File 55534b25-arm-provide-add_sized.patch of Package xen.6117
# Commit 890674d13feb4a270aa112ca452dcf62fdd53f34
# Date 2015-05-13 15:01:25 +0200
# Author David Vrabel <david.vrabel@citrix.com>
# Committer Jan Beulich <jbeulich@suse.com>
arm: provide add_sized()
add_sized(ptr, inc) adds inc to the value at ptr using only the correct
size of loads and stores for the type of *ptr. The add is /not/ atomic.
This is needed for ticket locks to ensure the increment of the head ticket
does not affect the tail ticket.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
--- a/xen/include/asm-arm/atomic.h
+++ b/xen/include/asm-arm/atomic.h
@@ -23,6 +23,17 @@ static inline void name(volatile type *a
: reg (val)); \
}
+#define build_add_sized(name, size, width, type, reg) \
+static inline void name(volatile type *addr, type val) \
+{ \
+ type t; \
+ asm volatile("ldr" size " %"width"1,%0\n" \
+ "add %"width"1,%"width"1,%"width"2\n" \
+ "str" size " %"width"1,%0" \
+ : "=m" (*(volatile type *)addr), "=r" (t) \
+ : reg (val)); \
+}
+
#if defined (CONFIG_ARM_32)
#define BYTE ""
#define WORD ""
@@ -46,6 +57,10 @@ build_atomic_read(read_u64_atomic, "x",
build_atomic_write(write_u64_atomic, "x", uint64_t, "r")
#endif
+build_add_sized(add_u8_sized, "b", BYTE, uint8_t, "ri")
+build_add_sized(add_u16_sized, "h", WORD, uint16_t, "ri")
+build_add_sized(add_u32_sized, "", WORD, uint32_t, "ri")
+
void __bad_atomic_size(void);
#define read_atomic(p) ({ \
@@ -70,6 +85,17 @@ void __bad_atomic_size(void);
__x; \
})
+#define add_sized(p, x) ({ \
+ typeof(*(p)) __x = (x); \
+ switch ( sizeof(*(p)) ) \
+ { \
+ case 1: add_u8_sized((uint8_t *)(p), __x); break; \
+ case 2: add_u16_sized((uint16_t *)(p), __x); break; \
+ case 4: add_u32_sized((uint32_t *)(p), __x); break; \
+ default: __bad_atomic_size(); break; \
+ } \
+})
+
/*
* NB. I've pushed the volatile qualifier into the operations. This allows
* fast accessors such as _atomic_read() and _atomic_set() which don't give
