[PATCH 3.16 14/72] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up

From: Ben Hutchings
Date: Sun Dec 08 2019 - 08:56:11 EST

3.16.79-rc1 review patch. If anyone has any objections, please let me know.


From: Luis Araneda <luaraneda@xxxxxxxxx>

commit b7005d4ef4f3aa2dc24019ffba03a322557ac43d upstream.

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@xxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
arch/arm/mach-zynq/platsmp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c
@@ -65,7 +65,7 @@ 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,
writel(address, zero + trampoline_size);