It's sufficient to use only 16 bits instead of 32 bits for the
length and condition fields of the alternative table.
bloat-o-meter shows a reduction of -0.01% by this change:
Total: Before=10196505, After=10195529, chg -0.01%
$ ls -la vmlinux vmlinux.before
-rwxr-xr-x 14437324 vmlinux
-rwxr-xr-x 14449512 vmlinux.before
Signed-off-by: Helge Deller <deller@xxxxxx>
---
arch/parisc/include/asm/alternative.h | 21 ++++++++++++---------
arch/parisc/kernel/alternative.c | 7 ++++---
2 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/arch/parisc/include/asm/alternative.h b/arch/parisc/include/asm/alternative.h
index 0ec54f43d6d2..1ed45fd085d3 100644
--- a/arch/parisc/include/asm/alternative.h
+++ b/arch/parisc/include/asm/alternative.h
@@ -22,10 +22,10 @@
struct alt_instr {
s32 orig_offset; /* offset to original instructions */
- s32 len; /* end of original instructions */
- u32 cond; /* see ALT_COND_XXX */
+ s16 len; /* end of original instructions */
+ u16 cond; /* see ALT_COND_XXX */
u32 replacement; /* replacement instruction or code */
-};
+} __packed;
void set_kernel_text_rw(int enable_read_write);
void apply_alternatives_all(void);
@@ -35,8 +35,9 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end,
/* Alternative SMP implementation. */
#define ALTERNATIVE(cond, replacement) "!0:" \
".section .altinstructions, \"aw\" !" \
- ".word (0b-4-.), 1, " __stringify(cond) "," \
- __stringify(replacement) " !" \
+ ".word (0b-4-.) !" \
+ ".hword 1, " __stringify(cond) " !" \
+ ".word " __stringify(replacement) " !" \
".previous"
#else
@@ -44,15 +45,17 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end,
/* to replace one single instructions by a new instruction */
#define ALTERNATIVE(from, to, cond, replacement)\
.section .altinstructions, "aw" ! \
- .word (from - .), (to - from)/4 ! \
- .word cond, replacement ! \
+ .word (from - .) ! \
+ .hword (to - from)/4, cond ! \
+ .word replacement ! \
.previous
/* to replace multiple instructions by new code */
#define ALTERNATIVE_CODE(from, num_instructions, cond, new_instr_ptr)\
.section .altinstructions, "aw" ! \
- .word (from - .), -num_instructions ! \
- .word cond, (new_instr_ptr - .) ! \
+ .word (from - .) ! \
+ .hword -num_instructions, cond ! \
+ .word (new_instr_ptr - .) ! \
.previous
#endif /* __ASSEMBLY__ */
diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c
index daa1e9047275..66f5672c70bd 100644
--- a/arch/parisc/kernel/alternative.c
+++ b/arch/parisc/kernel/alternative.c
@@ -26,7 +26,7 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
struct alt_instr *entry;
int index = 0, applied = 0;
int num_cpus = num_online_cpus();
- u32 cond_check;
+ u16 cond_check;
cond_check = ALT_COND_ALWAYS |
((num_cpus == 1) ? ALT_COND_NO_SMP : 0) |
@@ -45,8 +45,9 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
for (entry = start; entry < end; entry++, index++) {
- u32 *from, cond, replacement;
- s32 len;
+ u32 *from, replacement;
+ u16 cond;
+ s16 len;
from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
len = entry->len;
--
2.37.3
