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Diffstat (limited to 'arch/x86/kernel/fpu/xstate.h')
-rw-r--r--arch/x86/kernel/fpu/xstate.h116
1 files changed, 79 insertions, 37 deletions
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 5ad47031383b..52ce19289989 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -5,6 +5,7 @@
#include <asm/cpufeature.h>
#include <asm/fpu/xstate.h>
#include <asm/fpu/xcr.h>
+#include <asm/msr.h>
#ifdef CONFIG_X86_64
DECLARE_PER_CPU(u64, xfd_state);
@@ -22,7 +23,7 @@ static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask)
static inline u64 xstate_get_group_perm(bool guest)
{
- struct fpu *fpu = &current->group_leader->thread.fpu;
+ struct fpu *fpu = x86_task_fpu(current->group_leader);
struct fpu_state_perm *perm;
/* Pairs with WRITE_ONCE() in xstate_request_perm() */
@@ -43,17 +44,18 @@ enum xstate_copy_mode {
struct membuf;
extern void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
- u32 pkru_val, enum xstate_copy_mode copy_mode);
+ u64 xfeatures, u32 pkru_val,
+ enum xstate_copy_mode copy_mode);
extern void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
enum xstate_copy_mode mode);
-extern int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf);
-extern int copy_sigframe_from_user_to_xstate(struct fpstate *fpstate, const void __user *ubuf);
+extern int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf, u32 *pkru);
+extern int copy_sigframe_from_user_to_xstate(struct task_struct *tsk, const void __user *ubuf);
extern void fpu__init_cpu_xstate(void);
extern void fpu__init_system_xstate(unsigned int legacy_size);
-extern void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
+extern void __user *get_xsave_addr_user(struct xregs_state __user *xsave, int xfeature_nr);
static inline u64 xfeatures_mask_supervisor(void)
{
@@ -63,38 +65,73 @@ static inline u64 xfeatures_mask_supervisor(void)
static inline u64 xfeatures_mask_independent(void)
{
if (!cpu_feature_enabled(X86_FEATURE_ARCH_LBR))
- return XFEATURE_MASK_INDEPENDENT & ~XFEATURE_MASK_LBR;
+ return fpu_kernel_cfg.independent_features & ~XFEATURE_MASK_LBR;
- return XFEATURE_MASK_INDEPENDENT;
+ return fpu_kernel_cfg.independent_features;
+}
+
+static inline int set_xfeature_in_sigframe(struct xregs_state __user *xbuf, u64 mask)
+{
+ u64 xfeatures;
+ int err;
+
+ /* Read the xfeatures value already saved in the user buffer */
+ err = __get_user(xfeatures, &xbuf->header.xfeatures);
+ xfeatures |= mask;
+ err |= __put_user(xfeatures, &xbuf->header.xfeatures);
+
+ return err;
+}
+
+/*
+ * Update the value of PKRU register that was already pushed onto the signal frame.
+ */
+static inline int update_pkru_in_sigframe(struct xregs_state __user *buf, u32 pkru)
+{
+ int err;
+
+ if (unlikely(!cpu_feature_enabled(X86_FEATURE_OSPKE)))
+ return 0;
+
+ /* Mark PKRU as in-use so that it is restored correctly. */
+ err = set_xfeature_in_sigframe(buf, XFEATURE_MASK_PKRU);
+ if (err)
+ return err;
+
+ /* Update PKRU value in the userspace xsave buffer. */
+ return __put_user(pkru, (unsigned int __user *)get_xsave_addr_user(buf, XFEATURE_PKRU));
}
/* XSAVE/XRSTOR wrapper functions */
#ifdef CONFIG_X86_64
-#define REX_PREFIX "0x48, "
+#define REX_SUFFIX "64"
#else
-#define REX_PREFIX
+#define REX_SUFFIX
#endif
-/* These macros all use (%edi)/(%rdi) as the single memory argument. */
-#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27"
-#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37"
-#define XSAVEC ".byte " REX_PREFIX "0x0f,0xc7,0x27"
-#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f"
-#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f"
-#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f"
+#define XSAVE "xsave" REX_SUFFIX " %[xa]"
+#define XSAVEOPT "xsaveopt" REX_SUFFIX " %[xa]"
+#define XSAVEC "xsavec" REX_SUFFIX " %[xa]"
+#define XSAVES "xsaves" REX_SUFFIX " %[xa]"
+#define XRSTOR "xrstor" REX_SUFFIX " %[xa]"
+#define XRSTORS "xrstors" REX_SUFFIX " %[xa]"
/*
* After this @err contains 0 on success or the trap number when the
* operation raises an exception.
+ *
+ * The [xa] input parameter below represents the struct xregs_state pointer
+ * and the asm symbolic name for the argument used in the XSAVE/XRSTOR insns
+ * above.
*/
#define XSTATE_OP(op, st, lmask, hmask, err) \
asm volatile("1:" op "\n\t" \
"xor %[err], %[err]\n" \
- "2:\n\t" \
+ "2:\n" \
_ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FAULT_MCE_SAFE) \
: [err] "=a" (err) \
- : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
+ : [xa] "m" (*(st)), "a" (lmask), "d" (hmask) \
: "memory")
/*
@@ -107,23 +144,19 @@ static inline u64 xfeatures_mask_independent(void)
* Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
* supports modified optimization which is not supported by XSAVE.
*
- * We use XSAVE as a fallback.
- *
- * The 661 label is defined in the ALTERNATIVE* macros as the address of the
- * original instruction which gets replaced. We need to use it here as the
- * address of the instruction where we might get an exception at.
+ * Use XSAVE as a fallback.
*/
#define XSTATE_XSAVE(st, lmask, hmask, err) \
- asm volatile(ALTERNATIVE_3(XSAVE, \
+ asm volatile("1: " ALTERNATIVE_3(XSAVE, \
XSAVEOPT, X86_FEATURE_XSAVEOPT, \
XSAVEC, X86_FEATURE_XSAVEC, \
XSAVES, X86_FEATURE_XSAVES) \
- "\n" \
+ "\n\t" \
"xor %[err], %[err]\n" \
"3:\n" \
- _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
+ _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
: [err] "=r" (err) \
- : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
+ : [xa] "m" (*(st)), "a" (lmask), "d" (hmask) \
: "memory")
/*
@@ -131,13 +164,13 @@ static inline u64 xfeatures_mask_independent(void)
* XSAVE area format.
*/
#define XSTATE_XRESTORE(st, lmask, hmask) \
- asm volatile(ALTERNATIVE(XRSTOR, \
+ asm volatile("1: " ALTERNATIVE(XRSTOR, \
XRSTORS, X86_FEATURE_XSAVES) \
"\n" \
"3:\n" \
- _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE) \
+ _ASM_EXTABLE_TYPE(1b, 3b, EX_TYPE_FPU_RESTORE) \
: \
- : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
+ : [xa] "m" (*(st)), "a" (lmask), "d" (hmask) \
: "memory")
#if defined(CONFIG_X86_64) && defined(CONFIG_X86_DEBUG_FPU)
@@ -147,20 +180,26 @@ static inline void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rs
#endif
#ifdef CONFIG_X86_64
+static inline void xfd_set_state(u64 xfd)
+{
+ wrmsrq(MSR_IA32_XFD, xfd);
+ __this_cpu_write(xfd_state, xfd);
+}
+
static inline void xfd_update_state(struct fpstate *fpstate)
{
if (fpu_state_size_dynamic()) {
u64 xfd = fpstate->xfd;
- if (__this_cpu_read(xfd_state) != xfd) {
- wrmsrl(MSR_IA32_XFD, xfd);
- __this_cpu_write(xfd_state, xfd);
- }
+ if (__this_cpu_read(xfd_state) != xfd)
+ xfd_set_state(xfd);
}
}
extern int __xfd_enable_feature(u64 which, struct fpu_guest *guest_fpu);
#else
+static inline void xfd_set_state(u64 xfd) { }
+
static inline void xfd_update_state(struct fpstate *fpstate) { }
static inline int __xfd_enable_feature(u64 which, struct fpu_guest *guest_fpu) {
@@ -253,14 +292,14 @@ static inline u64 xfeatures_need_sigframe_write(void)
* The caller has to zero buf::header before calling this because XSAVE*
* does not touch the reserved fields in the header.
*/
-static inline int xsave_to_user_sigframe(struct xregs_state __user *buf)
+static inline int xsave_to_user_sigframe(struct xregs_state __user *buf, u32 pkru)
{
/*
* Include the features which are not xsaved/rstored by the kernel
* internally, e.g. PKRU. That's user space ABI and also required
* to allow the signal handler to modify PKRU.
*/
- struct fpstate *fpstate = current->thread.fpu.fpstate;
+ struct fpstate *fpstate = x86_task_fpu(current)->fpstate;
u64 mask = fpstate->user_xfeatures;
u32 lmask;
u32 hmask;
@@ -278,6 +317,9 @@ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf)
XSTATE_OP(XSAVE, buf, lmask, hmask, err);
clac();
+ if (!err)
+ err = update_pkru_in_sigframe(buf, pkru);
+
return err;
}
@@ -291,7 +333,7 @@ static inline int xrstor_from_user_sigframe(struct xregs_state __user *buf, u64
u32 hmask = mask >> 32;
int err;
- xfd_validate_state(current->thread.fpu.fpstate, mask, true);
+ xfd_validate_state(x86_task_fpu(current)->fpstate, mask, true);
stac();
XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.