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-rw-r--r--arch/x86/include/asm/i387.h448
1 files changed, 18 insertions, 430 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index a29571821b99..257d9cca214f 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -13,360 +13,18 @@
#ifndef __ASSEMBLY__
#include <linux/sched.h>
-#include <linux/kernel_stat.h>
-#include <linux/regset.h>
#include <linux/hardirq.h>
-#include <linux/slab.h>
-#include <asm/asm.h>
-#include <asm/cpufeature.h>
-#include <asm/processor.h>
-#include <asm/sigcontext.h>
-#include <asm/user.h>
-#include <asm/uaccess.h>
-#include <asm/xsave.h>
-extern unsigned int sig_xstate_size;
-extern void fpu_init(void);
-extern void mxcsr_feature_mask_init(void);
+struct pt_regs;
+struct user_i387_struct;
+
extern int init_fpu(struct task_struct *child);
-extern void math_state_restore(void);
-extern void __math_state_restore(void);
extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
+extern void math_state_restore(void);
-extern user_regset_active_fn fpregs_active, xfpregs_active;
-extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get,
- xstateregs_get;
-extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set,
- xstateregs_set;
-
-/*
- * xstateregs_active == fpregs_active. Please refer to the comment
- * at the definition of fpregs_active.
- */
-#define xstateregs_active fpregs_active
-
-extern struct _fpx_sw_bytes fx_sw_reserved;
-#ifdef CONFIG_IA32_EMULATION
-extern unsigned int sig_xstate_ia32_size;
-extern struct _fpx_sw_bytes fx_sw_reserved_ia32;
-struct _fpstate_ia32;
-struct _xstate_ia32;
-extern int save_i387_xstate_ia32(void __user *buf);
-extern int restore_i387_xstate_ia32(void __user *buf);
-#endif
-
-#ifdef CONFIG_MATH_EMULATION
-extern void finit_soft_fpu(struct i387_soft_struct *soft);
-#else
-static inline void finit_soft_fpu(struct i387_soft_struct *soft) {}
-#endif
-
-#define X87_FSW_ES (1 << 7) /* Exception Summary */
-
-static __always_inline __pure bool use_xsaveopt(void)
-{
- return static_cpu_has(X86_FEATURE_XSAVEOPT);
-}
-
-static __always_inline __pure bool use_xsave(void)
-{
- return static_cpu_has(X86_FEATURE_XSAVE);
-}
-
-static __always_inline __pure bool use_fxsr(void)
-{
- return static_cpu_has(X86_FEATURE_FXSR);
-}
-
-extern void __sanitize_i387_state(struct task_struct *);
-
-static inline void sanitize_i387_state(struct task_struct *tsk)
-{
- if (!use_xsaveopt())
- return;
- __sanitize_i387_state(tsk);
-}
-
-#ifdef CONFIG_X86_64
-static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
-{
- int err;
-
- /* See comment in fxsave() below. */
-#ifdef CONFIG_AS_FXSAVEQ
- asm volatile("1: fxrstorq %[fx]\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)
- : [fx] "m" (*fx), "0" (0));
-#else
- asm volatile("1: rex64/fxrstor (%[fx])\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)
- : [fx] "R" (fx), "m" (*fx), "0" (0));
-#endif
- return err;
-}
-
-static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
-{
- int err;
-
- /*
- * Clear the bytes not touched by the fxsave and reserved
- * for the SW usage.
- */
- err = __clear_user(&fx->sw_reserved,
- sizeof(struct _fpx_sw_bytes));
- if (unlikely(err))
- return -EFAULT;
-
- /* See comment in fxsave() below. */
-#ifdef CONFIG_AS_FXSAVEQ
- asm volatile("1: fxsaveq %[fx]\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), [fx] "=m" (*fx)
- : "0" (0));
-#else
- asm volatile("1: rex64/fxsave (%[fx])\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), "=m" (*fx)
- : [fx] "R" (fx), "0" (0));
-#endif
- if (unlikely(err) &&
- __clear_user(fx, sizeof(struct i387_fxsave_struct)))
- err = -EFAULT;
- /* No need to clear here because the caller clears USED_MATH */
- return err;
-}
-
-static inline void fpu_fxsave(struct fpu *fpu)
-{
- /* Using "rex64; fxsave %0" is broken because, if the memory operand
- uses any extended registers for addressing, a second REX prefix
- will be generated (to the assembler, rex64 followed by semicolon
- is a separate instruction), and hence the 64-bitness is lost. */
-
-#ifdef CONFIG_AS_FXSAVEQ
- /* Using "fxsaveq %0" would be the ideal choice, but is only supported
- starting with gas 2.16. */
- __asm__ __volatile__("fxsaveq %0"
- : "=m" (fpu->state->fxsave));
-#else
- /* Using, as a workaround, the properly prefixed form below isn't
- accepted by any binutils version so far released, complaining that
- the same type of prefix is used twice if an extended register is
- needed for addressing (fix submitted to mainline 2005-11-21).
- asm volatile("rex64/fxsave %0"
- : "=m" (fpu->state->fxsave));
- This, however, we can work around by forcing the compiler to select
- an addressing mode that doesn't require extended registers. */
- asm volatile("rex64/fxsave (%[fx])"
- : "=m" (fpu->state->fxsave)
- : [fx] "R" (&fpu->state->fxsave));
-#endif
-}
-
-#else /* CONFIG_X86_32 */
-
-/* perform fxrstor iff the processor has extended states, otherwise frstor */
-static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
-{
- /*
- * The "nop" is needed to make the instructions the same
- * length.
- */
- alternative_input(
- "nop ; frstor %1",
- "fxrstor %1",
- X86_FEATURE_FXSR,
- "m" (*fx));
-
- return 0;
-}
-
-static inline void fpu_fxsave(struct fpu *fpu)
-{
- asm volatile("fxsave %[fx]"
- : [fx] "=m" (fpu->state->fxsave));
-}
-
-#endif /* CONFIG_X86_64 */
-
-/* We need a safe address that is cheap to find and that is already
- in L1 during context switch. The best choices are unfortunately
- different for UP and SMP */
-#ifdef CONFIG_SMP
-#define safe_address (__per_cpu_offset[0])
-#else
-#define safe_address (__get_cpu_var(kernel_cpustat).cpustat[CPUTIME_USER])
-#endif
-
-/*
- * These must be called with preempt disabled
- */
-static inline void fpu_save_init(struct fpu *fpu)
-{
- if (use_xsave()) {
- fpu_xsave(fpu);
-
- /*
- * xsave header may indicate the init state of the FP.
- */
- if (!(fpu->state->xsave.xsave_hdr.xstate_bv & XSTATE_FP))
- return;
- } else if (use_fxsr()) {
- fpu_fxsave(fpu);
- } else {
- asm volatile("fnsave %[fx]; fwait"
- : [fx] "=m" (fpu->state->fsave));
- return;
- }
-
- if (unlikely(fpu->state->fxsave.swd & X87_FSW_ES))
- asm volatile("fnclex");
-
- /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
- is pending. Clear the x87 state here by setting it to fixed
- values. safe_address is a random variable that should be in L1 */
- alternative_input(
- ASM_NOP8 ASM_NOP2,
- "emms\n\t" /* clear stack tags */
- "fildl %P[addr]", /* set F?P to defined value */
- X86_FEATURE_FXSAVE_LEAK,
- [addr] "m" (safe_address));
-}
-
-static inline void __save_init_fpu(struct task_struct *tsk)
-{
- fpu_save_init(&tsk->thread.fpu);
- task_thread_info(tsk)->status &= ~TS_USEDFPU;
-}
-
-static inline int fpu_fxrstor_checking(struct fpu *fpu)
-{
- return fxrstor_checking(&fpu->state->fxsave);
-}
-
-static inline int fpu_restore_checking(struct fpu *fpu)
-{
- if (use_xsave())
- return fpu_xrstor_checking(fpu);
- else
- return fpu_fxrstor_checking(fpu);
-}
-
-static inline int restore_fpu_checking(struct task_struct *tsk)
-{
- return fpu_restore_checking(&tsk->thread.fpu);
-}
-
-/*
- * Signal frame handlers...
- */
-extern int save_i387_xstate(void __user *buf);
-extern int restore_i387_xstate(void __user *buf);
-
-static inline void __unlazy_fpu(struct task_struct *tsk)
-{
- if (task_thread_info(tsk)->status & TS_USEDFPU) {
- __save_init_fpu(tsk);
- stts();
- } else
- tsk->fpu_counter = 0;
-}
-
-static inline void __clear_fpu(struct task_struct *tsk)
-{
- if (task_thread_info(tsk)->status & TS_USEDFPU) {
- /* Ignore delayed exceptions from user space */
- asm volatile("1: fwait\n"
- "2:\n"
- _ASM_EXTABLE(1b, 2b));
- task_thread_info(tsk)->status &= ~TS_USEDFPU;
- stts();
- }
-}
-
-/*
- * Were we in an interrupt that interrupted kernel mode?
- *
- * We can do a kernel_fpu_begin/end() pair *ONLY* if that
- * pair does nothing at all: TS_USEDFPU must be clear (so
- * that we don't try to save the FPU state), and TS must
- * be set (so that the clts/stts pair does nothing that is
- * visible in the interrupted kernel thread).
- */
-static inline bool interrupted_kernel_fpu_idle(void)
-{
- return !(current_thread_info()->status & TS_USEDFPU) &&
- (read_cr0() & X86_CR0_TS);
-}
-
-/*
- * Were we in user mode (or vm86 mode) when we were
- * interrupted?
- *
- * Doing kernel_fpu_begin/end() is ok if we are running
- * in an interrupt context from user mode - we'll just
- * save the FPU state as required.
- */
-static inline bool interrupted_user_mode(void)
-{
- struct pt_regs *regs = get_irq_regs();
- return regs && user_mode_vm(regs);
-}
-
-/*
- * Can we use the FPU in kernel mode with the
- * whole "kernel_fpu_begin/end()" sequence?
- *
- * It's always ok in process context (ie "not interrupt")
- * but it is sometimes ok even from an irq.
- */
-static inline bool irq_fpu_usable(void)
-{
- return !in_interrupt() ||
- interrupted_user_mode() ||
- interrupted_kernel_fpu_idle();
-}
-
-static inline void kernel_fpu_begin(void)
-{
- struct thread_info *me = current_thread_info();
-
- WARN_ON_ONCE(!irq_fpu_usable());
- preempt_disable();
- if (me->status & TS_USEDFPU)
- __save_init_fpu(me->task);
- else
- clts();
-}
-
-static inline void kernel_fpu_end(void)
-{
- stts();
- preempt_enable();
-}
+extern bool irq_fpu_usable(void);
+extern void kernel_fpu_begin(void);
+extern void kernel_fpu_end(void);
/*
* Some instructions like VIA's padlock instructions generate a spurious
@@ -400,91 +58,21 @@ static inline void irq_ts_restore(int TS_state)
}
/*
- * These disable preemption on their own and are safe
- */
-static inline void save_init_fpu(struct task_struct *tsk)
-{
- WARN_ON_ONCE(task_thread_info(tsk)->status & TS_USEDFPU);
- preempt_disable();
- __save_init_fpu(tsk);
- stts();
- preempt_enable();
-}
-
-static inline void unlazy_fpu(struct task_struct *tsk)
-{
- preempt_disable();
- __unlazy_fpu(tsk);
- preempt_enable();
-}
-
-static inline void clear_fpu(struct task_struct *tsk)
-{
- preempt_disable();
- __clear_fpu(tsk);
- preempt_enable();
-}
-
-/*
- * i387 state interaction
+ * The question "does this thread have fpu access?"
+ * is slightly racy, since preemption could come in
+ * and revoke it immediately after the test.
+ *
+ * However, even in that very unlikely scenario,
+ * we can just assume we have FPU access - typically
+ * to save the FP state - we'll just take a #NM
+ * fault and get the FPU access back.
*/
-static inline unsigned short get_fpu_cwd(struct task_struct *tsk)
-{
- if (cpu_has_fxsr) {
- return tsk->thread.fpu.state->fxsave.cwd;
- } else {
- return (unsigned short)tsk->thread.fpu.state->fsave.cwd;
- }
-}
-
-static inline unsigned short get_fpu_swd(struct task_struct *tsk)
-{
- if (cpu_has_fxsr) {
- return tsk->thread.fpu.state->fxsave.swd;
- } else {
- return (unsigned short)tsk->thread.fpu.state->fsave.swd;
- }
-}
-
-static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk)
-{
- if (cpu_has_xmm) {
- return tsk->thread.fpu.state->fxsave.mxcsr;
- } else {
- return MXCSR_DEFAULT;
- }
-}
-
-static bool fpu_allocated(struct fpu *fpu)
-{
- return fpu->state != NULL;
-}
-
-static inline int fpu_alloc(struct fpu *fpu)
-{
- if (fpu_allocated(fpu))
- return 0;
- fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
- if (!fpu->state)
- return -ENOMEM;
- WARN_ON((unsigned long)fpu->state & 15);
- return 0;
-}
-
-static inline void fpu_free(struct fpu *fpu)
-{
- if (fpu->state) {
- kmem_cache_free(task_xstate_cachep, fpu->state);
- fpu->state = NULL;
- }
-}
-
-static inline void fpu_copy(struct fpu *dst, struct fpu *src)
+static inline int user_has_fpu(void)
{
- memcpy(dst->state, src->state, xstate_size);
+ return current->thread.fpu.has_fpu;
}
-extern void fpu_finit(struct fpu *fpu);
+extern void unlazy_fpu(struct task_struct *tsk);
#endif /* __ASSEMBLY__ */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.