Alexandre Julliard : ntdll: Use ret instead of jmp to return from syscall dispatchers.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 0aae4b05633cb9b38eb37cc662f5a3aadb3ce108
URL:    https://gitlab.winehq.org/wine/wine/-/commit/0aae4b05633cb9b38eb37cc662f5a3a...

Author: Alexandre Julliard 
Date:   Fri Dec  2 14:51:54 2022 +0100

ntdll: Use ret instead of jmp to return from syscall dispatchers.

---

dlls/ntdll/unix/signal_i386.c   | 8 ++++++--
 dlls/ntdll/unix/signal_x86_64.c | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index 6aa5219f963..d665e281176 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -2669,7 +2669,9 @@ __ASM_GLOBAL_FUNC( __wine_syscall_dispatcher,
                    __ASM_CFI(".cfi_register %eip, %ecx\n\t")
                    "movl 0x0c(%esp),%esp\n\t"      /* frame->esp */
                    __ASM_CFI(".cfi_same_value %esp\n\t")
-                   "jmpl *%ecx\n"
+                   "pushl %ecx\n\t"
+                   __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
+                   "ret\n"
                    __ASM_CFI("\t.cfi_restore_state\n")
                    "1:\ttestl $0x2 << 16,%ecx\n\t" /* CONTEXT_INTEGER */
                    "jz 1f\n\t"
@@ -2770,7 +2772,9 @@ __ASM_GLOBAL_FUNC( __wine_unix_call_dispatcher,
                    __ASM_CFI(".cfi_register %eip, %ecx\n\t")
                    "movl 0x0c(%esp),%esp\n\t"  /* frame->esp */
                    __ASM_CFI(".cfi_same_value %esp\n\t")
-                   "jmpl *%ecx" )
+                   "pushl %ecx\n\t"
+                   __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
+                   "ret" )

/***********************************************************************
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 460f81545a3..fa8660ca914 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -2798,7 +2798,9 @@ __ASM_GLOBAL_FUNC( __wine_syscall_dispatcher,
                    __ASM_CFI(".cfi_same_value rsp\n\t")
                    "movq 0x70(%rcx),%rcx\n\t"      /* frame->rip */
                    __ASM_CFI(".cfi_register rip, rcx\n\t")
-                   "jmpq *%rcx\n\t"
+                   "pushq %rcx\n\t"
+                   __ASM_CFI(".cfi_adjust_cfa_offset 8\n\t")
+                   "ret\n\t"
                    /* $rcx is now pointing to "frame" again */
                    __ASM_CFI(".cfi_restore_state\n\t")
                    /* remember state when $rcx is pointing to "frame" */
@@ -2938,7 +2940,9 @@ __ASM_GLOBAL_FUNC( __wine_unix_call_dispatcher,
                    "movq 0x88(%rcx),%rsp\n\t"
                    __ASM_CFI(".cfi_def_cfa rsp, 0\n\t")
                    __ASM_CFI(".cfi_same_value rsp\n\t")
-                   "jmpq *0x70(%rcx)" )      /* frame->rip */
+                   "pushq 0x70(%rcx)\n\t"          /* frame->rip */
+                   __ASM_CFI(".cfi_adjust_cfa_offset 8\n\t")
+                   "ret" )

/***********************************************************************