Author: kib Date: Sat Mar 16 11:12:02 2019 New Revision: 345225 URL: https://svnweb.freebsd.org/changeset/base/345225
Log: amd64: rewrite cpu_switch.S fragment to reload tss.rsp0 on context switch. New code avoids jumps. Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D19514 Modified: head/sys/amd64/amd64/cpu_switch.S Modified: head/sys/amd64/amd64/cpu_switch.S ============================================================================== --- head/sys/amd64/amd64/cpu_switch.S Sat Mar 16 10:51:11 2019 (r345224) +++ head/sys/amd64/amd64/cpu_switch.S Sat Mar 16 11:12:02 2019 (r345225) @@ -209,14 +209,11 @@ do_kthread: done_tss: movq %r8,PCPU(RSP0) movq %r8,PCPU(CURPCB) - /* Update the TSS_RSP0 pointer for the next interrupt */ - cmpq $~0,PCPU(UCR3) - je 1f movq PCPU(PTI_RSP0),%rax + cmpq $~0,PCPU(UCR3) + cmove %r8,%rax movq %rax,TSS_RSP0(%rdx) - jmp 2f -1: movq %r8,TSS_RSP0(%rdx) -2: movq %r12,PCPU(CURTHREAD) /* into next thread */ + movq %r12,PCPU(CURTHREAD) /* into next thread */ /* Test if debug registers should be restored. */ testl $PCB_DBREGS,PCB_FLAGS(%r8) _______________________________________________ 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"
