Author: mjg
Date: Wed Aug 2 11:25:38 2017
New Revision: 321922
URL: https://svnweb.freebsd.org/changeset/base/321922
Log:
amd64: annotate the syscall return address check with __predict_false
before:
0xffffffff80b03ebb <+2059>: mov 0x460(%r14),%rax
0xffffffff80b03ec2 <+2066>: mov 0x98(%rax),%rax
0xffffffff80b03ec9 <+2073>: shr $0x2f,%rax
0xffffffff80b03ecd <+2077>: je 0xffffffff80b03edd
<amd64_syscall+2093>
0xffffffff80b03ecf <+2079>: mov 0x3f8(%r14),%rax
0xffffffff80b03ed6 <+2086>: orl $0x1,0xc8(%rax)
0xffffffff80b03edd <+2093>: add $0xf8,%rsp
after:
0xffffffff80b03ebb <+2059>: mov 0x460(%r14),%rax
0xffffffff80b03ec2 <+2066>: mov 0x98(%rax),%rax
0xffffffff80b03ec9 <+2073>: shr $0x2f,%rax
0xffffffff80b03ecd <+2077>: jne 0xffffffff80b03eef
<amd64_syscall+2111>
0xffffffff80b03ecf <+2079>: add $0xf8,%rsp
Reviewed by: kib
MFC after: 1 week
Modified:
head/sys/amd64/amd64/trap.c
Modified: head/sys/amd64/amd64/trap.c
==============================================================================
--- head/sys/amd64/amd64/trap.c Wed Aug 2 10:33:47 2017 (r321921)
+++ head/sys/amd64/amd64/trap.c Wed Aug 2 11:25:38 2017 (r321922)
@@ -935,6 +935,6 @@ amd64_syscall(struct thread *td, int traced)
* not be safe. Instead, use the full return path which
* catches the problem safely.
*/
- if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS)
+ if (__predict_false(td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS))
set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
}
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
