UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

arch/sparc: Introduce xchg16 for SPARC 

SPARC supports 32 bit and 64 bit xchg right now. Add the support
for 16 bit (2 byte) xchg. This is required to support queued spinlock
feature which uses 2 byte xchg. This is achieved using 4 byte cas
instructions with byte manipulations.

Also re-arranged the code to call __cmpxchg_u32 inside xchg16.

Signed-off-by: Babu Moger <babu.moger@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Babu Moger 2017-05-24 17:55:14 -06:00 committed by David S. Miller
parent a37594f198
commit 79d39e2bab
1 changed files with 39 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
arch/sparc/include/asm/cmpxchg_64.h
View File

@ -6,6 +6,17 @@
#ifndef __ARCH_SPARC64_CMPXCHG__
#define __ARCH_SPARC64_CMPXCHG__
static inline unsigned long
__cmpxchg_u32(volatile int *m, int old, int new)
{
__asm__ __volatile__("cas [%2], %3, %0"
: "=&r" (new)
: "0" (new), "r" (m), "r" (old)
: "memory");
return new;
}
static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
{
unsigned long tmp1, tmp2;
@ -44,10 +55,38 @@ static inline unsigned long xchg64(__volatile__ unsigned long *m, unsigned long
void __xchg_called_with_bad_pointer(void);
/*
* Use 4 byte cas instruction to achieve 2 byte xchg. Main logic
* here is to get the bit shift of the byte we are interested in.
* The XOR is handy for reversing the bits for big-endian byte order.
*/
static inline unsigned long
xchg16(__volatile__ unsigned short *m, unsigned short val)
{
unsigned long maddr = (unsigned long)m;
int bit_shift = (((unsigned long)m & 2) ^ 2) << 3;
unsigned int mask = 0xffff << bit_shift;
unsigned int *ptr = (unsigned int *) (maddr & ~2);
unsigned int old32, new32, load32;
/* Read the old value */
load32 = *ptr;
do {
old32 = load32;
new32 = (load32 & (~mask)) | val << bit_shift;
load32 = __cmpxchg_u32(ptr, old32, new32);
} while (load32 != old32);
return (load32 & mask) >> bit_shift;
}
static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
int size)
{
switch (size) {
case 2:
return xchg16(ptr, x);
case 4:
return xchg32(ptr, x);
case 8:
@ -65,16 +104,6 @@ static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr,
#include <asm-generic/cmpxchg-local.h>
static inline unsigned long
__cmpxchg_u32(volatile int *m, int old, int new)
{
__asm__ __volatile__("cas [%2], %3, %0"
: "=&r" (new)
: "0" (new), "r" (m), "r" (old)
: "memory");
return new;
}
static inline unsigned long
__cmpxchg_u64(volatile long *m, unsigned long old, unsigned long new)