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-rw-r--r--arch/x86/kernel/xsave.c517
1 files changed, 336 insertions, 181 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 3d3e2070911..ada87a329ed 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -10,9 +10,7 @@
#include <linux/compat.h>
#include <asm/i387.h>
#include <asm/fpu-internal.h>
-#ifdef CONFIG_IA32_EMULATION
-#include <asm/sigcontext32.h>
-#endif
+#include <asm/sigframe.h>
#include <asm/xcr.h>
/*
@@ -23,13 +21,9 @@ u64 pcntxt_mask;
/*
* Represents init state for the supported extended state.
*/
-static struct xsave_struct *init_xstate_buf;
-
-struct _fpx_sw_bytes fx_sw_reserved;
-#ifdef CONFIG_IA32_EMULATION
-struct _fpx_sw_bytes fx_sw_reserved_ia32;
-#endif
+struct xsave_struct *init_xstate_buf;
+static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
/*
@@ -44,9 +38,9 @@ static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
*/
void __sanitize_i387_state(struct task_struct *tsk)
{
- u64 xstate_bv;
- int feature_bit = 0x2;
struct i387_fxsave_struct *fx = &tsk->thread.fpu.state->fxsave;
+ int feature_bit = 0x2;
+ u64 xstate_bv;
if (!fx)
return;
@@ -104,213 +98,326 @@ void __sanitize_i387_state(struct task_struct *tsk)
* Check for the presence of extended state information in the
* user fpstate pointer in the sigcontext.
*/
-int check_for_xstate(struct i387_fxsave_struct __user *buf,
- void __user *fpstate,
- struct _fpx_sw_bytes *fx_sw_user)
+static inline int check_for_xstate(struct i387_fxsave_struct __user *buf,
+ void __user *fpstate,
+ struct _fpx_sw_bytes *fx_sw)
{
int min_xstate_size = sizeof(struct i387_fxsave_struct) +
sizeof(struct xsave_hdr_struct);
unsigned int magic2;
- int err;
- err = __copy_from_user(fx_sw_user, &buf->sw_reserved[0],
- sizeof(struct _fpx_sw_bytes));
- if (err)
- return -EFAULT;
+ if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
+ return -1;
- /*
- * First Magic check failed.
- */
- if (fx_sw_user->magic1 != FP_XSTATE_MAGIC1)
- return -EINVAL;
+ /* Check for the first magic field and other error scenarios. */
+ if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
+ fx_sw->xstate_size < min_xstate_size ||
+ fx_sw->xstate_size > xstate_size ||
+ fx_sw->xstate_size > fx_sw->extended_size)
+ return -1;
/*
- * Check for error scenarios.
- */
- if (fx_sw_user->xstate_size < min_xstate_size ||
- fx_sw_user->xstate_size > xstate_size ||
- fx_sw_user->xstate_size > fx_sw_user->extended_size)
- return -EINVAL;
-
- err = __get_user(magic2, (__u32 *) (((void *)fpstate) +
- fx_sw_user->extended_size -
- FP_XSTATE_MAGIC2_SIZE));
- if (err)
- return err;
- /*
* Check for the presence of second magic word at the end of memory
* layout. This detects the case where the user just copied the legacy
* fpstate layout with out copying the extended state information
* in the memory layout.
*/
- if (magic2 != FP_XSTATE_MAGIC2)
- return -EFAULT;
+ if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
+ || magic2 != FP_XSTATE_MAGIC2)
+ return -1;
return 0;
}
-#ifdef CONFIG_X86_64
/*
* Signal frame handlers.
*/
-
-int save_i387_xstate(void __user *buf)
+static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
{
- struct task_struct *tsk = current;
- int err = 0;
-
- if (!access_ok(VERIFY_WRITE, buf, sig_xstate_size))
- return -EACCES;
+ if (use_fxsr()) {
+ struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+ struct user_i387_ia32_struct env;
+ struct _fpstate_ia32 __user *fp = buf;
- BUG_ON(sig_xstate_size < xstate_size);
+ convert_from_fxsr(&env, tsk);
- if ((unsigned long)buf % 64)
- pr_err("%s: bad fpstate %p\n", __func__, buf);
-
- if (!used_math())
- return 0;
-
- if (user_has_fpu()) {
- if (use_xsave())
- err = xsave_user(buf);
- else
- err = fxsave_user(buf);
-
- if (err)
- return err;
- user_fpu_end();
+ if (__copy_to_user(buf, &env, sizeof(env)) ||
+ __put_user(xsave->i387.swd, &fp->status) ||
+ __put_user(X86_FXSR_MAGIC, &fp->magic))
+ return -1;
} else {
- sanitize_i387_state(tsk);
- if (__copy_to_user(buf, &tsk->thread.fpu.state->fxsave,
- xstate_size))
+ struct i387_fsave_struct __user *fp = buf;
+ u32 swd;
+ if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
return -1;
}
- clear_used_math(); /* trigger finit */
+ return 0;
+}
- if (use_xsave()) {
- struct _fpstate __user *fx = buf;
- struct _xstate __user *x = buf;
- u64 xstate_bv;
+static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
+{
+ struct xsave_struct __user *x = buf;
+ struct _fpx_sw_bytes *sw_bytes;
+ u32 xstate_bv;
+ int err;
- err = __copy_to_user(&fx->sw_reserved, &fx_sw_reserved,
- sizeof(struct _fpx_sw_bytes));
+ /* Setup the bytes not touched by the [f]xsave and reserved for SW. */
+ sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved;
+ err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes));
- err |= __put_user(FP_XSTATE_MAGIC2,
- (__u32 __user *) (buf + sig_xstate_size
- - FP_XSTATE_MAGIC2_SIZE));
+ if (!use_xsave())
+ return err;
- /*
- * 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);
+ err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
- /*
- * 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;
+ /*
+ * Read the xstate_bv which we copied (directly from the cpu or
+ * from the state in task struct) to the user buffers.
+ */
+ err |= __get_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
- err |= __put_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;
- if (err)
- return err;
- }
+ err |= __put_user(xstate_bv, (__u32 *)&x->xsave_hdr.xstate_bv);
- return 1;
+ return err;
+}
+
+static inline int save_user_xstate(struct xsave_struct __user *buf)
+{
+ int err;
+
+ if (use_xsave())
+ err = xsave_user(buf);
+ else if (use_fxsr())
+ err = fxsave_user((struct i387_fxsave_struct __user *) buf);
+ else
+ err = fsave_user((struct i387_fsave_struct __user *) buf);
+
+ if (unlikely(err) && __clear_user(buf, xstate_size))
+ err = -EFAULT;
+ return err;
}
/*
- * Restore the extended state if present. Otherwise, restore the FP/SSE
- * state.
+ * Save the fpu, extended register state to the user signal frame.
+ *
+ * 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
+ * state is copied.
+ * 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
+ *
+ * buf == buf_fx for 64-bit frames and 32-bit fsave frame.
+ * buf != buf_fx for 32-bit frames with fxstate.
+ *
+ * If the fpu, extended register state is live, save the state directly
+ * to the user frame pointed by the aligned pointer 'buf_fx'. Otherwise,
+ * copy the thread's fpu state to the user frame starting at 'buf_fx'.
+ *
+ * If this is a 32-bit frame with fxstate, put a fsave header before
+ * the aligned state at 'buf_fx'.
+ *
+ * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
+ * indicating the absence/presence of the extended state to the user.
*/
-static int restore_user_xstate(void __user *buf)
+int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
{
- struct _fpx_sw_bytes fx_sw_user;
- u64 mask;
- int err;
+ struct xsave_struct *xsave = &current->thread.fpu.state->xsave;
+ struct task_struct *tsk = current;
+ int ia32_fxstate = (buf != buf_fx);
- if (((unsigned long)buf % 64) ||
- check_for_xstate(buf, buf, &fx_sw_user))
- goto fx_only;
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
- mask = fx_sw_user.xstate_bv;
+ if (!access_ok(VERIFY_WRITE, buf, size))
+ return -EACCES;
- /*
- * restore the state passed by the user.
- */
- err = xrestore_user(buf, mask);
- if (err)
- return err;
+ if (!HAVE_HWFP)
+ return fpregs_soft_get(current, NULL, 0,
+ sizeof(struct user_i387_ia32_struct), NULL,
+ (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
- /*
- * init the state skipped by the user.
- */
- mask = pcntxt_mask & ~mask;
- if (unlikely(mask))
- xrstor_state(init_xstate_buf, mask);
+ if (user_has_fpu()) {
+ /* Save the live register state to the user directly. */
+ if (save_user_xstate(buf_fx))
+ return -1;
+ /* Update the thread's fxstate to save the fsave header. */
+ if (ia32_fxstate)
+ fpu_fxsave(&tsk->thread.fpu);
+ } else {
+ sanitize_i387_state(tsk);
+ if (__copy_to_user(buf_fx, xsave, xstate_size))
+ return -1;
+ }
+
+ /* Save the fsave header for the 32-bit frames. */
+ if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
+ return -1;
+
+ if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
+ return -1;
+
+ drop_init_fpu(tsk); /* trigger finit */
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);
+static inline void
+sanitize_restored_xstate(struct task_struct *tsk,
+ struct user_i387_ia32_struct *ia32_env,
+ u64 xstate_bv, int fx_only)
+{
+ struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+ struct xsave_hdr_struct *xsave_hdr = &xsave->xsave_hdr;
+
+ if (use_xsave()) {
+ /* 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 not enabled by the OS.
+ */
+ if (fx_only)
+ xsave_hdr->xstate_bv = XSTATE_FPSSE;
+ else
+ xsave_hdr->xstate_bv &= (pcntxt_mask & xstate_bv);
+ }
+
+ if (use_fxsr()) {
+ /*
+ * mscsr reserved bits must be masked to zero for security
+ * reasons.
+ */
+ xsave->i387.mxcsr &= mxcsr_feature_mask;
+
+ convert_to_fxsr(tsk, ia32_env);
+ }
}
/*
- * This restores directly out of user space. Exceptions are handled.
+ * Restore the extended state if present. Otherwise, restore the FP/SSE state.
*/
-int restore_i387_xstate(void __user *buf)
+static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
{
+ if (use_xsave()) {
+ if ((unsigned long)buf % 64 || fx_only) {
+ u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
+ xrstor_state(init_xstate_buf, init_bv);
+ return fxrstor_user(buf);
+ } else {
+ u64 init_bv = pcntxt_mask & ~xbv;
+ if (unlikely(init_bv))
+ xrstor_state(init_xstate_buf, init_bv);
+ return xrestore_user(buf, xbv);
+ }
+ } else if (use_fxsr()) {
+ return fxrstor_user(buf);
+ } else
+ return frstor_user(buf);
+}
+
+int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
+{
+ int ia32_fxstate = (buf != buf_fx);
struct task_struct *tsk = current;
- int err = 0;
+ int state_size = xstate_size;
+ u64 xstate_bv = 0;
+ int fx_only = 0;
+
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
if (!buf) {
- if (used_math())
- goto clear;
+ drop_init_fpu(tsk);
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 (!access_ok(VERIFY_READ, buf, size))
+ return -EACCES;
+
+ if (!used_math() && init_fpu(tsk))
+ return -1;
+
+ if (!HAVE_HWFP) {
+ return fpregs_soft_set(current, NULL,
+ 0, sizeof(struct user_i387_ia32_struct),
+ NULL, buf) != 0;
}
- user_fpu_begin();
- if (use_xsave())
- err = restore_user_xstate(buf);
- else
- err = fxrstor_checking((__force struct i387_fxsave_struct *)
- buf);
- if (unlikely(err)) {
+ if (use_xsave()) {
+ struct _fpx_sw_bytes fx_sw_user;
+ if (unlikely(check_for_xstate(buf_fx, buf_fx, &fx_sw_user))) {
+ /*
+ * Couldn't find the extended state information in the
+ * memory layout. Restore just the FP/SSE and init all
+ * the other extended state.
+ */
+ state_size = sizeof(struct i387_fxsave_struct);
+ fx_only = 1;
+ } else {
+ state_size = fx_sw_user.xstate_size;
+ xstate_bv = fx_sw_user.xstate_bv;
+ }
+ }
+
+ if (ia32_fxstate) {
+ /*
+ * For 32-bit frames with fxstate, copy the user state to the
+ * thread's fpu state, reconstruct fxstate from the fsave
+ * header. Sanitize the copied state etc.
+ */
+ struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;
+ struct user_i387_ia32_struct env;
+ int err = 0;
+
+ /*
+ * Drop the current fpu which clears used_math(). This ensures
+ * that any context-switch during the copy of the new state,
+ * avoids the intermediate state from getting restored/saved.
+ * Thus avoiding the new restored state from getting corrupted.
+ * We will be ready to restore/save the state only after
+ * set_used_math() is again set.
+ */
+ drop_fpu(tsk);
+
+ if (__copy_from_user(xsave, buf_fx, state_size) ||
+ __copy_from_user(&env, buf, sizeof(env))) {
+ err = -1;
+ } else {
+ sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
+ set_used_math();
+ }
+
+ if (use_eager_fpu())
+ math_state_restore();
+
+ return err;
+ } else {
/*
- * Encountered an error while doing the restore from the
- * user buffer, clear the fpu state.
+ * For 64-bit frames and 32-bit fsave frames, restore the user
+ * state to the registers directly (with exceptions handled).
*/
-clear:
- clear_fpu(tsk);
- clear_used_math();
+ user_fpu_begin();
+ if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
+ drop_init_fpu(tsk);
+ return -1;
+ }
}
- return err;
+
+ return 0;
}
-#endif
/*
* Prepare the SW reserved portion of the fxsave memory layout, indicating
@@ -321,31 +428,22 @@ clear:
*/
static void prepare_fx_sw_frame(void)
{
- int size_extended = (xstate_size - sizeof(struct i387_fxsave_struct)) +
- FP_XSTATE_MAGIC2_SIZE;
+ int fsave_header_size = sizeof(struct i387_fsave_struct);
+ int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
- sig_xstate_size = sizeof(struct _fpstate) + size_extended;
-
-#ifdef CONFIG_IA32_EMULATION
- sig_xstate_ia32_size = sizeof(struct _fpstate_ia32) + size_extended;
-#endif
-
- memset(&fx_sw_reserved, 0, sizeof(fx_sw_reserved));
+ if (config_enabled(CONFIG_X86_32))
+ size += fsave_header_size;
fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
- fx_sw_reserved.extended_size = sig_xstate_size;
+ fx_sw_reserved.extended_size = size;
fx_sw_reserved.xstate_bv = pcntxt_mask;
fx_sw_reserved.xstate_size = xstate_size;
-#ifdef CONFIG_IA32_EMULATION
- memcpy(&fx_sw_reserved_ia32, &fx_sw_reserved,
- sizeof(struct _fpx_sw_bytes));
- fx_sw_reserved_ia32.extended_size = sig_xstate_ia32_size;
-#endif
-}
-#ifdef CONFIG_X86_64
-unsigned int sig_xstate_size = sizeof(struct _fpstate);
-#endif
+ if (config_enabled(CONFIG_IA32_EMULATION)) {
+ fx_sw_reserved_ia32 = fx_sw_reserved;
+ fx_sw_reserved_ia32.extended_size += fsave_header_size;
+ }
+}
/*
* Enable the extended processor state save/restore feature
@@ -384,19 +482,21 @@ static void __init setup_xstate_features(void)
/*
* setup the xstate image representing the init state
*/
-static void __init setup_xstate_init(void)
+static void __init setup_init_fpu_buf(void)
{
- setup_xstate_features();
-
/*
* Setup init_xstate_buf to represent the init state of
* all the features managed by the xsave
*/
init_xstate_buf = alloc_bootmem_align(xstate_size,
__alignof__(struct xsave_struct));
- init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
+ fx_finit(&init_xstate_buf->i387);
+
+ if (!cpu_has_xsave)
+ return;
+
+ setup_xstate_features();
- clts();
/*
* Init all the features state with header_bv being 0x0
*/
@@ -406,9 +506,21 @@ static void __init setup_xstate_init(void)
* of any feature which is not represented by all zero's.
*/
xsave_state(init_xstate_buf, -1);
- stts();
}
+static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
+static int __init eager_fpu_setup(char *s)
+{
+ if (!strcmp(s, "on"))
+ eagerfpu = ENABLE;
+ else if (!strcmp(s, "off"))
+ eagerfpu = DISABLE;
+ else if (!strcmp(s, "auto"))
+ eagerfpu = AUTO;
+ return 1;
+}
+__setup("eagerfpu=", eager_fpu_setup);
+
/*
* Enable and initialize the xsave feature.
*/
@@ -445,8 +557,11 @@ static void __init xstate_enable_boot_cpu(void)
update_regset_xstate_info(xstate_size, pcntxt_mask);
prepare_fx_sw_frame();
+ setup_init_fpu_buf();
- setup_xstate_init();
+ /* Auto enable eagerfpu for xsaveopt */
+ if (cpu_has_xsaveopt && eagerfpu != DISABLE)
+ eagerfpu = ENABLE;
pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n",
pcntxt_mask, xstate_size);
@@ -471,3 +586,43 @@ void __cpuinit xsave_init(void)
next_func = xstate_enable;
this_func();
}
+
+static inline void __init eager_fpu_init_bp(void)
+{
+ current->thread.fpu.state =
+ alloc_bootmem_align(xstate_size, __alignof__(struct xsave_struct));
+ if (!init_xstate_buf)
+ setup_init_fpu_buf();
+}
+
+void __cpuinit eager_fpu_init(void)
+{
+ static __refdata void (*boot_func)(void) = eager_fpu_init_bp;
+
+ clear_used_math();
+ current_thread_info()->status = 0;
+
+ if (eagerfpu == ENABLE)
+ setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
+
+ if (!cpu_has_eager_fpu) {
+ stts();
+ return;
+ }
+
+ if (boot_func) {
+ boot_func();
+ boot_func = NULL;
+ }
+
+ /*
+ * This is same as math_state_restore(). But use_xsave() is
+ * not yet patched to use math_state_restore().
+ */
+ init_fpu(current);
+ __thread_fpu_begin(current);
+ if (cpu_has_xsave)
+ xrstor_state(init_xstate_buf, -1);
+ else
+ fxrstor_checking(&init_xstate_buf->i387);
+}