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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Luis Araneda <luaraneda@gmail.com>,
        Michal Simek <michal.simek@xilinx.com>
Subject: [PATCH 4.4 86/99] ARM: zynq: Use memcpy_toio instead of memcpy on smp bring-up
Date:   Thu,  3 Oct 2019 17:53:49 +0200
Message-Id: <20191003154338.035880919@linuxfoundation.org>
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From: Luis Araneda <luaraneda@gmail.com>

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@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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,
 							trampoline_size);
 			writel(address, zero + trampoline_size);