diff options
| author | Ralf Baechle <ralf@linux-mips.org> | 2006-09-27 20:45:21 -0400 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2007-02-13 17:40:50 -0500 |
| commit | f65e4fa8e0c6022ad58dc88d1b11b12589ed7f9f (patch) | |
| tree | 2405e012e079693e0fcfde9ff981c549d6c68a21 /include/asm-mips/system.h | |
| parent | 509cb37e173d4e39cec47238397e91b718730794 (diff) | |
[MIPS] Improve branch prediction in ll/sc atomic operations.
Now that finally all supported versions of binutils have functioning
support for .subsection use .subsection to tweak the branch prediction
I did not modify the R10000 errata variants because it seems unclear if
this will invalidate the workaround which actually relies on the cheesy
prediction of branch likely to cause a misspredict if the sc was
successful.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'include/asm-mips/system.h')
| -rw-r--r-- | include/asm-mips/system.h | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/include/asm-mips/system.h b/include/asm-mips/system.h index 5e1289c85ed9..597a3743f6a1 100644 --- a/include/asm-mips/system.h +++ b/include/asm-mips/system.h | |||
| @@ -110,7 +110,10 @@ static inline unsigned long __xchg_u32(volatile int * m, unsigned int val) | |||
| 110 | " move %2, %z4 \n" | 110 | " move %2, %z4 \n" |
| 111 | " .set mips3 \n" | 111 | " .set mips3 \n" |
| 112 | " sc %2, %1 \n" | 112 | " sc %2, %1 \n" |
| 113 | " beqz %2, 1b \n" | 113 | " beqz %2, 2f \n" |
| 114 | " .subsection 2 \n" | ||
| 115 | "2: b 1b \n" | ||
| 116 | " .previous \n" | ||
| 114 | " .set mips0 \n" | 117 | " .set mips0 \n" |
| 115 | : "=&r" (retval), "=m" (*m), "=&r" (dummy) | 118 | : "=&r" (retval), "=m" (*m), "=&r" (dummy) |
| 116 | : "R" (*m), "Jr" (val) | 119 | : "R" (*m), "Jr" (val) |
| @@ -155,7 +158,10 @@ static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val) | |||
| 155 | "1: lld %0, %3 # xchg_u64 \n" | 158 | "1: lld %0, %3 # xchg_u64 \n" |
| 156 | " move %2, %z4 \n" | 159 | " move %2, %z4 \n" |
| 157 | " scd %2, %1 \n" | 160 | " scd %2, %1 \n" |
| 158 | " beqz %2, 1b \n" | 161 | " beqz %2, 2f \n" |
| 162 | " .subsection 2 \n" | ||
| 163 | "2: b 1b \n" | ||
| 164 | " .previous \n" | ||
| 159 | " .set mips0 \n" | 165 | " .set mips0 \n" |
| 160 | : "=&r" (retval), "=m" (*m), "=&r" (dummy) | 166 | : "=&r" (retval), "=m" (*m), "=&r" (dummy) |
| 161 | : "R" (*m), "Jr" (val) | 167 | : "R" (*m), "Jr" (val) |
| @@ -232,8 +238,11 @@ static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old, | |||
| 232 | " move $1, %z4 \n" | 238 | " move $1, %z4 \n" |
| 233 | " .set mips3 \n" | 239 | " .set mips3 \n" |
| 234 | " sc $1, %1 \n" | 240 | " sc $1, %1 \n" |
| 235 | " beqz $1, 1b \n" | 241 | " beqz $1, 3f \n" |
| 236 | "2: \n" | 242 | "2: \n" |
| 243 | " .subsection 2 \n" | ||
| 244 | "3: b 1b \n" | ||
| 245 | " .previous \n" | ||
| 237 | " .set pop \n" | 246 | " .set pop \n" |
| 238 | : "=&r" (retval), "=R" (*m) | 247 | : "=&r" (retval), "=R" (*m) |
| 239 | : "R" (*m), "Jr" (old), "Jr" (new) | 248 | : "R" (*m), "Jr" (old), "Jr" (new) |
| @@ -283,8 +292,11 @@ static inline unsigned long __cmpxchg_u64(volatile int * m, unsigned long old, | |||
| 283 | " bne %0, %z3, 2f \n" | 292 | " bne %0, %z3, 2f \n" |
| 284 | " move $1, %z4 \n" | 293 | " move $1, %z4 \n" |
| 285 | " scd $1, %1 \n" | 294 | " scd $1, %1 \n" |
| 286 | " beqz $1, 1b \n" | 295 | " beqz $1, 3f \n" |
| 287 | "2: \n" | 296 | "2: \n" |
| 297 | " .subsection 2 \n" | ||
| 298 | "3: b 1b \n" | ||
| 299 | " .previous \n" | ||
| 288 | " .set pop \n" | 300 | " .set pop \n" |
| 289 | : "=&r" (retval), "=R" (*m) | 301 | : "=&r" (retval), "=R" (*m) |
| 290 | : "R" (*m), "Jr" (old), "Jr" (new) | 302 | : "R" (*m), "Jr" (old), "Jr" (new) |