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[MIPS] Fast path for rdhwr emulation for TLS 

Add special short path for emulationg RDHWR which is used to support TLS.
Add an extra prologue for cpu_has_vtag_icache case.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Atsushi Nemoto 2006-09-11 17:50:29 +09:00 committed by Ralf Baechle
parent 656be92f9a
commit 5b10496b6e
2 changed files with 77 additions and 1 deletions
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63
arch/mips/kernel/genex.S
View File

@ -19,6 +19,7 @@
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/war.h>
#include <asm/page.h>
#define PANIC_PIC(msg) \
.set push; \
@ -378,6 +379,68 @@ NESTED(nmi_handler, PT_SIZE, sp)
BUILD_HANDLER dsp dsp sti silent /* #26 */
BUILD_HANDLER reserved reserved sti verbose /* others */
.align 5
LEAF(handle_ri_rdhwr_vivt)
#ifdef CONFIG_MIPS_MT_SMTC
PANIC_PIC("handle_ri_rdhwr_vivt called")
#else
.set push
.set noat
.set noreorder
/* check if TLB contains a entry for EPC */
MFC0 k1, CP0_ENTRYHI
andi k1, 0xff /* ASID_MASK */
MFC0 k0, CP0_EPC
PTR_SRL k0, PAGE_SHIFT + 1
PTR_SLL k0, PAGE_SHIFT + 1
or k1, k0
MTC0 k1, CP0_ENTRYHI
mtc0_tlbw_hazard
tlbp
tlb_probe_hazard
mfc0 k1, CP0_INDEX
.set pop
bltz k1, handle_ri /* slow path */
/* fall thru */
#endif
END(handle_ri_rdhwr_vivt)
LEAF(handle_ri_rdhwr)
.set push
.set noat
.set noreorder
/* 0x7c03e83b: rdhwr v1,$29 */
MFC0 k1, CP0_EPC
lui k0, 0x7c03
lw k1, (k1)
ori k0, 0xe83b
.set reorder
bne k0, k1, handle_ri /* if not ours */
/* The insn is rdhwr. No need to check CAUSE.BD here. */
get_saved_sp /* k1 := current_thread_info */
.set noreorder
MFC0 k0, CP0_EPC
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
ori k1, _THREAD_MASK
xori k1, _THREAD_MASK
LONG_L v1, TI_TP_VALUE(k1)
LONG_ADDIU k0, 4
jr k0
rfe
#else
LONG_ADDIU k0, 4 /* stall on $k0 */
MTC0 k0, CP0_EPC
/* I hope three instructions between MTC0 and ERET are enough... */
ori k1, _THREAD_MASK
xori k1, _THREAD_MASK
LONG_L v1, TI_TP_VALUE(k1)
.set mips3
eret
.set mips0
#endif
.set pop
END(handle_ri_rdhwr)
#ifdef CONFIG_64BIT
/* A temporary overflow handler used by check_daddi(). */

15
arch/mips/kernel/traps.c
View File

@ -54,6 +54,8 @@ extern asmlinkage void handle_dbe(void);
extern asmlinkage void handle_sys(void);
extern asmlinkage void handle_bp(void);
extern asmlinkage void handle_ri(void);
extern asmlinkage void handle_ri_rdhwr_vivt(void);
extern asmlinkage void handle_ri_rdhwr(void);
extern asmlinkage void handle_cpu(void);
extern asmlinkage void handle_ov(void);
extern asmlinkage void handle_tr(void);
@ -1423,6 +1425,15 @@ void __init set_uncached_handler (unsigned long offset, void *addr, unsigned lon
memcpy((void *)(uncached_ebase + offset), addr, size);
}
static int __initdata rdhwr_noopt;
static int __init set_rdhwr_noopt(char *str)
{
rdhwr_noopt = 1;
return 1;
}
__setup("rdhwr_noopt", set_rdhwr_noopt);
void __init trap_init(void)
{
extern char except_vec3_generic, except_vec3_r4000;
@ -1502,7 +1513,9 @@ void __init trap_init(void)
set_except_vector(8, handle_sys);
set_except_vector(9, handle_bp);
set_except_vector(10, handle_ri);
set_except_vector(10, rdhwr_noopt ? handle_ri :
(cpu_has_vtag_icache ?
handle_ri_rdhwr_vivt : handle_ri_rdhwr));
set_except_vector(11, handle_cpu);
set_except_vector(12, handle_ov);
set_except_vector(13, handle_tr);