[PATCH v5 02/28] x86/fpu/xstate: Modify state copy helpers to handle both static and dynamic buffers

Chang S. Bae
2021-05-23T19:38:39Z

Have all the functions copying xstate take a struct fpu * pointer in
preparation for dynamic state buffer support.

No functional change.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from v3:
* Updated the changelog. (Borislav Petkov)

Changes from v2:
* Updated the changelog with task->fpu removed. (Borislav Petkov)
---
arch/x86/include/asm/fpu/xstate.h | 8 ++++----
arch/x86/kernel/fpu/regset.c | 6 +++---
arch/x86/kernel/fpu/signal.c | 16 +++++++---------
arch/x86/kernel/fpu/xstate.c | 19 +++++++++++++++----
4 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 47a92232d595..e0f1b22f53ce 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -105,10 +105,10 @@ const void *get_xsave_field_ptr(int xfeature_nr);
int using_compacted_format(void);
int xfeature_size(int xfeature_nr);
struct membuf;
-void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave);
-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);
-void copy_supervisor_to_kernel(struct xregs_state *xsave);
+void copy_xstate_to_kernel(struct membuf to, struct fpu *fpu);
+int copy_kernel_to_xstate(struct fpu *fpu, const void *kbuf);
+int copy_user_to_xstate(struct fpu *fpu, const void __user *ubuf);
+void copy_supervisor_to_kernel(struct fpu *fpu);
void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask);
void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask);

diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 4c4d9059ff36..5e13e58d11d4 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -85,7 +85,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
fpu__prepare_read(fpu);

if (using_compacted_format()) {
- copy_xstate_to_kernel(to, xsave);
+ copy_xstate_to_kernel(to, fpu);
return 0;
} else {
fpstate_sanitize_xstate(fpu);
@@ -126,9 +126,9 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,

if (using_compacted_format()) {
if (kbuf)
- ret = copy_kernel_to_xstate(xsave, kbuf);
+ ret = copy_kernel_to_xstate(fpu, kbuf);
else
- ret = copy_user_to_xstate(xsave, ubuf);
+ ret = copy_user_to_xstate(fpu, ubuf);
} else {
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
if (!ret)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index a4ec65317a7f..0d6deb75c507 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -212,11 +212,11 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
}

static inline void
-sanitize_restored_user_xstate(union fpregs_state *state,
+sanitize_restored_user_xstate(struct fpu *fpu,
struct user_i387_ia32_struct *ia32_env,
u64 user_xfeatures, int fx_only)
{
- struct xregs_state *xsave = &state->xsave;
+ struct xregs_state *xsave = &fpu->state.xsave;
struct xstate_header *header = &xsave->header;

if (use_xsave()) {
@@ -253,7 +253,7 @@ sanitize_restored_user_xstate(union fpregs_state *state,
xsave->i387.mxcsr &= mxcsr_feature_mask;

if (ia32_env)
- convert_to_fxsr(&state->fxsave, ia32_env);
+ convert_to_fxsr(&fpu->state.fxsave, ia32_env);
}
}

@@ -396,7 +396,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
* current supervisor states first and invalidate the FPU regs.
*/
if (xfeatures_mask_supervisor())
- copy_supervisor_to_kernel(&fpu->state.xsave);
+ copy_supervisor_to_kernel(fpu);
set_thread_flag(TIF_NEED_FPU_LOAD);
}
__fpu_invalidate_fpregs_state(fpu);
@@ -406,7 +406,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
u64 init_bv = xfeatures_mask_user() & ~user_xfeatures;

if (using_compacted_format()) {
- ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx);
+ ret = copy_user_to_xstate(fpu, buf_fx);
} else {
ret = __copy_from_user(&fpu->state.xsave, buf_fx, state_size);

@@ -416,8 +416,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
if (ret)
goto err_out;

- sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures,
- fx_only);
+ sanitize_restored_user_xstate(fpu, envp, user_xfeatures, fx_only);

fpregs_lock();
if (unlikely(init_bv))
@@ -437,8 +436,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
goto err_out;
}

- sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures,
- fx_only);
+ sanitize_restored_user_xstate(fpu, envp, user_xfeatures, fx_only);

fpregs_lock();
if (use_xsave()) {
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 767ad6b008c2..cb634c6afbb2 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1071,14 +1071,17 @@ static void copy_part(struct membuf *to, unsigned *last, unsigned offset,
* It supports partial copy but pos always starts from zero. This is called
* from xstateregs_get() and there we check the CPU has XSAVES.
*/
-void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave)
+void copy_xstate_to_kernel(struct membuf to, struct fpu *fpu)
{
struct xstate_header header;
const unsigned off_mxcsr = offsetof(struct fxregs_state, mxcsr);
+ struct xregs_state *xsave;
unsigned size = to.left;
unsigned last = 0;
int i;

+ xsave = &fpu->state.xsave;
+
/*
* The destination is a ptrace buffer; we put in only user xstates:
*/
@@ -1127,8 +1130,9 @@ void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave)
* 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 copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
+int copy_kernel_to_xstate(struct fpu *fpu, const void *kbuf)
{
+ struct xregs_state *xsave;
unsigned int offset, size;
int i;
struct xstate_header hdr;
@@ -1141,6 +1145,8 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
if (validate_user_xstate_header(&hdr))
return -EINVAL;

+ xsave = &fpu->state.xsave;
+
for (i = 0; i < XFEATURE_MAX; i++) {
u64 mask = ((u64)1 << i);

@@ -1180,8 +1186,9 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
* 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)
+int copy_user_to_xstate(struct fpu *fpu, const void __user *ubuf)
{
+ struct xregs_state *xsave;
unsigned int offset, size;
int i;
struct xstate_header hdr;
@@ -1195,6 +1202,8 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf)
if (validate_user_xstate_header(&hdr))
return -EINVAL;

+ xsave = &fpu->state.xsave;
+
for (i = 0; i < XFEATURE_MAX; i++) {
u64 mask = ((u64)1 << i);

@@ -1235,9 +1244,10 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf)
* old states, and is intended to be used only in __fpu__restore_sig(), where
* user states are restored from the user buffer.
*/
-void copy_supervisor_to_kernel(struct xregs_state *xstate)
+void copy_supervisor_to_kernel(struct fpu *fpu)
{
struct xstate_header *header;
+ struct xregs_state *xstate;
u64 max_bit, min_bit;
u32 lmask, hmask;
int err, i;
@@ -1251,6 +1261,7 @@ void copy_supervisor_to_kernel(struct xregs_state *xstate)
max_bit = __fls(xfeatures_mask_supervisor());
min_bit = __ffs(xfeatures_mask_supervisor());

+ xstate = &fpu->state.xsave;
lmask = xfeatures_mask_supervisor();
hmask = xfeatures_mask_supervisor() >> 32;
XSTATE_OP(XSAVES, xstate, lmask, hmask, err);
--
2.17.1