On 2/9/22 17:34, Jinoh Kang wrote:
On 2/8/22 04:05, Rémi Bernon wrote:
For pthread_exit unwinding purposes, as libunwind needs to retrieve %rip and we don't want to let it unwind the PE frames, we need to keep track of a unix-only return address chain.
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52213 Signed-off-by: Rémi Bernon rbernon@codeweavers.com
dlls/ntdll/unix/signal_i386.c | 7 +++++-- dlls/ntdll/unix/signal_x86_64.c | 5 ++++- 2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c index 0e3b1daf51a..d98a3b1d4bb 100644 --- a/dlls/ntdll/unix/signal_i386.c +++ b/dlls/ntdll/unix/signal_i386.c @@ -463,9 +463,10 @@ struct syscall_frame * 32-bit mode, but some processors fault if they're not in writable memory. */ DECLSPEC_ALIGN(64) XSTATE xstate; /* 240 */
- DWORD unwind_eip; /* 380 */ };
-C_ASSERT( sizeof(struct syscall_frame) == 0x380 ); +C_ASSERT( sizeof(struct syscall_frame) == 0x3c0 );
struct x86_thread_data { @@ -2432,7 +2433,7 @@ __ASM_GLOBAL_FUNC( signal_start_thread, "movl 0x1f8(%ecx),%eax\n\t" /* x86_thread_data()->syscall_frame */ "orl %eax,%eax\n\t" "jnz 1f\n\t"
"leal -0x380(%esp),%eax\n\t" /* sizeof(struct syscall_frame) */
"leal -0x3c0(%esp),%eax\n\t" /* sizeof(struct syscall_frame) */ "andl $~63,%eax\n\t" "movl %eax,0x1f8(%ecx)\n" /* x86_thread_data()->syscall_frame */ "1:\tmovl %eax,%esp\n\t"@@ -2591,6 +2592,8 @@ __ASM_GLOBAL_FUNC( __wine_syscall_dispatcher, "6:\tmovl $0xc000000d,%eax\n\t" /* STATUS_INVALID_PARAMETER */ "jmp 5b\n" __ASM_NAME("__wine_syscall_dispatcher_return") ":\n\t"
"movl 0(%esp),%eax\n\t""movl %eax,0x380(%esp)\n\t" /* frame->unwind_eip */We can't unwind to the caller without also saving the caller's nonvolatile registers. Also, KeUserModeCallback is one of the callers of __wine_syscall_dispatcher_return, and returning to it would not be useful since it is usually called from PE modules anyway. Maybe just use prev_frame directly, and set unwind_eip to an hardcoded address? (Speaking of which, we could use .cfi_val_encoded_addr here, but it's a GNU-only extension AFAIK.)
Hmm, I'm pretty sure that KeUserModeCallback is meant to be called from the unix side (although it's a Windows kernel API, it is meant to be called from kernel mode, which is our unix world), and would switch back to the PE stack, pushing a new syscall frame on the unix stack.
What I meant to do here, is to keep track of the unix caller (so either call_init_thunk or KeUserModeCallback), so that we will later link to it when a new syscall will be done, to the exit frame, as if we were returning to call_init_thunk and wherever the thread was started from, when the thread exits.
Regarding the registers, I think it's what __wine_setjmpex does, no? Otherwise it would have trouble already. Maybe call_init_thunk should do it too, although it's never supposed to returning to it normally (only through unwinding in pthread_exit).