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| author | kib <kib@FreeBSD.org> | 2009-07-09 09:34:11 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2009-07-09 09:34:11 +0000 |
| commit | 1596f53aae0639b74921f046885b0fe1b57766b4 (patch) | |
| tree | 72e1f854630487c503e885bb3cc1df1eeb575521 /sys/amd64/amd64/cpu_switch.S | |
| parent | 2706e21f2c2e081ec96cde8bfe4e71021535961e (diff) | |
| download | FreeBSD-src-1596f53aae0639b74921f046885b0fe1b57766b4.zip FreeBSD-src-1596f53aae0639b74921f046885b0fe1b57766b4.tar.gz | |
Restore the segment registers and segment base MSRs for amd64 syscall
return path only when neither thread was context switched while
executing syscall code nor syscall explicitely modified LDT or MSRs.
Save segment registers in trap handlers before interrupts are enabled,
to not allow context switches to happen before registers are saved.
Use separated byte in pcb for indication of fast/full return, since
pcb_flags are not synchronized with context switches.
The change puts back syscall microbenchmark numbers that were slowed
down after commit of the support for LDT on amd64.
Reviewed by: jeff
Tested (and tested, and tested ...) by: pho
Approved by: re (kensmith)
Diffstat (limited to 'sys/amd64/amd64/cpu_switch.S')
| -rw-r--r-- | sys/amd64/amd64/cpu_switch.S | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S index 6fc8290..364875e 100644 --- a/sys/amd64/amd64/cpu_switch.S +++ b/sys/amd64/amd64/cpu_switch.S @@ -97,6 +97,7 @@ END(cpu_throw) ENTRY(cpu_switch) /* Switch to new thread. First, save context. */ movq TD_PCB(%rdi),%r8 + movb $1,PCB_FULL_IRET(%r8) movq (%rsp),%rax /* Hardware registers */ movq %r15,PCB_R15(%r8) |
