powerpc/pseries/ras: fwnmi avoid modifying r3 in error case (dff681e9) · Commits · 戴 / test

If there is some error with the fwnmi save area, r3 has already been modified which doesn't help with debugging. Only update r3 when to restore the saved value. Signed-off-by:

Nicholas Piggin <npiggin@gmail.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200508043408.886394-8-npiggin@gmail.com

arch/powerpc/platforms/pseries/ras.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -423,18 +423,19 @@ static inline struct rtas_error_log *fwnmi_get_errlog(void)
		*/
		static struct rtas_error_log fwnmi_get_errinfo(struct pt_regs regs)
		{
		unsigned long savep_ra;
		unsigned long *savep;
		struct rtas_error_log *h;

		/* Mask top two bits */
		regs->gpr[3] &= ~(0x3UL << 62);
		savep_ra = regs->gpr[3] & ~(0x3UL << 62);

		if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
		if (!VALID_FWNMI_BUFFER(savep_ra)) {
		printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
		return NULL;
		}

		savep = __va(regs->gpr[3]);
		savep = __va(savep_ra);
		regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */

		h = (struct rtas_error_log *)&savep[1];

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