = get_api(
-    'js_api_set_prefetch_disable',
-    'void',
-    []);
-
-const js_api_set_instrument_no_optimize = get_api(
-    'js_api_set_instrument_no_optimize',
-    'void',
-    []);
-
-const js_api_set_instrument_trace = get_api(
-    'js_api_set_instrument_trace',
-    'void',
-    []);
-
-const js_api_set_instrument_trace_unique = get_api(
-    'js_api_set_instrument_trace_unique',
-    'void',
-    []);
-
-const js_api_set_stdout = get_api(
-    'js_api_set_stdout',
-    'void',
-    ['pointer']);
-
-const js_api_set_stderr = get_api(
-    'js_api_set_stderr',
-    'void',
-    ['pointer']);
-
-const js_api_set_stats_file = get_api(
-    'js_api_set_stats_file',
-    'void',
-    ['pointer']);
-
-const js_api_set_stats_interval = get_api(
-    'js_api_set_stats_interval',
-    'void',
-    ['uint64']);
-
-const js_api_set_stats_transitions = get_api(
-    'js_api_set_stats_transitions',
-    'void',
-    []);
-
-const afl = {
-    print: function (msg) {
+"use strict";
+class Afl {
+    /**
+     * This is equivalent to setting a value in `AFL_FRIDA_EXCLUDE_RANGES`,
+     * it takes as arguments a `NativePointer` and a `number`. It can be
+     * called multiple times to exclude several ranges.
+     */
+    static addExcludedRange(addressess, size) {
+        Afl.jsApiAddExcludeRange(addressess, size);
+    }
+    /**
+     * This is equivalent to setting a value in `AFL_FRIDA_INST_RANGES`,
+     * it takes as arguments a `NativePointer` and a `number`. It can be
+     * called multiple times to include several ranges.
+     */
+    static addIncludedRange(addressess, size) {
+        Afl.jsApiAddIncludeRange(addressess, size);
+    }
+    /**
+     * This must always be called at the end of your script. This lets
+     * FRIDA mode know that your configuration is finished and that
+     * execution has reached the end of your script. Failure to call
+     * this will result in a fatal error.
+     */
+    static done() {
+        Afl.jsApiDone();
+    }
+    /**
+     * This function can be called within your script to cause FRIDA
+     * mode to trigger a fatal error. This is useful if for example you
+     * discover a problem you weren't expecting and want everything to
+     * stop. The user will need to enable `AFL_DEBUG_CHILD=1` to view
+     * this error message.
+     */
+    static error(msg) {
+        const buf = Memory.allocUtf8String(msg);
+        Afl.jsApiError(buf);
+    }
+    /**
+     * Function used to provide access to `__afl_fuzz_ptr`, which contains the length of
+     * fuzzing data when using in-memory test case fuzzing.
+     */
+    static getAflFuzzLen() {
+        return Afl.jsApiGetSymbol("__afl_fuzz_len");
+    }
+    /**
+     * Function used to provide access to `__afl_fuzz_ptr`, which contains the fuzzing
+     * data when using in-memory test case fuzzing.
+     */
+    static getAflFuzzPtr() {
+        return Afl.jsApiGetSymbol("__afl_fuzz_ptr");
+    }
+    /**
+     * Print a message to the STDOUT. This should be preferred to
+     * FRIDA's `console.log` since FRIDA will queue it's log messages.
+     * If `console.log` is used in a callback in particular, then there
+     * may no longer be a thread running to service this queue.
+     */
+    static print(msg) {
         const STDOUT_FILENO = 2;
         const log = `${msg}\n`;
         const buf = Memory.allocUtf8String(log);
-        write(STDOUT_FILENO, buf, log.length);
-    },
-    done: function() {
-        js_api_done();
-    },
-    error: function(msg) {
-        const buf = Memory.allocUtf8String(msg);
-        js_api_error(buf);
-    },
-    setEntryPoint: function(addr) {
-        js_api_set_entrypoint(addr);
-    },
-    setPersistentAddress: function(addr) {
-        js_api_set_persistent_address(addr);
-    },
-    setPersistentReturn: function(addr) {
-        js_api_set_persistent_return(addr);
-    },
-    setPersistentCount: function(addr) {
-        js_api_set_persistent_count(addr);
-    },
-    setPersistentDebug: function() {
-        js_api_set_persistent_debug();
-    },
-    setDebugMaps: function() {
-        js_api_set_debug_maps();
-    },
-    addIncludedRange: function(address, size) {
-        js_api_add_include_range(address, size);
-    },
-    addExcludedRange: function(address, size) {
-        js_api_add_exclude_range(address, size);
-    },
-    setInstrumentLibraries: function() {
-        js_api_set_instrument_libraries();
-    },
-    setInstrumentDebugFile: function(file) {
+        Afl.jsApiWrite(STDOUT_FILENO, buf, log.length);
+    }
+    /**
+     * See `AFL_FRIDA_DEBUG_MAPS`.
+     */
+    static setDebugMaps() {
+        Afl.jsApiSetDebugMaps();
+    }
+    /**
+     * This has the same effect as setting `AFL_ENTRYPOINT`, but has the
+     * convenience of allowing you to use FRIDAs APIs to determine the
+     * address you would like to configure, rather than having to grep
+     * the output of `readelf` or something similarly ugly. This
+     * function should be called with a `NativePointer` as its
+     * argument.
+     */
+    static setEntryPoint(address) {
+        Afl.jsApiSetEntryPoint(address);
+    }
+    /**
+     * Function used to enable in-memory test cases for fuzzing.
+     */
+    static setInMemoryFuzzing() {
+        Afl.jsApiAflSharedMemFuzzing.writeInt(1);
+    }
+    /**
+     * See `AFL_FRIDA_INST_DEBUG_FILE`. This function takes a single `string` as
+     * an argument.
+     */
+    static setInstrumentDebugFile(file) {
         const buf = Memory.allocUtf8String(file);
-        js_api_set_instrument_debug_file(buf)
-    },
-    setPrefetchDisable: function() {
-        js_api_set_prefetch_disable();
-    },
-    setInstrumentNoOptimize: function() {
-        js_api_set_instrument_no_optimize();
-    },
-    setInstrumentEnableTracing: function() {
-        js_api_set_instrument_trace();
-    },
-    setInstrumentTracingUnique: function() {
-        js_api_set_instrument_trace_unique();
-    },
-    setStdOut: function(file) {
+        Afl.jsApiSetInstrumentDebugFile(buf);
+    }
+    /**
+     * See `AFL_FRIDA_INST_TRACE`.
+     */
+    static setInstrumentEnableTracing() {
+        Afl.jsApiSetInstrumentTrace();
+    }
+    /**
+     * See `AFL_INST_LIBS`.
+     */
+    static setInstrumentLibraries() {
+        Afl.jsApiSetInstrumentLibraries();
+    }
+    /**
+     * See `AFL_FRIDA_INST_NO_OPTIMIZE`
+     */
+    static setInstrumentNoOptimize() {
+        Afl.jsApiSetInstrumentNoOptimize();
+    }
+    /**
+     * See `AFL_FRIDA_INST_TRACE_UNIQUE`.
+     */
+    static setInstrumentTracingUnique() {
+        Afl.jsApiSetInstrumentTraceUnique();
+    }
+    /**
+     * This is equivalent to setting `AFL_FRIDA_PERSISTENT_ADDR`, again a
+     * `NativePointer` should be provided as it's argument.
+     */
+    static setPersistentAddress(address) {
+        Afl.jsApiSetPersistentAddress(address);
+    }
+    /**
+     * This is equivalent to setting `AFL_FRIDA_PERSISTENT_CNT`, a
+     * `number` should be provided as it's argument.
+     */
+    static setPersistentCount(count) {
+        Afl.jsApiSetPersistentCount(count);
+    }
+    /**
+     * See `AFL_FRIDA_PERSISTENT_DEBUG`.
+     */
+    static setPersistentDebug() {
+        Afl.jsApiSetPersistentDebug();
+    }
+    /**
+     * See `AFL_FRIDA_PERSISTENT_ADDR`. This function takes a NativePointer as an
+     * argument. See above for examples of use.
+     */
+    static setPersistentHook(address) {
+        Afl.jsApiSetPersistentHook(address);
+    }
+    /**
+     * This is equivalent to setting `AFL_FRIDA_PERSISTENT_RET`, again a
+     * `NativePointer` should be provided as it's argument.
+     */
+    static setPersistentReturn(address) {
+        Afl.jsApiSetPersistentReturn(address);
+    }
+    /**
+     * See `AFL_FRIDA_INST_NO_PREFETCH`.
+     */
+    static setPrefetchDisable() {
+        Afl.jsApiSetPrefetchDisable();
+    }
+    /*
+     * Set a function to be called for each instruction which is instrumented
+     * by AFL FRIDA mode.
+     */
+    static setStalkerCallback(callback) {
+        Afl.jsApiSetStalkerCallback(callback);
+    }
+    /**
+     * See `AFL_FRIDA_STATS_FILE`. This function takes a single `string` as
+     * an argument.
+     */
+    static setStatsFile(file) {
         const buf = Memory.allocUtf8String(file);
-        js_api_set_stdout(buf)
-    },
-    setStdErr: function(file) {
+        Afl.jsApiSetStatsFile(buf);
+    }
+    /**
+     * See `AFL_FRIDA_STATS_INTERVAL`. This function takes a `number` as an
+     * argument
+     */
+    static setStatsInterval(interval) {
+        Afl.jsApiSetStatsInterval(interval);
+    }
+    /**
+     * See `AFL_FRIDA_STATS_TRANSITIONS`
+     */
+    static setStatsTransitions() {
+        Afl.jsApiSetStatsTransitions();
+    }
+    /**
+     * See `AFL_FRIDA_OUTPUT_STDERR`. This function takes a single `string` as
+     * an argument.
+     */
+    static setStdErr(file) {
         const buf = Memory.allocUtf8String(file);
-        js_api_set_stderr(buf)
-    },
-    setStatsFile: function(file) {
+        Afl.jsApiSetStdErr(buf);
+    }
+    /**
+     * See `AFL_FRIDA_OUTPUT_STDOUT`. This function takes a single `string` as
+     * an argument.
+     */
+    static setStdOut(file) {
         const buf = Memory.allocUtf8String(file);
-        js_api_set_stats_file(buf)
-    },
-    setStatsInterval: function(interval) {
-        js_api_set_stats_interval(interval);
-    },
-    setStatsTransitions: function() {
-        js_api_set_stats_transitions();
-    }
-
-};
-
-Object.defineProperty(global, 'Afl', {value: afl, writeable: false});
-
-////////////////////////////////////////////////////////////////////////////////
-//                          END OF API                                        //
-////////////////////////////////////////////////////////////////////////////////
+        Afl.jsApiSetStdOut(buf);
+    }
+    static jsApiGetFunction(name, retType, argTypes) {
+        const addr = Afl.module.getExportByName(name);
+        return new NativeFunction(addr, retType, argTypes);
+    }
+    static jsApiGetSymbol(name) {
+        return Afl.module.getExportByName(name);
+    }
+}
+/**
+ * Field containing the `Module` object for `afl-frida-trace.so` (the FRIDA mode
+ * implementation).
+ */
+Afl.module = Process.getModuleByName("afl-frida-trace.so");
+Afl.jsApiAddExcludeRange = Afl.jsApiGetFunction("js_api_add_exclude_range", "void", ["pointer", "size_t"]);
+Afl.jsApiAddIncludeRange = Afl.jsApiGetFunction("js_api_add_include_range", "void", ["pointer", "size_t"]);
+Afl.jsApiAflSharedMemFuzzing = Afl.jsApiGetSymbol("__afl_sharedmem_fuzzing");
+Afl.jsApiDone = Afl.jsApiGetFunction("js_api_done", "void", []);
+Afl.jsApiError = Afl.jsApiGetFunction("js_api_error", "void", ["pointer"]);
+Afl.jsApiSetDebugMaps = Afl.jsApiGetFunction("js_api_set_debug_maps", "void", []);
+Afl.jsApiSetEntryPoint = Afl.jsApiGetFunction("js_api_set_entrypoint", "void", ["pointer"]);
+Afl.jsApiSetInstrumentDebugFile = Afl.jsApiGetFunction("js_api_set_instrument_debug_file", "void", ["pointer"]);
+Afl.jsApiSetInstrumentLibraries = Afl.jsApiGetFunction("js_api_set_instrument_libraries", "void", []);
+Afl.jsApiSetInstrumentNoOptimize = Afl.jsApiGetFunction("js_api_set_instrument_no_optimize", "void", []);
+Afl.jsApiSetInstrumentTrace = Afl.jsApiGetFunction("js_api_set_instrument_trace", "void", []);
+Afl.jsApiSetInstrumentTraceUnique = Afl.jsApiGetFunction("js_api_set_instrument_trace_unique", "void", []);
+Afl.jsApiSetPersistentAddress = Afl.jsApiGetFunction("js_api_set_persistent_address", "void", ["pointer"]);
+Afl.jsApiSetPersistentCount = Afl.jsApiGetFunction("js_api_set_persistent_count", "void", ["uint64"]);
+Afl.jsApiSetPersistentDebug = Afl.jsApiGetFunction("js_api_set_persistent_debug", "void", []);
+Afl.jsApiSetPersistentHook = Afl.jsApiGetFunction("js_api_set_persistent_hook", "void", ["pointer"]);
+Afl.jsApiSetPersistentReturn = Afl.jsApiGetFunction("js_api_set_persistent_return", "void", ["pointer"]);
+Afl.jsApiSetPrefetchDisable = Afl.jsApiGetFunction("js_api_set_prefetch_disable", "void", []);
+Afl.jsApiSetStalkerCallback = Afl.jsApiGetFunction("js_api_set_stalker_callback", "void", ["pointer"]);
+Afl.jsApiSetStatsFile = Afl.jsApiGetFunction("js_api_set_stats_file", "void", ["pointer"]);
+Afl.jsApiSetStatsInterval = Afl.jsApiGetFunction("js_api_set_stats_interval", "void", ["uint64"]);
+Afl.jsApiSetStatsTransitions = Afl.jsApiGetFunction("js_api_set_stats_transitions", "void", []);
+Afl.jsApiSetStdErr = Afl.jsApiGetFunction("js_api_set_stderr", "void", ["pointer"]);
+Afl.jsApiSetStdOut = Afl.jsApiGetFunction("js_api_set_stdout", "void", ["pointer"]);
+Afl.jsApiWrite = new NativeFunction(
+/* tslint:disable-next-line:no-null-keyword */
+Module.getExportByName(null, "write"), "int", ["int", "pointer", "int"]);
diff --git a/frida_mode/src/js/js.c b/frida_mode/src/js/js.c
index 79e716ad..ed378d2c 100644
--- a/frida_mode/src/js/js.c
+++ b/frida_mode/src/js/js.c
@@ -5,8 +5,9 @@
 #include "js.h"
 #include "util.h"
 
-static char *js_script = NULL;
-gboolean     js_done = FALSE;
+static char *             js_script = NULL;
+gboolean                  js_done = FALSE;
+js_api_stalker_callback_t js_user_callback = NULL;
 
 static gchar *           filename = "afl.js";
 static gchar *           contents;
@@ -111,3 +112,11 @@ void js_start(void) {
 
 }
 
+gboolean js_stalker_callback(const cs_insn *insn, gboolean begin,
+                             gboolean excluded, GumStalkerOutput *output) {
+
+  if (js_user_callback == NULL) { return TRUE; }
+  return js_user_callback(insn, begin, excluded, output);
+
+}
+
diff --git a/frida_mode/src/js/js_api.c b/frida_mode/src/js/js_api.c
index 018c0b9a..91dccab2 100644
--- a/frida_mode/src/js/js_api.c
+++ b/frida_mode/src/js/js_api.c
@@ -138,5 +138,15 @@ void js_api_set_stats_transitions() {
 
 }
 
-// "AFL_FRIDA_PERSISTENT_HOOK",
+void js_api_set_persistent_hook(void *address) {
+
+  persistent_hook = address;
+
+}
+
+void js_api_set_stalker_callback(const js_api_stalker_callback_t callback) {
+
+  js_user_callback = callback;
+
+}
 
diff --git a/frida_mode/src/persistent/persistent.c b/frida_mode/src/persistent/persistent.c
index e3e0b0ca..bcc59ea7 100644
--- a/frida_mode/src/persistent/persistent.c
+++ b/frida_mode/src/persistent/persistent.c
@@ -47,19 +47,6 @@ void persistent_config(void) {
 
   }
 
-}
-
-void persistent_init(void) {
-
-  OKF("Instrumentation - persistent mode [%c] (0x%016" G_GINT64_MODIFIER "X)",
-      persistent_start == 0 ? ' ' : 'X', persistent_start);
-  OKF("Instrumentation - persistent count [%c] (%" G_GINT64_MODIFIER "d)",
-      persistent_start == 0 ? ' ' : 'X', persistent_count);
-  OKF("Instrumentation - hook [%s]", hook_name);
-
-  OKF("Instrumentation - persistent ret [%c] (0x%016" G_GINT64_MODIFIER "X)",
-      persistent_ret == 0 ? ' ' : 'X', persistent_ret);
-
   if (hook_name == NULL) { return; }
 
   void *hook_obj = dlopen(hook_name, RTLD_NOW);
@@ -79,7 +66,20 @@ void persistent_init(void) {
   if (persistent_hook == NULL)
     FATAL("Failed to find afl_persistent_hook in %s", hook_name);
 
-  __afl_sharedmem_fuzzing = 1;
+}
+
+void persistent_init(void) {
+
+  OKF("Instrumentation - persistent mode [%c] (0x%016" G_GINT64_MODIFIER "X)",
+      persistent_start == 0 ? ' ' : 'X', persistent_start);
+  OKF("Instrumentation - persistent count [%c] (%" G_GINT64_MODIFIER "d)",
+      persistent_start == 0 ? ' ' : 'X', persistent_count);
+  OKF("Instrumentation - hook [%s]", hook_name);
+
+  OKF("Instrumentation - persistent ret [%c] (0x%016" G_GINT64_MODIFIER "X)",
+      persistent_ret == 0 ? ' ' : 'X', persistent_ret);
+
+  if (persistent_hook != NULL) { __afl_sharedmem_fuzzing = 1; }
 
 }
 
diff --git a/frida_mode/src/persistent/persistent_arm64.c b/frida_mode/src/persistent/persistent_arm64.c
index e618fbac..003f058a 100644
--- a/frida_mode/src/persistent/persistent_arm64.c
+++ b/frida_mode/src/persistent/persistent_arm64.c
@@ -9,99 +9,15 @@
 #include "util.h"
 
 #if defined(__aarch64__)
+typedef struct {
 
-struct arm64_regs {
+  GumCpuContext ctx;
+  uint64_t      rflags;
 
-  uint64_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10;
+} persistent_ctx_t;
 
-  union {
-
-    uint64_t x11;
-    uint32_t fp_32;
-
-  };
-
-  union {
-
-    uint64_t x12;
-    uint32_t ip_32;
-
-  };
-
-  union {
-
-    uint64_t x13;
-    uint32_t sp_32;
-
-  };
-
-  union {
-
-    uint64_t x14;
-    uint32_t lr_32;
-
-  };
-
-  union {
-
-    uint64_t x15;
-    uint32_t pc_32;
-
-  };
-
-  union {
-
-    uint64_t x16;
-    uint64_t ip0;
-
-  };
-
-  union {
-
-    uint64_t x17;
-    uint64_t ip1;
-
-  };
-
-  uint64_t x18, x19, x20, x21, x22, x23, x24, x25, x26, x27, x28;
-
-  union {
-
-    uint64_t x29;
-    uint64_t fp;
-
-  };
-
-  union {
-
-    uint64_t x30;
-    uint64_t lr;
-
-  };
-
-  union {
-
-    uint64_t x31;
-    uint64_t sp;
-
-  };
-
-  // the zero register is not saved here ofc
-
-  uint64_t pc;
-
-  uint32_t cpsr;
-
-  uint8_t  vfp_zregs[32][16 * 16];
-  uint8_t  vfp_pregs[17][32];
-  uint32_t vfp_xregs[16];
-
-};
-
-typedef struct arm64_regs arch_api_regs;
-
-static arch_api_regs saved_regs = {0};
-static gpointer      saved_lr = NULL;
+static persistent_ctx_t saved_regs = {0};
+static gpointer         saved_lr = NULL;
 
 gboolean persistent_is_supported(void) {
 
@@ -109,8 +25,8 @@ gboolean persistent_is_supported(void) {
 
 }
 
-static void instrument_persitent_save_regs(GumArm64Writer *   cw,
-                                           struct arm64_regs *regs) {
+static void instrument_persitent_save_regs(GumArm64Writer *  cw,
+                                           persistent_ctx_t *regs) {
 
   GumAddress    regs_address = GUM_ADDRESS(regs);
   const guint32 mrs_x1_nzcv = 0xd53b4201;
@@ -129,83 +45,87 @@ static void instrument_persitent_save_regs(GumArm64Writer *   cw,
 
   /* Skip x0 & x1 we'll do that later */
 
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X3,
-                                              ARM64_REG_X0, (16 * 1),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X4, ARM64_REG_X5,
-                                              ARM64_REG_X0, (16 * 2),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X6, ARM64_REG_X7,
-                                              ARM64_REG_X0, (16 * 3),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X8, ARM64_REG_X9,
-                                              ARM64_REG_X0, (16 * 4),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X10, ARM64_REG_X11,
-                                              ARM64_REG_X0, (16 * 5),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X12, ARM64_REG_X13,
-                                              ARM64_REG_X0, (16 * 6),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X14, ARM64_REG_X15,
-                                              ARM64_REG_X0, (16 * 7),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X16, ARM64_REG_X17,
-                                              ARM64_REG_X0, (16 * 8),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X18, ARM64_REG_X19,
-                                              ARM64_REG_X0, (16 * 9),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X20, ARM64_REG_X21,
-                                              ARM64_REG_X0, (16 * 10),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X22, ARM64_REG_X23,
-                                              ARM64_REG_X0, (16 * 11),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X24, ARM64_REG_X25,
-                                              ARM64_REG_X0, (16 * 12),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X26, ARM64_REG_X27,
-                                              ARM64_REG_X0, (16 * 13),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X28, ARM64_REG_X29,
-                                              ARM64_REG_X0, (16 * 14),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X2, ARM64_REG_X3, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[2]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X4, ARM64_REG_X5, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[4]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X6, ARM64_REG_X7, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[6]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X8, ARM64_REG_X9, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[8]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X10, ARM64_REG_X11, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[10]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X12, ARM64_REG_X13, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[12]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X14, ARM64_REG_X15, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[14]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X16, ARM64_REG_X17, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[16]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X18, ARM64_REG_X19, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[18]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X20, ARM64_REG_X21, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[20]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X22, ARM64_REG_X23, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[22]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X24, ARM64_REG_X25, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[24]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X26, ARM64_REG_X27, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[26]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X28, ARM64_REG_X29, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[28]), GUM_INDEX_SIGNED_OFFSET);
 
-  /* LR & Adjusted SP */
-  gum_arm64_writer_put_add_reg_reg_imm(cw, ARM64_REG_X2, ARM64_REG_SP,
-                                       (GUM_RED_ZONE_SIZE + 32));
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X30, ARM64_REG_X2,
-                                              ARM64_REG_X0, (16 * 15),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  /* LR (x30) */
+  gum_arm64_writer_put_str_reg_reg_offset(cw, ARM64_REG_X30, ARM64_REG_X0,
+                                          offsetof(GumCpuContext, x[30]));
 
-  /* PC & CPSR */
+  /* PC & Adjusted SP (31) */
   gum_arm64_writer_put_ldr_reg_address(cw, ARM64_REG_X2,
                                        GUM_ADDRESS(persistent_start));
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X1,
-                                              ARM64_REG_X0, (16 * 16),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_add_reg_reg_imm(cw, ARM64_REG_X3, ARM64_REG_SP,
+                                       (GUM_RED_ZONE_SIZE + 32));
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X2, ARM64_REG_X3, ARM64_REG_X0, offsetof(GumCpuContext, pc),
+      GUM_INDEX_SIGNED_OFFSET);
 
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_Q0, ARM64_REG_Q1,
-                                              ARM64_REG_X0, (16 * 17),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_Q2, ARM64_REG_Q3,
-                                              ARM64_REG_X0, (16 * 18),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_Q4, ARM64_REG_Q5,
-                                              ARM64_REG_X0, (16 * 19),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_Q6, ARM64_REG_Q7,
-                                              ARM64_REG_X0, (16 * 20),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  /* CPSR */
+  gum_arm64_writer_put_str_reg_reg_offset(cw, ARM64_REG_X1, ARM64_REG_X0,
+                                          offsetof(persistent_ctx_t, rflags));
+
+  /* Q */
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q0, ARM64_REG_Q1, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[0]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q2, ARM64_REG_Q3, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[16]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q4, ARM64_REG_Q5, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[32]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q6, ARM64_REG_Q7, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[48]), GUM_INDEX_SIGNED_OFFSET);
 
   /* x0 & x1 */
   gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X3,
                                               ARM64_REG_SP, 16,
                                               GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_stp_reg_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X3,
-                                              ARM64_REG_X0, (16 * 0),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_stp_reg_reg_reg_offset(
+      cw, ARM64_REG_X2, ARM64_REG_X3, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[0]), GUM_INDEX_SIGNED_OFFSET);
 
   /* Pop the saved values */
   gum_arm64_writer_put_ldp_reg_reg_reg_offset(
@@ -217,8 +137,8 @@ static void instrument_persitent_save_regs(GumArm64Writer *   cw,
 
 }
 
-static void instrument_persitent_restore_regs(GumArm64Writer *   cw,
-                                              struct arm64_regs *regs) {
+static void instrument_persitent_restore_regs(GumArm64Writer *  cw,
+                                              persistent_ctx_t *regs) {
 
   GumAddress    regs_address = GUM_ADDRESS(regs);
   const guint32 msr_nzcv_x1 = 0xd51b4201;
@@ -228,82 +148,81 @@ static void instrument_persitent_restore_regs(GumArm64Writer *   cw,
 
   /* Skip x0 - x3 we'll do that last */
 
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X4, ARM64_REG_X5,
-                                              ARM64_REG_X0, (16 * 2),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X6, ARM64_REG_X7,
-                                              ARM64_REG_X0, (16 * 3),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X8, ARM64_REG_X9,
-                                              ARM64_REG_X0, (16 * 4),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X10, ARM64_REG_X11,
-                                              ARM64_REG_X0, (16 * 5),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X12, ARM64_REG_X13,
-                                              ARM64_REG_X0, (16 * 6),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X14, ARM64_REG_X15,
-                                              ARM64_REG_X0, (16 * 7),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X16, ARM64_REG_X17,
-                                              ARM64_REG_X0, (16 * 8),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X18, ARM64_REG_X19,
-                                              ARM64_REG_X0, (16 * 9),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X20, ARM64_REG_X21,
-                                              ARM64_REG_X0, (16 * 10),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X22, ARM64_REG_X23,
-                                              ARM64_REG_X0, (16 * 11),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X24, ARM64_REG_X25,
-                                              ARM64_REG_X0, (16 * 12),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X26, ARM64_REG_X27,
-                                              ARM64_REG_X0, (16 * 13),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X28, ARM64_REG_X29,
-                                              ARM64_REG_X0, (16 * 14),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X4, ARM64_REG_X5, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[4]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X6, ARM64_REG_X7, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[6]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X8, ARM64_REG_X9, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[8]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X10, ARM64_REG_X11, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[10]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X12, ARM64_REG_X13, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[12]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X14, ARM64_REG_X15, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[14]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X16, ARM64_REG_X17, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[16]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X18, ARM64_REG_X19, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[18]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X20, ARM64_REG_X21, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[20]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X22, ARM64_REG_X23, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[22]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X24, ARM64_REG_X25, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[24]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X26, ARM64_REG_X27, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[26]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X28, ARM64_REG_X29, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[28]), GUM_INDEX_SIGNED_OFFSET);
 
-  /* LR & Adjusted SP (use x1 as clobber) */
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X30, ARM64_REG_X1,
-                                              ARM64_REG_X0, (16 * 15),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  /* LR (x30) */
+  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X30, ARM64_REG_X0,
+                                          offsetof(GumCpuContext, x[30]));
 
+  /* Adjusted SP (31) (use x1 as clobber)*/
+  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X1, ARM64_REG_X0,
+                                          offsetof(GumCpuContext, sp));
   gum_arm64_writer_put_mov_reg_reg(cw, ARM64_REG_SP, ARM64_REG_X1);
 
-  /* Don't restore RIP use x1-x3 as clobber */
-
-  /* PC (x2) & CPSR (x1) */
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X1,
-                                              ARM64_REG_X0, (16 * 16),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  /* CPSR */
+  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X1, ARM64_REG_X0,
+                                          offsetof(persistent_ctx_t, rflags));
   gum_arm64_writer_put_instruction(cw, msr_nzcv_x1);
 
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_Q0, ARM64_REG_Q1,
-                                              ARM64_REG_X0, (16 * 17),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_Q2, ARM64_REG_Q3,
-                                              ARM64_REG_X0, (16 * 18),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_Q4, ARM64_REG_Q5,
-                                              ARM64_REG_X0, (16 * 19),
-                                              GUM_INDEX_SIGNED_OFFSET);
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_Q6, ARM64_REG_Q7,
-                                              ARM64_REG_X0, (16 * 20),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q0, ARM64_REG_Q1, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[0]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q2, ARM64_REG_Q3, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[16]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q4, ARM64_REG_Q5, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[32]), GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_Q6, ARM64_REG_Q7, ARM64_REG_X0,
+      offsetof(GumCpuContext, q[48]), GUM_INDEX_SIGNED_OFFSET);
 
   /* x2 & x3 */
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X3,
-                                              ARM64_REG_X0, (16 * 1),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X2, ARM64_REG_X3, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[2]), GUM_INDEX_SIGNED_OFFSET);
   /* x0 & x1 */
-  gum_arm64_writer_put_ldp_reg_reg_reg_offset(cw, ARM64_REG_X0, ARM64_REG_X1,
-                                              ARM64_REG_X0, (16 * 0),
-                                              GUM_INDEX_SIGNED_OFFSET);
+  gum_arm64_writer_put_ldp_reg_reg_reg_offset(
+      cw, ARM64_REG_X0, ARM64_REG_X1, ARM64_REG_X0,
+      offsetof(GumCpuContext, x[0]), GUM_INDEX_SIGNED_OFFSET);
 
 }
 
@@ -334,29 +253,29 @@ static void instrument_afl_persistent_loop(GumArm64Writer *cw) {
 
 }
 
-static void persistent_prologue_hook(GumArm64Writer *   cw,
-                                     struct arm64_regs *regs) {
+static void persistent_prologue_hook(GumArm64Writer *  cw,
+                                     persistent_ctx_t *regs) {
 
   if (persistent_hook == NULL) return;
 
   gum_arm64_writer_put_sub_reg_reg_imm(cw, ARM64_REG_SP, ARM64_REG_SP,
                                        GUM_RED_ZONE_SIZE);
-  gum_arm64_writer_put_ldr_reg_address(cw, ARM64_REG_X3,
+  gum_arm64_writer_put_ldr_reg_address(cw, ARM64_REG_X2,
                                        GUM_ADDRESS(&__afl_fuzz_len));
-  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X3, ARM64_REG_X3, 0);
-  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X3, ARM64_REG_X3, 0);
+  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X2, 0);
+  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X2, 0);
 
-  gum_arm64_writer_put_and_reg_reg_imm(cw, ARM64_REG_X3, ARM64_REG_X3,
+  gum_arm64_writer_put_and_reg_reg_imm(cw, ARM64_REG_X2, ARM64_REG_X2,
                                        G_MAXULONG);
 
-  gum_arm64_writer_put_ldr_reg_address(cw, ARM64_REG_X2,
+  gum_arm64_writer_put_ldr_reg_address(cw, ARM64_REG_X1,
                                        GUM_ADDRESS(&__afl_fuzz_ptr));
-  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X2, ARM64_REG_X2, 0);
+  gum_arm64_writer_put_ldr_reg_reg_offset(cw, ARM64_REG_X1, ARM64_REG_X1, 0);
 
   gum_arm64_writer_put_call_address_with_arguments(
-      cw, GUM_ADDRESS(persistent_hook), 4, GUM_ARG_ADDRESS, GUM_ADDRESS(regs),
-      GUM_ARG_ADDRESS, GUM_ADDRESS(0), GUM_ARG_REGISTER, ARM64_REG_X2,
-      GUM_ARG_REGISTER, ARM64_REG_X3);
+      cw, GUM_ADDRESS(persistent_hook), 3, GUM_ARG_ADDRESS,
+      GUM_ADDRESS(&regs->ctx), GUM_ARG_REGISTER, ARM64_REG_X1, GUM_ARG_REGISTER,
+      ARM64_REG_X2);
 
   gum_arm64_writer_put_add_reg_reg_imm(cw, ARM64_REG_SP, ARM64_REG_SP,
                                        GUM_RED_ZONE_SIZE);
@@ -406,6 +325,8 @@ void persistent_prologue(GumStalkerOutput *output) {
 
   gconstpointer loop = cw->code + 1;
 
+  OKF("Persistent loop reached");
+
   instrument_persitent_save_regs(cw, &saved_regs);
 
   /* loop: */
diff --git a/frida_mode/src/persistent/persistent_x64.c b/frida_mode/src/persistent/persistent_x64.c
index a91abc1c..b2186db1 100644
--- a/frida_mode/src/persistent/persistent_x64.c
+++ b/frida_mode/src/persistent/persistent_x64.c
@@ -10,40 +10,15 @@
 
 #if defined(__x86_64__)
 
-struct x86_64_regs {
+typedef struct {
 
-  uint64_t rax, rbx, rcx, rdx, rdi, rsi, rbp, r8, r9, r10, r11, r12, r13, r14,
-      r15;
+  GumCpuContext ctx;
+  uint64_t      rflags;
 
-  union {
+} persistent_ctx_t;
 
-    uint64_t rip;
-    uint64_t pc;
-
-  };
-
-  union {
-
-    uint64_t rsp;
-    uint64_t sp;
-
-  };
-
-  union {
-
-    uint64_t rflags;
-    uint64_t flags;
-
-  };
-
-  uint8_t zmm_regs[32][64];
-
-};
-
-typedef struct x86_64_regs arch_api_regs;
-
-static arch_api_regs saved_regs = {0};
-static gpointer      saved_ret = NULL;
+static persistent_ctx_t saved_regs = {0};
+static gpointer         saved_ret = NULL;
 
 gboolean persistent_is_supported(void) {
 
@@ -51,8 +26,8 @@ gboolean persistent_is_supported(void) {
 
 }
 
-static void instrument_persitent_save_regs(GumX86Writer *      cw,
-                                           struct x86_64_regs *regs) {
+static void instrument_persitent_save_regs(GumX86Writer *    cw,
+                                           persistent_ctx_t *regs) {
 
   GumAddress regs_address = GUM_ADDRESS(regs);
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_RSP, GUM_REG_RSP,
@@ -64,41 +39,41 @@ static void instrument_persitent_save_regs(GumX86Writer *      cw,
 
   gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RAX, regs_address);
 
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 1),
-                                            GUM_REG_RBX);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 2),
-                                            GUM_REG_RCX);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 3),
-                                            GUM_REG_RDX);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 4),
-                                            GUM_REG_RDI);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 5),
-                                            GUM_REG_RSI);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 6),
-                                            GUM_REG_RBP);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 7),
-                                            GUM_REG_R8);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 8),
-                                            GUM_REG_R9);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 9),
-                                            GUM_REG_R10);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 10),
-                                            GUM_REG_R11);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 11),
-                                            GUM_REG_R12);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 12),
-                                            GUM_REG_R13);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 13),
-                                            GUM_REG_R14);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 14),
-                                            GUM_REG_R15);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rbx), GUM_REG_RBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rcx), GUM_REG_RCX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rdx), GUM_REG_RDX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rdi), GUM_REG_RDI);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rsi), GUM_REG_RSI);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rbp), GUM_REG_RBP);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r8), GUM_REG_R8);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r9), GUM_REG_R9);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r10), GUM_REG_R10);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r11), GUM_REG_R11);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r12), GUM_REG_R12);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r13), GUM_REG_R13);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r14), GUM_REG_R14);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, r15), GUM_REG_R15);
 
   /* Store RIP */
   gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RBX,
                                      GUM_ADDRESS(persistent_start));
 
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 15),
-                                            GUM_REG_RBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rip), GUM_REG_RBX);
 
   /* Store adjusted RSP */
   gum_x86_writer_put_mov_reg_reg(cw, GUM_REG_RBX, GUM_REG_RSP);
@@ -106,18 +81,18 @@ static void instrument_persitent_save_regs(GumX86Writer *      cw,
   /* RED_ZONE + Saved flags, RAX, alignment */
   gum_x86_writer_put_add_reg_imm(cw, GUM_REG_RBX,
                                  GUM_RED_ZONE_SIZE + (0x8 * 2));
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 16),
-                                            GUM_REG_RBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rsp), GUM_REG_RBX);
 
   /* Save the flags */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RBX, GUM_REG_RSP, 0x8);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 17),
-                                            GUM_REG_RBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(persistent_ctx_t, rflags), GUM_REG_RBX);
 
   /* Save the RAX */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RBX, GUM_REG_RSP, 0x0);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_RAX, (0x8 * 0),
-                                            GUM_REG_RBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_RAX, offsetof(GumCpuContext, rax), GUM_REG_RBX);
 
   /* Pop the saved values */
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_RSP, GUM_REG_RSP, 0x10);
@@ -127,56 +102,56 @@ static void instrument_persitent_save_regs(GumX86Writer *      cw,
 
 }
 
-static void instrument_persitent_restore_regs(GumX86Writer *      cw,
-                                              struct x86_64_regs *regs) {
+static void instrument_persitent_restore_regs(GumX86Writer *    cw,
+                                              persistent_ctx_t *regs) {
 
   GumAddress regs_address = GUM_ADDRESS(regs);
   gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RAX, regs_address);
 
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RCX, GUM_REG_RAX,
-                                            (0x8 * 2));
+                                            offsetof(GumCpuContext, rcx));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RDX, GUM_REG_RAX,
-                                            (0x8 * 3));
+                                            offsetof(GumCpuContext, rdx));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RDI, GUM_REG_RAX,
-                                            (0x8 * 4));
+                                            offsetof(GumCpuContext, rdi));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RSI, GUM_REG_RAX,
-                                            (0x8 * 5));
+                                            offsetof(GumCpuContext, rsi));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RBP, GUM_REG_RAX,
-                                            (0x8 * 6));
+                                            offsetof(GumCpuContext, rbp));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R8, GUM_REG_RAX,
-                                            (0x8 * 7));
+                                            offsetof(GumCpuContext, r8));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R9, GUM_REG_RAX,
-                                            (0x8 * 8));
+                                            offsetof(GumCpuContext, r9));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R10, GUM_REG_RAX,
-                                            (0x8 * 9));
+                                            offsetof(GumCpuContext, r10));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R11, GUM_REG_RAX,
-                                            (0x8 * 10));
+                                            offsetof(GumCpuContext, r11));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R12, GUM_REG_RAX,
-                                            (0x8 * 11));
+                                            offsetof(GumCpuContext, r12));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R13, GUM_REG_RAX,
-                                            (0x8 * 12));
+                                            offsetof(GumCpuContext, r13));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R14, GUM_REG_RAX,
-                                            (0x8 * 13));
+                                            offsetof(GumCpuContext, r14));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_R15, GUM_REG_RAX,
-                                            (0x8 * 14));
+                                            offsetof(GumCpuContext, r15));
 
   /* Don't restore RIP */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RSP, GUM_REG_RAX,
-                                            (0x8 * 16));
+                                            offsetof(GumCpuContext, rsp));
 
   /* Restore RBX, RAX & Flags */
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_RSP, GUM_REG_RSP,
                                         -(GUM_RED_ZONE_SIZE));
 
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RBX, GUM_REG_RAX,
-                                            (0x8 * 1));
+                                            offsetof(GumCpuContext, rbx));
   gum_x86_writer_put_push_reg(cw, GUM_REG_RBX);
 
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RBX, GUM_REG_RAX,
-                                            (0x8 * 0));
+                                            offsetof(GumCpuContext, rax));
   gum_x86_writer_put_push_reg(cw, GUM_REG_RBX);
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RBX, GUM_REG_RAX,
-                                            (0x8 * 17));
+                                            offsetof(persistent_ctx_t, rflags));
   gum_x86_writer_put_push_reg(cw, GUM_REG_RBX);
 
   gum_x86_writer_put_popfx(cw);
@@ -217,28 +192,27 @@ static void instrument_afl_persistent_loop(GumX86Writer *cw) {
 
 }
 
-static void persistent_prologue_hook(GumX86Writer *      cw,
-                                     struct x86_64_regs *regs) {
+static void persistent_prologue_hook(GumX86Writer *cw, persistent_ctx_t *regs) {
 
   if (persistent_hook == NULL) return;
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_RSP, GUM_REG_RSP,
                                         -(GUM_RED_ZONE_SIZE));
 
-  gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RCX,
+  gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RDX,
                                      GUM_ADDRESS(&__afl_fuzz_len));
-  gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RCX, GUM_REG_RCX, 0);
-  gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RCX, GUM_REG_RCX, 0);
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RDX, GUM_REG_RDX, 0);
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RDX, GUM_REG_RDX, 0);
   gum_x86_writer_put_mov_reg_u64(cw, GUM_REG_RDI, 0xffffffff);
-  gum_x86_writer_put_and_reg_reg(cw, GUM_REG_RCX, GUM_REG_RDI);
+  gum_x86_writer_put_and_reg_reg(cw, GUM_REG_RDX, GUM_REG_RDI);
 
-  gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RDX,
+  gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RSI,
                                      GUM_ADDRESS(&__afl_fuzz_ptr));
-  gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RDX, GUM_REG_RDX, 0);
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_RSI, GUM_REG_RSI, 0);
 
   gum_x86_writer_put_call_address_with_arguments(
-      cw, GUM_CALL_CAPI, GUM_ADDRESS(persistent_hook), 4, GUM_ARG_ADDRESS,
-      GUM_ADDRESS(regs), GUM_ARG_ADDRESS, GUM_ADDRESS(0), GUM_ARG_REGISTER,
-      GUM_REG_RDX, GUM_ARG_REGISTER, GUM_REG_RCX);
+      cw, GUM_CALL_CAPI, GUM_ADDRESS(persistent_hook), 3, GUM_ARG_ADDRESS,
+      GUM_ADDRESS(&regs->ctx), GUM_ARG_REGISTER, GUM_REG_RSI, GUM_ARG_REGISTER,
+      GUM_REG_RDX);
 
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_RSP, GUM_REG_RSP,
                                         (GUM_RED_ZONE_SIZE));
@@ -296,6 +270,8 @@ void persistent_prologue(GumStalkerOutput *output) {
 
   gconstpointer loop = cw->code + 1;
 
+  OKF("Persistent loop reached");
+
   /* Pop the return value */
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_RSP, GUM_REG_RSP, 8);
 
diff --git a/frida_mode/src/persistent/persistent_x86.c b/frida_mode/src/persistent/persistent_x86.c
index 1d01d8e4..f50bccb0 100644
--- a/frida_mode/src/persistent/persistent_x86.c
+++ b/frida_mode/src/persistent/persistent_x86.c
@@ -1,45 +1,23 @@
 #include "frida-gumjs.h"
 
 #include "config.h"
+#include "debug.h"
 
 #include "instrument.h"
 #include "persistent.h"
 
 #if defined(__i386__)
 
-struct x86_regs {
+typedef struct {
 
-  uint32_t eax, ebx, ecx, edx, edi, esi, ebp;
+  GumCpuContext ctx;
+  uint32_t      eflags;
 
-  union {
+} persistent_ctx_t;
 
-    uint32_t eip;
-    uint32_t pc;
+static persistent_ctx_t saved_regs = {0};
 
-  };
-
-  union {
-
-    uint32_t esp;
-    uint32_t sp;
-
-  };
-
-  union {
-
-    uint32_t eflags;
-    uint32_t flags;
-
-  };
-
-  uint8_t xmm_regs[8][16];
-
-};
-
-typedef struct x86_regs arch_api_regs;
-
-static arch_api_regs saved_regs = {0};
-static gpointer      saved_ret = NULL;
+static gpointer saved_ret = NULL;
 
 gboolean persistent_is_supported(void) {
 
@@ -47,8 +25,8 @@ gboolean persistent_is_supported(void) {
 
 }
 
-static void instrument_persitent_save_regs(GumX86Writer *   cw,
-                                           struct x86_regs *regs) {
+static void instrument_persitent_save_regs(GumX86Writer *    cw,
+                                           persistent_ctx_t *regs) {
 
   GumAddress regs_address = GUM_ADDRESS(regs);
 
@@ -58,80 +36,80 @@ static void instrument_persitent_save_regs(GumX86Writer *   cw,
 
   gum_x86_writer_put_mov_reg_address(cw, GUM_REG_EAX, regs_address);
 
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 1),
-                                            GUM_REG_EBX);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 2),
-                                            GUM_REG_ECX);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 3),
-                                            GUM_REG_EDX);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 4),
-                                            GUM_REG_EDI);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 5),
-                                            GUM_REG_ESI);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 6),
-                                            GUM_REG_EBP);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, ebx), GUM_REG_EBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, ecx), GUM_REG_ECX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, edx), GUM_REG_EDX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, edi), GUM_REG_EDI);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, esi), GUM_REG_ESI);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, ebp), GUM_REG_EBP);
 
   /* Store RIP */
   gum_x86_writer_put_mov_reg_address(cw, GUM_REG_EBX,
                                      GUM_ADDRESS(persistent_start));
 
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 7),
-                                            GUM_REG_EBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, eip), GUM_REG_EBX);
 
   /* Store adjusted RSP */
   gum_x86_writer_put_mov_reg_reg(cw, GUM_REG_EBX, GUM_REG_ESP);
 
   /* RED_ZONE + Saved flags, RAX */
   gum_x86_writer_put_add_reg_imm(cw, GUM_REG_EBX, (0x4 * 2));
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 8),
-                                            GUM_REG_EBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, esp), GUM_REG_EBX);
 
   /* Save the flags */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBX, GUM_REG_ESP, 0x4);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 9),
-                                            GUM_REG_EBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(persistent_ctx_t, eflags), GUM_REG_EBX);
 
   /* Save the RAX */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBX, GUM_REG_ESP, 0x0);
-  gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, (0x4 * 0),
-                                            GUM_REG_EBX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_EAX, offsetof(GumCpuContext, eax), GUM_REG_EBX);
 
   /* Pop the saved values */
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_ESP, GUM_REG_ESP, 0x8);
 
 }
 
-static void instrument_persitent_restore_regs(GumX86Writer *   cw,
-                                              struct x86_regs *regs) {
+static void instrument_persitent_restore_regs(GumX86Writer *    cw,
+                                              persistent_ctx_t *regs) {
 
   GumAddress regs_address = GUM_ADDRESS(regs);
   gum_x86_writer_put_mov_reg_address(cw, GUM_REG_EAX, regs_address);
 
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_ECX, GUM_REG_EAX,
-                                            (0x4 * 2));
+                                            offsetof(GumCpuContext, ecx));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EDX, GUM_REG_EAX,
-                                            (0x4 * 3));
+                                            offsetof(GumCpuContext, edx));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EDI, GUM_REG_EAX,
-                                            (0x4 * 4));
+                                            offsetof(GumCpuContext, edi));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_ESI, GUM_REG_EAX,
-                                            (0x4 * 5));
+                                            offsetof(GumCpuContext, esi));
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBP, GUM_REG_EAX,
-                                            (0x4 * 6));
+                                            offsetof(GumCpuContext, ebp));
 
   /* Don't restore RIP */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_ESP, GUM_REG_EAX,
-                                            (0x4 * 8));
+                                            offsetof(GumCpuContext, esp));
 
   /* Restore RBX, RAX & Flags */
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBX, GUM_REG_EAX,
-                                            (0x4 * 1));
+                                            offsetof(GumCpuContext, ebx));
   gum_x86_writer_put_push_reg(cw, GUM_REG_EBX);
 
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBX, GUM_REG_EAX,
-                                            (0x4 * 0));
+                                            offsetof(GumCpuContext, eax));
   gum_x86_writer_put_push_reg(cw, GUM_REG_EBX);
   gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBX, GUM_REG_EAX,
-                                            (0x4 * 9));
+                                            offsetof(persistent_ctx_t, eflags));
   gum_x86_writer_put_push_reg(cw, GUM_REG_EBX);
 
   gum_x86_writer_put_popfx(cw);
@@ -165,7 +143,7 @@ static void instrument_afl_persistent_loop(GumX86Writer *cw) {
 
 }
 
-static void persistent_prologue_hook(GumX86Writer *cw, struct x86_regs *regs) {
+static void persistent_prologue_hook(GumX86Writer *cw, persistent_ctx_t *regs) {
 
   if (persistent_hook == NULL) return;
 
@@ -180,9 +158,8 @@ static void persistent_prologue_hook(GumX86Writer *cw, struct x86_regs *regs) {
 
   /* Base address is 64-bits (hence two zero arguments) */
   gum_x86_writer_put_call_address_with_arguments(
-      cw, GUM_CALL_CAPI, GUM_ADDRESS(persistent_hook), 5, GUM_ARG_ADDRESS,
-      GUM_ADDRESS(regs), GUM_ARG_ADDRESS, GUM_ADDRESS(0), GUM_ARG_ADDRESS,
-      GUM_ADDRESS(0), GUM_ARG_REGISTER, GUM_REG_EDX, GUM_ARG_REGISTER,
+      cw, GUM_CALL_CAPI, GUM_ADDRESS(persistent_hook), 3, GUM_ARG_ADDRESS,
+      GUM_ADDRESS(&regs->ctx), GUM_ARG_REGISTER, GUM_REG_EDX, GUM_ARG_REGISTER,
       GUM_REG_ECX);
 
 }
@@ -233,6 +210,8 @@ void persistent_prologue(GumStalkerOutput *output) {
 
   gconstpointer loop = cw->code + 1;
 
+  OKF("Persistent loop reached");
+
   /* Pop the return value */
   gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_ESP, GUM_REG_ESP, 4);