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Commit d96f234f authored by Anton Blanchard's avatar Anton Blanchard Committed by Michael Ellerman
Browse files

powerpc: Avoid load hit store in setup_sigcontext() 



In setup_sigcontext(), we set current->thread.vrsave then use it
straight after. Since current is hidden from the compiler via inline
assembly, it cannot optimise this and we end up with a load hit store.

Fix this by using a temporary.

Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 8eb98037

arch/powerpc/kernel/signal_64.c

+8 −3
Original line number Original line Diff line number Diff line
@@ -104,6 +104,7 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 
	 */

	 */

#ifdef CONFIG_ALTIVEC

#ifdef CONFIG_ALTIVEC

	elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);

	elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);

	unsigned long vrsave;

#endif

#endif

	unsigned long msr = regs->msr;

	unsigned long msr = regs->msr;

	long err = 0;

	long err = 0;
@@ -125,9 +126,13 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 
	/* We always copy to/from vrsave, it's 0 if we don't have or don't

	/* We always copy to/from vrsave, it's 0 if we don't have or don't

	 * use altivec.

	 * use altivec.

	 */

	 */

	if (cpu_has_feature(CPU_FTR_ALTIVEC))

	vrsave = 0;

		current->thread.vrsave = mfspr(SPRN_VRSAVE);

	if (cpu_has_feature(CPU_FTR_ALTIVEC)) {

	err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);

		vrsave = mfspr(SPRN_VRSAVE);

		current->thread.vrsave = vrsave;

	}



	err |= __put_user(vrsave, (u32 __user *)&v_regs[33]);

#else /* CONFIG_ALTIVEC */

#else /* CONFIG_ALTIVEC */

	err |= __put_user(0, &sc->v_regs);

	err |= __put_user(0, &sc->v_regs);

#endif /* CONFIG_ALTIVEC */

#endif /* CONFIG_ALTIVEC */