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Subject[PATCH 194/208] x86/fpu: Factor out fpu/signal.c
Date
fpu/xstate.c has a lot of generic FPU signal frame handling routines,
move them into a separate file: fpu/signal.c.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/fpu/signal.h | 2 +
arch/x86/kernel/fpu/Makefile | 2 +-
arch/x86/kernel/fpu/signal.c | 404 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/fpu/xstate.c | 394 +-------------------------------------------------------
4 files changed, 409 insertions(+), 393 deletions(-)

diff --git a/arch/x86/include/asm/fpu/signal.h b/arch/x86/include/asm/fpu/signal.h
index 0803dc2aba80..7358e9d61f1e 100644
--- a/arch/x86/include/asm/fpu/signal.h
+++ b/arch/x86/include/asm/fpu/signal.h
@@ -28,4 +28,6 @@ unsigned long
fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
unsigned long *buf_fx, unsigned long *size);

+extern void fpu__init_prepare_fx_sw_frame(void);
+
#endif /* _ASM_X86_FPU_SIGNAL_H */
diff --git a/arch/x86/kernel/fpu/Makefile b/arch/x86/kernel/fpu/Makefile
index 6ae59bccdd2f..5c697ded57f2 100644
--- a/arch/x86/kernel/fpu/Makefile
+++ b/arch/x86/kernel/fpu/Makefile
@@ -2,4 +2,4 @@
# Build rules for the FPU support code:
#

-obj-y += init.o bugs.o core.o xstate.o
+obj-y += init.o bugs.o core.o signal.o xstate.o
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
new file mode 100644
index 000000000000..8d0c26ab5123
--- /dev/null
+++ b/arch/x86/kernel/fpu/signal.c
@@ -0,0 +1,404 @@
+/*
+ * FPU signal frame handling routines.
+ */
+
+#include <linux/compat.h>
+#include <linux/cpu.h>
+
+#include <asm/fpu/internal.h>
+#include <asm/fpu/signal.h>
+#include <asm/fpu/regset.h>
+
+#include <asm/sigframe.h>
+
+static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
+
+/*
+ * Check for the presence of extended state information in the
+ * user fpstate pointer in the sigcontext.
+ */
+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 xstate_header);
+ unsigned int magic2;
+
+ if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
+ return -1;
+
+ /* 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 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 (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
+ || magic2 != FP_XSTATE_MAGIC2)
+ return -1;
+
+ return 0;
+}
+
+/*
+ * Signal frame handlers.
+ */
+static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
+{
+ if (use_fxsr()) {
+ struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
+ struct user_i387_ia32_struct env;
+ struct _fpstate_ia32 __user *fp = buf;
+
+ convert_from_fxsr(&env, tsk);
+
+ 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 {
+ struct i387_fsave_struct __user *fp = buf;
+ u32 swd;
+ if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
+ return -1;
+ }
+
+ return 0;
+}
+
+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 xfeatures;
+ int err;
+
+ /* 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));
+
+ if (!use_xsave())
+ return err;
+
+ err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
+
+ /*
+ * Read the xfeatures which we copied (directly from the cpu or
+ * from the state in task struct) to the user buffers.
+ */
+ err |= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
+
+ /*
+ * 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
+ * xfeatures in the xsave header.
+ *
+ * xsave aware apps can change the xfeatures in the xsave
+ * header as well as change any contents in the memory layout.
+ * xrestore as part of sigreturn will capture all the changes.
+ */
+ xfeatures |= XSTATE_FPSSE;
+
+ err |= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
+
+ return err;
+}
+
+static inline int copy_fpregs_to_sigframe(struct xsave_struct __user *buf)
+{
+ int err;
+
+ if (use_xsave())
+ err = copy_xregs_to_user(buf);
+ else if (use_fxsr())
+ err = copy_fxregs_to_user((struct i387_fxsave_struct __user *) buf);
+ else
+ err = copy_fregs_to_user((struct i387_fsave_struct __user *) buf);
+
+ if (unlikely(err) && __clear_user(buf, xstate_size))
+ err = -EFAULT;
+ return err;
+}
+
+/*
+ * 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.
+ */
+int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
+{
+ struct xsave_struct *xsave = &current->thread.fpu.state.xsave;
+ struct task_struct *tsk = current;
+ int ia32_fxstate = (buf != buf_fx);
+
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
+
+ if (!access_ok(VERIFY_WRITE, buf, size))
+ return -EACCES;
+
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return fpregs_soft_get(current, NULL, 0,
+ sizeof(struct user_i387_ia32_struct), NULL,
+ (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
+
+ if (fpregs_active()) {
+ /* 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);
+ } else {
+ fpstate_sanitize_xstate(&tsk->thread.fpu);
+ 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;
+
+ return 0;
+}
+
+static inline void
+sanitize_restored_xstate(struct task_struct *tsk,
+ struct user_i387_ia32_struct *ia32_env,
+ u64 xfeatures, int fx_only)
+{
+ struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
+ struct xstate_header *header = &xsave->header;
+
+ if (use_xsave()) {
+ /* These bits must be zero. */
+ memset(header->reserved, 0, 48);
+
+ /*
+ * Init the state that is not present in the memory
+ * layout and not enabled by the OS.
+ */
+ if (fx_only)
+ header->xfeatures = XSTATE_FPSSE;
+ else
+ header->xfeatures &= (xfeatures_mask & xfeatures);
+ }
+
+ 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);
+ }
+}
+
+/*
+ * Restore the extended state if present. Otherwise, restore the FP/SSE state.
+ */
+static inline int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only)
+{
+ if (use_xsave()) {
+ if ((unsigned long)buf % 64 || fx_only) {
+ u64 init_bv = xfeatures_mask & ~XSTATE_FPSSE;
+ copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+ return copy_user_to_fxregs(buf);
+ } else {
+ u64 init_bv = xfeatures_mask & ~xbv;
+ if (unlikely(init_bv))
+ copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+ return copy_user_to_xregs(buf, xbv);
+ }
+ } else if (use_fxsr()) {
+ return copy_user_to_fxregs(buf);
+ } else
+ return copy_user_to_fregs(buf);
+}
+
+static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
+{
+ int ia32_fxstate = (buf != buf_fx);
+ struct task_struct *tsk = current;
+ struct fpu *fpu = &tsk->thread.fpu;
+ int state_size = xstate_size;
+ u64 xfeatures = 0;
+ int fx_only = 0;
+
+ ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
+ config_enabled(CONFIG_IA32_EMULATION));
+
+ if (!buf) {
+ fpu__clear(fpu);
+ return 0;
+ }
+
+ if (!access_ok(VERIFY_READ, buf, size))
+ return -EACCES;
+
+ fpu__activate_curr(fpu);
+
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return fpregs_soft_set(current, NULL,
+ 0, sizeof(struct user_i387_ia32_struct),
+ NULL, buf) != 0;
+
+ 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;
+ xfeatures = fx_sw_user.xfeatures;
+ }
+ }
+
+ 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 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
+ * 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__drop(fpu);
+
+ if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
+ __copy_from_user(&env, buf, sizeof(env))) {
+ fpstate_init(&fpu->state);
+ err = -1;
+ } else {
+ sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
+ }
+
+ fpu->fpstate_active = 1;
+ if (use_eager_fpu()) {
+ preempt_disable();
+ fpu__restore();
+ preempt_enable();
+ }
+
+ return err;
+ } else {
+ /*
+ * For 64-bit frames and 32-bit fsave frames, restore the user
+ * state to the registers directly (with exceptions handled).
+ */
+ user_fpu_begin();
+ if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
+ fpu__clear(fpu);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static inline int xstate_sigframe_size(void)
+{
+ return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
+}
+
+/*
+ * Restore FPU state from a sigframe:
+ */
+int fpu__restore_sig(void __user *buf, int ia32_frame)
+{
+ void __user *buf_fx = buf;
+ int size = xstate_sigframe_size();
+
+ if (ia32_frame && use_fxsr()) {
+ buf_fx = buf + sizeof(struct i387_fsave_struct);
+ size += sizeof(struct i387_fsave_struct);
+ }
+
+ return __fpu__restore_sig(buf, buf_fx, size);
+}
+
+unsigned long
+fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
+ unsigned long *buf_fx, unsigned long *size)
+{
+ unsigned long frame_size = xstate_sigframe_size();
+
+ *buf_fx = sp = round_down(sp - frame_size, 64);
+ if (ia32_frame && use_fxsr()) {
+ frame_size += sizeof(struct i387_fsave_struct);
+ sp -= sizeof(struct i387_fsave_struct);
+ }
+
+ *size = frame_size;
+
+ return sp;
+}
+/*
+ * Prepare the SW reserved portion of the fxsave memory layout, indicating
+ * the presence of the extended state information in the memory layout
+ * pointed by the fpstate pointer in the sigcontext.
+ * This will be saved when ever the FP and extended state context is
+ * saved on the user stack during the signal handler delivery to the user.
+ */
+void fpu__init_prepare_fx_sw_frame(void)
+{
+ int fsave_header_size = sizeof(struct i387_fsave_struct);
+ int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
+
+ if (config_enabled(CONFIG_X86_32))
+ size += fsave_header_size;
+
+ fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
+ fx_sw_reserved.extended_size = size;
+ fx_sw_reserved.xfeatures = xfeatures_mask;
+ fx_sw_reserved.xstate_size = xstate_size;
+
+ if (config_enabled(CONFIG_IA32_EMULATION)) {
+ fx_sw_reserved_ia32 = fx_sw_reserved;
+ fx_sw_reserved_ia32.extended_size += fsave_header_size;
+ }
+}
+
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 336b3dae59ca..3629e2ef3c94 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -10,7 +10,7 @@
#include <asm/fpu/internal.h>
#include <asm/fpu/signal.h>
#include <asm/fpu/regset.h>
-#include <asm/sigframe.h>
+
#include <asm/tlbflush.h>

static const char *xfeature_names[] =
@@ -31,7 +31,6 @@ static const char *xfeature_names[] =
*/
u64 xfeatures_mask __read_mostly;

-static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
static unsigned int xstate_offsets[XFEATURES_NR_MAX], xstate_sizes[XFEATURES_NR_MAX];
static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];

@@ -155,395 +154,6 @@ void fpstate_sanitize_xstate(struct fpu *fpu)
}

/*
- * Check for the presence of extended state information in the
- * user fpstate pointer in the sigcontext.
- */
-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 xstate_header);
- unsigned int magic2;
-
- if (__copy_from_user(fx_sw, &buf->sw_reserved[0], sizeof(*fx_sw)))
- return -1;
-
- /* 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 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 (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))
- || magic2 != FP_XSTATE_MAGIC2)
- return -1;
-
- return 0;
-}
-
-/*
- * Signal frame handlers.
- */
-static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
-{
- if (use_fxsr()) {
- struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
- struct user_i387_ia32_struct env;
- struct _fpstate_ia32 __user *fp = buf;
-
- convert_from_fxsr(&env, tsk);
-
- 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 {
- struct i387_fsave_struct __user *fp = buf;
- u32 swd;
- if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
- return -1;
- }
-
- return 0;
-}
-
-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 xfeatures;
- int err;
-
- /* 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));
-
- if (!use_xsave())
- return err;
-
- err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
-
- /*
- * Read the xfeatures which we copied (directly from the cpu or
- * from the state in task struct) to the user buffers.
- */
- err |= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
-
- /*
- * 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
- * xfeatures in the xsave header.
- *
- * xsave aware apps can change the xfeatures in the xsave
- * header as well as change any contents in the memory layout.
- * xrestore as part of sigreturn will capture all the changes.
- */
- xfeatures |= XSTATE_FPSSE;
-
- err |= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
-
- return err;
-}
-
-static inline int copy_fpregs_to_sigframe(struct xsave_struct __user *buf)
-{
- int err;
-
- if (use_xsave())
- err = copy_xregs_to_user(buf);
- else if (use_fxsr())
- err = copy_fxregs_to_user((struct i387_fxsave_struct __user *) buf);
- else
- err = copy_fregs_to_user((struct i387_fsave_struct __user *) buf);
-
- if (unlikely(err) && __clear_user(buf, xstate_size))
- err = -EFAULT;
- return err;
-}
-
-/*
- * 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.
- */
-int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
-{
- struct xsave_struct *xsave = &current->thread.fpu.state.xsave;
- struct task_struct *tsk = current;
- int ia32_fxstate = (buf != buf_fx);
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!access_ok(VERIFY_WRITE, buf, size))
- return -EACCES;
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_get(current, NULL, 0,
- sizeof(struct user_i387_ia32_struct), NULL,
- (struct _fpstate_ia32 __user *) buf) ? -1 : 1;
-
- if (fpregs_active()) {
- /* 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);
- } else {
- fpstate_sanitize_xstate(&tsk->thread.fpu);
- 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;
-
- return 0;
-}
-
-static inline void
-sanitize_restored_xstate(struct task_struct *tsk,
- struct user_i387_ia32_struct *ia32_env,
- u64 xfeatures, int fx_only)
-{
- struct xsave_struct *xsave = &tsk->thread.fpu.state.xsave;
- struct xstate_header *header = &xsave->header;
-
- if (use_xsave()) {
- /* These bits must be zero. */
- memset(header->reserved, 0, 48);
-
- /*
- * Init the state that is not present in the memory
- * layout and not enabled by the OS.
- */
- if (fx_only)
- header->xfeatures = XSTATE_FPSSE;
- else
- header->xfeatures &= (xfeatures_mask & xfeatures);
- }
-
- 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);
- }
-}
-
-/*
- * Restore the extended state if present. Otherwise, restore the FP/SSE state.
- */
-static inline int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only)
-{
- if (use_xsave()) {
- if ((unsigned long)buf % 64 || fx_only) {
- u64 init_bv = xfeatures_mask & ~XSTATE_FPSSE;
- copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
- return copy_user_to_fxregs(buf);
- } else {
- u64 init_bv = xfeatures_mask & ~xbv;
- if (unlikely(init_bv))
- copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
- return copy_user_to_xregs(buf, xbv);
- }
- } else if (use_fxsr()) {
- return copy_user_to_fxregs(buf);
- } else
- return copy_user_to_fregs(buf);
-}
-
-static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
-{
- int ia32_fxstate = (buf != buf_fx);
- struct task_struct *tsk = current;
- struct fpu *fpu = &tsk->thread.fpu;
- int state_size = xstate_size;
- u64 xfeatures = 0;
- int fx_only = 0;
-
- ia32_fxstate &= (config_enabled(CONFIG_X86_32) ||
- config_enabled(CONFIG_IA32_EMULATION));
-
- if (!buf) {
- fpu__clear(fpu);
- return 0;
- }
-
- if (!access_ok(VERIFY_READ, buf, size))
- return -EACCES;
-
- fpu__activate_curr(fpu);
-
- if (!static_cpu_has(X86_FEATURE_FPU))
- return fpregs_soft_set(current, NULL,
- 0, sizeof(struct user_i387_ia32_struct),
- NULL, buf) != 0;
-
- 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;
- xfeatures = fx_sw_user.xfeatures;
- }
- }
-
- 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 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
- * 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__drop(fpu);
-
- if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
- __copy_from_user(&env, buf, sizeof(env))) {
- fpstate_init(&fpu->state);
- err = -1;
- } else {
- sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
- }
-
- fpu->fpstate_active = 1;
- if (use_eager_fpu()) {
- preempt_disable();
- fpu__restore();
- preempt_enable();
- }
-
- return err;
- } else {
- /*
- * For 64-bit frames and 32-bit fsave frames, restore the user
- * state to the registers directly (with exceptions handled).
- */
- user_fpu_begin();
- if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
- fpu__clear(fpu);
- return -1;
- }
- }
-
- return 0;
-}
-
-static inline int xstate_sigframe_size(void)
-{
- return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
-}
-
-/*
- * Restore FPU state from a sigframe:
- */
-int fpu__restore_sig(void __user *buf, int ia32_frame)
-{
- void __user *buf_fx = buf;
- int size = xstate_sigframe_size();
-
- if (ia32_frame && use_fxsr()) {
- buf_fx = buf + sizeof(struct i387_fsave_struct);
- size += sizeof(struct i387_fsave_struct);
- }
-
- return __fpu__restore_sig(buf, buf_fx, size);
-}
-
-unsigned long
-fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
- unsigned long *buf_fx, unsigned long *size)
-{
- unsigned long frame_size = xstate_sigframe_size();
-
- *buf_fx = sp = round_down(sp - frame_size, 64);
- if (ia32_frame && use_fxsr()) {
- frame_size += sizeof(struct i387_fsave_struct);
- sp -= sizeof(struct i387_fsave_struct);
- }
-
- *size = frame_size;
-
- return sp;
-}
-/*
- * Prepare the SW reserved portion of the fxsave memory layout, indicating
- * the presence of the extended state information in the memory layout
- * pointed by the fpstate pointer in the sigcontext.
- * This will be saved when ever the FP and extended state context is
- * saved on the user stack during the signal handler delivery to the user.
- */
-static void prepare_fx_sw_frame(void)
-{
- int fsave_header_size = sizeof(struct i387_fsave_struct);
- int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
-
- if (config_enabled(CONFIG_X86_32))
- size += fsave_header_size;
-
- fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
- fx_sw_reserved.extended_size = size;
- fx_sw_reserved.xfeatures = xfeatures_mask;
- fx_sw_reserved.xstate_size = xstate_size;
-
- 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.
* Called once per CPU onlining.
*/
@@ -741,7 +351,7 @@ void fpu__init_system_xstate(void)
init_xstate_size();

update_regset_xstate_info(xstate_size, xfeatures_mask);
- prepare_fx_sw_frame();
+ fpu__init_prepare_fx_sw_frame();
setup_init_fpu_buf();

pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is 0x%x bytes, using '%s' format.\n",
--
2.1.0


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