From c7d9df6350b610bb1fbed77e337f0beda0e823e0 Mon Sep 17 00:00:00 2001
From: Christian Prochaska <christian.prochaska@genode-labs.com>
Date: Mon, 15 Apr 2019 14:15:52 +0200
Subject: [PATCH] lx_kit: update 'arch_execute()' functions based on libc

This ensures proper stack alignment for FPU instructions on x86_64.

Fixes #3356
---
 .../spec/arm/lx_kit/internal/arch_execute.h        |  1 +
 .../spec/x86_32/lx_kit/internal/arch_execute.h     |  1 +
 .../spec/x86_64/lx_kit/internal/arch_execute.h     | 14 +++++++++-----
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/repos/dde_linux/src/include/spec/arm/lx_kit/internal/arch_execute.h b/repos/dde_linux/src/include/spec/arm/lx_kit/internal/arch_execute.h
index 45d22167cc..d4e86e4af5 100644
--- a/repos/dde_linux/src/include/spec/arm/lx_kit/internal/arch_execute.h
+++ b/repos/dde_linux/src/include/spec/arm/lx_kit/internal/arch_execute.h
@@ -34,6 +34,7 @@ void arch_execute(void *sp, void *func, void *arg)
 {
 	asm volatile ("mov r0, %2;"  /* set arg */
 	              "mov sp, %0;"  /* set stack */
+	              "mov fp, #0;"  /* clear frame pointer */
 	              "mov pc, %1;"  /* call func */
 	              ""
 	              : : "r"(sp), "r"(func), "r"(arg) : "r0");
diff --git a/repos/dde_linux/src/include/spec/x86_32/lx_kit/internal/arch_execute.h b/repos/dde_linux/src/include/spec/x86_32/lx_kit/internal/arch_execute.h
index 09cbd72130..176572a18a 100644
--- a/repos/dde_linux/src/include/spec/x86_32/lx_kit/internal/arch_execute.h
+++ b/repos/dde_linux/src/include/spec/x86_32/lx_kit/internal/arch_execute.h
@@ -35,6 +35,7 @@ void arch_execute(void *sp, void *func, void *arg)
 	asm volatile ("movl %2, 0(%0);"
 	              "movl %1, -0x4(%0);"
 	              "movl %0, %%esp;"
+	              "xorl %%ebp, %%ebp;"  /* clear frame pointer */
 	              "call *-4(%%esp);"
 	              : : "r" (sp), "r" (func), "r" (arg));
 }
diff --git a/repos/dde_linux/src/include/spec/x86_64/lx_kit/internal/arch_execute.h b/repos/dde_linux/src/include/spec/x86_64/lx_kit/internal/arch_execute.h
index 0367439a41..18f2116fb6 100644
--- a/repos/dde_linux/src/include/spec/x86_64/lx_kit/internal/arch_execute.h
+++ b/repos/dde_linux/src/include/spec/x86_64/lx_kit/internal/arch_execute.h
@@ -33,11 +33,15 @@ extern "C" {
 static inline
 void arch_execute(void *sp, void *func, void *arg)
 {
-	asm volatile ("movq %2, %%rdi;"
-	              "movq %1, 0(%0);"
-	              "movq %0, %%rsp;"
-	              "call *0(%%rsp);"
-	              : "+r" (sp), "+r" (func), "+r" (arg) : : "memory");
+	asm volatile ("movq %0,  %%rsp;"     /* load stack pointer */
+	              "movq %%rsp, %%rbp;"   /* caller stack frame (for GDB debugging) */
+	              "movq %0, -8(%%rbp);"
+	              "movq %1, -16(%%rbp);"
+	              "movq %2, -24(%%rbp);"
+	              "sub  $24, %%rsp;"     /* adjust to next stack frame */
+	              "movq %2, %%rdi;"      /* 1st argument */
+	              "call *-16(%%rbp);"    /* call func */
+	              : : "r" (sp), "r" (func), "r" (arg));
 }
 
 #endif /* _ARCH_EXECUTE_H_ */