Merge branch 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-xsave-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, xsave: Make xstate_enable_boot_cpu() __init, protect on CPU 0 x86, xsave: Add __init attribute to setup_xstate_features() x86, xsave: Make init_xstate_buf static x86, xsave: Check cpuid level for XSTATE_CPUID (0x0d) x86, xsave: Introduce xstate enable functions x86, xsave: Separate fpu and xsave initialization x86, xsave: Move boot cpu initialization to xsave_init() x86, xsave: 32/64 bit boot cpu check unification in initialization x86, xsave: Do not include asm/i387.h in asm/xsave.h x86, xsave: Use xsaveopt in context-switch path when supported x86, xsave: Sync xsave memory layout with its header for user handling x86, xsave: Track the offset, size of state in the xsave layout
This commit is contained in:
Linus Torvalds
Коммит
4a386c3e17
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@ -31,7 +31,6 @@ extern void mxcsr_feature_mask_init(void);
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extern int init_fpu(struct task_struct *child);
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extern asmlinkage void math_state_restore(void);
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extern void __math_state_restore(void);
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extern void init_thread_xstate(void);
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extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
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extern user_regset_active_fn fpregs_active, xfpregs_active;
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@ -58,11 +57,25 @@ extern int restore_i387_xstate_ia32(void __user *buf);
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#define X87_FSW_ES (1 << 7) /* Exception Summary */
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static __always_inline __pure bool use_xsaveopt(void)
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{
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return static_cpu_has(X86_FEATURE_XSAVEOPT);
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}
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static __always_inline __pure bool use_xsave(void)
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{
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return static_cpu_has(X86_FEATURE_XSAVE);
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}
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extern void __sanitize_i387_state(struct task_struct *);
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static inline void sanitize_i387_state(struct task_struct *tsk)
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{
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if (!use_xsaveopt())
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return;
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__sanitize_i387_state(tsk);
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}
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#ifdef CONFIG_X86_64
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/* Ignore delayed exceptions from user space */
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@ -3,7 +3,8 @@
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#include <linux/types.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#define XSTATE_CPUID 0x0000000d
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#define XSTATE_FP 0x1
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#define XSTATE_SSE 0x2
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@ -32,10 +33,8 @@
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extern unsigned int xstate_size;
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extern u64 pcntxt_mask;
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extern struct xsave_struct *init_xstate_buf;
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extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
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extern void xsave_cntxt_init(void);
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extern void xsave_init(void);
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extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
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extern int init_fpu(struct task_struct *child);
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@ -127,12 +126,25 @@ static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
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: "memory");
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}
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static inline void xsave_state(struct xsave_struct *fx, u64 mask)
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{
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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}
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static inline void fpu_xsave(struct fpu *fpu)
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{
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/* This, however, we can work around by forcing the compiler to select
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an addressing mode that doesn't require extended registers. */
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__asm__ __volatile__(".byte " REX_PREFIX "0x0f,0xae,0x27"
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: : "D" (&(fpu->state->xsave)),
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"a" (-1), "d"(-1) : "memory");
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alternative_input(
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".byte " REX_PREFIX "0x0f,0xae,0x27",
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".byte " REX_PREFIX "0x0f,0xae,0x37",
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X86_FEATURE_XSAVEOPT,
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[fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
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"memory");
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}
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#endif
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@ -140,10 +140,18 @@ EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
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static int __init x86_xsave_setup(char *s)
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{
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setup_clear_cpu_cap(X86_FEATURE_XSAVE);
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setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
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return 1;
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}
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__setup("noxsave", x86_xsave_setup);
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static int __init x86_xsaveopt_setup(char *s)
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{
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setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
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return 1;
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}
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__setup("noxsaveopt", x86_xsaveopt_setup);
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#ifdef CONFIG_X86_32
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static int cachesize_override __cpuinitdata = -1;
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static int disable_x86_serial_nr __cpuinitdata = 1;
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@ -1202,6 +1210,7 @@ void __cpuinit cpu_init(void)
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dbg_restore_debug_regs();
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fpu_init();
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xsave_init();
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raw_local_save_flags(kernel_eflags);
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@ -1262,12 +1271,7 @@ void __cpuinit cpu_init(void)
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clear_used_math();
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mxcsr_feature_mask_init();
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/*
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* Boot processor to setup the FP and extended state context info.
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*/
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if (smp_processor_id() == boot_cpu_id)
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init_thread_xstate();
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fpu_init();
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xsave_init();
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}
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#endif
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@ -59,18 +59,18 @@ void __cpuinit mxcsr_feature_mask_init(void)
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stts();
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}
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void __cpuinit init_thread_xstate(void)
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static void __cpuinit init_thread_xstate(void)
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{
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/*
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* Note that xstate_size might be overwriten later during
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* xsave_init().
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*/
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if (!HAVE_HWFP) {
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xstate_size = sizeof(struct i387_soft_struct);
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return;
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}
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if (cpu_has_xsave) {
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xsave_cntxt_init();
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return;
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}
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if (cpu_has_fxsr)
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xstate_size = sizeof(struct i387_fxsave_struct);
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#ifdef CONFIG_X86_32
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@ -84,6 +84,7 @@ void __cpuinit init_thread_xstate(void)
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* Called at bootup to set up the initial FPU state that is later cloned
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* into all processes.
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*/
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void __cpuinit fpu_init(void)
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{
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unsigned long oldcr0 = read_cr0();
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@ -93,19 +94,24 @@ void __cpuinit fpu_init(void)
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write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */
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/*
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* Boot processor to setup the FP and extended state context info.
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*/
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if (!smp_processor_id())
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init_thread_xstate();
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xsave_init();
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mxcsr_feature_mask_init();
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/* clean state in init */
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current_thread_info()->status = 0;
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clear_used_math();
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}
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#endif /* CONFIG_X86_64 */
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#else /* CONFIG_X86_64 */
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void __cpuinit fpu_init(void)
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{
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if (!smp_processor_id())
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init_thread_xstate();
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}
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#endif /* CONFIG_X86_32 */
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void fpu_finit(struct fpu *fpu)
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{
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@ -191,6 +197,8 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
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if (ret)
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return ret;
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sanitize_i387_state(target);
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return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
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&target->thread.fpu.state->fxsave, 0, -1);
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}
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@ -208,6 +216,8 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
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if (ret)
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return ret;
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sanitize_i387_state(target);
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ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
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&target->thread.fpu.state->fxsave, 0, -1);
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@ -447,6 +457,8 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
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-1);
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}
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sanitize_i387_state(target);
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if (kbuf && pos == 0 && count == sizeof(env)) {
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convert_from_fxsr(kbuf, target);
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return 0;
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@ -468,6 +480,8 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
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if (ret)
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return ret;
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sanitize_i387_state(target);
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if (!HAVE_HWFP)
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return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
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@ -534,6 +548,9 @@ static int save_i387_xsave(void __user *buf)
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struct _fpstate_ia32 __user *fx = buf;
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int err = 0;
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sanitize_i387_state(tsk);
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/*
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* For legacy compatible, we always set FP/SSE bits in the bit
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* vector while saving the state to the user context.
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@ -16,11 +16,88 @@
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*/
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u64 pcntxt_mask;
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/*
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* Represents init state for the supported extended state.
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*/
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static struct xsave_struct *init_xstate_buf;
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struct _fpx_sw_bytes fx_sw_reserved;
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#ifdef CONFIG_IA32_EMULATION
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struct _fpx_sw_bytes fx_sw_reserved_ia32;
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#endif
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static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
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/*
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* If a processor implementation discern that a processor state component is
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* in its initialized state it may modify the corresponding bit in the
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* xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory
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* layout in the case of xsaveopt. While presenting the xstate information to
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* the user, we always ensure that the memory layout of a feature will be in
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* the init state if the corresponding header bit is zero. This is to ensure
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* that the user doesn't see some stale state in the memory layout during
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* signal handling, debugging etc.
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*/
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void __sanitize_i387_state(struct task_struct *tsk)
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{
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u64 xstate_bv;
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int feature_bit = 0x2;
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struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
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if (!fx)
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return;
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BUG_ON(task_thread_info(tsk)->status & TS_USEDFPU);
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xstate_bv = tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv;
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/*
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* None of the feature bits are in init state. So nothing else
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* to do for us, as the memory layout is upto date.
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*/
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if ((xstate_bv & pcntxt_mask) == pcntxt_mask)
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return;
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/*
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* FP is in init state
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*/
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if (!(xstate_bv & XSTATE_FP)) {
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fx->cwd = 0x37f;
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fx->swd = 0;
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fx->twd = 0;
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fx->fop = 0;
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fx->rip = 0;
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fx->rdp = 0;
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memset(&fx->st_space[0], 0, 128);
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}
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/*
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* SSE is in init state
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*/
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if (!(xstate_bv & XSTATE_SSE))
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memset(&fx->xmm_space[0], 0, 256);
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xstate_bv = (pcntxt_mask & ~xstate_bv) >> 2;
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/*
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* Update all the other memory layouts for which the corresponding
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* header bit is in the init state.
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*/
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while (xstate_bv) {
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if (xstate_bv & 0x1) {
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int offset = xstate_offsets[feature_bit];
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int size = xstate_sizes[feature_bit];
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memcpy(((void *) fx) + offset,
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((void *) init_xstate_buf) + offset,
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size);
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}
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xstate_bv >>= 1;
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feature_bit++;
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}
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}
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/*
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* Check for the presence of extended state information in the
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* user fpstate pointer in the sigcontext.
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@ -102,6 +179,7 @@ int save_i387_xstate(void __user *buf)
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task_thread_info(tsk)->status &= ~TS_USEDFPU;
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stts();
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} else {
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sanitize_i387_state(tsk);
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if (__copy_to_user(buf, &tsk->thread.fpu.state->fxsave,
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xstate_size))
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return -1;
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@ -267,11 +345,6 @@ static void prepare_fx_sw_frame(void)
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#endif
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}
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/*
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* Represents init state for the supported extended state.
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*/
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struct xsave_struct *init_xstate_buf;
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#ifdef CONFIG_X86_64
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unsigned int sig_xstate_size = sizeof(struct _fpstate);
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#endif
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@ -279,37 +352,77 @@ unsigned int sig_xstate_size = sizeof(struct _fpstate);
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/*
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* Enable the extended processor state save/restore feature
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*/
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void __cpuinit xsave_init(void)
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static inline void xstate_enable(void)
|
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{
|
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if (!cpu_has_xsave)
|
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return;
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|
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set_in_cr4(X86_CR4_OSXSAVE);
|
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|
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/*
|
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* Enable all the features that the HW is capable of
|
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* and the Linux kernel is aware of.
|
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*/
|
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xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
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}
|
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|
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/*
|
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* Record the offsets and sizes of different state managed by the xsave
|
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* memory layout.
|
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*/
|
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static void __init setup_xstate_features(void)
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{
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int eax, ebx, ecx, edx, leaf = 0x2;
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|
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xstate_features = fls64(pcntxt_mask);
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xstate_offsets = alloc_bootmem(xstate_features * sizeof(int));
|
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xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
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|
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do {
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cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
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|
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if (eax == 0)
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break;
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xstate_offsets[leaf] = ebx;
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xstate_sizes[leaf] = eax;
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|
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leaf++;
|
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} while (1);
|
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}
|
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|
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/*
|
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* setup the xstate image representing the init state
|
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*/
|
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static void __init setup_xstate_init(void)
|
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{
|
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setup_xstate_features();
|
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|
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/*
|
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* Setup init_xstate_buf to represent the init state of
|
||||
* all the features managed by the xsave
|
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*/
|
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init_xstate_buf = alloc_bootmem(xstate_size);
|
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init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
|
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|
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clts();
|
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/*
|
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* Init all the features state with header_bv being 0x0
|
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*/
|
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xrstor_state(init_xstate_buf, -1);
|
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/*
|
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* Dump the init state again. This is to identify the init state
|
||||
* of any feature which is not represented by all zero's.
|
||||
*/
|
||||
xsave_state(init_xstate_buf, -1);
|
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stts();
|
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}
|
||||
|
||||
/*
|
||||
* Enable and initialize the xsave feature.
|
||||
*/
|
||||
void __ref xsave_cntxt_init(void)
|
||||
static void __init xstate_enable_boot_cpu(void)
|
||||
{
|
||||
unsigned int eax, ebx, ecx, edx;
|
||||
|
||||
cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
|
||||
if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
|
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WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
|
||||
return;
|
||||
}
|
||||
|
||||
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
|
||||
pcntxt_mask = eax + ((u64)edx << 32);
|
||||
|
||||
if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
|
||||
|
|
@ -322,12 +435,13 @@ void __ref xsave_cntxt_init(void)
|
|||
* Support only the state known to OS.
|
||||
*/
|
||||
pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
|
||||
xsave_init();
|
||||
|
||||
xstate_enable();
|
||||
|
||||
/*
|
||||
* Recompute the context size for enabled features
|
||||
*/
|
||||
cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
|
||||
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
|
||||
xstate_size = ebx;
|
||||
|
||||
update_regset_xstate_info(xstate_size, pcntxt_mask);
|
||||
|
|
@ -339,3 +453,23 @@ void __ref xsave_cntxt_init(void)
|
|||
"cntxt size 0x%x\n",
|
||||
pcntxt_mask, xstate_size);
|
||||
}
|
||||
|
||||
/*
|
||||
* For the very first instance, this calls xstate_enable_boot_cpu();
|
||||
* for all subsequent instances, this calls xstate_enable().
|
||||
*
|
||||
* This is somewhat obfuscated due to the lack of powerful enough
|
||||
* overrides for the section checks.
|
||||
*/
|
||||
void __cpuinit xsave_init(void)
|
||||
{
|
||||
static __refdata void (*next_func)(void) = xstate_enable_boot_cpu;
|
||||
void (*this_func)(void);
|
||||
|
||||
if (!cpu_has_xsave)
|
||||
return;
|
||||
|
||||
this_func = next_func;
|
||||
next_func = xstate_enable;
|
||||
this_func();
|
||||
}
|
||||
|
|
|
|||
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