From d2e59d0ff4c44d1f6f8ed884a5bea7d1bb7fd98c Mon Sep 17 00:00:00 2001 From: Krunoslav Kovac Date: Thu, 6 Aug 2020 17:54:47 -0400 Subject: [PATCH] drm/amd/display: fix pow() crashing when given base 0 [Why&How] pow(a,x) is implemented as exp(x*log(a)). log(0) will crash. So return 0^x = 0, unless x=0, convention seems to be 0^0 = 1. Cc: stable@vger.kernel.org Signed-off-by: Krunoslav Kovac Reviewed-by: Anthony Koo Acked-by: Rodrigo Siqueira Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/include/fixed31_32.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/amd/display/include/fixed31_32.h b/drivers/gpu/drm/amd/display/include/fixed31_32.h index 89ef9f6860e5..16df2a485dd0 100644 --- a/drivers/gpu/drm/amd/display/include/fixed31_32.h +++ b/drivers/gpu/drm/amd/display/include/fixed31_32.h @@ -431,6 +431,9 @@ struct fixed31_32 dc_fixpt_log(struct fixed31_32 arg); */ static inline struct fixed31_32 dc_fixpt_pow(struct fixed31_32 arg1, struct fixed31_32 arg2) { + if (arg1.value == 0) + return arg2.value == 0 ? dc_fixpt_one : dc_fixpt_zero; + return dc_fixpt_exp( dc_fixpt_mul( dc_fixpt_log(arg1),