Stefano Stabellini
2013-Nov-15 17:16 UTC
[PATCH v2] arm: remove !CPU_V6 and !GENERIC_ATOMIC64 build dependencies for XEN
Remove !GENERIC_ATOMIC64 build dependency:
- rename atomic64_xchg to armv7_atomic64_xchg and define it even ifdef
GENERIC_ATOMIC64;
- call armv7_atomic64_xchg directly from xen/events.h.
Remove !CPU_V6 build dependency:
- introduce __cmpxchg8 and __cmpxchg16, compiled even ifdef
CONFIG_CPU_V6;
- implement sync_cmpxchg using __cmpxchg8 and __cmpxchg16.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: arnd@arndb.de
CC: linux@arm.linux.org.uk
Changes in v2:
- handle return value of __cmpxchg8 and __cmpxchg16 in __cmpxchg;
- remove sync_cmpxchg to sync_cmpxchg16 rename in grant-table.c,
implement a generic sync_cmpxchg instead.
---
arch/arm/Kconfig | 3 +-
arch/arm/include/asm/atomic.h | 47 +++++++++++++++------------
arch/arm/include/asm/cmpxchg.h | 60 ++++++++++++++++++++++++------------
arch/arm/include/asm/sync_bitops.h | 24 ++++++++++++++-
arch/arm/include/asm/xen/events.h | 2 +-
5 files changed, 91 insertions(+), 45 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 01f7013..3a888e1 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1885,8 +1885,7 @@ config XEN_DOM0
config XEN
bool "Xen guest support on ARM (EXPERIMENTAL)"
depends on ARM && AEABI && OF
- depends on CPU_V7 && !CPU_V6
- depends on !GENERIC_ATOMIC64
+ depends on CPU_V7
select ARM_PSCI
select SWIOTLB_XEN
help
diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index da1c77d..35568a8 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -398,26 +398,7 @@ static inline u64 atomic64_cmpxchg(atomic64_t *ptr, u64
old, u64 new)
return oldval;
}
-static inline u64 atomic64_xchg(atomic64_t *ptr, u64 new)
-{
- u64 result;
- unsigned long tmp;
-
- smp_mb();
-
- __asm__ __volatile__("@ atomic64_xchg\n"
-"1: ldrexd %0, %H0, [%3]\n"
-" strexd %1, %4, %H4, [%3]\n"
-" teq %1, #0\n"
-" bne 1b"
- : "=&r" (result), "=&r" (tmp), "+Qo"
(ptr->counter)
- : "r" (&ptr->counter), "r" (new)
- : "cc");
-
- smp_mb();
-
- return result;
-}
+#define armv7_atomic64_xchg atomic64_xchg
static inline u64 atomic64_dec_if_positive(atomic64_t *v)
{
@@ -485,6 +466,30 @@ static inline int atomic64_add_unless(atomic64_t *v, u64 a,
u64 u)
#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL)
-#endif /* !CONFIG_GENERIC_ATOMIC64 */
+#else /* !CONFIG_GENERIC_ATOMIC64 */
+#include <asm-generic/atomic64.h>
+#endif
+
+static inline u64 armv7_atomic64_xchg(atomic64_t *ptr, u64 new)
+{
+ u64 result;
+ unsigned long tmp;
+
+ smp_mb();
+
+ __asm__ __volatile__("@ armv7_atomic64_xchg\n"
+"1: ldrexd %0, %H0, [%3]\n"
+" strexd %1, %4, %H4, [%3]\n"
+" teq %1, #0\n"
+" bne 1b"
+ : "=&r" (result), "=&r" (tmp), "+Qo"
(ptr->counter)
+ : "r" (&ptr->counter), "r" (new)
+ : "cc");
+
+ smp_mb();
+
+ return result;
+}
+
#endif
#endif
diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h
index 4f009c1..451b5ec 100644
--- a/arch/arm/include/asm/cmpxchg.h
+++ b/arch/arm/include/asm/cmpxchg.h
@@ -133,6 +133,44 @@ extern void __bad_cmpxchg(volatile void *ptr, int size);
* cmpxchg only support 32-bits operands on ARMv6.
*/
+static inline unsigned long __cmpxchg8(volatile void *ptr, unsigned long old,
+ unsigned long new)
+{
+ unsigned long oldval, res;
+
+ do {
+ asm volatile("@ __cmpxchg1\n"
+ " ldrexb %1, [%2]\n"
+ " mov %0, #0\n"
+ " teq %1, %3\n"
+ " strexbeq %0, %4, [%2]\n"
+ : "=&r" (res), "=&r" (oldval)
+ : "r" (ptr), "Ir" (old), "r" (new)
+ : "memory", "cc");
+ } while (res);
+
+ return oldval;
+}
+
+static inline unsigned long __cmpxchg16(volatile void *ptr, unsigned long old,
+ unsigned long new)
+{
+ unsigned long oldval, res;
+
+ do {
+ asm volatile("@ __cmpxchg1\n"
+ " ldrexh %1, [%2]\n"
+ " mov %0, #0\n"
+ " teq %1, %3\n"
+ " strexheq %0, %4, [%2]\n"
+ : "=&r" (res), "=&r" (oldval)
+ : "r" (ptr), "Ir" (old), "r" (new)
+ : "memory", "cc");
+ } while (res);
+
+ return oldval;
+}
+
static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
unsigned long new, int size)
{
@@ -141,28 +179,10 @@ static inline unsigned long __cmpxchg(volatile void *ptr,
unsigned long old,
switch (size) {
#ifndef CONFIG_CPU_V6 /* min ARCH >= ARMv6K */
case 1:
- do {
- asm volatile("@ __cmpxchg1\n"
- " ldrexb %1, [%2]\n"
- " mov %0, #0\n"
- " teq %1, %3\n"
- " strexbeq %0, %4, [%2]\n"
- : "=&r" (res), "=&r" (oldval)
- : "r" (ptr), "Ir" (old), "r" (new)
- : "memory", "cc");
- } while (res);
+ oldval = __cmpxchg8(ptr, old, new);
break;
case 2:
- do {
- asm volatile("@ __cmpxchg1\n"
- " ldrexh %1, [%2]\n"
- " mov %0, #0\n"
- " teq %1, %3\n"
- " strexheq %0, %4, [%2]\n"
- : "=&r" (res), "=&r" (oldval)
- : "r" (ptr), "Ir" (old), "r" (new)
- : "memory", "cc");
- } while (res);
+ oldval = __cmpxchg16(ptr, old, new);
break;
#endif
case 4:
diff --git a/arch/arm/include/asm/sync_bitops.h
b/arch/arm/include/asm/sync_bitops.h
index 63479ee..942659a 100644
--- a/arch/arm/include/asm/sync_bitops.h
+++ b/arch/arm/include/asm/sync_bitops.h
@@ -21,7 +21,29 @@
#define sync_test_and_clear_bit(nr, p) _test_and_clear_bit(nr, p)
#define sync_test_and_change_bit(nr, p) _test_and_change_bit(nr, p)
#define sync_test_bit(nr, addr) test_bit(nr, addr)
-#define sync_cmpxchg cmpxchg
+static inline unsigned long sync_cmpxchg(volatile void *ptr,
+ unsigned long old,
+ unsigned long new)
+{
+ unsigned long oldval;
+ int size = sizeof(*(ptr));
+
+ smp_mb();
+ switch (size) {
+ case 1:
+ oldval = __cmpxchg8(ptr, old, new);
+ break;
+ case 2:
+ oldval = __cmpxchg16(ptr, old, new);
+ break;
+ default:
+ oldval = __cmpxchg(ptr, old, new, size);
+ break;
+ }
+ smp_mb();
+
+ return oldval;
+}
#endif
diff --git a/arch/arm/include/asm/xen/events.h
b/arch/arm/include/asm/xen/events.h
index 8b1f37b..4269519 100644
--- a/arch/arm/include/asm/xen/events.h
+++ b/arch/arm/include/asm/xen/events.h
@@ -16,7 +16,7 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
return raw_irqs_disabled_flags(regs->ARM_cpsr);
}
-#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((ptr), \
+#define xchg_xen_ulong(ptr, val) armv7_atomic64_xchg(container_of((ptr), \
atomic64_t, \
counter), (val))
--
1.7.2.5