[glibc] hurd: Fix aligning signal stack pointer

[glibc] hurd: Fix aligning signal stack pointer

[Samuel Thibault]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ff0f87632a74a369a2b992f4436ae406065a4012

commit ff0f87632a74a369a2b992f4436ae406065a4012
Author: Sergey Bugaev <bugaevc@gmail.com>
Date:   Mon May 15 11:33:20 2023 +0300

    hurd: Fix aligning signal stack pointer
    
    Fixes 60f9bf974694d50daf58d46347b06a5975ac5ddd
    "hurd: Port trampoline.c to x86_64"
    
    Checked on x86_64-gnu.
    
    Reported-by: Bruno Haible <bruno@clisp.org>
    Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
    Message-Id: <20230515083323.1358039-2-bugaevc@gmail.com>

Diff:
---
 sysdeps/mach/hurd/x86/trampoline.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sysdeps/mach/hurd/x86/trampoline.c b/sysdeps/mach/hurd/x86/trampoline.c
index e13c5d85f5..19bddad8e1 100644
--- a/sysdeps/mach/hurd/x86/trampoline.c
+++ b/sysdeps/mach/hurd/x86/trampoline.c
@@ -200,7 +200,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, const struct sigaction *action
   /* Align SP at 16 bytes.  Coupled with the fact that sigreturn_addr is
      16-byte aligned within the stackframe struct, this ensures that it ends
      up on a 16-byte aligned address, as required by the ABI.  */
-  sigsp = (void *) ((uintptr_t) sigsp & 16UL);
+  sigsp = (void *) ((uintptr_t) sigsp & ~15UL);
 #endif
 
   /* Push the arguments to call `trampoline' on the stack.  */