From: Nicholas Piggin Date: Fri, 8 May 2020 04:33:58 +0000 (+1000) Subject: powerpc/pseries/ras: Fix FWNMI_VALID off by one X-Git-Tag: v5.8-rc1~132^2~166 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=deb70f7a35a22dffa55b2c3aac71bc6fb0f486ce;p=thirdparty%2Fkernel%2Flinux.git powerpc/pseries/ras: Fix FWNMI_VALID off by one This was discovered developing qemu fwnmi sreset support. This off-by-one bug means the last 16 bytes of the rtas area can not be used for a 16 byte save area. It's not a serious bug, and QEMU implementation has to retain a workaround for old kernels, but it's good to tighten it. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Acked-by: Mahesh Salgaonkar Link: https://lore.kernel.org/r/20200508043408.886394-7-npiggin@gmail.com --- diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index ac92f8687ea37..a5bd0f747bb16 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -395,10 +395,11 @@ static irqreturn_t ras_error_interrupt(int irq, void *dev_id) /* * Some versions of FWNMI place the buffer inside the 4kB page starting at * 0x7000. Other versions place it inside the rtas buffer. We check both. + * Minimum size of the buffer is 16 bytes. */ #define VALID_FWNMI_BUFFER(A) \ - ((((A) >= 0x7000) && ((A) < 0x7ff0)) || \ - (((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16)))) + ((((A) >= 0x7000) && ((A) <= 0x8000 - 16)) || \ + (((A) >= rtas.base) && ((A) <= (rtas.base + rtas.size - 16)))) static inline struct rtas_error_log *fwnmi_get_errlog(void) {