parisc: Mark pointers volatile in __xchg8(), __xchg32() and __xchg64()

Let the complier treat the pointers volatile to ensure that they get accessed atomicly. Signed-off-by: John David Anglin <[email protected]> Signed-off-by: Helge Deller <[email protected]>
berg · Oct 15, 2020 · 2a7d4ee · 2a7d4ee
1 parent 4df82ce
commit 2a7d4ee
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Showing 2 changed files with 10 additions and 10 deletions.
diff --git a/arch/parisc/include/asm/cmpxchg.h b/arch/parisc/include/asm/cmpxchg.h
@@ -14,22 +14,22 @@
 extern void __xchg_called_with_bad_pointer(void);
 
 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */
-extern unsigned long __xchg8(char, char *);
-extern unsigned long __xchg32(int, int *);
+extern unsigned long __xchg8(char, volatile char *);
+extern unsigned long __xchg32(int, volatile int *);
 #ifdef CONFIG_64BIT
-extern unsigned long __xchg64(unsigned long, unsigned long *);
+extern unsigned long __xchg64(unsigned long, volatile unsigned long *);
 #endif
 
 /* optimizer better get rid of switch since size is a constant */
 static inline unsigned long
-__xchg(unsigned long x, __volatile__ void *ptr, int size)
+__xchg(unsigned long x, volatile void *ptr, int size)
 {
 	switch (size) {
 #ifdef CONFIG_64BIT
-	case 8: return __xchg64(x, (unsigned long *) ptr);
+	case 8: return __xchg64(x, (volatile unsigned long *) ptr);
 #endif
-	case 4: return __xchg32((int) x, (int *) ptr);
-	case 1: return __xchg8((char) x, (char *) ptr);
+	case 4: return __xchg32((int) x, (volatile int *) ptr);
+	case 1: return __xchg8((char) x, (volatile char *) ptr);
 	}
 	__xchg_called_with_bad_pointer();
 	return x;

diff --git a/arch/parisc/lib/bitops.c b/arch/parisc/lib/bitops.c
@@ -18,7 +18,7 @@ arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
 #endif
 
 #ifdef CONFIG_64BIT
-unsigned long __xchg64(unsigned long x, unsigned long *ptr)
+unsigned long __xchg64(unsigned long x, volatile unsigned long *ptr)
 {
 	unsigned long temp, flags;
 
@@ -30,7 +30,7 @@ unsigned long __xchg64(unsigned long x, unsigned long *ptr)
 }
 #endif
 
-unsigned long __xchg32(int x, int *ptr)
+unsigned long __xchg32(int x, volatile int *ptr)
 {
 	unsigned long flags;
 	long temp;
@@ -43,7 +43,7 @@ unsigned long __xchg32(int x, int *ptr)
 }
 
 
-unsigned long __xchg8(char x, char *ptr)
+unsigned long __xchg8(char x, volatile char *ptr)
 {
 	unsigned long flags;
 	long temp;