4.4-stable review patch. If anyone has any objections, please let me know.
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From: Will Deacon will.deacon@arm.com
commit 32c3fa7cdf0c4a3eb8405fc3e13398de019e828b upstream.
For LSE atomics that read and write a register operand, we need to ensure that these operands are annotated as "early clobber" if the register is written before all of the input operands have been consumed. Failure to do so can result in the compiler allocating the same register to both operands, leading to splats such as:
Unable to handle kernel paging request at virtual address 11111122222221 [...] x1 : 1111111122222222 x0 : 1111111122222221 Process swapper/0 (pid: 1, stack limit = 0x000000008209f908) Call trace: test_atomic64+0x1360/0x155c
where x0 has been allocated as both the value to be stored and also the atomic_t pointer.
This patch adds the missing clobbers.
Cc: stable@vger.kernel.org Cc: Dave Martin dave.martin@arm.com Cc: Robin Murphy robin.murphy@arm.com Reported-by: Mark Salter msalter@redhat.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/include/asm/atomic_lse.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
--- a/arch/arm64/include/asm/atomic_lse.h +++ b/arch/arm64/include/asm/atomic_lse.h @@ -114,7 +114,7 @@ static inline void atomic_and(int i, ato /* LSE atomics */ " mvn %w[i], %w[i]\n" " stclr %w[i], %[v]") - : [i] "+r" (w0), [v] "+Q" (v->counter) + : [i] "+&r" (w0), [v] "+Q" (v->counter) : "r" (x1) : "x30"); } @@ -131,7 +131,7 @@ static inline void atomic_sub(int i, ato /* LSE atomics */ " neg %w[i], %w[i]\n" " stadd %w[i], %[v]") - : [i] "+r" (w0), [v] "+Q" (v->counter) + : [i] "+&r" (w0), [v] "+Q" (v->counter) : "r" (x1) : "x30"); } @@ -151,7 +151,7 @@ static inline int atomic_sub_return##nam " neg %w[i], %w[i]\n" \ " ldadd" #mb " %w[i], w30, %[v]\n" \ " add %w[i], %w[i], w30") \ - : [i] "+r" (w0), [v] "+Q" (v->counter) \ + : [i] "+&r" (w0), [v] "+Q" (v->counter) \ : "r" (x1) \ : "x30" , ##cl); \ \ @@ -255,7 +255,7 @@ static inline void atomic64_and(long i, /* LSE atomics */ " mvn %[i], %[i]\n" " stclr %[i], %[v]") - : [i] "+r" (x0), [v] "+Q" (v->counter) + : [i] "+&r" (x0), [v] "+Q" (v->counter) : "r" (x1) : "x30"); } @@ -272,7 +272,7 @@ static inline void atomic64_sub(long i, /* LSE atomics */ " neg %[i], %[i]\n" " stadd %[i], %[v]") - : [i] "+r" (x0), [v] "+Q" (v->counter) + : [i] "+&r" (x0), [v] "+Q" (v->counter) : "r" (x1) : "x30"); } @@ -292,7 +292,7 @@ static inline long atomic64_sub_return## " neg %[i], %[i]\n" \ " ldadd" #mb " %[i], x30, %[v]\n" \ " add %[i], %[i], x30") \ - : [i] "+r" (x0), [v] "+Q" (v->counter) \ + : [i] "+&r" (x0), [v] "+Q" (v->counter) \ : "r" (x1) \ : "x30" , ##cl); \ \ @@ -412,7 +412,7 @@ static inline long __cmpxchg_double##nam " eor %[old1], %[old1], %[oldval1]\n" \ " eor %[old2], %[old2], %[oldval2]\n" \ " orr %[old1], %[old1], %[old2]") \ - : [old1] "+r" (x0), [old2] "+r" (x1), \ + : [old1] "+&r" (x0), [old2] "+&r" (x1), \ [v] "+Q" (*(unsigned long *)ptr) \ : [new1] "r" (x2), [new2] "r" (x3), [ptr] "r" (x4), \ [oldval1] "r" (oldval1), [oldval2] "r" (oldval2) \