Messages in this thread Patch in this message | | | From | Hans Rosenfeld <> | Subject | [RFC 2/3] Allow saving of individual states in fpu_xsave(). | Date | Tue, 5 Oct 2010 20:30:28 +0200 |
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Add a feature mask argument to fpu_xsave(). Introduce XCNTXT_DEFAULT to specify which feature states are to be saved/restored by default at context switches. Rename XCNTXT_MASK to XCNTXT_SUPPORTED to make clear what it really is.
Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com> --- arch/x86/include/asm/i387.h | 4 ++-- arch/x86/include/asm/xsave.h | 14 +++++++++++--- arch/x86/kernel/xsave.c | 2 +- 3 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h index de8593b..33600d3 100644 --- a/arch/x86/include/asm/i387.h +++ b/arch/x86/include/asm/i387.h @@ -201,7 +201,7 @@ static inline void fpu_save_init(struct fpu *fpu) if (use_xsave()) { struct xsave_struct *xstate = &fpu->state->xsave; - fpu_xsave(xstate); + fpu_xsave(xstate, XCNTXT_DEFAULT); /* * xsave header may indicate the init state of the FP. @@ -239,7 +239,7 @@ static inline void __save_init_fpu(struct task_struct *tsk) static inline int fpu_restore_checking(struct fpu *fpu) { if (use_xsave()) - return xrstor_checking(&fpu->state->xsave, -1); + return xrstor_checking(&fpu->state->xsave, XCNTXT_DEFAULT); else return fxrstor_checking(&fpu->state->fxsave); } diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 8bcbbce..8820b57 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -23,7 +23,12 @@ /* * These are the features that the OS can handle currently. */ -#define XCNTXT_MASK (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) +#define XCNTXT_SUPPORTED (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) + +/* + * These are the features that the OS saves/restores by default. + */ +#define XCNTXT_DEFAULT (-1) #ifdef CONFIG_X86_64 #define REX_PREFIX "0x48, " @@ -113,15 +118,18 @@ static inline void xsave_state(struct xsave_struct *fx, u64 mask) : "memory"); } -static inline void fpu_xsave(struct xsave_struct *fx) +static inline void fpu_xsave(struct xsave_struct *fx, u64 mask) { + u32 lmask = mask; + u32 hmask = mask >> 32; + /* This, however, we can work around by forcing the compiler to select an addressing mode that doesn't require extended registers. */ alternative_input( ".byte " REX_PREFIX "0x0f,0xae,0x27", ".byte " REX_PREFIX "0x0f,0xae,0x37", X86_FEATURE_XSAVEOPT, - [fx] "D" (fx), "a" (-1), "d" (-1) : + [fx] "D" (fx), "a" (lmask), "d" (hmask) : "memory"); } #endif diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 5eb15d4..11c3445 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -434,7 +434,7 @@ static void __init xstate_enable_boot_cpu(void) /* * Support only the state known to OS. */ - pcntxt_mask = pcntxt_mask & XCNTXT_MASK; + pcntxt_mask = pcntxt_mask & XCNTXT_SUPPORTED; xstate_enable(); -- 1.5.6.5
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