diff options
| author | Paul Mundt <lethal@linux-sh.org> | 2006-09-27 15:00:04 +0900 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2006-09-27 15:00:04 +0900 |
| commit | b7e108ee63624176af85b97d4d80bef6fe099395 (patch) | |
| tree | 747d9a2e760c6aa955dd4f228caaf433228ce5a0 /arch/sh | |
| parent | 298476220d1f793ca0ac6c9e5dc817e1ad3e9851 (diff) | |
sh: BSS init bugfix and barrier in entry point.
A synco is needed before we jump to start_kernel().
While we're at it, also move the sh_cpu_init() jump until after
we've zeroed BSS, as this has caused some undesirable results
in sh_cpu_init().
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh')
| -rw-r--r-- | arch/sh/kernel/head.S | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/arch/sh/kernel/head.S b/arch/sh/kernel/head.S index 00cd4708ef46..c5e363872b91 100644 --- a/arch/sh/kernel/head.S +++ b/arch/sh/kernel/head.S @@ -12,6 +12,17 @@ */ #include <linux/linkage.h> +#ifdef CONFIG_CPU_SH4A +#define SYNCO() synco + +#define PREFI(label, reg) \ + mov.l label, reg; \ + prefi @reg +#else +#define SYNCO() +#define PREFI(label, reg) +#endif + .section .empty_zero_page, "aw" ENTRY(empty_zero_page) .long 1 /* MOUNT_ROOT_RDONLY */ @@ -42,6 +53,17 @@ ENTRY(_stext) ! Initialize global interrupt mask mov #0, r0 ldc r0, r6_bank + + /* + * Prefetch if possible to reduce cache miss penalty. + * + * We do this early on for SH-4A as a micro-optimization, + * as later on we will have speculative execution enabled + * and this will become less of an issue. + */ + PREFI(5f, r0) + PREFI(6f, r0) + ! mov.l 2f, r0 mov r0, r15 ! Set initial r15 (stack pointer) @@ -49,11 +71,7 @@ ENTRY(_stext) shll8 r1 ! r1 = 8192 sub r1, r0 ! ldc r0, r7_bank ! ... and initial thread_info - ! - ! Additional CPU initialization - mov.l 6f, r0 - jsr @r0 - nop + ! Clear BSS area mov.l 3f, r1 add #4, r1 @@ -62,6 +80,14 @@ ENTRY(_stext) 9: cmp/hs r2, r1 bf/s 9b ! while (r1 < r2) mov.l r0,@-r2 + + ! Additional CPU initialization + mov.l 6f, r0 + jsr @r0 + nop + + SYNCO() ! Wait for pending instructions.. + ! Start kernel mov.l 5f, r0 jmp @r0 |