[RFC 4/8] x86, xsave: remove unused code

From: Hans Rosenfeld
Date: Wed Mar 09 2011 - 14:16:46 EST

The patches to rework the fpu/xsave handling and signal frame setup have
made a lot of code unused. This patch removes all this now useless stuff.

Signed-off-by: Hans Rosenfeld <hans.rosenfeld@xxxxxxx>
---
arch/x86/include/asm/i387.h | 155 ++----------------------------
arch/x86/include/asm/xsave.h | 51 ----------
arch/x86/kernel/i387.c | 221 ------------------------------------------
arch/x86/kernel/traps.c | 22 ----
arch/x86/kernel/xsave.c | 163 -------------------------------
5 files changed, 7 insertions(+), 605 deletions(-)

diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 30930bf..97867ea 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -29,8 +29,6 @@
# include <asm/sigcontext32.h>
# include <asm/user32.h>
#else
-# define save_i387_xstate_ia32 save_i387_xstate
-# define restore_i387_xstate_ia32 restore_i387_xstate
# define _fpstate_ia32 _fpstate
# define _xstate_ia32 _xstate
# define sig_xstate_ia32_size sig_xstate_size
@@ -108,75 +106,16 @@ static inline void sanitize_i387_state(struct task_struct *tsk)
}

#ifdef CONFIG_X86_64
-static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
+static inline void fxrstor(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));
+ asm volatile("fxrstorq %[fx]\n\t"
+ : : [fx] "m" (*fx));
#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));
+ asm volatile("rex64/fxrstor (%[fx])\n\t"
+ : : [fx] "R" (fx), "m" (*fx));
#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)
@@ -209,7 +148,7 @@ static inline void fpu_fxsave(struct fpu *fpu)
#else /* CONFIG_X86_32 */

/* perform fxrstor iff the processor has extended states, otherwise frstor */
-static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
+static inline void fxrstor(struct i387_fxsave_struct *fx)
{
/*
* The "nop" is needed to make the instructions the same
@@ -220,8 +159,6 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
"fxrstor %1",
X86_FEATURE_FXSR,
"m" (*fx));
-
- return 0;
}

static inline void fpu_fxsave(struct fpu *fpu)
@@ -246,7 +183,7 @@ static inline void fpu_fxsave(struct fpu *fpu)
*/
static inline void fpu_restore(struct fpu *fpu)
{
- fxrstor_checking(&fpu->state->fxsave);
+ fxrstor(&fpu->state->fxsave);
}

static inline void fpu_save(struct fpu *fpu)
@@ -278,69 +215,6 @@ static inline void fpu_clean(struct fpu *fpu)
[addr] "m" (safe_address));
}

-static inline void fpu_save_init(struct fpu *fpu)
-{
- if (use_xsave()) {
- struct xsave_struct *xstate = &fpu->state->xsave;
-
- fpu_xsave(xstate, -1);
-
- /*
- * xsave header may indicate the init state of the FP.
- */
- if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
- return;
- } else if (use_fxsr()) {
- fpu_fxsave(fpu);
- } else {
- asm volatile("fsave %[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_restore_checking(struct fpu *fpu)
-{
- if (use_xsave())
- return xrstor_checking(&fpu->state->xsave, -1);
- else
- return fxrstor_checking(&fpu->state->fxsave);
-}
-
-/*
- * 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) {
@@ -409,21 +283,6 @@ 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)
-{
- 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();
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 200c56d..742da4a 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -51,26 +51,6 @@ extern int check_for_xstate(struct i387_fxsave_struct __user *buf,
unsigned int size,
struct _fpx_sw_bytes *sw);

-static inline int xrstor_checking(struct xsave_struct *fx, u64 mask)
-{
- int err;
- u32 lmask = mask;
- u32 hmask = mask >> 32;
-
- 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" (lmask), "d" (hmask), "0" (0)
- : "memory");
-
- return err;
-}
-
static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
{
u32 lmask = mask;
@@ -81,37 +61,6 @@ static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
: "memory");
}

-static inline int xsave_checking(struct xsave_struct __user *buf)
-{
- int err;
-
- /*
- * Clear the xsave header first, so that reserved fields are
- * initialized to zero.
- */
- err = __clear_user(&buf->xsave_hdr,
- sizeof(struct xsave_hdr_struct));
- if (unlikely(err))
- return -EFAULT;
-
- asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b,3b)
- : [err] "=r" (err)
- : "D" (buf), "a" (-1), "d" (-1), "0" (0)
- : "memory");
-
- if (unlikely(err) && __clear_user(buf, xstate_size))
- err = -EFAULT;
-
- /* No need to clear here because the caller clears USED_MATH */
- return err;
-}
-
static inline void xsave_state(struct xsave_struct *fx, u64 mask)
{
u32 lmask = mask;
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 5cec7c2..d2d2b69 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -490,227 +490,6 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
}

/*
- * Signal frame handlers.
- */
-
-static inline int save_i387_fsave(struct _fpstate_ia32 __user *buf)
-{
- struct task_struct *tsk = current;
- struct i387_fsave_struct *fp = &tsk->thread.fpu.state->fsave;
-
- fp->status = fp->swd;
- if (__copy_to_user(buf, fp, sizeof(struct i387_fsave_struct)))
- return -1;
- return 1;
-}
-
-static int save_i387_fxsave(struct _fpstate_ia32 __user *buf)
-{
- struct task_struct *tsk = current;
- struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
- struct user_i387_ia32_struct env;
- int err = 0;
-
- convert_from_fxsr(&env, tsk);
- if (__copy_to_user(buf, &env, sizeof(env)))
- return -1;
-
- err |= __put_user(fx->swd, &buf->status);
- err |= __put_user(X86_FXSR_MAGIC, &buf->magic);
- if (err)
- return -1;
-
- if (__copy_to_user(&buf->_fxsr_env[0], fx, xstate_size))
- return -1;
- return 1;
-}
-
-static int save_i387_xsave(void __user *buf)
-{
- struct task_struct *tsk = current;
- struct _fpstate_ia32 __user *fx = buf;
- int err = 0;
-
-
- sanitize_i387_state(tsk);
-
- /*
- * For legacy compatible, we always set FP/SSE bits in the bit
- * vector while saving the state to the user context.
- * This will enable us capturing any changes(during sigreturn) to
- * the FP/SSE bits by the legacy applications which don't touch
- * xstate_bv in the xsave header.
- *
- * xsave aware applications can change the xstate_bv in the xsave
- * header as well as change any contents in the memory layout.
- * xrestore as part of sigreturn will capture all the changes.
- */
- tsk->thread.fpu.state->xsave.xsave_hdr.xstate_bv |= XSTATE_FPSSE;
-
- if (save_i387_fxsave(fx) < 0)
- return -1;
-
- err = __copy_to_user(&fx->sw_reserved, &fx_sw_reserved_ia32,
- sizeof(struct _fpx_sw_bytes));
- err |= __put_user(FP_XSTATE_MAGIC2,
- (__u32 __user *) (buf + sig_xstate_ia32_size
- - FP_XSTATE_MAGIC2_SIZE));
- if (err)
- return -1;
-
- return 1;
-}
-
-int save_i387_xstate_ia32(void __user *buf)
-{
- struct _fpstate_ia32 __user *fp = (struct _fpstate_ia32 __user *) buf;
- struct task_struct *tsk = current;
-
- if (!used_math())
- return 0;
-
- if (!access_ok(VERIFY_WRITE, buf, sig_xstate_ia32_size))
- return -EACCES;
- /*
- * This will cause a "finit" to be triggered by the next
- * attempted FPU operation by the 'current' process.
- */
- clear_used_math();
-
- if (!HAVE_HWFP) {
- return fpregs_soft_get(current, NULL,
- 0, sizeof(struct user_i387_ia32_struct),
- NULL, fp) ? -1 : 1;
- }
-
- preempt_disable();
- save_xstates(tsk);
- preempt_enable();
-
- if (cpu_has_xsave)
- return save_i387_xsave(fp);
- if (cpu_has_fxsr)
- return save_i387_fxsave(fp);
- else
- return save_i387_fsave(fp);
-}
-
-static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
-{
- struct task_struct *tsk = current;
-
- return __copy_from_user(&tsk->thread.fpu.state->fsave, buf,
- sizeof(struct i387_fsave_struct));
-}
-
-static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf,
- unsigned int size)
-{
- struct task_struct *tsk = current;
- struct user_i387_ia32_struct env;
- int err;
-
- err = __copy_from_user(&tsk->thread.fpu.state->fxsave, &buf->_fxsr_env[0],
- size);
- /* mxcsr reserved bits must be masked to zero for security reasons */
- tsk->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask;
- if (err || __copy_from_user(&env, buf, sizeof(env)))
- return 1;
- convert_to_fxsr(tsk, &env);
-
- return 0;
-}
-
-static int restore_i387_xsave(void __user *buf)
-{
- struct _fpx_sw_bytes fx_sw_user;
- struct _fpstate_ia32 __user *fx_user =
- ((struct _fpstate_ia32 __user *) buf);
- struct i387_fxsave_struct __user *fx =
- (struct i387_fxsave_struct __user *) &fx_user->_fxsr_env[0];
- struct xsave_hdr_struct *xsave_hdr =
- &current->thread.fpu.state->xsave.xsave_hdr;
- u64 mask;
- int err;
-
- if (check_for_xstate(fx, sig_xstate_ia32_size -
- offsetof(struct _fpstate_ia32, _fxsr_env),
- &fx_sw_user))
- goto fx_only;
-
- mask = fx_sw_user.xstate_bv;
-
- err = restore_i387_fxsave(buf, fx_sw_user.xstate_size);
-
- xsave_hdr->xstate_bv &= pcntxt_mask;
- /*
- * These bits must be zero.
- */
- xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
-
- /*
- * Init the state that is not present in the memory layout
- * and enabled by the OS.
- */
- mask = ~(pcntxt_mask & ~mask);
- xsave_hdr->xstate_bv &= mask;
-
- return err;
-fx_only:
- /*
- * Couldn't find the extended state information in the memory
- * layout. Restore the FP/SSE and init the other extended state
- * enabled by the OS.
- */
- xsave_hdr->xstate_bv = XSTATE_FPSSE;
- return restore_i387_fxsave(buf, sizeof(struct i387_fxsave_struct));
-}
-
-int restore_i387_xstate_ia32(void __user *buf)
-{
- int err;
- struct task_struct *tsk = current;
- struct _fpstate_ia32 __user *fp = (struct _fpstate_ia32 __user *) buf;
-
- if (HAVE_HWFP)
- clear_fpu(tsk);
-
- if (!buf) {
- if (used_math()) {
- clear_fpu(tsk);
- clear_used_math();
- }
-
- return 0;
- } else
- if (!access_ok(VERIFY_READ, buf, sig_xstate_ia32_size))
- return -EACCES;
-
- if (!used_math()) {
- err = init_fpu(tsk);
- if (err)
- return err;
- }
-
- if (HAVE_HWFP) {
- if (cpu_has_xsave)
- err = restore_i387_xsave(buf);
- else if (cpu_has_fxsr)
- err = restore_i387_fxsave(fp, sizeof(struct
- i387_fxsave_struct));
- else
- err = restore_i387_fsave(fp);
- } else {
- err = fpregs_soft_set(current, NULL,
- 0, sizeof(struct user_i387_ia32_struct),
- NULL, fp) != 0;
- }
- set_used_math();
-
- return err;
-}
-
-/*
* FPU state for core dumps.
* This is only used for a.out dumps now.
* It is declared generically using elf_fpregset_t (which is
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 072c30e..872fc78 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -720,28 +720,6 @@ asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
}

/*
- * __math_state_restore assumes that cr0.TS is already clear and the
- * fpu state is all ready for use. Used during context switch.
- */
-void __math_state_restore(void)
-{
- struct thread_info *thread = current_thread_info();
- struct task_struct *tsk = thread->task;
-
- /*
- * Paranoid restore. send a SIGSEGV if we fail to restore the state.
- */
- if (unlikely(fpu_restore_checking(&tsk->thread.fpu))) {
- stts();
- force_sig(SIGSEGV, tsk);
- return;
- }
-
- thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
- tsk->fpu_counter++;
-}
-
-/*
* 'math_state_restore()' saves the current math information in the
* old math state array, and gets the new ones from the current task
*
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index df9b0bb..a10c13e 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -249,169 +249,6 @@ int save_xstates_sigframe(void __user *buf, unsigned int size)
return 1;
}

-#ifdef CONFIG_X86_64
-int save_i387_xstate(void __user *buf)
-{
- struct task_struct *tsk = current;
- int err = 0;
-
- if (!access_ok(VERIFY_WRITE, buf, sig_xstate_size))
- return -EACCES;
-
- BUG_ON(sig_xstate_size < xstate_size);
-
- if ((unsigned long)buf % 64)
- printk("save_i387_xstate: bad fpstate %p\n", buf);
-
- if (!used_math())
- return 0;
-
- if (task_thread_info(tsk)->status & TS_USEDFPU) {
- if (use_xsave())
- err = xsave_checking(buf);
- else
- err = fxsave_user(buf);
-
- if (err)
- return err;
- task_thread_info(tsk)->status &= ~TS_USEDFPU;
- stts();
- } else {
- sanitize_i387_state(tsk);
- if (__copy_to_user(buf, &tsk->thread.fpu.state->fxsave,
- xstate_size))
- return -1;
- }
-
- clear_used_math(); /* trigger finit */
-
- if (use_xsave()) {
- struct _fpstate __user *fx = buf;
- struct _xstate __user *x = buf;
- u64 xstate_bv;
-
- err = __copy_to_user(&fx->sw_reserved, &fx_sw_reserved,
- sizeof(struct _fpx_sw_bytes));
-
- err |= __put_user(FP_XSTATE_MAGIC2,
- (__u32 __user *) (buf + sig_xstate_size
- - FP_XSTATE_MAGIC2_SIZE));
-
- /*
- * Read the xstate_bv which we copied (directly from the cpu or
- * from the state in task struct) to the user buffers and
- * set the FP/SSE bits.
- */
- err |= __get_user(xstate_bv, &x->xstate_hdr.xstate_bv);
-
- /*
- * For legacy compatible, we always set FP/SSE bits in the bit
- * vector while saving the state to the user context. This will
- * enable us capturing any changes(during sigreturn) to
- * the FP/SSE bits by the legacy applications which don't touch
- * xstate_bv in the xsave header.
- *
- * xsave aware apps can change the xstate_bv in the xsave
- * header as well as change any contents in the memory layout.
- * xrestore as part of sigreturn will capture all the changes.
- */
- xstate_bv |= XSTATE_FPSSE;
-
- err |= __put_user(xstate_bv, &x->xstate_hdr.xstate_bv);
-
- if (err)
- return err;
- }
-
- return 1;
-}
-
-/*
- * Restore the extended state if present. Otherwise, restore the FP/SSE
- * state.
- */
-static int restore_user_xstate(void __user *buf)
-{
- struct _fpx_sw_bytes fx_sw_user;
- u64 mask;
- int err;
-
- if (((unsigned long)buf % 64) ||
- check_for_xstate(buf, sig_xstate_size, &fx_sw_user))
- goto fx_only;
-
- mask = fx_sw_user.xstate_bv;
-
- /*
- * restore the state passed by the user.
- */
- err = xrstor_checking((__force struct xsave_struct *)buf, mask);
- if (err)
- return err;
-
- /*
- * init the state skipped by the user.
- */
- mask = pcntxt_mask & ~mask;
- if (unlikely(mask))
- xrstor_state(init_xstate_buf, mask);
-
- return 0;
-
-fx_only:
- /*
- * couldn't find the extended state information in the
- * memory layout. Restore just the FP/SSE and init all
- * the other extended state.
- */
- xrstor_state(init_xstate_buf, pcntxt_mask & ~XSTATE_FPSSE);
- return fxrstor_checking((__force struct i387_fxsave_struct *)buf);
-}
-
-/*
- * This restores directly out of user space. Exceptions are handled.
- */
-int restore_i387_xstate(void __user *buf)
-{
- struct task_struct *tsk = current;
- int err = 0;
-
- if (!buf) {
- if (used_math())
- goto clear;
- return 0;
- } else
- if (!access_ok(VERIFY_READ, buf, sig_xstate_size))
- return -EACCES;
-
- if (!used_math()) {
- err = init_fpu(tsk);
- if (err)
- return err;
- }
-
- if (!(task_thread_info(current)->status & TS_USEDFPU)) {
- clts();
- task_thread_info(current)->status |= TS_USEDFPU;
- }
- if (use_xsave())
- err = restore_user_xstate(buf);
- else
- err = fxrstor_checking((__force struct i387_fxsave_struct *)
- buf);
- if (unlikely(err)) {
- /*
- * Encountered an error while doing the restore from the
- * user buffer, clear the fpu state.
- */
-clear:
- clear_fpu(tsk);
- clear_used_math();
- }
- return err;
-}
-#endif
-
int restore_xstates_sigframe(void __user *buf, unsigned int size)
{
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
--
1.5.6.5


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