From a130fb4fb8bfb893f2bd0d402cb7490de48da235 Mon Sep 17 00:00:00 2001
From: Petr Shumilov <p.shumilov@vkteam.ru>
Date: Mon, 28 Oct 2024 00:39:09 +0400
Subject: [PATCH] Fix getcontext return value for aarch64/darwin

Signed-off-by: Petr Shumilov <p.shumilov@vkteam.ru>
---
 common/ucontext/darwin/aarch64/context.cpp | 35 ++++++++++++----------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/common/ucontext/darwin/aarch64/context.cpp b/common/ucontext/darwin/aarch64/context.cpp
index d5150554b..685de4b82 100644
--- a/common/ucontext/darwin/aarch64/context.cpp
+++ b/common/ucontext/darwin/aarch64/context.cpp
@@ -78,23 +78,8 @@ asm(".global " NAME(getcontext_portable) ";\n"
     ".align  2;\n"
     NAME(getcontext_portable) ":\n"
     "str	xzr, [x0, #((184) + ((0) * (8)))]\n"       // #REG_OFFSET(0)
-    /* save GPRs */
-    "stp	x0, x1,   [x0, #((184) + ((0) * (8)))]\n"  // REG_OFFSET(0)
+    /* save x2 and x3 for reuse */
     "stp	x2, x3,   [x0, #((184) + ((2) * (8)))]\n"  // REG_OFFSET(2)
-    "stp	x4, x5,   [x0, #((184) + ((4) * (8)))]\n"  // REG_OFFSET(4)
-    "stp	x6, x7,   [x0, #((184) + ((6) * (8)))]\n"  // REG_OFFSET(6)
-    "stp	x8, x9,   [x0, #((184) + ((8) * (8)))]\n"  // REG_OFFSET(8)
-    "stp	x10, x11, [x0, #((184) + ((10) * (8)))]\n" // REG_OFFSET(10)
-    "stp	x12, x13, [x0, #((184) + ((12) * (8)))]\n" // REG_OFFSET(12)
-    "stp	x14, x15, [x0, #((184) + ((14) * (8)))]\n" // REG_OFFSET(14)
-    "stp	x16, x17, [x0, #((184) + ((16) * (8)))]\n" // REG_OFFSET(16)
-    "stp	x18, x19, [x0, #((184) + ((18) * (8)))]\n" // REG_OFFSET(18)
-    "stp	x20, x21, [x0, #((184) + ((20) * (8)))]\n" // REG_OFFSET(20)
-    "stp	x22, x23, [x0, #((184) + ((22) * (8)))]\n" // REG_OFFSET(22)
-    "stp	x24, x25, [x0, #((184) + ((24) * (8)))]\n" // REG_OFFSET(24)
-    "stp	x26, x27, [x0, #((184) + ((26) * (8)))]\n" // REG_OFFSET(26)
-    "stp	x28, x29, [x0, #((184) + ((28) * (8)))]\n" // REG_OFFSET(28)
-    "str	x30,      [x0, #((184) + ((30) * (8)))]\n" // REG_OFFSET(30)
     /* save current program counter in link register */
     "str	x30, [x0, #440]\n"                         // PC_OFFSET
     /* save current stack pointer */
@@ -107,7 +92,25 @@ asm(".global " NAME(getcontext_portable) ";\n"
     "stp q10, q11, [x2, #176]\n"
     "stp q12, q13, [x2, #208]\n"
     "stp q14, q15, [x2, #240]\n"
+    /* save GPRs and return value 0 */
+	  "mov	x2, x0\n"
     "mov	x0, #0\n"
+    "stp	x0, x1,   [x2, #((184) + ((0) * (8)))]\n"  // REG_OFFSET(0)
+    /* x2 and x3 have already been saved */
+    "stp	x4, x5,   [x2, #((184) + ((4) * (8)))]\n"  // REG_OFFSET(4)
+    "stp	x6, x7,   [x2, #((184) + ((6) * (8)))]\n"  // REG_OFFSET(6)
+    "stp	x8, x9,   [x2, #((184) + ((8) * (8)))]\n"  // REG_OFFSET(8)
+    "stp	x10, x11, [x2, #((184) + ((10) * (8)))]\n" // REG_OFFSET(10)
+    "stp	x12, x13, [x2, #((184) + ((12) * (8)))]\n" // REG_OFFSET(12)
+    "stp	x14, x15, [x2, #((184) + ((14) * (8)))]\n" // REG_OFFSET(14)
+    "stp	x16, x17, [x2, #((184) + ((16) * (8)))]\n" // REG_OFFSET(16)
+    "stp	x18, x19, [x2, #((184) + ((18) * (8)))]\n" // REG_OFFSET(18)
+    "stp	x20, x21, [x2, #((184) + ((20) * (8)))]\n" // REG_OFFSET(20)
+    "stp	x22, x23, [x2, #((184) + ((22) * (8)))]\n" // REG_OFFSET(22)
+    "stp	x24, x25, [x2, #((184) + ((24) * (8)))]\n" // REG_OFFSET(24)
+    "stp	x26, x27, [x2, #((184) + ((26) * (8)))]\n" // REG_OFFSET(26)
+    "stp	x28, x29, [x2, #((184) + ((28) * (8)))]\n" // REG_OFFSET(28)
+    "str	x30,      [x2, #((184) + ((30) * (8)))]\n" // REG_OFFSET(30)
     "ret\n");
 
 asm(".global " NAME(setcontext_portable) ";\n"