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-rw-r--r--arch/x86/kernel/Makefile2
-rw-r--r--arch/x86/kernel/cpu/common.c13
-rw-r--r--arch/x86/kernel/i387.c154
-rw-r--r--arch/x86/kernel/sigframe.h14
-rw-r--r--arch/x86/kernel/signal_32.c45
-rw-r--r--arch/x86/kernel/signal_64.c95
-rw-r--r--arch/x86/kernel/traps_32.c1
-rw-r--r--arch/x86/kernel/traps_64.c6
-rw-r--r--arch/x86/kernel/xsave.c316
9 files changed, 507 insertions, 139 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index dac24c4390d..c9be69fedb7 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -38,7 +38,7 @@ obj-y += tsc.o io_delay.o rtc.o
obj-$(CONFIG_X86_TRAMPOLINE) += trampoline.o
obj-y += process.o
-obj-y += i387.o
+obj-y += i387.o xsave.o
obj-y += ptrace.o
obj-y += ds.o
obj-$(CONFIG_X86_32) += tls.o
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 0785b3c8d04..c63ec65f484 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -739,9 +739,20 @@ void __cpuinit cpu_init(void)
/*
* Force FPU initialization:
*/
- current_thread_info()->status = 0;
+ if (cpu_has_xsave)
+ current_thread_info()->status = TS_XSAVE;
+ else
+ current_thread_info()->status = 0;
clear_used_math();
mxcsr_feature_mask_init();
+
+ /*
+ * Boot processor to setup the FP and extended state context info.
+ */
+ if (!smp_processor_id())
+ init_thread_xstate();
+
+ xsave_init();
}
#ifdef CONFIG_HOTPLUG_CPU
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index eb9ddd8efb8..45723f1fe19 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -21,9 +21,12 @@
# include <asm/sigcontext32.h>
# include <asm/user32.h>
#else
-# define save_i387_ia32 save_i387
-# define restore_i387_ia32 restore_i387
+# 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
+# define fx_sw_reserved_ia32 fx_sw_reserved
# define user_i387_ia32_struct user_i387_struct
# define user32_fxsr_struct user_fxsr_struct
#endif
@@ -36,6 +39,7 @@
static unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
unsigned int xstate_size;
+unsigned int sig_xstate_ia32_size = sizeof(struct _fpstate_ia32);
static struct i387_fxsave_struct fx_scratch __cpuinitdata;
void __cpuinit mxcsr_feature_mask_init(void)
@@ -61,6 +65,11 @@ void __init init_thread_xstate(void)
return;
}
+ if (cpu_has_xsave) {
+ xsave_cntxt_init();
+ return;
+ }
+
if (cpu_has_fxsr)
xstate_size = sizeof(struct i387_fxsave_struct);
#ifdef CONFIG_X86_32
@@ -83,9 +92,19 @@ void __cpuinit fpu_init(void)
write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */
+ /*
+ * Boot processor to setup the FP and extended state context info.
+ */
+ if (!smp_processor_id())
+ init_thread_xstate();
+ xsave_init();
+
mxcsr_feature_mask_init();
/* clean state in init */
- current_thread_info()->status = 0;
+ if (cpu_has_xsave)
+ current_thread_info()->status = TS_XSAVE;
+ else
+ current_thread_info()->status = 0;
clear_used_math();
}
#endif /* CONFIG_X86_64 */
@@ -195,6 +214,13 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
*/
target->thread.xstate->fxsave.mxcsr &= mxcsr_feature_mask;
+ /*
+ * update the header bits in the xsave header, indicating the
+ * presence of FP and SSE state.
+ */
+ if (cpu_has_xsave)
+ target->thread.xstate->xsave.xsave_hdr.xstate_bv |= XSTATE_FPSSE;
+
return ret;
}
@@ -395,6 +421,12 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
if (!ret)
convert_to_fxsr(target, &env);
+ /*
+ * update the header bit in the xsave header, indicating the
+ * presence of FP.
+ */
+ if (cpu_has_xsave)
+ target->thread.xstate->xsave.xsave_hdr.xstate_bv |= XSTATE_FP;
return ret;
}
@@ -407,7 +439,6 @@ static inline int save_i387_fsave(struct _fpstate_ia32 __user *buf)
struct task_struct *tsk = current;
struct i387_fsave_struct *fp = &tsk->thread.xstate->fsave;
- unlazy_fpu(tsk);
fp->status = fp->swd;
if (__copy_to_user(buf, fp, sizeof(struct i387_fsave_struct)))
return -1;
@@ -421,8 +452,6 @@ static int save_i387_fxsave(struct _fpstate_ia32 __user *buf)
struct user_i387_ia32_struct env;
int err = 0;
- unlazy_fpu(tsk);
-
convert_from_fxsr(&env, tsk);
if (__copy_to_user(buf, &env, sizeof(env)))
return -1;
@@ -432,16 +461,40 @@ static int save_i387_fxsave(struct _fpstate_ia32 __user *buf)
if (err)
return -1;
- if (__copy_to_user(&buf->_fxsr_env[0], fx,
- sizeof(struct i387_fxsave_struct)))
+ if (__copy_to_user(&buf->_fxsr_env[0], fx, xstate_size))
return -1;
return 1;
}
-int save_i387_ia32(struct _fpstate_ia32 __user *buf)
+static int save_i387_xsave(void __user *buf)
+{
+ struct _fpstate_ia32 __user *fx = buf;
+ int err = 0;
+
+ 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.
@@ -451,13 +504,17 @@ int save_i387_ia32(struct _fpstate_ia32 __user *buf)
if (!HAVE_HWFP) {
return fpregs_soft_get(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
- NULL, buf) ? -1 : 1;
+ NULL, fp) ? -1 : 1;
}
+ unlazy_fpu(tsk);
+
+ if (cpu_has_xsave)
+ return save_i387_xsave(fp);
if (cpu_has_fxsr)
- return save_i387_fxsave(buf);
+ return save_i387_fxsave(fp);
else
- return save_i387_fsave(buf);
+ return save_i387_fsave(fp);
}
static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
@@ -468,14 +525,15 @@ static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
sizeof(struct i387_fsave_struct));
}
-static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf)
+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.xstate->fxsave, &buf->_fxsr_env[0],
- sizeof(struct i387_fxsave_struct));
+ size);
/* mxcsr reserved bits must be masked to zero for security reasons */
tsk->thread.xstate->fxsave.mxcsr &= mxcsr_feature_mask;
if (err || __copy_from_user(&env, buf, sizeof(env)))
@@ -485,14 +543,69 @@ static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf)
return 0;
}
-int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
+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.xstate->xsave.xsave_hdr;
+ u64 mask;
+ int err;
+
+ if (check_for_xstate(fx, buf, &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)
@@ -500,14 +613,17 @@ int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
}
if (HAVE_HWFP) {
- if (cpu_has_fxsr)
- err = restore_i387_fxsave(buf);
+ 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(buf);
+ err = restore_i387_fsave(fp);
} else {
err = fpregs_soft_set(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
- NULL, buf) != 0;
+ NULL, fp) != 0;
}
set_used_math();
diff --git a/arch/x86/kernel/sigframe.h b/arch/x86/kernel/sigframe.h
index 72bbb519d2d..6dd7e2b70a4 100644
--- a/arch/x86/kernel/sigframe.h
+++ b/arch/x86/kernel/sigframe.h
@@ -3,9 +3,18 @@ struct sigframe {
char __user *pretcode;
int sig;
struct sigcontext sc;
- struct _fpstate fpstate;
+ /*
+ * fpstate is unused. fpstate is moved/allocated after
+ * retcode[] below. This movement allows to have the FP state and the
+ * future state extensions (xsave) stay together.
+ * And at the same time retaining the unused fpstate, prevents changing
+ * the offset of extramask[] in the sigframe and thus prevent any
+ * legacy application accessing/modifying it.
+ */
+ struct _fpstate fpstate_unused;
unsigned long extramask[_NSIG_WORDS-1];
char retcode[8];
+ /* fp state follows here */
};
struct rt_sigframe {
@@ -15,13 +24,14 @@ struct rt_sigframe {
void __user *puc;
struct siginfo info;
struct ucontext uc;
- struct _fpstate fpstate;
char retcode[8];
+ /* fp state follows here */
};
#else
struct rt_sigframe {
char __user *pretcode;
struct ucontext uc;
struct siginfo info;
+ /* fp state follows here */
};
#endif
diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 0c727f64e79..8d380b699c0 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -160,28 +160,14 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
}
{
- struct _fpstate __user *buf;
+ void __user *buf;
err |= __get_user(buf, &sc->fpstate);
- if (buf) {
- if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
- goto badframe;
- err |= restore_i387(buf);
- } else {
- struct task_struct *me = current;
-
- if (used_math()) {
- clear_fpu(me);
- clear_used_math();
- }
- }
+ err |= restore_i387_xstate(buf);
}
err |= __get_user(*pax, &sc->ax);
return err;
-
-badframe:
- return 1;
}
asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
@@ -263,7 +249,7 @@ badframe:
* Set up a signal frame.
*/
static int
-setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
+setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
struct pt_regs *regs, unsigned long mask)
{
int tmp, err = 0;
@@ -290,7 +276,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
err |= __put_user(regs->sp, &sc->sp_at_signal);
err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
- tmp = save_i387(fpstate);
+ tmp = save_i387_xstate(fpstate);
if (tmp < 0)
err = 1;
else
@@ -307,7 +293,8 @@ setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
* Determine which stack to use..
*/
static inline void __user *
-get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
+ void **fpstate)
{
unsigned long sp;
@@ -333,6 +320,11 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
sp = (unsigned long) ka->sa.sa_restorer;
}
+ if (used_math()) {
+ sp = sp - sig_xstate_size;
+ *fpstate = (struct _fpstate *) sp;
+ }
+
sp -= frame_size;
/*
* Align the stack pointer according to the i386 ABI,
@@ -351,8 +343,9 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
void __user *restorer;
int err = 0;
int usig;
+ void __user *fpstate = NULL;
- frame = get_sigframe(ka, regs, sizeof(*frame));
+ frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
@@ -367,7 +360,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
if (err)
goto give_sigsegv;
- err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
+ err = setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]);
if (err)
goto give_sigsegv;
@@ -428,8 +421,9 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
void __user *restorer;
int err = 0;
int usig;
+ void __user *fpstate = NULL;
- frame = get_sigframe(ka, regs, sizeof(*frame));
+ frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
@@ -448,13 +442,16 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
goto give_sigsegv;
/* Create the ucontext. */
- err |= __put_user(0, &frame->uc.uc_flags);
+ if (cpu_has_xsave)
+ err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
+ else
+ err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->sp),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
- err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 2f146405005..4665b598a37 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -55,69 +55,6 @@ sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
}
/*
- * Signal frame handlers.
- */
-
-static inline int save_i387(struct _fpstate __user *buf)
-{
- struct task_struct *tsk = current;
- int err = 0;
-
- BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
- sizeof(tsk->thread.xstate->fxsave));
-
- if ((unsigned long)buf % 16)
- printk("save_i387: bad fpstate %p\n", buf);
-
- if (!used_math())
- return 0;
- clear_used_math(); /* trigger finit */
- if (task_thread_info(tsk)->status & TS_USEDFPU) {
- err = save_i387_checking((struct i387_fxsave_struct __user *)
- buf);
- if (err)
- return err;
- task_thread_info(tsk)->status &= ~TS_USEDFPU;
- stts();
- } else {
- if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
- sizeof(struct i387_fxsave_struct)))
- return -1;
- }
- return 1;
-}
-
-/*
- * This restores directly out of user space. Exceptions are handled.
- */
-static inline int restore_i387(struct _fpstate __user *buf)
-{
- struct task_struct *tsk = current;
- int err;
-
- 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;
- }
- err = restore_fpu_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_fpu(tsk);
- clear_used_math();
- }
- return err;
-}
-
-/*
* Do a signal return; undo the signal stack.
*/
static int
@@ -161,25 +98,11 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
{
struct _fpstate __user * buf;
err |= __get_user(buf, &sc->fpstate);
-
- if (buf) {
- if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
- goto badframe;
- err |= restore_i387(buf);
- } else {
- struct task_struct *me = current;
- if (used_math()) {
- clear_fpu(me);
- clear_used_math();
- }
- }
+ err |= restore_i387_xstate(buf);
}
err |= __get_user(*pax, &sc->ax);
return err;
-
-badframe:
- return 1;
}
asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
@@ -270,26 +193,23 @@ get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
sp = current->sas_ss_sp + current->sas_ss_size;
}
- return (void __user *)round_down(sp - size, 16);
+ return (void __user *)round_down(sp - size, 64);
}
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs * regs)
{
struct rt_sigframe __user *frame;
- struct _fpstate __user *fp = NULL;
+ void __user *fp = NULL;
int err = 0;
struct task_struct *me = current;
if (used_math()) {
- fp = get_stack(ka, regs, sizeof(struct _fpstate));
+ fp = get_stack(ka, regs, sig_xstate_size);
frame = (void __user *)round_down(
(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
- if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
- goto give_sigsegv;
-
- if (save_i387(fp) < 0)
+ if (save_i387_xstate(fp) < 0)
err |= -1;
} else
frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
@@ -304,7 +224,10 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
}
/* Create the ucontext. */
- err |= __put_user(0, &frame->uc.uc_flags);
+ if (cpu_has_xsave)
+ err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
+ else
+ err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->sp),
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 03df8e45e5a..da5a5964fcc 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -1228,7 +1228,6 @@ void __init trap_init(void)
set_bit(SYSCALL_VECTOR, used_vectors);
- init_thread_xstate();
/*
* Should be a barrier for any external CPU state:
*/
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 513caaca711..38eb76156a4 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -1134,7 +1134,7 @@ asmlinkage void math_state_restore(void)
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
- if (unlikely(restore_fpu_checking(&me->thread.xstate->fxsave))) {
+ if (unlikely(restore_fpu_checking(me))) {
stts();
force_sig(SIGSEGV, me);
return;
@@ -1173,10 +1173,6 @@ void __init trap_init(void)
set_system_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
#endif
/*
- * initialize the per thread extended state:
- */
- init_thread_xstate();
- /*
* Should be a barrier for any external CPU state:
*/
cpu_init();
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
new file mode 100644
index 00000000000..07713d64deb
--- /dev/null
+++ b/arch/x86/kernel/xsave.c
@@ -0,0 +1,316 @@
+/*
+ * xsave/xrstor support.
+ *
+ * Author: Suresh Siddha <suresh.b.siddha@intel.com>
+ */
+#include <linux/bootmem.h>
+#include <linux/compat.h>
+#include <asm/i387.h>
+#ifdef CONFIG_IA32_EMULATION
+#include <asm/sigcontext32.h>
+#endif
+#include <asm/xcr.h>
+
+/*
+ * Supported feature mask by the CPU and the kernel.
+ */
+u64 pcntxt_mask;
+
+struct _fpx_sw_bytes fx_sw_reserved;
+#ifdef CONFIG_IA32_EMULATION
+struct _fpx_sw_bytes fx_sw_reserved_ia32;
+#endif
+
+/*
+ * 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)
+{
+ 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 err;
+
+ /*
+ * First Magic check failed.
+ */
+ if (fx_sw_user->magic1 != FP_XSTATE_MAGIC1)
+ 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 -1;
+
+ err = __get_user(magic2, (__u32 *) (((void *)fpstate) +
+ fx_sw_user->extended_size -
+ FP_XSTATE_MAGIC2_SIZE));
+ /*
+ * 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 (err || magic2 != FP_XSTATE_MAGIC2)
+ return -1;
+
+ return 0;
+}
+
+#ifdef CONFIG_X86_64
+/*
+ * Signal frame handlers.
+ */
+
+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;
+ clear_used_math(); /* trigger finit */
+ if (task_thread_info(tsk)->status & TS_USEDFPU) {
+ /*
+ * Start with clearing the user buffer. This will present a
+ * clean context for the bytes not touched by the fxsave/xsave.
+ */
+ __clear_user(buf, sig_xstate_size);
+
+ if (task_thread_info(tsk)->status & TS_XSAVE)
+ err = xsave_user(buf);
+ else
+ err = fxsave_user(buf);
+
+ if (err)
+ return err;
+ task_thread_info(tsk)->status &= ~TS_USEDFPU;
+ stts();
+ } else {
+ if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
+ xstate_size))
+ return -1;
+ }
+
+ if (task_thread_info(tsk)->status & TS_XSAVE) {
+ struct _fpstate __user *fx = buf;
+
+ 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));
+ }
+
+ return 1;
+}
+
+/*
+ * Restore the extended state if present. Otherwise, restore the FP/SSE
+ * state.
+ */
+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, buf, &fx_sw_user))
+ goto fx_only;
+
+ mask = fx_sw_user.xstate_bv;
+
+ /*
+ * restore the state passed by the user.
+ */
+ err = xrestore_user(buf, mask);
+ if (err)
+ return err;
+
+ /*
+ * init the state skipped by the user.
+ */
+ mask = pcntxt_mask & ~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 (task_thread_info(tsk)->status & TS_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
+
+/*
+ * 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 prepare_fx_sw_frame(void)
+{
+ int size_extended = (xstate_size - sizeof(struct i387_fxsave_struct)) +
+ 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));
+
+ fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
+ fx_sw_reserved.extended_size = sig_xstate_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
+}
+
+/*
+ * Represents init state for the supported extended state.
+ */
+struct xsave_struct *init_xstate_buf;
+
+#ifdef CONFIG_X86_64
+unsigned int sig_xstate_size = sizeof(struct _fpstate);
+#endif
+
+/*
+ * Enable the extended processor state save/restore feature
+ */
+void __cpuinit xsave_init(void)
+{
+ if (!cpu_has_xsave)
+ return;
+
+ set_in_cr4(X86_CR4_OSXSAVE);
+
+ /*
+ * Enable all the features that the HW is capable of
+ * and the Linux kernel is aware of.
+ */
+ xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask);
+}
+
+/*
+ * setup the xstate image representing the init state
+ */
+void setup_xstate_init(void)
+{
+ init_xstate_buf = alloc_bootmem(xstate_size);
+ init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT;
+}
+
+/*
+ * Enable and initialize the xsave feature.
+ */
+void __init xsave_cntxt_init(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+
+ cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
+ pcntxt_mask = eax + ((u64)edx << 32);
+
+ if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
+ printk(KERN_ERR "FP/SSE not shown under xsave features 0x%llx\n",
+ pcntxt_mask);
+ BUG();
+ }
+
+ /*
+ * for now OS knows only about FP/SSE
+ */
+ pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
+ xsave_init();
+
+ /*
+ * Recompute the context size for enabled features
+ */
+ cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
+ xstate_size = ebx;
+
+ prepare_fx_sw_frame();
+
+ setup_xstate_init();
+
+ printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%llx, "
+ "cntxt size 0x%x\n",
+ pcntxt_mask, xstate_size);
+}
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