Atomic instructions require data they operate on to be aligned according to data size. I.e. 32-bit atomic values must be 32-bit aligned while 64-bit values must be 64-bit aligned.
Otherwise even if CPU may handle not-aligend normal data access, still atomic instructions fail and typically raise an exception leaving us dead in the water. This came-up during lengthly discussion here: http://lists.infradead.org/pipermail/linux-snps-arc/2018-July/004022.html Signed-off-by: Alexey Brodkin <abrod...@synopsys.com> Cc: Will Deacon <will.dea...@arm.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Boqun Feng <boqun.f...@gmail.com> Cc: Russell King <li...@armlinux.org.uk> Cc: Arnd Bergmann <a...@arndb.de> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ingo Molnar <mi...@redhat.com> Cc: Darren Hart <dvh...@infradead.org> Cc: Shuah Khan <sh...@kernel.org> Cc: "Paul E. McKenney" <paul...@linux.vnet.ibm.com> Cc: Josh Triplett <j...@joshtriplett.org> Cc: Steven Rostedt <rost...@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> Cc: Lai Jiangshan <jiangshan...@gmail.com> Cc: David Laight <david.lai...@aculab.com> Cc: Geert Uytterhoeven <ge...@linux-m68k.org> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/arm/include/asm/atomic.h | 2 +- include/asm-generic/atomic64.h | 2 +- include/linux/types.h | 4 ++-- tools/include/linux/types.h | 2 +- tools/testing/selftests/futex/include/atomic.h | 2 +- .../rcutorture/formal/srcu-cbmc/include/linux/types.h | 4 ++-- 6 files changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h index 66d0e215a773..2ed6d7cf1407 100644 --- a/arch/arm/include/asm/atomic.h +++ b/arch/arm/include/asm/atomic.h @@ -267,7 +267,7 @@ ATOMIC_OPS(xor, ^=, eor) #ifndef CONFIG_GENERIC_ATOMIC64 typedef struct { - long long counter; + u64 __aligned(8) counter; } atomic64_t; #define ATOMIC64_INIT(i) { (i) } diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h index 8d28eb010d0d..b94b749b5952 100644 --- a/include/asm-generic/atomic64.h +++ b/include/asm-generic/atomic64.h @@ -13,7 +13,7 @@ #define _ASM_GENERIC_ATOMIC64_H typedef struct { - long long counter; + u64 __aligned(8) counter; } atomic64_t; #define ATOMIC64_INIT(i) { (i) } diff --git a/include/linux/types.h b/include/linux/types.h index 9834e90aa010..e2f631782621 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -174,12 +174,12 @@ typedef phys_addr_t resource_size_t; typedef unsigned long irq_hw_number_t; typedef struct { - int counter; + u32 __aligned(4) counter; } atomic_t; #ifdef CONFIG_64BIT typedef struct { - long counter; + u64 __aligned(8) counter; } atomic64_t; #endif diff --git a/tools/include/linux/types.h b/tools/include/linux/types.h index 154eb4e3ca7c..c913e26ea4eb 100644 --- a/tools/include/linux/types.h +++ b/tools/include/linux/types.h @@ -59,7 +59,7 @@ typedef __u64 __bitwise __le64; typedef __u64 __bitwise __be64; typedef struct { - int counter; + u32 __aligned(4) counter; } atomic_t; #ifndef __aligned_u64 diff --git a/tools/testing/selftests/futex/include/atomic.h b/tools/testing/selftests/futex/include/atomic.h index f861da3e31ab..34e14295e492 100644 --- a/tools/testing/selftests/futex/include/atomic.h +++ b/tools/testing/selftests/futex/include/atomic.h @@ -23,7 +23,7 @@ #define _ATOMIC_H typedef struct { - volatile int val; + volatile u32 __aligned(4) val; } atomic_t; #define ATOMIC_INITIALIZER { 0 } diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h index 891ad13e95b2..32ce965187b3 100644 --- a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h +++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h @@ -100,12 +100,12 @@ typedef phys_addr_t resource_size_t; typedef unsigned long irq_hw_number_t; typedef struct { - int counter; + u32 __aligned(4) counter; } atomic_t; #ifdef CONFIG_64BIT typedef struct { - long counter; + u64 __aligned(8) counter; } atomic64_t; #endif -- 2.17.1 _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
