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-rw-r--r--arch/x86/ia32/ia32_signal.c2
-rw-r--r--arch/x86/include/asm/fpu/internal.h90
-rw-r--r--arch/x86/include/asm/fpu/types.h32
-rw-r--r--arch/x86/include/asm/fpu/xstate.h12
-rw-r--r--arch/x86/include/asm/trace/fpu.h11
-rw-r--r--arch/x86/kernel/fpu/core.c155
-rw-r--r--arch/x86/kernel/fpu/init.c2
-rw-r--r--arch/x86/kernel/fpu/regset.c48
-rw-r--r--arch/x86/kernel/fpu/signal.c37
-rw-r--r--arch/x86/kernel/fpu/xstate.c264
-rw-r--r--arch/x86/kernel/signal.c6
-rw-r--r--arch/x86/kvm/x86.c2
-rw-r--r--arch/x86/math-emu/fpu_entry.c2
-rw-r--r--arch/x86/mm/extable.c24
-rw-r--r--arch/x86/mm/pkeys.c3
15 files changed, 375 insertions, 315 deletions
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index e0bb46c02857..0e2a5edbce00 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -231,7 +231,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
ksig->ka.sa.sa_restorer)
sp = (unsigned long) ksig->ka.sa.sa_restorer;
- if (fpu->fpstate_active) {
+ if (fpu->initialized) {
unsigned long fx_aligned, math_size;
sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 554cdb205d17..e3221ffa304e 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -23,11 +23,9 @@
/*
* High level FPU state handling functions:
*/
-extern void fpu__activate_curr(struct fpu *fpu);
-extern void fpu__activate_fpstate_read(struct fpu *fpu);
-extern void fpu__activate_fpstate_write(struct fpu *fpu);
-extern void fpu__current_fpstate_write_begin(void);
-extern void fpu__current_fpstate_write_end(void);
+extern void fpu__initialize(struct fpu *fpu);
+extern void fpu__prepare_read(struct fpu *fpu);
+extern void fpu__prepare_write(struct fpu *fpu);
extern void fpu__save(struct fpu *fpu);
extern void fpu__restore(struct fpu *fpu);
extern int fpu__restore_sig(void __user *buf, int ia32_frame);
@@ -120,20 +118,11 @@ extern void fpstate_sanitize_xstate(struct fpu *fpu);
err; \
})
-#define check_insn(insn, output, input...) \
-({ \
- int err; \
+#define kernel_insn(insn, output, input...) \
asm volatile("1:" #insn "\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), output \
- : "0"(0), input); \
- err; \
-})
+ _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_fprestore) \
+ : output : input)
static inline int copy_fregs_to_user(struct fregs_state __user *fx)
{
@@ -153,20 +142,16 @@ static inline int copy_fxregs_to_user(struct fxregs_state __user *fx)
static inline void copy_kernel_to_fxregs(struct fxregs_state *fx)
{
- int err;
-
if (IS_ENABLED(CONFIG_X86_32)) {
- err = check_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
+ kernel_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
} else {
if (IS_ENABLED(CONFIG_AS_FXSAVEQ)) {
- err = check_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
+ kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
} else {
/* See comment in copy_fxregs_to_kernel() below. */
- err = check_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), "m" (*fx));
+ kernel_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), "m" (*fx));
}
}
- /* Copying from a kernel buffer to FPU registers should never fail: */
- WARN_ON_FPU(err);
}
static inline int copy_user_to_fxregs(struct fxregs_state __user *fx)
@@ -183,9 +168,7 @@ static inline int copy_user_to_fxregs(struct fxregs_state __user *fx)
static inline void copy_kernel_to_fregs(struct fregs_state *fx)
{
- int err = check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
-
- WARN_ON_FPU(err);
+ kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
}
static inline int copy_user_to_fregs(struct fregs_state __user *fx)
@@ -281,18 +264,13 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
* Use XRSTORS to restore context if it is enabled. XRSTORS supports compact
* XSAVE area format.
*/
-#define XSTATE_XRESTORE(st, lmask, hmask, err) \
+#define XSTATE_XRESTORE(st, lmask, hmask) \
asm volatile(ALTERNATIVE(XRSTOR, \
XRSTORS, X86_FEATURE_XSAVES) \
"\n" \
- "xor %[err], %[err]\n" \
"3:\n" \
- ".pushsection .fixup,\"ax\"\n" \
- "4: movl $-2, %[err]\n" \
- "jmp 3b\n" \
- ".popsection\n" \
- _ASM_EXTABLE(661b, 4b) \
- : [err] "=r" (err) \
+ _ASM_EXTABLE_HANDLE(661b, 3b, ex_handler_fprestore)\
+ : \
: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
: "memory")
@@ -336,7 +314,10 @@ static inline void copy_kernel_to_xregs_booting(struct xregs_state *xstate)
else
XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
- /* We should never fault when copying from a kernel buffer: */
+ /*
+ * We should never fault when copying from a kernel buffer, and the FPU
+ * state we set at boot time should be valid.
+ */
WARN_ON_FPU(err);
}
@@ -350,7 +331,7 @@ static inline void copy_xregs_to_kernel(struct xregs_state *xstate)
u32 hmask = mask >> 32;
int err;
- WARN_ON(!alternatives_patched);
+ WARN_ON_FPU(!alternatives_patched);
XSTATE_XSAVE(xstate, lmask, hmask, err);
@@ -365,12 +346,8 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask)
{
u32 lmask = mask;
u32 hmask = mask >> 32;
- int err;
-
- XSTATE_XRESTORE(xstate, lmask, hmask, err);
- /* We should never fault when copying from a kernel buffer: */
- WARN_ON_FPU(err);
+ XSTATE_XRESTORE(xstate, lmask, hmask);
}
/*
@@ -526,38 +503,17 @@ static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu)
*/
static inline void fpregs_deactivate(struct fpu *fpu)
{
- WARN_ON_FPU(!fpu->fpregs_active);
-
- fpu->fpregs_active = 0;
this_cpu_write(fpu_fpregs_owner_ctx, NULL);
trace_x86_fpu_regs_deactivated(fpu);
}
static inline void fpregs_activate(struct fpu *fpu)
{
- WARN_ON_FPU(fpu->fpregs_active);
-
- fpu->fpregs_active = 1;
this_cpu_write(fpu_fpregs_owner_ctx, fpu);
trace_x86_fpu_regs_activated(fpu);
}
/*
- * 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 int fpregs_active(void)
-{
- return current->thread.fpu.fpregs_active;
-}
-
-/*
* FPU state switching for scheduling.
*
* This is a two-stage process:
@@ -571,14 +527,13 @@ static inline int fpregs_active(void)
static inline void
switch_fpu_prepare(struct fpu *old_fpu, int cpu)
{
- if (old_fpu->fpregs_active) {
+ if (old_fpu->initialized) {
if (!copy_fpregs_to_fpstate(old_fpu))
old_fpu->last_cpu = -1;
else
old_fpu->last_cpu = cpu;
/* But leave fpu_fpregs_owner_ctx! */
- old_fpu->fpregs_active = 0;
trace_x86_fpu_regs_deactivated(old_fpu);
} else
old_fpu->last_cpu = -1;
@@ -595,7 +550,7 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu)
static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu)
{
bool preload = static_cpu_has(X86_FEATURE_FPU) &&
- new_fpu->fpstate_active;
+ new_fpu->initialized;
if (preload) {
if (!fpregs_state_valid(new_fpu, cpu))
@@ -617,8 +572,7 @@ static inline void user_fpu_begin(void)
struct fpu *fpu = &current->thread.fpu;
preempt_disable();
- if (!fpregs_active())
- fpregs_activate(fpu);
+ fpregs_activate(fpu);
preempt_enable();
}
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 3c80f5b9c09d..a1520575d86b 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -68,6 +68,9 @@ struct fxregs_state {
/* Default value for fxregs_state.mxcsr: */
#define MXCSR_DEFAULT 0x1f80
+/* Copy both mxcsr & mxcsr_flags with a single u64 memcpy: */
+#define MXCSR_AND_FLAGS_SIZE sizeof(u64)
+
/*
* Software based FPU emulation state. This is arbitrary really,
* it matches the x87 format to make it easier to understand:
@@ -290,36 +293,13 @@ struct fpu {
unsigned int last_cpu;
/*
- * @fpstate_active:
+ * @initialized:
*
- * This flag indicates whether this context is active: if the task
+ * This flag indicates whether this context is initialized: if the task
* is not running then we can restore from this context, if the task
* is running then we should save into this context.
*/
- unsigned char fpstate_active;
-
- /*
- * @fpregs_active:
- *
- * This flag determines whether a given context is actively
- * loaded into the FPU's registers and that those registers
- * represent the task's current FPU state.
- *
- * Note the interaction with fpstate_active:
- *
- * # task does not use the FPU:
- * fpstate_active == 0
- *
- * # task uses the FPU and regs are active:
- * fpstate_active == 1 && fpregs_active == 1
- *
- * # the regs are inactive but still match fpstate:
- * fpstate_active == 1 && fpregs_active == 0 && fpregs_owner == fpu
- *
- * The third state is what we use for the lazy restore optimization
- * on lazy-switching CPUs.
- */
- unsigned char fpregs_active;
+ unsigned char initialized;
/*
* @state:
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 1b2799e0699a..83fee2469eb7 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -48,8 +48,12 @@ void fpu__xstate_clear_all_cpu_caps(void);
void *get_xsave_addr(struct xregs_state *xsave, int xstate);
const void *get_xsave_field_ptr(int xstate_field);
int using_compacted_format(void);
-int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
- void __user *ubuf, struct xregs_state *xsave);
-int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
- struct xregs_state *xsave);
+int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
+int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
+int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
+int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
+
+/* Validate an xstate header supplied by userspace (ptrace or sigreturn) */
+extern int validate_xstate_header(const struct xstate_header *hdr);
+
#endif
diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h
index 342e59789fcd..39f7a27bef13 100644
--- a/arch/x86/include/asm/trace/fpu.h
+++ b/arch/x86/include/asm/trace/fpu.h
@@ -12,25 +12,22 @@ DECLARE_EVENT_CLASS(x86_fpu,
TP_STRUCT__entry(
__field(struct fpu *, fpu)
- __field(bool, fpregs_active)
- __field(bool, fpstate_active)
+ __field(bool, initialized)
__field(u64, xfeatures)
__field(u64, xcomp_bv)
),
TP_fast_assign(
__entry->fpu = fpu;
- __entry->fpregs_active = fpu->fpregs_active;
- __entry->fpstate_active = fpu->fpstate_active;
+ __entry->initialized = fpu->initialized;
if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
__entry->xfeatures = fpu->state.xsave.header.xfeatures;
__entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv;
}
),
- TP_printk("x86/fpu: %p fpregs_active: %d fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
+ TP_printk("x86/fpu: %p initialized: %d xfeatures: %llx xcomp_bv: %llx",
__entry->fpu,
- __entry->fpregs_active,
- __entry->fpstate_active,
+ __entry->initialized,
__entry->xfeatures,
__entry->xcomp_bv
)
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index e1114f070c2d..f92a6593de1e 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -100,7 +100,7 @@ void __kernel_fpu_begin(void)
kernel_fpu_disable();
- if (fpu->fpregs_active) {
+ if (fpu->initialized) {
/*
* Ignore return value -- we don't care if reg state
* is clobbered.
@@ -116,7 +116,7 @@ void __kernel_fpu_end(void)
{
struct fpu *fpu = &current->thread.fpu;
- if (fpu->fpregs_active)
+ if (fpu->initialized)
copy_kernel_to_fpregs(&fpu->state);
kernel_fpu_enable();
@@ -148,7 +148,7 @@ void fpu__save(struct fpu *fpu)
preempt_disable();
trace_x86_fpu_before_save(fpu);
- if (fpu->fpregs_active) {
+ if (fpu->initialized) {
if (!copy_fpregs_to_fpstate(fpu)) {
copy_kernel_to_fpregs(&fpu->state);
}
@@ -189,10 +189,9 @@ EXPORT_SYMBOL_GPL(fpstate_init);
int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
{
- dst_fpu->fpregs_active = 0;
dst_fpu->last_cpu = -1;
- if (!src_fpu->fpstate_active || !static_cpu_has(X86_FEATURE_FPU))
+ if (!src_fpu->initialized || !static_cpu_has(X86_FEATURE_FPU))
return 0;
WARN_ON_FPU(src_fpu != &current->thread.fpu);
@@ -206,26 +205,14 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
/*
* Save current FPU registers directly into the child
* FPU context, without any memory-to-memory copying.
- * In lazy mode, if the FPU context isn't loaded into
- * fpregs, CR0.TS will be set and do_device_not_available
- * will load the FPU context.
*
- * We have to do all this with preemption disabled,
- * mostly because of the FNSAVE case, because in that
- * case we must not allow preemption in the window
- * between the FNSAVE and us marking the context lazy.
- *
- * It shouldn't be an issue as even FNSAVE is plenty
- * fast in terms of critical section length.
+ * ( The function 'fails' in the FNSAVE case, which destroys
+ * register contents so we have to copy them back. )
*/
- preempt_disable();
if (!copy_fpregs_to_fpstate(dst_fpu)) {
- memcpy(&src_fpu->state, &dst_fpu->state,
- fpu_kernel_xstate_size);
-
+ memcpy(&src_fpu->state, &dst_fpu->state, fpu_kernel_xstate_size);
copy_kernel_to_fpregs(&src_fpu->state);
}
- preempt_enable();
trace_x86_fpu_copy_src(src_fpu);
trace_x86_fpu_copy_dst(dst_fpu);
@@ -237,45 +224,48 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
* Activate the current task's in-memory FPU context,
* if it has not been used before:
*/
-void fpu__activate_curr(struct fpu *fpu)
+void fpu__initialize(struct fpu *fpu)
{
WARN_ON_FPU(fpu != &current->thread.fpu);
- if (!fpu->fpstate_active) {
+ if (!fpu->initialized) {
fpstate_init(&fpu->state);
trace_x86_fpu_init_state(fpu);
trace_x86_fpu_activate_state(fpu);
/* Safe to do for the current task: */
- fpu->fpstate_active = 1;
+ fpu->initialized = 1;
}
}
-EXPORT_SYMBOL_GPL(fpu__activate_curr);
+EXPORT_SYMBOL_GPL(fpu__initialize);
/*
* This function must be called before we read a task's fpstate.
*
- * If the task has not used the FPU before then initialize its
- * fpstate.
+ * There's two cases where this gets called:
+ *
+ * - for the current task (when coredumping), in which case we have
+ * to save the latest FPU registers into the fpstate,
+ *
+ * - or it's called for stopped tasks (ptrace), in which case the
+ * registers were already saved by the context-switch code when
+ * the task scheduled out - we only have to initialize the registers
+ * if they've never been initialized.
*
* If the task has used the FPU before then save it.
*/
-void fpu__activate_fpstate_read(struct fpu *fpu)
+void fpu__prepare_read(struct fpu *fpu)
{
- /*
- * If fpregs are active (in the current CPU), then
- * copy them to the fpstate:
- */
- if (fpu->fpregs_active) {
+ if (fpu == &current->thread.fpu) {
fpu__save(fpu);
} else {
- if (!fpu->fpstate_active) {
+ if (!fpu->initialized) {
fpstate_init(&fpu->state);
trace_x86_fpu_init_state(fpu);
trace_x86_fpu_activate_state(fpu);
/* Safe to do for current and for stopped child tasks: */
- fpu->fpstate_active = 1;
+ fpu->initialized = 1;
}
}
}
@@ -283,17 +273,17 @@ void fpu__activate_fpstate_read(struct fpu *fpu)
/*
* This function must be called before we write a task's fpstate.
*
- * If the task has used the FPU before then unlazy it.
+ * If the task has used the FPU before then invalidate any cached FPU registers.
* If the task has not used the FPU before then initialize its fpstate.
*
* After this function call, after registers in the fpstate are
* modified and the child task has woken up, the child task will
* restore the modified FPU state from the modified context. If we
- * didn't clear its lazy status here then the lazy in-registers
+ * didn't clear its cached status here then the cached in-registers
* state pending on its former CPU could be restored, corrupting
* the modifications.
*/
-void fpu__activate_fpstate_write(struct fpu *fpu)
+void fpu__prepare_write(struct fpu *fpu)
{
/*
* Only stopped child tasks can be used to modify the FPU
@@ -301,8 +291,8 @@ void fpu__activate_fpstate_write(struct fpu *fpu)
*/
WARN_ON_FPU(fpu == &current->thread.fpu);
- if (fpu->fpstate_active) {
- /* Invalidate any lazy state: */
+ if (fpu->initialized) {
+ /* Invalidate any cached state: */
__fpu_invalidate_fpregs_state(fpu);
} else {
fpstate_init(&fpu->state);
@@ -310,74 +300,11 @@ void fpu__activate_fpstate_write(struct fpu *fpu)
trace_x86_fpu_activate_state(fpu);
/* Safe to do for stopped child tasks: */
- fpu->fpstate_active = 1;
+ fpu->initialized = 1;
}
}
/*
- * This function must be called before we write the current
- * task's fpstate.
- *
- * This call gets the current FPU register state and moves
- * it in to the 'fpstate'. Preemption is disabled so that
- * no writes to the 'fpstate' can occur from context
- * swiches.
- *
- * Must be followed by a fpu__current_fpstate_write_end().
- */
-void fpu__current_fpstate_write_begin(void)
-{
- struct fpu *fpu = &current->thread.fpu;
-
- /*
- * Ensure that the context-switching code does not write
- * over the fpstate while we are doing our update.
- */
- preempt_disable();
-
- /*
- * Move the fpregs in to the fpu's 'fpstate'.
- */
- fpu__activate_fpstate_read(fpu);
-
- /*
- * The caller is about to write to 'fpu'. Ensure that no
- * CPU thinks that its fpregs match the fpstate. This
- * ensures we will not be lazy and skip a XRSTOR in the
- * future.
- */
- __fpu_invalidate_fpregs_state(fpu);
-}
-
-/*
- * This function must be paired with fpu__current_fpstate_write_begin()
- *
- * This will ensure that the modified fpstate gets placed back in
- * the fpregs if necessary.
- *
- * Note: This function may be called whether or not an _actual_
- * write to the fpstate occurred.
- */
-void fpu__current_fpstate_write_end(void)
-{
- struct fpu *fpu = &current->thread.fpu;
-
- /*
- * 'fpu' now has an updated copy of the state, but the
- * registers may still be out of date. Update them with
- * an XRSTOR if they are active.
- */
- if (fpregs_active())
- copy_kernel_to_fpregs(&fpu->state);
-
- /*
- * Our update is done and the fpregs/fpstate are in sync
- * if necessary. Context switches can happen again.
- */
- preempt_enable();
-}
-
-/*
* 'fpu__restore()' is called to copy FPU registers from
* the FPU fpstate to the live hw registers and to activate
* access to the hardware registers, so that FPU instructions
@@ -389,7 +316,7 @@ void fpu__current_fpstate_write_end(void)
*/
void fpu__restore(struct fpu *fpu)
{
- fpu__activate_curr(fpu);
+ fpu__initialize(fpu);
/* Avoid __kernel_fpu_begin() right after fpregs_activate() */
kernel_fpu_disable();
@@ -414,15 +341,17 @@ void fpu__drop(struct fpu *fpu)
{
preempt_disable();
- if (fpu->fpregs_active) {
- /* Ignore delayed exceptions from user space */
- asm volatile("1: fwait\n"
- "2:\n"
- _ASM_EXTABLE(1b, 2b));
- fpregs_deactivate(fpu);
+ if (fpu == &current->thread.fpu) {
+ if (fpu->initialized) {
+ /* Ignore delayed exceptions from user space */
+ asm volatile("1: fwait\n"
+ "2:\n"
+ _ASM_EXTABLE(1b, 2b));
+ fpregs_deactivate(fpu);
+ }
}
- fpu->fpstate_active = 0;
+ fpu->initialized = 0;
trace_x86_fpu_dropped(fpu);
@@ -462,9 +391,11 @@ void fpu__clear(struct fpu *fpu)
* Make sure fpstate is cleared and initialized.
*/
if (static_cpu_has(X86_FEATURE_FPU)) {
- fpu__activate_curr(fpu);
+ preempt_disable();
+ fpu__initialize(fpu);
user_fpu_begin();
copy_init_fpstate_to_fpregs();
+ preempt_enable();
}
}
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index d5d44c452624..7affb7e3d9a5 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -240,7 +240,7 @@ static void __init fpu__init_system_ctx_switch(void)
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
- WARN_ON_FPU(current->thread.fpu.fpstate_active);
+ WARN_ON_FPU(current->thread.fpu.initialized);
}
/*
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index b188b16841e3..3ea151372389 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -16,14 +16,14 @@ int regset_fpregs_active(struct task_struct *target, const struct user_regset *r
{
struct fpu *target_fpu = &target->thread.fpu;
- return target_fpu->fpstate_active ? regset->n : 0;
+ return target_fpu->initialized ? regset->n : 0;
}
int regset_xregset_fpregs_active(struct task_struct *target, const struct user_regset *regset)
{
struct fpu *target_fpu = &target->thread.fpu;
- if (boot_cpu_has(X86_FEATURE_FXSR) && target_fpu->fpstate_active)
+ if (boot_cpu_has(X86_FEATURE_FXSR) && target_fpu->initialized)
return regset->n;
else
return 0;
@@ -38,7 +38,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
if (!boot_cpu_has(X86_FEATURE_FXSR))
return -ENODEV;
- fpu__activate_fpstate_read(fpu);
+ fpu__prepare_read(fpu);
fpstate_sanitize_xstate(fpu);
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
@@ -55,7 +55,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
if (!boot_cpu_has(X86_FEATURE_FXSR))
return -ENODEV;
- fpu__activate_fpstate_write(fpu);
+ fpu__prepare_write(fpu);
fpstate_sanitize_xstate(fpu);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
@@ -89,10 +89,13 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
xsave = &fpu->state.xsave;
- fpu__activate_fpstate_read(fpu);
+ fpu__prepare_read(fpu);
if (using_compacted_format()) {
- ret = copyout_from_xsaves(pos, count, kbuf, ubuf, xsave);
+ if (kbuf)
+ ret = copy_xstate_to_kernel(kbuf, xsave, pos, count);
+ else
+ ret = copy_xstate_to_user(ubuf, xsave, pos, count);
} else {
fpstate_sanitize_xstate(fpu);
/*
@@ -129,28 +132,29 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
xsave = &fpu->state.xsave;
- fpu__activate_fpstate_write(fpu);
+ fpu__prepare_write(fpu);
- if (boot_cpu_has(X86_FEATURE_XSAVES))
- ret = copyin_to_xsaves(kbuf, ubuf, xsave);
- else
+ if (using_compacted_format()) {
+ if (kbuf)
+ ret = copy_kernel_to_xstate(xsave, kbuf);
+ else
+ ret = copy_user_to_xstate(xsave, ubuf);
+ } else {
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
-
- /*
- * In case of failure, mark all states as init:
- */
- if (ret)
- fpstate_init(&fpu->state);
+ if (!ret)
+ ret = validate_xstate_header(&xsave->header);
+ }
/*
* mxcsr reserved bits must be masked to zero for security reasons.
*/
xsave->i387.mxcsr &= mxcsr_feature_mask;
- xsave->header.xfeatures &= xfeatures_mask;
+
/*
- * These bits must be zero.
+ * In case of failure, mark all states as init:
*/
- memset(&xsave->header.reserved, 0, 48);
+ if (ret)
+ fpstate_init(&fpu->state);
return ret;
}
@@ -299,7 +303,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
struct fpu *fpu = &target->thread.fpu;
struct user_i387_ia32_struct env;
- fpu__activate_fpstate_read(fpu);
+ fpu__prepare_read(fpu);
if (!boot_cpu_has(X86_FEATURE_FPU))
return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
@@ -329,7 +333,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
struct user_i387_ia32_struct env;
int ret;
- fpu__activate_fpstate_write(fpu);
+ fpu__prepare_write(fpu);
fpstate_sanitize_xstate(fpu);
if (!boot_cpu_has(X86_FEATURE_FPU))
@@ -369,7 +373,7 @@ int dump_fpu(struct pt_regs *regs, struct user_i387_struct *ufpu)
struct fpu *fpu = &tsk->thread.fpu;
int fpvalid;
- fpvalid = fpu->fpstate_active;
+ fpvalid = fpu->initialized;
if (fpvalid)
fpvalid = !fpregs_get(tsk, NULL,
0, sizeof(struct user_i387_ia32_struct),
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 83c23c230b4c..fb639e70048f 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -155,7 +155,8 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
*/
int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
{
- struct xregs_state *xsave = &current->thread.fpu.state.xsave;
+ struct fpu *fpu = &current->thread.fpu;
+ struct xregs_state *xsave = &fpu->state.xsave;
struct task_struct *tsk = current;
int ia32_fxstate = (buf != buf_fx);
@@ -170,13 +171,13 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
sizeof(struct user_i387_ia32_struct), NULL,
(struct _fpstate_32 __user *) buf) ? -1 : 1;
- if (fpregs_active() || using_compacted_format()) {
+ if (fpu->initialized || using_compacted_format()) {
/* Save the live register state to the user directly. */
if (copy_fpregs_to_sigframe(buf_fx))
return -1;
/* Update the thread's fxstate to save the fsave header. */
if (ia32_fxstate)
- copy_fxregs_to_kernel(&tsk->thread.fpu);
+ copy_fxregs_to_kernel(fpu);
} else {
/*
* It is a *bug* if kernel uses compacted-format for xsave
@@ -189,7 +190,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
return -1;
}
- fpstate_sanitize_xstate(&tsk->thread.fpu);
+ fpstate_sanitize_xstate(fpu);
if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size))
return -1;
}
@@ -213,8 +214,11 @@ sanitize_restored_xstate(struct task_struct *tsk,
struct xstate_header *header = &xsave->header;
if (use_xsave()) {
- /* These bits must be zero. */
- memset(header->reserved, 0, 48);
+ /*
+ * Note: we don't need to zero the reserved bits in the
+ * xstate_header here because we either didn't copy them at all,
+ * or we checked earlier that they aren't set.
+ */
/*
* Init the state that is not present in the memory
@@ -223,7 +227,7 @@ sanitize_restored_xstate(struct task_struct *tsk,
if (fx_only)
header->xfeatures = XFEATURE_MASK_FPSSE;
else
- header->xfeatures &= (xfeatures_mask & xfeatures);
+ header->xfeatures &= xfeatures;
}
if (use_fxsr()) {
@@ -279,7 +283,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
if (!access_ok(VERIFY_READ, buf, size))
return -EACCES;
- fpu__activate_curr(fpu);
+ fpu__initialize(fpu);
if (!static_cpu_has(X86_FEATURE_FPU))
return fpregs_soft_set(current, NULL,
@@ -307,28 +311,29 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
/*
* 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.
+ * header. Validate and sanitize the copied state.
*/
struct fpu *fpu = &tsk->thread.fpu;
struct user_i387_ia32_struct env;
int err = 0;
/*
- * Drop the current fpu which clears fpu->fpstate_active. This ensures
+ * Drop the current fpu which clears fpu->initialized. 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
- * fpu->fpstate_active is again set.
+ * fpu->initialized is again set.
*/
fpu__drop(fpu);
if (using_compacted_format()) {
- err = copyin_to_xsaves(NULL, buf_fx,
- &fpu->state.xsave);
+ err = copy_user_to_xstate(&fpu->state.xsave, buf_fx);
} else {
- err = __copy_from_user(&fpu->state.xsave,
- buf_fx, state_size);
+ err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size);
+
+ if (!err && state_size > offsetof(struct xregs_state, header))
+ err = validate_xstate_header(&fpu->state.xsave.header);
}
if (err || __copy_from_user(&env, buf, sizeof(env))) {
@@ -339,7 +344,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
}
- fpu->fpstate_active = 1;
+ fpu->initialized = 1;
preempt_disable();
fpu__restore(fpu);
preempt_enable();
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index c24ac1efb12d..f1d5476c9022 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -483,6 +483,30 @@ int using_compacted_format(void)
return boot_cpu_has(X86_FEATURE_XSAVES);
}
+/* Validate an xstate header supplied by userspace (ptrace or sigreturn) */
+int validate_xstate_header(const struct xstate_header *hdr)
+{
+ /* No unknown or supervisor features may be set */
+ if (hdr->xfeatures & (~xfeatures_mask | XFEATURE_MASK_SUPERVISOR))
+ return -EINVAL;
+
+ /* Userspace must use the uncompacted format */
+ if (hdr->xcomp_bv)
+ return -EINVAL;
+
+ /*
+ * If 'reserved' is shrunken to add a new field, make sure to validate
+ * that new field here!
+ */
+ BUILD_BUG_ON(sizeof(hdr->reserved) != 48);
+
+ /* No reserved bits may be set */
+ if (memchr_inv(hdr->reserved, 0, sizeof(hdr->reserved)))
+ return -EINVAL;
+
+ return 0;
+}
+
static void __xstate_dump_leaves(void)
{
int i;
@@ -867,7 +891,7 @@ const void *get_xsave_field_ptr(int xsave_state)
{
struct fpu *fpu = &current->thread.fpu;
- if (!fpu->fpstate_active)
+ if (!fpu->initialized)
return NULL;
/*
* fpu__save() takes the CPU's xstate registers
@@ -921,38 +945,129 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
#endif /* ! CONFIG_ARCH_HAS_PKEYS */
/*
+ * Weird legacy quirk: SSE and YMM states store information in the
+ * MXCSR and MXCSR_FLAGS fields of the FP area. That means if the FP
+ * area is marked as unused in the xfeatures header, we need to copy
+ * MXCSR and MXCSR_FLAGS if either SSE or YMM are in use.
+ */
+static inline bool xfeatures_mxcsr_quirk(u64 xfeatures)
+{
+ if (!(xfeatures & (XFEATURE_MASK_SSE|XFEATURE_MASK_YMM)))
+ return false;
+
+ if (xfeatures & XFEATURE_MASK_FP)
+ return false;
+
+ return true;
+}
+
+/*
* This is similar to user_regset_copyout(), but will not add offset to
* the source data pointer or increment pos, count, kbuf, and ubuf.
*/
-static inline int xstate_copyout(unsigned int pos, unsigned int count,
- void *kbuf, void __user *ubuf,
- const void *data, const int start_pos,
- const int end_pos)
+static inline void
+__copy_xstate_to_kernel(void *kbuf, const void *data,
+ unsigned int offset, unsigned int size, unsigned int size_total)
{
- if ((count == 0) || (pos < start_pos))
- return 0;
+ if (offset < size_total) {
+ unsigned int copy = min(size, size_total - offset);
- if (end_pos < 0 || pos < end_pos) {
- unsigned int copy = (end_pos < 0 ? count : min(count, end_pos - pos));
+ memcpy(kbuf + offset, data, copy);
+ }
+}
- if (kbuf) {
- memcpy(kbuf + pos, data, copy);
- } else {
- if (__copy_to_user(ubuf + pos, data, copy))
- return -EFAULT;
+/*
+ * Convert from kernel XSAVES compacted format to standard format and copy
+ * to a kernel-space ptrace buffer.
+ *
+ * It supports partial copy but pos always starts from zero. This is called
+ * from xstateregs_get() and there we check the CPU has XSAVES.
+ */
+int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total)
+{
+ unsigned int offset, size;
+ struct xstate_header header;
+ int i;
+
+ /*
+ * Currently copy_regset_to_user() starts from pos 0:
+ */
+ if (unlikely(offset_start != 0))
+ return -EFAULT;
+
+ /*
+ * The destination is a ptrace buffer; we put in only user xstates:
+ */
+ memset(&header, 0, sizeof(header));
+ header.xfeatures = xsave->header.xfeatures;
+ header.xfeatures &= ~XFEATURE_MASK_SUPERVISOR;
+
+ /*
+ * Copy xregs_state->header:
+ */
+ offset = offsetof(struct xregs_state, header);
+ size = sizeof(header);
+
+ __copy_xstate_to_kernel(kbuf, &header, offset, size, size_total);
+
+ for (i = 0; i < XFEATURE_MAX; i++) {
+ /*
+ * Copy only in-use xstates:
+ */
+ if ((header.xfeatures >> i) & 1) {
+ void *src = __raw_xsave_addr(xsave, 1 << i);
+
+ offset = xstate_offsets[i];
+ size = xstate_sizes[i];
+
+ /* The next component has to fit fully into the output buffer: */
+ if (offset + size > size_total)
+ break;
+
+ __copy_xstate_to_kernel(kbuf, src, offset, size, size_total);
}
+
+ }
+
+ if (xfeatures_mxcsr_quirk(header.xfeatures)) {
+ offset = offsetof(struct fxregs_state, mxcsr);
+ size = MXCSR_AND_FLAGS_SIZE;
+ __copy_xstate_to_kernel(kbuf, &xsave->i387.mxcsr, offset, size, size_total);
+ }
+
+ /*
+ * Fill xsave->i387.sw_reserved value for ptrace frame:
+ */
+ offset = offsetof(struct fxregs_state, sw_reserved);
+ size = sizeof(xstate_fx_sw_bytes);
+
+ __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, size_total);
+
+ return 0;
+}
+
+static inline int
+__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int offset, unsigned int size, unsigned int size_total)
+{
+ if (!size)
+ return 0;
+
+ if (offset < size_total) {
+ unsigned int copy = min(size, size_total - offset);
+
+ if (__copy_to_user(ubuf + offset, data, copy))
+ return -EFAULT;
}
return 0;
}
/*
* Convert from kernel XSAVES compacted format to standard format and copy
- * to a ptrace buffer. It supports partial copy but pos always starts from
+ * to a user-space buffer. It supports partial copy but pos always starts from
* zero. This is called from xstateregs_get() and there we check the CPU
* has XSAVES.
*/
-int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
- void __user *ubuf, struct xregs_state *xsave)
+int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total)
{
unsigned int offset, size;
int ret, i;
@@ -961,7 +1076,7 @@ int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
/*
* Currently copy_regset_to_user() starts from pos 0:
*/
- if (unlikely(pos != 0))
+ if (unlikely(offset_start != 0))
return -EFAULT;
/*
@@ -977,8 +1092,7 @@ int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
offset = offsetof(struct xregs_state, header);
size = sizeof(header);
- ret = xstate_copyout(offset, size, kbuf, ubuf, &header, 0, count);
-
+ ret = __copy_xstate_to_user(ubuf, &header, offset, size, size_total);
if (ret)
return ret;
@@ -992,25 +1106,30 @@ int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
offset = xstate_offsets[i];
size = xstate_sizes[i];
- ret = xstate_copyout(offset, size, kbuf, ubuf, src, 0, count);
+ /* The next component has to fit fully into the output buffer: */
+ if (offset + size > size_total)
+ break;
+ ret = __copy_xstate_to_user(ubuf, src, offset, size, size_total);
if (ret)
return ret;
-
- if (offset + size >= count)
- break;
}
}
+ if (xfeatures_mxcsr_quirk(header.xfeatures)) {
+ offset = offsetof(struct fxregs_state, mxcsr);
+ size = MXCSR_AND_FLAGS_SIZE;
+ __copy_xstate_to_user(ubuf, &xsave->i387.mxcsr, offset, size, size_total);
+ }
+
/*
* Fill xsave->i387.sw_reserved value for ptrace frame:
*/
offset = offsetof(struct fxregs_state, sw_reserved);
size = sizeof(xstate_fx_sw_bytes);
- ret = xstate_copyout(offset, size, kbuf, ubuf, xstate_fx_sw_bytes, 0, count);
-
+ ret = __copy_xstate_to_user(ubuf, xstate_fx_sw_bytes, offset, size, size_total);
if (ret)
return ret;
@@ -1018,55 +1137,98 @@ int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
}
/*
- * Convert from a ptrace standard-format buffer to kernel XSAVES format
- * and copy to the target thread. This is called from xstateregs_set() and
- * there we check the CPU has XSAVES and a whole standard-sized buffer
- * exists.
+ * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format
+ * and copy to the target thread. This is called from xstateregs_set().
*/
-int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
- struct xregs_state *xsave)
+int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
{
unsigned int offset, size;
int i;
- u64 xfeatures;
- u64 allowed_features;
+ struct xstate_header hdr;
offset = offsetof(struct xregs_state, header);
- size = sizeof(xfeatures);
+ size = sizeof(hdr);
- if (kbuf) {
- memcpy(&xfeatures, kbuf + offset, size);
- } else {
- if (__copy_from_user(&xfeatures, ubuf + offset, size))
- return -EFAULT;
+ memcpy(&hdr, kbuf + offset, size);
+
+ if (validate_xstate_header(&hdr))
+ return -EINVAL;
+
+ for (i = 0; i < XFEATURE_MAX; i++) {
+ u64 mask = ((u64)1 << i);
+
+ if (hdr.xfeatures & mask) {
+ void *dst = __raw_xsave_addr(xsave, 1 << i);
+
+ offset = xstate_offsets[i];
+ size = xstate_sizes[i];
+
+ memcpy(dst, kbuf + offset, size);
+ }
+ }
+
+ if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
+ offset = offsetof(struct fxregs_state, mxcsr);
+ size = MXCSR_AND_FLAGS_SIZE;
+ memcpy(&xsave->i387.mxcsr, kbuf + offset, size);
}
/*
- * Reject if the user sets any disabled or supervisor features:
+ * The state that came in from userspace was user-state only.
+ * Mask all the user states out of 'xfeatures':
+ */
+ xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;
+
+ /*
+ * Add back in the features that came in from userspace:
*/
- allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;
+ xsave->header.xfeatures |= hdr.xfeatures;
- if (xfeatures & ~allowed_features)
+ return 0;
+}
+
+/*
+ * Convert from a ptrace or sigreturn standard-format user-space buffer to
+ * kernel XSAVES format and copy to the target thread. This is called from
+ * xstateregs_set(), as well as potentially from the sigreturn() and
+ * rt_sigreturn() system calls.
+ */
+int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf)
+{
+ unsigned int offset, size;
+ int i;
+ struct xstate_header hdr;
+
+ offset = offsetof(struct xregs_state, header);
+ size = sizeof(hdr);
+
+ if (__copy_from_user(&hdr, ubuf + offset, size))
+ return -EFAULT;
+
+ if (validate_xstate_header(&hdr))
return -EINVAL;
for (i = 0; i < XFEATURE_MAX; i++) {
u64 mask = ((u64)1 << i);
- if (xfeatures & mask) {
+ if (hdr.xfeatures & mask) {
void *dst = __raw_xsave_addr(xsave, 1 << i);
offset = xstate_offsets[i];
size = xstate_sizes[i];
- if (kbuf) {
- memcpy(dst, kbuf + offset, size);
- } else {
- if (__copy_from_user(dst, ubuf + offset, size))
- return -EFAULT;
- }
+ if (__copy_from_user(dst, ubuf + offset, size))
+ return -EFAULT;
}
}
+ if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
+ offset = offsetof(struct fxregs_state, mxcsr);
+ size = MXCSR_AND_FLAGS_SIZE;
+ if (__copy_from_user(&xsave->i387.mxcsr, ubuf + offset, size))
+ return -EFAULT;
+ }
+
/*
* The state that came in from userspace was user-state only.
* Mask all the user states out of 'xfeatures':
@@ -1076,7 +1238,7 @@ int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
/*
* Add back in the features that came in from userspace:
*/
- xsave->header.xfeatures |= xfeatures;
+ xsave->header.xfeatures |= hdr.xfeatures;
return 0;
}
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index e04442345fc0..4e188fda5961 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -263,7 +263,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
sp = (unsigned long) ka->sa.sa_restorer;
}
- if (fpu->fpstate_active) {
+ if (fpu->initialized) {
sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
&buf_fx, &math_size);
*fpstate = (void __user *)sp;
@@ -279,7 +279,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
return (void __user *)-1L;
/* save i387 and extended state */
- if (fpu->fpstate_active &&
+ if (fpu->initialized &&
copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
return (void __user *)-1L;
@@ -755,7 +755,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
/*
* Ensure the signal handler starts with the new fpu state.
*/
- if (fpu->fpstate_active)
+ if (fpu->initialized)
fpu__clear(fpu);
}
signal_setup_done(failed, ksig, stepping);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cd17b7d9a107..03869eb7fcd6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7225,7 +7225,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
int r;
sigset_t sigsaved;
- fpu__activate_curr(fpu);
+ fpu__initialize(fpu);
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index d4a7df2205b8..220638a4cb94 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -114,7 +114,7 @@ void math_emulate(struct math_emu_info *info)
struct desc_struct code_descriptor;
struct fpu *fpu = &current->thread.fpu;
- fpu__activate_curr(fpu);
+ fpu__initialize(fpu);
#ifdef RE_ENTRANT_CHECKING
if (emulating) {
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index c076f710de4c..c3521e2be396 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -2,6 +2,7 @@
#include <linux/uaccess.h>
#include <linux/sched/debug.h>
+#include <asm/fpu/internal.h>
#include <asm/traps.h>
#include <asm/kdebug.h>
@@ -78,6 +79,29 @@ bool ex_handler_refcount(const struct exception_table_entry *fixup,
}
EXPORT_SYMBOL_GPL(ex_handler_refcount);
+/*
+ * Handler for when we fail to restore a task's FPU state. We should never get
+ * here because the FPU state of a task using the FPU (task->thread.fpu.state)
+ * should always be valid. However, past bugs have allowed userspace to set
+ * reserved bits in the XSAVE area using PTRACE_SETREGSET or sys_rt_sigreturn().
+ * These caused XRSTOR to fail when switching to the task, leaking the FPU
+ * registers of the task previously executing on the CPU. Mitigate this class
+ * of vulnerability by restoring from the initial state (essentially, zeroing
+ * out all the FPU registers) if we can't restore from the task's FPU state.
+ */
+bool ex_handler_fprestore(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int trapnr)
+{
+ regs->ip = ex_fixup_addr(fixup);
+
+ WARN_ONCE(1, "Bad FPU state detected at %pB, reinitializing FPU registers.",
+ (void *)instruction_pointer(regs));
+
+ __copy_kernel_to_fpregs(&init_fpstate, -1);
+ return true;
+}
+EXPORT_SYMBOL_GPL(ex_handler_fprestore);
+
bool ex_handler_ext(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 2dab69a706ec..d7bc0eea20a5 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -18,7 +18,6 @@
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/mmu_context.h> /* vma_pkey() */
-#include <asm/fpu/internal.h> /* fpregs_active() */
int __execute_only_pkey(struct mm_struct *mm)
{
@@ -45,7 +44,7 @@ int __execute_only_pkey(struct mm_struct *mm)
*/
preempt_disable();
if (!need_to_set_mm_pkey &&
- fpregs_active() &&
+ current->thread.fpu.initialized &&
!__pkru_allows_read(read_pkru(), execute_only_pkey)) {
preempt_enable();
return execute_only_pkey;
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-27 01:52:49 +0300