Revert "The arm64 architecture has the ability to exclusively load and store"

Steve Capper has posted a v2 of the patch that gives a better path
performance.

This reverts commit 64b57f9219ea2f251c4c3c43c3b36187287d7f9d.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ca9130851f8aeec45d1efeaee5b81b40f1da931e..c52894e6130b5737b97cb463a09fa8f22d41dea4 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -29,13 +29,11 @@ config ARM64
        select GENERIC_STRNLEN_USER
        select GENERIC_TIME_VSYSCALL
        select HARDIRQS_SW_RESEND
-       select HAVE_ALIGNED_STRUCT_PAGE if SLUB
        select HAVE_ARCH_AUDITSYSCALL
        select HAVE_ARCH_JUMP_LABEL
        select HAVE_ARCH_KGDB
        select HAVE_ARCH_TRACEHOOK
        select HAVE_C_RECORDMCOUNT
-       select HAVE_CMPXCHG_DOUBLE
        select HAVE_DEBUG_BUGVERBOSE
        select HAVE_DEBUG_KMEMLEAK
        select HAVE_DMA_API_DEBUG

diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h
index ad3d7d1f842a1c3aa114f0ed0eb2cbdf66bdc8cb..57c0fa7bf71141c62f954f730d50fddb8669cfa7 100644 (file)
--- a/arch/arm64/include/asm/cmpxchg.h
+++ b/arch/arm64/include/asm/cmpxchg.h
@@ -19,7 +19,6 @@
 #define __ASM_CMPXCHG_H
 
 #include <linux/bug.h>
-#include <linux/mmdebug.h>
 
 #include <asm/barrier.h>
 
@@ -148,51 +147,6 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
        return oldval;
 }
 
-#define system_has_cmpxchg_double()     1
-
-static inline int __cmpxchg_double(volatile void *ptr1, volatile void *ptr2,
-               unsigned long old1, unsigned long old2,
-               unsigned long new1, unsigned long new2, int size)
-{
-       unsigned long loop, lost;
-
-       switch (size) {
-       case 8:
-               VM_BUG_ON((unsigned long *)ptr2 - (unsigned long *)ptr1 != 1);
-               do {
-                       asm volatile("// __cmpxchg_double8\n"
-                       "       ldxp    %0, %1, %2\n"
-                       "       eor     %0, %0, %3\n"
-                       "       eor     %1, %1, %4\n"
-                       "       orr     %1, %0, %1\n"
-                       "       mov     %w0, #0\n"
-                       "       cbnz    %1, 1f\n"
-                       "       stxp    %w0, %5, %6, %2\n"
-                       "1:\n"
-                               : "=&r"(loop), "=&r"(lost), "+Q" (*(u64 *)ptr1)
-                               : "r" (old1), "r"(old2), "r"(new1), "r"(new2));
-               } while (loop);
-               break;
-       default:
-               BUILD_BUG();
-       }
-
-       return !lost;
-}
-
-static inline int __cmpxchg_double_mb(volatile void *ptr1, volatile void *ptr2,
-                       unsigned long old1, unsigned long old2,
-                       unsigned long new1, unsigned long new2, int size)
-{
-       int ret;
-
-       smp_mb();
-       ret = __cmpxchg_double(ptr1, ptr2, old1, old2, new1, new2, size);
-       smp_mb();
-
-       return ret;
-}
-
 static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
                                         unsigned long new, int size)
 {
@@ -214,15 +168,6 @@ static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
        __ret; \
 })
 
-#define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
-({\
-       int __ret;\
-       __ret = __cmpxchg_double_mb((ptr1), (ptr2), (unsigned long)(o1), \
-                       (unsigned long)(o2), (unsigned long)(n1), \
-                       (unsigned long)(n2), sizeof(*(ptr1)));\
-       __ret; \
-})
-
 #define cmpxchg_local(ptr, o, n) \
 ({ \
        __typeof__(*(ptr)) __ret; \
@@ -232,28 +177,6 @@ static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
        __ret; \
 })
 
-#define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2) \
-({\
-       int __ret;\
-       unsigned long flags;\
-       raw_local_irq_save(flags);\
-       __ret = cmpxchg_double(raw_cpu_ptr(&(ptr1)), raw_cpu_ptr(&(ptr2)), \
-                       o1, o2, n1, n2); \
-       raw_local_irq_restore(flags); \
-       __ret; \
-})
-
-#define this_cpu_cmpxchg_double_4(ptr1, ptr2, o1, o2, n1, n2) \
-({\
-       int __ret;\
-       unsigned long flags;\
-       raw_local_irq_save(flags);\
-       __ret = cmpxchg_double(raw_cpu_ptr(&(ptr1)), raw_cpu_ptr(&(ptr2)), \
-                       o1, o2, n1, n2); \
-       raw_local_irq_restore(flags); \
-       __ret; \
-})
-
 #define cmpxchg64(ptr,o,n)             cmpxchg((ptr),(o),(n))
 #define cmpxchg64_local(ptr,o,n)       cmpxchg_local((ptr),(o),(n))