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arm64: armv8_deprecated: ensure extension of addr 

Our compat swp emulation holds the compat user address in an unsigned
int, which it passes to __user_swpX_asm(). When a 32-bit value is passed
in a register, the upper 32 bits of the register are unknown, and we
must extend the value to 64 bits before we can use it as a base address.

This patch casts the address to unsigned long to ensure it has been
suitably extended, avoiding the potential issue, and silencing a related
warning from clang.

Fixes: bd35a4adc4 ("arm64: Port SWP/SWPB emulation support from arm")
Cc: <stable@vger.kernel.org> # 3.19.x-
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2017-05-03 16:09:36 +01:00 committed by Catalin Marinas
parent a06040d7a7
commit 55de49f9aa
1 changed files with 2 additions and 1 deletions
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arch/arm64/kernel/armv8_deprecated.c
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@ -306,7 +306,8 @@ do { \
_ASM_EXTABLE(0b, 4b) \ _ASM_EXTABLE(0b, 4b) \
_ASM_EXTABLE(1b, 4b) \ _ASM_EXTABLE(1b, 4b) \
: "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2) \ : "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2) \
: "r" (addr), "i" (-EAGAIN), "i" (-EFAULT), \ : "r" ((unsigned long)addr), "i" (-EAGAIN), \
"i" (-EFAULT), \
"i" (__SWP_LL_SC_LOOPS) \ "i" (__SWP_LL_SC_LOOPS) \
: "memory"); \ : "memory"); \
uaccess_disable(); \ uaccess_disable(); \