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-rw-r--r--arch/x86/kernel/i387.c88
1 files changed, 46 insertions, 42 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index d2e39e69aaf8..8f8102d967b3 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -5,45 +5,41 @@
* General FPU state handling cleanups
* Gareth Hughes <gareth@valinux.com>, May 2000
*/
-
-#include <linux/sched.h>
#include <linux/module.h>
#include <linux/regset.h>
+#include <linux/sched.h>
+
+#include <asm/sigcontext.h>
#include <asm/processor.h>
-#include <asm/i387.h>
#include <asm/math_emu.h>
-#include <asm/sigcontext.h>
-#include <asm/user.h>
-#include <asm/ptrace.h>
#include <asm/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/i387.h>
+#include <asm/user.h>
#ifdef CONFIG_X86_64
-
-#include <asm/sigcontext32.h>
-#include <asm/user32.h>
-
+# include <asm/sigcontext32.h>
+# include <asm/user32.h>
#else
-
-#define save_i387_ia32 save_i387
-#define restore_i387_ia32 restore_i387
-
-#define _fpstate_ia32 _fpstate
-#define user_i387_ia32_struct user_i387_struct
-#define user32_fxsr_struct user_fxsr_struct
-
+# define save_i387_ia32 save_i387
+# define restore_i387_ia32 restore_i387
+# define _fpstate_ia32 _fpstate
+# define user_i387_ia32_struct user_i387_struct
+# define user32_fxsr_struct user_fxsr_struct
#endif
#ifdef CONFIG_MATH_EMULATION
-#define HAVE_HWFP (boot_cpu_data.hard_math)
+# define HAVE_HWFP (boot_cpu_data.hard_math)
#else
-#define HAVE_HWFP 1
+# define HAVE_HWFP 1
#endif
-static unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
+static unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
void mxcsr_feature_mask_init(void)
{
unsigned long mask = 0;
+
clts();
if (cpu_has_fxsr) {
memset(&current->thread.i387.fxsave, 0,
@@ -69,10 +65,11 @@ void __cpuinit fpu_init(void)
if (offsetof(struct task_struct, thread.i387.fxsave) & 15)
__bad_fxsave_alignment();
+
set_in_cr4(X86_CR4_OSFXSR);
set_in_cr4(X86_CR4_OSXMMEXCPT);
- write_cr0(oldcr0 & ~((1UL<<3)|(1UL<<2))); /* clear TS and EM */
+ write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */
mxcsr_feature_mask_init();
/* clean state in init */
@@ -178,6 +175,7 @@ static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
+
return tmp;
}
@@ -232,8 +230,8 @@ static inline u32 twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave)
* FXSR floating point environment conversions.
*/
-static void convert_from_fxsr(struct user_i387_ia32_struct *env,
- struct task_struct *tsk)
+static void
+convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
{
struct i387_fxsave_struct *fxsave = &tsk->thread.i387.fxsave;
struct _fpreg *to = (struct _fpreg *) &env->st_space[0];
@@ -252,10 +250,11 @@ static void convert_from_fxsr(struct user_i387_ia32_struct *env,
* should be actually ds/cs at fpu exception time, but
* that information is not available in 64bit mode.
*/
- asm("mov %%ds,%0" : "=r" (env->fos));
- asm("mov %%cs,%0" : "=r" (env->fcs));
+ asm("mov %%ds, %[fos]" : [fos] "=r" (env->fos));
+ asm("mov %%cs, %[fcs]" : [fcs] "=r" (env->fcs));
} else {
struct pt_regs *regs = task_pt_regs(tsk);
+
env->fos = 0xffff0000 | tsk->thread.ds;
env->fcs = regs->cs;
}
@@ -309,9 +308,10 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
init_fpu(target);
- if (!cpu_has_fxsr)
+ if (!cpu_has_fxsr) {
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.i387.fsave, 0, -1);
+ }
if (kbuf && pos == 0 && count == sizeof(env)) {
convert_from_fxsr(kbuf, target);
@@ -319,6 +319,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
}
convert_from_fxsr(&env, target);
+
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
}
@@ -335,9 +336,10 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
init_fpu(target);
set_stopped_child_used_math(target);
- if (!cpu_has_fxsr)
+ if (!cpu_has_fxsr) {
return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.i387.fsave, 0, -1);
+ }
if (pos > 0 || count < sizeof(env))
convert_from_fxsr(&env, target);
@@ -392,28 +394,28 @@ int save_i387_ia32(struct _fpstate_ia32 __user *buf)
{
if (!used_math())
return 0;
-
- /* This will cause a "finit" to be triggered by the next
+ /*
+ * This will cause a "finit" to be triggered by the next
* attempted FPU operation by the 'current' process.
*/
clear_used_math();
- if (HAVE_HWFP) {
- if (cpu_has_fxsr) {
- return save_i387_fxsave(buf);
- } else {
- return save_i387_fsave(buf);
- }
- } else {
+ if (!HAVE_HWFP) {
return fpregs_soft_get(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
NULL, buf) ? -1 : 1;
}
+
+ if (cpu_has_fxsr)
+ return save_i387_fxsave(buf);
+ else
+ return save_i387_fsave(buf);
}
static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
{
struct task_struct *tsk = current;
+
clear_fpu(tsk);
return __copy_from_user(&tsk->thread.i387.fsave, buf,
sizeof(struct i387_fsave_struct));
@@ -421,9 +423,10 @@ static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf)
static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf)
{
- int err;
struct task_struct *tsk = current;
struct user_i387_ia32_struct env;
+ int err;
+
clear_fpu(tsk);
err = __copy_from_user(&tsk->thread.i387.fxsave, &buf->_fxsr_env[0],
sizeof(struct i387_fxsave_struct));
@@ -432,6 +435,7 @@ static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf)
if (err || __copy_from_user(&env, buf, sizeof(env)))
return 1;
convert_to_fxsr(tsk, &env);
+
return 0;
}
@@ -440,17 +444,17 @@ int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
int err;
if (HAVE_HWFP) {
- if (cpu_has_fxsr) {
+ if (cpu_has_fxsr)
err = restore_i387_fxsave(buf);
- } else {
+ else
err = restore_i387_fsave(buf);
- }
} else {
err = fpregs_soft_set(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
NULL, buf) != 0;
}
set_used_math();
+
return err;
}
@@ -463,8 +467,8 @@ int restore_i387_ia32(struct _fpstate_ia32 __user *buf)
*/
int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu)
{
- int fpvalid;
struct task_struct *tsk = current;
+ int fpvalid;
fpvalid = !!used_math();
if (fpvalid)
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.