x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 400 insertions, 0 deletions

diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
new file mode 100644
index 000000000000..9ba862a4eac0
--- /dev/null
+++ b/arch/x86/include/asm/i387.h
@@ -0,0 +1,400 @@
+/*
+ * Copyright (C) 1994 Linus Torvalds
+ *
+ * Pentium III FXSR, SSE support
+ * General FPU state handling cleanups
+ *      Gareth Hughes <gareth@valinux.com>, May 2000
+ * x86-64 work by Andi Kleen 2002
+ */
+
+#ifndef ASM_X86__I387_H
+#define ASM_X86__I387_H
+
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <linux/regset.h>
+#include <linux/hardirq.h>
+#include <asm/asm.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);
+extern int init_fpu(struct task_struct *child);
+extern asmlinkage void math_state_restore(void);
+extern void init_thread_xstate(void);
+extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
+
+extern user_regset_active_fn fpregs_active, xfpregs_active;
+extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get;
+extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set;
+
+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
+
+#define X87_FSW_ES (1 << 7)     /* Exception Summary */
+
+#ifdef CONFIG_X86_64
+
+/* Ignore delayed exceptions from user space */
+static inline void tolerant_fwait(void)
+{
+        asm volatile("1: fwait\n"
+                     "2:\n"
+                     _ASM_EXTABLE(1b, 2b));
+}
+
+static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
+{
+        int err;
+
+        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)
+#if 0 /* See comment in __save_init_fpu() below. */
+                     : [fx] "r" (fx), "m" (*fx), "0" (0));
+#else
+                     : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0));
+#endif
+        return err;
+}
+
+static inline int restore_fpu_checking(struct task_struct *tsk)
+{
+        if (task_thread_info(tsk)->status & TS_XSAVE)
+                return xrstor_checking(&tsk->thread.xstate->xsave);
+        else
+                return fxrstor_checking(&tsk->thread.xstate->fxsave);
+}
+
+/* AMD CPUs don't save/restore FDP/FIP/FOP unless an exception
+   is pending. Clear the x87 state here by setting it to fixed
+   values. The kernel data segment can be sometimes 0 and sometimes
+   new user value. Both should be ok.
+   Use the PDA as safe address because it should be already in L1. */
+static inline void clear_fpu_state(struct task_struct *tsk)
+{
+        struct xsave_struct *xstate = &tsk->thread.xstate->xsave;
+        struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave;
+
+        /*
+         * xsave header may indicate the init state of the FP.
+         */
+        if ((task_thread_info(tsk)->status & TS_XSAVE) &&
+            !(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
+                return;
+
+        if (unlikely(fx->swd & X87_FSW_ES))
+                asm volatile("fnclex");
+        alternative_input(ASM_NOP8 ASM_NOP2,
+                          "    emms\n"          /* clear stack tags */
+                          "    fildl %%gs:0",   /* load to clear state */
+                          X86_FEATURE_FXSAVE_LEAK);
+}
+
+static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
+{
+        int err;
+
+        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)
+#if 0 /* See comment in __fxsave_clear() below. */
+                     : [fx] "r" (fx), "0" (0));
+#else
+                     : [fx] "cdaSDb" (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 fxsave(struct task_struct *tsk)
+{
+        /* 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. */
+#if 0
+        /* Using "fxsaveq %0" would be the ideal choice, but is only supported
+           starting with gas 2.16. */
+        __asm__ __volatile__("fxsaveq %0"
+                             : "=m" (tsk->thread.xstate->fxsave));
+#elif 0
+        /* 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" (tsk->thread.xstate->fxsave));
+#else
+        /* 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 (%1)"
+                             : "=m" (tsk->thread.xstate->fxsave)
+                             : "cdaSDb" (&tsk->thread.xstate->fxsave));
+#endif
+}
+
+static inline void __save_init_fpu(struct task_struct *tsk)
+{
+        if (task_thread_info(tsk)->status & TS_XSAVE)
+                xsave(tsk);
+        else
+                fxsave(tsk);
+
+        clear_fpu_state(tsk);
+        task_thread_info(tsk)->status &= ~TS_USEDFPU;
+}
+
+#else  /* CONFIG_X86_32 */
+
+extern void finit(void);
+
+static inline void tolerant_fwait(void)
+{
+        asm volatile("fnclex ; fwait");
+}
+
+static inline void restore_fpu(struct task_struct *tsk)
+{
+        if (task_thread_info(tsk)->status & TS_XSAVE) {
+                xrstor_checking(&tsk->thread.xstate->xsave);
+                return;
+        }
+        /*
+         * The "nop" is needed to make the instructions the same
+         * length.
+         */
+        alternative_input(
+                "nop ; frstor %1",
+                "fxrstor %1",
+                X86_FEATURE_FXSR,
+                "m" (tsk->thread.xstate->fxsave));
+}
+
+/* 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 (kstat_cpu(0).cpustat.user)
+#endif
+
+/*
+ * These must be called with preempt disabled
+ */
+static inline void __save_init_fpu(struct task_struct *tsk)
+{
+        if (task_thread_info(tsk)->status & TS_XSAVE) {
+                struct xsave_struct *xstate = &tsk->thread.xstate->xsave;
+                struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave;
+
+                xsave(tsk);
+
+                /*
+                 * xsave header may indicate the init state of the FP.
+                 */
+                if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
+                        goto end;
+
+                if (unlikely(fx->swd & X87_FSW_ES))
+                        asm volatile("fnclex");
+
+                /*
+                 * we can do a simple return here or be paranoid :)
+                 */
+                goto clear_state;
+        }
+
+        /* Use more nops than strictly needed in case the compiler
+           varies code */
+        alternative_input(
+                "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
+                "fxsave %[fx]\n"
+                "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
+                X86_FEATURE_FXSR,
+                [fx] "m" (tsk->thread.xstate->fxsave),
+                [fsw] "m" (tsk->thread.xstate->fxsave.swd) : "memory");
+clear_state:
+        /* 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(
+                GENERIC_NOP8 GENERIC_NOP2,
+                "emms\n\t"              /* clear stack tags */
+                "fildl %[addr]",        /* set F?P to defined value */
+                X86_FEATURE_FXSAVE_LEAK,
+                [addr] "m" (safe_address));
+end:
+        task_thread_info(tsk)->status &= ~TS_USEDFPU;
+}
+
+#endif  /* CONFIG_X86_64 */
+
+/*
+ * 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) {
+                tolerant_fwait();
+                task_thread_info(tsk)->status &= ~TS_USEDFPU;
+                stts();
+        }
+}
+
+static inline void kernel_fpu_begin(void)
+{
+        struct thread_info *me = current_thread_info();
+        preempt_disable();
+        if (me->status & TS_USEDFPU)
+                __save_init_fpu(me->task);
+        else
+                clts();
+}
+
+static inline void kernel_fpu_end(void)
+{
+        stts();
+        preempt_enable();
+}
+
+/*
+ * Some instructions like VIA's padlock instructions generate a spurious
+ * DNA fault but don't modify SSE registers. And these instructions
+ * get used from interrupt context aswell. To prevent these kernel instructions
+ * in interrupt context interact wrongly with other user/kernel fpu usage, we
+ * should use them only in the context of irq_ts_save/restore()
+ */
+static inline int irq_ts_save(void)
+{
+        /*
+         * If we are in process context, we are ok to take a spurious DNA fault.
+         * Otherwise, doing clts() in process context require pre-emption to
+         * be disabled or some heavy lifting like kernel_fpu_begin()
+         */
+        if (!in_interrupt())
+                return 0;
+
+        if (read_cr0() & X86_CR0_TS) {
+                clts();
+                return 1;
+        }
+
+        return 0;
+}
+
+static inline void irq_ts_restore(int TS_state)
+{
+        if (TS_state)
+                stts();
+}
+
+#ifdef CONFIG_X86_64
+
+static inline void save_init_fpu(struct task_struct *tsk)
+{
+        __save_init_fpu(tsk);
+        stts();
+}
+
+#define unlazy_fpu      __unlazy_fpu
+#define clear_fpu       __clear_fpu
+
+#else  /* CONFIG_X86_32 */
+
+/*
+ * These disable preemption on their own and are safe
+ */
+static inline void save_init_fpu(struct task_struct *tsk)
+{
+        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();
+}
+
+#endif  /* CONFIG_X86_64 */
+
+/*
+ * i387 state interaction
+ */
+static inline unsigned short get_fpu_cwd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.xstate->fxsave.cwd;
+        } else {
+                return (unsigned short)tsk->thread.xstate->fsave.cwd;
+        }
+}
+
+static inline unsigned short get_fpu_swd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.xstate->fxsave.swd;
+        } else {
+                return (unsigned short)tsk->thread.xstate->fsave.swd;
+        }
+}
+
+static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk)
+{
+        if (cpu_has_xmm) {
+                return tsk->thread.xstate->fxsave.mxcsr;
+        } else {
+                return MXCSR_DEFAULT;
+        }
+}
+
+#endif /* ASM_X86__I387_H */