Commit 073e627a authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145323.025695590@linutronix.de
parent be31dfdf

arch/x86/kernel/fpu/core.c

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/fpu/signal.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

arch/x86/kernel/fpu/xstate.h

+3 −3
Original line number Diff line number Diff line
@@ -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);