x86/fpu/xstate: Use fpstate for os_xsave()

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>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145323.025695590@linutronix.de

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index cb48c80..f4db70b 100644 (file)
--- 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

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index aa93291..5aca418 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -349,7 +349,6 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
        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 __user *buf, void __user *buf_fx,
                 * 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;

diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 99f8cfe..24a1479 100644 (file)
--- 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_state *xsave, int xfeature_nr);
  * 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);