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authorMaciej W. Rozycki <macro@linux-mips.org>2005-06-13 20:24:00 +0000
committerRalf Baechle <ralf@linux-mips.org>2005-10-29 19:31:22 +0100
commitfded2e508a1d3c26ab477ab3b98f13274d4359ba (patch)
treea720d2799e7ea32cb96d664bc55b2aa149b77550
parentd925c262dd8bee2202b0d1b85ce0b332f48dd34b (diff)
Optimize R3k TLB Load/Store/Modified handlers, by scheduling
delay slots properly and avoiding an unnecessary jump to a jump. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/mm/tlbex.c70
1 files changed, 30 insertions, 40 deletions
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index 68d24b80053..48546d18a5a 100644
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -6,6 +6,7 @@
* Synthesize TLB refill handlers at runtime.
*
* Copyright (C) 2004,2005 by Thiemo Seufer
+ * Copyright (C) 2005 Maciej W. Rozycki
*/
#include <stdarg.h>
@@ -410,7 +411,6 @@ enum label_id {
label_nopage_tlbm,
label_smp_pgtable_change,
label_r3000_write_probe_fail,
- label_r3000_write_probe_ok
};
struct label {
@@ -443,7 +443,6 @@ L_LA(_nopage_tlbs)
L_LA(_nopage_tlbm)
L_LA(_smp_pgtable_change)
L_LA(_r3000_write_probe_fail)
-L_LA(_r3000_write_probe_ok)
/* convenience macros for instructions */
#ifdef CONFIG_64BIT
@@ -1414,34 +1413,41 @@ build_pte_modifiable(u32 **p, struct label **l, struct reloc **r,
* R3000 style TLB load/store/modify handlers.
*/
-/* This places the pte in the page table at PTR into ENTRYLO0. */
+/*
+ * This places the pte into ENTRYLO0 and writes it with tlbwi.
+ * Then it returns.
+ */
static void __init
-build_r3000_pte_reload(u32 **p, unsigned int ptr)
+build_r3000_pte_reload_tlbwi(u32 **p, unsigned int pte, unsigned int tmp)
{
- i_lw(p, ptr, 0, ptr);
- i_nop(p); /* load delay */
- i_mtc0(p, ptr, C0_ENTRYLO0);
- i_nop(p); /* cp0 delay */
+ i_mtc0(p, pte, C0_ENTRYLO0); /* cp0 delay */
+ i_mfc0(p, tmp, C0_EPC); /* cp0 delay */
+ i_tlbwi(p);
+ i_jr(p, tmp);
+ i_rfe(p); /* branch delay */
}
/*
- * The index register may have the probe fail bit set,
- * because we would trap on access kseg2, i.e. without refill.
+ * This places the pte into ENTRYLO0 and writes it with tlbwi
+ * or tlbwr as appropriate. This is because the index register
+ * may have the probe fail bit set as a result of a trap on a
+ * kseg2 access, i.e. without refill. Then it returns.
*/
static void __init
-build_r3000_tlb_write(u32 **p, struct label **l, struct reloc **r,
- unsigned int tmp)
+build_r3000_tlb_reload_write(u32 **p, struct label **l, struct reloc **r,
+ unsigned int pte, unsigned int tmp)
{
i_mfc0(p, tmp, C0_INDEX);
- i_nop(p); /* cp0 delay */
- il_bltz(p, r, tmp, label_r3000_write_probe_fail);
- i_nop(p); /* branch delay */
- i_tlbwi(p);
- il_b(p, r, label_r3000_write_probe_ok);
- i_nop(p); /* branch delay */
+ i_mtc0(p, pte, C0_ENTRYLO0); /* cp0 delay */
+ il_bltz(p, r, tmp, label_r3000_write_probe_fail); /* cp0 delay */
+ i_mfc0(p, tmp, C0_EPC); /* branch delay */
+ i_tlbwi(p); /* cp0 delay */
+ i_jr(p, tmp);
+ i_rfe(p); /* branch delay */
l_r3000_write_probe_fail(l, *p);
- i_tlbwr(p);
- l_r3000_write_probe_ok(l, *p);
+ i_tlbwr(p); /* cp0 delay */
+ i_jr(p, tmp);
+ i_rfe(p); /* branch delay */
}
static void __init
@@ -1461,17 +1467,7 @@ build_r3000_tlbchange_handler_head(u32 **p, unsigned int pte,
i_andi(p, pte, pte, 0xffc); /* load delay */
i_addu(p, ptr, ptr, pte);
i_lw(p, pte, 0, ptr);
- i_nop(p); /* load delay */
- i_tlbp(p);
-}
-
-static void __init
-build_r3000_tlbchange_handler_tail(u32 **p, unsigned int tmp)
-{
- i_mfc0(p, tmp, C0_EPC);
- i_nop(p); /* cp0 delay */
- i_jr(p, tmp);
- i_rfe(p); /* branch delay */
+ i_tlbp(p); /* load delay */
}
static void __init build_r3000_tlb_load_handler(void)
@@ -1488,9 +1484,7 @@ static void __init build_r3000_tlb_load_handler(void)
build_pte_present(&p, &l, &r, K0, K1, label_nopage_tlbl);
i_nop(&p); /* load delay */
build_make_valid(&p, &r, K0, K1);
- build_r3000_pte_reload(&p, K1);
- build_r3000_tlb_write(&p, &l, &r, K0);
- build_r3000_tlbchange_handler_tail(&p, K0);
+ build_r3000_tlb_reload_write(&p, &l, &r, K0, K1);
l_nopage_tlbl(&l, p);
i_j(&p, (unsigned long)tlb_do_page_fault_0 & 0x0fffffff);
@@ -1530,9 +1524,7 @@ static void __init build_r3000_tlb_store_handler(void)
build_pte_writable(&p, &l, &r, K0, K1, label_nopage_tlbs);
i_nop(&p); /* load delay */
build_make_write(&p, &r, K0, K1);
- build_r3000_pte_reload(&p, K1);
- build_r3000_tlb_write(&p, &l, &r, K0);
- build_r3000_tlbchange_handler_tail(&p, K0);
+ build_r3000_tlb_reload_write(&p, &l, &r, K0, K1);
l_nopage_tlbs(&l, p);
i_j(&p, (unsigned long)tlb_do_page_fault_1 & 0x0fffffff);
@@ -1572,9 +1564,7 @@ static void __init build_r3000_tlb_modify_handler(void)
build_pte_modifiable(&p, &l, &r, K0, K1, label_nopage_tlbm);
i_nop(&p); /* load delay */
build_make_write(&p, &r, K0, K1);
- build_r3000_pte_reload(&p, K1);
- i_tlbwi(&p);
- build_r3000_tlbchange_handler_tail(&p, K0);
+ build_r3000_pte_reload_tlbwi(&p, K0, K1);
l_nopage_tlbm(&l, p);
i_j(&p, (unsigned long)tlb_do_page_fault_1 & 0x0fffffff);