[patch 16/21] x86/fpu/xstate: Use fpstate for os_xsave()

Thomas Gleixner
2021-10-13T14:56:41Z

With variable feature sets XSAVE[S} requires to know the feature set for
which the buffer is valid. Retrieve it from fpstate.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/fpu/core.c | 2 +-
arch/x86/kernel/fpu/signal.c | 4 ++--
arch/x86/kernel/fpu/xstate.h | 6 +++---
3 files changed, 6 insertions(+), 6 deletions(-)

--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -105,7 +105,7 @@ EXPORT_SYMBOL(irq_fpu_usable);
void save_fpregs_to_fpstate(struct fpu *fpu)
{
if (likely(use_xsave())) {
- os_xsave(&fpu->fpstate->regs.xsave);
+ os_xsave(fpu->fpstate);

/*
* AVX512 state is tracked here because its use is
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -349,7 +349,6 @@ static bool __fpu_restore_sig(void __use
if (__copy_from_user(&env, buf, sizeof(env)))
return false;

- fpregs = &fpu->fpstate->regs;
/*
* By setting TIF_NEED_FPU_LOAD it is ensured that our xstate is
* not modified on context switch and that the xstate is considered
@@ -367,13 +366,14 @@ static bool __fpu_restore_sig(void __use
* the right place in memory. It's ia32 mode. Shrug.
*/
if (xfeatures_mask_supervisor())
- os_xsave(&fpregs->xsave);
+ os_xsave(fpu->fpstate);
set_thread_flag(TIF_NEED_FPU_LOAD);
}
__fpu_invalidate_fpregs_state(fpu);
__cpu_invalidate_fpregs_state();
fpregs_unlock();

+ fpregs = &fpu->fpstate->regs;
if (use_xsave() && !fx_only) {
if (copy_sigframe_from_user_to_xstate(&fpregs->xsave, buf_fx))
return false;
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -101,16 +101,16 @@ extern void *get_xsave_addr(struct xregs
* Uses either XSAVE or XSAVEOPT or XSAVES depending on the CPU features
* and command line options. The choice is permanent until the next reboot.
*/
-static inline void os_xsave(struct xregs_state *xstate)
+static inline void os_xsave(struct fpstate *fpstate)
{
- u64 mask = xfeatures_mask_all;
+ u64 mask = fpstate->xfeatures;
u32 lmask = mask;
u32 hmask = mask >> 32;
int err;

WARN_ON_FPU(!alternatives_patched);

- XSTATE_XSAVE(xstate, lmask, hmask, err);
+ XSTATE_XSAVE(&fpstate->regs.xsave, lmask, hmask, err);

/* We should never fault when copying to a kernel buffer: */
WARN_ON_FPU(err);