wow64: Use the right SEH opcode in raise_exception on arm64.

On ARM and ARM64, each SEH opcode is supposed to map to exactly one instruction; the operation of writing x29+x30 with a stack offset with writeback is called ".seh_save_fplr_x". Using the right opcode would fix inconsistent unwinding if we would unwind from near the end of the prologue (which is implausible here). However, clang/LLVM might also get checking for mismatches between SEH opcodes and the prolog/epilog ranges (https://reviews.llvm.org/D131394), mainly to guard against inconsistencies in the unwind info generated by the compiler, but that would trigger on this handwritten function too.

wow64: Use the right SEH opcode in raise_exception on arm64.
4934c127 · Martin Storsjö · Alexandre Julliard · fd64cbc0 · 4934c127
Commit 4934c127 authored Oct 01, 2022 by Martin Storsjö Committed by Alexandre Julliard Oct 10, 2022
Show whitespace changes
Inline Side-by-side

Showing with 1 addition and 2 deletions

process.c dlls/wow64/process.c +1 -2

No files found.
--- a/dlls/wow64/process.c
+++ b/dlls/wow64/process.c
@@ -421,8 +421,7 @@ __ASM_GLOBAL_FUNC( raise_exception,
 #elif defined(__aarch64__)
 __ASM_GLOBAL_FUNC( raise_exception,
                   "stp x29, x30, [sp, #-32]!\n\t"
-                   __ASM_SEH(".seh_stackalloc 32\n\t")
+                   __ASM_SEH(".seh_save_fplr_x 32\n\t")
-                   __ASM_SEH(".seh_save_fplr 0\n\t")
                   __ASM_SEH(".seh_endprologue\n\t")
                   __ASM_CFI(".cfi_def_cfa x29, 32\n\t")
                   __ASM_CFI(".cfi_offset x30, -24\n\t")