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-rw-r--r--arch/sh/kernel/head.S43
1 files changed, 35 insertions, 8 deletions
diff --git a/arch/sh/kernel/head.S b/arch/sh/kernel/head.S
index 9b9e6ef..f5f53d1 100644
--- a/arch/sh/kernel/head.S
+++ b/arch/sh/kernel/head.S
@@ -11,6 +11,18 @@
* Head.S contains the SH exception handlers and startup code.
*/
#include <linux/linkage.h>
+#include <asm/thread_info.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)
@@ -42,18 +54,25 @@ 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)
- mov #0x20, r1 !
- shll8 r1 ! r1 = 8192
+ mov #(THREAD_SIZE >> 8), r1
+ shll8 r1 ! r1 = THREAD_SIZE
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 +81,14 @@ 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
@@ -69,7 +96,7 @@ ENTRY(_stext)
.balign 4
1: .long 0x400080F0 ! MD=1, RB=0, BL=0, FD=1, IMASK=0xF
-2: .long stack
+2: .long init_thread_union+THREAD_SIZE
3: .long __bss_start
4: .long _end
5: .long start_kernel
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