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| author | jhb <jhb@FreeBSD.org> | 2012-07-09 20:55:39 +0000 |
|---|---|---|
| committer | jhb <jhb@FreeBSD.org> | 2012-07-09 20:55:39 +0000 |
| commit | 501beca671a3ea893482559b54b30ab166ad3d75 (patch) | |
| tree | dc9080f4848fba24288806991434be319bb1d32a /sys/i386/isa | |
| parent | fb20c6fee6baf0d773d72b8e0a63489e2e7cb188 (diff) | |
| download | FreeBSD-src-501beca671a3ea893482559b54b30ab166ad3d75.zip FreeBSD-src-501beca671a3ea893482559b54b30ab166ad3d75.tar.gz | |
Add a clts() wrapper around the 'clts' instruction to <machine/cpufunc.h>
on x86 and use that to implement stop_emulating() in the fpu/npx code.
Reimplement start_emulating() in the non-XEN case by using load_cr0() and
rcr0() instead of the 'lmsw' and 'smsw' instructions. Intel explicitly
discourages the use of 'lmsw' and 'smsw' on 80386 and later processors in
the description of these instructions in Volume 2 of the ADM.
Reviewed by: kib
MFC after: 1 month
Diffstat (limited to 'sys/i386/isa')
| -rw-r--r-- | sys/i386/isa/npx.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/sys/i386/isa/npx.c b/sys/i386/isa/npx.c index 0da580f..50c812c 100644 --- a/sys/i386/isa/npx.c +++ b/sys/i386/isa/npx.c @@ -100,15 +100,6 @@ __FBSDID("$FreeBSD$"); #define fxrstor(addr) __asm __volatile("fxrstor %0" : : "m" (*(addr))) #define fxsave(addr) __asm __volatile("fxsave %0" : "=m" (*(addr))) #endif -#ifdef XEN -#define start_emulating() (HYPERVISOR_fpu_taskswitch(1)) -#define stop_emulating() (HYPERVISOR_fpu_taskswitch(0)) -#else -#define start_emulating() __asm __volatile( \ - "smsw %%ax; orb %0,%%al; lmsw %%ax" \ - : : "n" (CR0_TS) : "ax") -#define stop_emulating() __asm __volatile("clts") -#endif #else /* !(__GNUCLIKE_ASM && !lint) */ void fldcw(u_short cw); @@ -123,11 +114,17 @@ void frstor(caddr_t addr); void fxsave(caddr_t addr); void fxrstor(caddr_t addr); #endif -void start_emulating(void); -void stop_emulating(void); #endif /* __GNUCLIKE_ASM && !lint */ +#ifdef XEN +#define start_emulating() (HYPERVISOR_fpu_taskswitch(1)) +#define stop_emulating() (HYPERVISOR_fpu_taskswitch(0)) +#else +#define start_emulating() load_cr0(rcr0() | CR0_TS) +#define stop_emulating() clts() +#endif + #ifdef CPU_ENABLE_SSE #define GET_FPU_CW(thread) \ (cpu_fxsr ? \ |
