Date: Wed, 2 Aug 2017 11:25:38 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r321922 - head/sys/amd64/amd64 Message-ID: <201708021125.v72BPcB0089542@repo.freebsd.org>
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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); }
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