[patch 15/21] x86/fpu: Use fpstate::size

Thomas Gleixner
2021-10-13T14:56:12Z

Make use of fpstate::size in various places which require the buffer size
information for sanity checks or memcpy() sizing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/fpu/core.c | 13 ++++++-------
arch/x86/kernel/fpu/signal.c | 7 +++----
2 files changed, 9 insertions(+), 11 deletions(-)

--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -166,13 +166,12 @@ void fpu_swap_kvm_fpu(struct fpu *save,
fpregs_lock();

if (save) {
- if (test_thread_flag(TIF_NEED_FPU_LOAD)) {
- memcpy(&save->fpstate->regs,
- &current->thread.fpu.fpstate->regs,
- fpu_kernel_xstate_size);
- } else {
+ struct fpstate *fpcur = current->thread.fpu.fpstate;
+
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ memcpy(&save->fpstate->regs, &fpcur->regs, fpcur->size);
+ else
save_fpregs_to_fpstate(save);
- }
}

if (rstor) {
@@ -398,7 +397,7 @@ int fpu_clone(struct task_struct *dst)
fpregs_lock();
if (test_thread_flag(TIF_NEED_FPU_LOAD)) {
memcpy(&dst_fpu->fpstate->regs, &src_fpu->fpstate->regs,
- fpu_kernel_xstate_size);
+ dst_fpu->fpstate->size);
} else {
save_fpregs_to_fpstate(dst_fpu);
}
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -313,15 +313,13 @@ static bool restore_fpregs_from_user(voi
static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
bool ia32_fxstate)
{
- int state_size = fpu_kernel_xstate_size;
struct task_struct *tsk = current;
struct fpu *fpu = &tsk->thread.fpu;
struct user_i387_ia32_struct env;
+ bool success, fx_only = false;
union fpregs_state *fpregs;
+ unsigned int state_size;
u64 user_xfeatures = 0;
- bool fx_only = false;
- bool success;
-

if (use_xsave()) {
struct _fpx_sw_bytes fx_sw_user;
@@ -334,6 +332,7 @@ static bool __fpu_restore_sig(void __use
user_xfeatures = fx_sw_user.xfeatures;
} else {
user_xfeatures = XFEATURE_MASK_FPSSE;
+ state_size = fpu->fpstate->size;
}

if (likely(!ia32_fxstate)) {