ARM: 8731/1: Fix csum_partial_copy_from_user() stack mismatch

An additional 'ip' will be pushed to the stack, for restoring the
DACR later, if CONFIG_CPU_SW_DOMAIN_PAN defined.

However, the fixup still get the err_ptr by add #8*4 to sp, which
results in the fact that the code area pointed by the LR will be
overwritten, or the kernel will crash if CONFIG_DEBUG_RODATA is enabled.

This patch fixes the stack mismatch.

Fixes: a5e090acbf54 ("ARM: software-based priviledged-no-access support")
Signed-off-by: Lvqiang Huang <Lvqiang.Huang@spreadtrum.com>
Signed-off-by: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/lib/csumpartialcopyuser.S b/arch/arm/lib/csumpartialcopyuser.S
index 1712f13..b83fdc0 100644 (file)
--- a/arch/arm/lib/csumpartialcopyuser.S
+++ b/arch/arm/lib/csumpartialcopyuser.S
@@ -85,7 +85,11 @@
                .pushsection .text.fixup,"ax"
                .align  4
 9001:          mov     r4, #-EFAULT
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+               ldr     r5, [sp, #9*4]          @ *err_ptr
+#else
                ldr     r5, [sp, #8*4]          @ *err_ptr
+#endif
                str     r4, [r5]
                ldmia   sp, {r1, r2}            @ retrieve dst, len
                add     r2, r2, r1