linux-kernel - [PATCH v2 2/2] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

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Date:   Thu,  8 Aug 2019 08:52:43 -0400
From:   Luis Araneda <luaraneda@...il.com>
To:     linux@...linux.org.uk, michal.simek@...inx.com
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Luis Araneda <luaraneda@...il.com>, stable@...r.kernel.org
Subject: [PATCH v2 2/2] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

This fixes a kernel panic on memcpy when
FORTIFY_SOURCE is enabled.

The initial smp implementation on commit aa7eb2bb4e4a
("arm: zynq: Add smp support")
used memcpy, which worked fine until commit ee333554fed5
("ARM: 8749/1: Kconfig: Add ARCH_HAS_FORTIFY_SOURCE")
enabled overflow checks at runtime, producing a read
overflow panic.

The computed size of memcpy args are:
- p_size (dst): 4294967295 = (size_t) -1
- q_size (src): 1
- size (len): 8

Additionally, the memory is marked as __iomem, so one of
the memcpy_* functions should be used for read/write.

Fixes: aa7eb2bb4e4a ("arm: zynq: Add smp support")
Signed-off-by: Luis Araneda <luaraneda@...il.com>
Cc: stable@...r.kernel.org
---
Changes:
v1 -> v2:
- Reword commit message to include related commits
- Add Fixes tag
- Add Cc to stable
---
 arch/arm/mach-zynq/platsmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
index 38728badabd4..a10085be9073 100644
--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c
@@ -57,7 +57,7 @@ int zynq_cpun_start(u32 address, int cpu)
 			* 0x4: Jump by mov instruction
 			* 0x8: Jumping address
 			*/
-			memcpy((__force void *)zero, &zynq_secondary_trampoline,
+			memcpy_toio(zero, &zynq_secondary_trampoline,
 							trampoline_size);
 			writel(address, zero + trampoline_size);
 
-- 
2.22.0