diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2008-07-29 10:29:20 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-30 19:49:24 +0200 |
| commit | b359e8a434cc3d09847010fc4aeccf48d69740e4 (patch) | |
| tree | 8911c299dc1768c78d5452a1e7e0efd2fc8d5abb /include/asm-x86/xsave.h | |
| parent | dc1e35c6e95e8923cf1d3510438b63c600fee1e2 (diff) | |
x86, xsave: context switch support using xsave/xrstor
Uses xsave/xrstor (instead of traditional fxsave/fxrstor) in context switch
when available.
Introduces TS_XSAVE flag, which determine the need to use xsave/xrstor
instructions during context switch instead of the legacy fxsave/fxrstor
instructions. Thread-synchronous status word is already in L1 cache during
this code patch and thus minimizes the performance penality compared to
(cpu_has_xsave) checks.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-x86/xsave.h')
| -rw-r--r-- | include/asm-x86/xsave.h | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/include/asm-x86/xsave.h b/include/asm-x86/xsave.h index 6d70e62c6bd..e835a917ee1 100644 --- a/include/asm-x86/xsave.h +++ b/include/asm-x86/xsave.h @@ -17,10 +17,43 @@ #define XCNTXT_LMASK (XSTATE_FP | XSTATE_SSE) #define XCNTXT_HMASK 0x0 +#ifdef CONFIG_X86_64 +#define REX_PREFIX "0x48, " +#else +#define REX_PREFIX +#endif + extern unsigned int xstate_size, pcntxt_hmask, pcntxt_lmask; extern struct xsave_struct *init_xstate_buf; extern void xsave_cntxt_init(void); extern void xsave_init(void); - +extern int init_fpu(struct task_struct *child); + +static inline int xrstor_checking(struct xsave_struct *fx) +{ + int err; + + asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t" + "2:\n" + ".section .fixup,\"ax\"\n" + "3: movl $-1,%[err]\n" + " jmp 2b\n" + ".previous\n" + _ASM_EXTABLE(1b, 3b) + : [err] "=r" (err) + : "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0) + : "memory"); + + return err; +} + +static inline void xsave(struct task_struct *tsk) +{ + /* This, however, we can work around by forcing the compiler to select + an addressing mode that doesn't require extended registers. */ + __asm__ __volatile__(".byte " REX_PREFIX "0x0f,0xae,0x27" + : : "D" (&(tsk->thread.xstate->xsave)), + "a" (-1), "d"(-1) : "memory"); +} #endif |