[PATCH 5.4 23/62] ARM: vexpress/spc: Avoid negative array index when !SMP

Greg Kroah-Hartman
2022-04-26T08:42:50Z

From: Kees Cook <keescook@chromium.org>

[ Upstream commit b3f1dd52c991d79118f35e6d1bf4d7cb09882e38 ]

When building multi_v7_defconfig+CONFIG_SMP=n, -Warray-bounds exposes
a couple negative array index accesses:

arch/arm/mach-vexpress/spc.c: In function 've_spc_clk_init':
arch/arm/mach-vexpress/spc.c:583:21: warning: array subscript -1 is below array bounds of 'bool[2]' {aka '_Bool[2]'} [-Warray-bounds]
583 | if (init_opp_table[cluster])
| ~~~~~~~~~~~~~~^~~~~~~~~
arch/arm/mach-vexpress/spc.c:556:7: note: while referencing 'init_opp_table'
556 | bool init_opp_table[MAX_CLUSTERS] = { false };
| ^~~~~~~~~~~~~~
arch/arm/mach-vexpress/spc.c:592:18: warning: array subscript -1 is below array bounds of 'bool[2]' {aka '_Bool[2]'} [-Warray-bounds]
592 | init_opp_table[cluster] = true;
| ~~~~~~~~~~~~~~^~~~~~~~~
arch/arm/mach-vexpress/spc.c:556:7: note: while referencing 'init_opp_table'
556 | bool init_opp_table[MAX_CLUSTERS] = { false };
| ^~~~~~~~~~~~~~

Skip this logic when built !SMP.

Link: https://lore.kernel.org/r/20220331190443.851661-1-keescook@chromium.org
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/mach-vexpress/spc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-vexpress/spc.c b/arch/arm/mach-vexpress/spc.c
index 1da11bdb1dfb..1c6500c4e6a1 100644
--- a/arch/arm/mach-vexpress/spc.c
+++ b/arch/arm/mach-vexpress/spc.c
@@ -580,7 +580,7 @@ static int __init ve_spc_clk_init(void)
}

cluster = topology_physical_package_id(cpu_dev->id);
- if (init_opp_table[cluster])
+ if (cluster < 0 || init_opp_table[cluster])
continue;

if (ve_init_opp_table(cpu_dev))
--
2.35.1