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MIPS: Use C0_KScratch (if present) to hold PGD pointer. 

Decide at runtime to use either Context or KScratch to hold the PGD
pointer.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1876/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney 2010-12-21 14:19:11 -08:00 committed by Ralf Baechle
parent c42aef0947
commit 3d8bfdd030
3 changed files with 108 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/mips/include/asm/mmu_context.h
View File

@ -29,13 +29,7 @@
#define TLBMISS_HANDLER_SETUP_PGD(pgd) \
tlbmiss_handler_setup_pgd((unsigned long)(pgd))
static inline void tlbmiss_handler_setup_pgd(unsigned long pgd)
{
/* Check for swapper_pg_dir and convert to physical address. */
if ((pgd & CKSEG3) == CKSEG0)
pgd = CPHYSADDR(pgd);
write_c0_context(pgd << 11);
}
extern void tlbmiss_handler_setup_pgd(unsigned long pgd);
#define TLBMISS_HANDLER_SETUP() \
do { \

2
arch/mips/kernel/traps.c
View File

@ -1592,7 +1592,6 @@ void __cpuinit per_cpu_trap_init(void)
#endif /* CONFIG_MIPS_MT_SMTC */
cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
TLBMISS_HANDLER_SETUP();
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
@ -1614,6 +1613,7 @@ void __cpuinit per_cpu_trap_init(void)
write_c0_wired(0);
}
#endif /* CONFIG_MIPS_MT_SMTC */
TLBMISS_HANDLER_SETUP();
}
/* Install CPU exception handler */

116
arch/mips/mm/tlbex.c
View File

@ -26,8 +26,10 @@
#include <linux/smp.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/cache.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#include <asm/war.h>
#include <asm/uasm.h>
@ -173,11 +175,38 @@ static struct uasm_reloc relocs[128] __cpuinitdata;
static int check_for_high_segbits __cpuinitdata;
#endif
#ifndef CONFIG_MIPS_PGD_C0_CONTEXT
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
static unsigned int kscratch_used_mask __cpuinitdata;
static int __cpuinit allocate_kscratch(void)
{
int r;
unsigned int a = cpu_data[0].kscratch_mask & ~kscratch_used_mask;
r = ffs(a);
if (r == 0)
return -1;
r--; /* make it zero based */
kscratch_used_mask |= (1 << r);
return r;
}
static int pgd_reg __cpuinitdata;
#else /* !CONFIG_MIPS_PGD_C0_CONTEXT*/
/*
* CONFIG_MIPS_PGD_C0_CONTEXT implies 64 bit and lack of pgd_current,
* we cannot do r3000 under these circumstances.
*
* Declare pgd_current here instead of including mmu_context.h to avoid type
* conflicts for tlbmiss_handler_setup_pgd
*/
extern unsigned long pgd_current[];
/*
* The R3000 TLB handler is simple.
@ -573,13 +602,22 @@ build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r,
/* No uasm_i_nop needed here, since the next insn doesn't touch TMP. */
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
/*
* &pgd << 11 stored in CONTEXT [23..63].
*/
UASM_i_MFC0(p, ptr, C0_CONTEXT);
uasm_i_dins(p, ptr, 0, 0, 23); /* Clear lower 23 bits of context. */
uasm_i_ori(p, ptr, ptr, 0x540); /* 1 0 1 0 1 << 6 xkphys cached */
uasm_i_drotr(p, ptr, ptr, 11);
if (pgd_reg != -1) {
/* pgd is in pgd_reg */
UASM_i_MFC0(p, ptr, 31, pgd_reg);
} else {
/*
* &pgd << 11 stored in CONTEXT [23..63].
*/
UASM_i_MFC0(p, ptr, C0_CONTEXT);
/* Clear lower 23 bits of context. */
uasm_i_dins(p, ptr, 0, 0, 23);
/* 1 0 1 0 1 << 6 xkphys cached */
uasm_i_ori(p, ptr, ptr, 0x540);
uasm_i_drotr(p, ptr, ptr, 11);
}
#elif defined(CONFIG_SMP)
# ifdef CONFIG_MIPS_MT_SMTC
/*
@ -1014,6 +1052,55 @@ static void __cpuinit build_r4000_tlb_refill_handler(void)
u32 handle_tlbl[FASTPATH_SIZE] __cacheline_aligned;
u32 handle_tlbs[FASTPATH_SIZE] __cacheline_aligned;
u32 handle_tlbm[FASTPATH_SIZE] __cacheline_aligned;
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
u32 tlbmiss_handler_setup_pgd[16] __cacheline_aligned;
static void __cpuinit build_r4000_setup_pgd(void)
{
const int a0 = 4;
const int a1 = 5;
u32 *p = tlbmiss_handler_setup_pgd;
struct uasm_label *l = labels;
struct uasm_reloc *r = relocs;
memset(tlbmiss_handler_setup_pgd, 0, sizeof(tlbmiss_handler_setup_pgd));
memset(labels, 0, sizeof(labels));
memset(relocs, 0, sizeof(relocs));
pgd_reg = allocate_kscratch();
if (pgd_reg == -1) {
/* PGD << 11 in c0_Context */
/*
* If it is a ckseg0 address, convert to a physical
* address. Shifting right by 29 and adding 4 will
* result in zero for these addresses.
*
*/
UASM_i_SRA(&p, a1, a0, 29);
UASM_i_ADDIU(&p, a1, a1, 4);
uasm_il_bnez(&p, &r, a1, label_tlbl_goaround1);
uasm_i_nop(&p);
uasm_i_dinsm(&p, a0, 0, 29, 64 - 29);
uasm_l_tlbl_goaround1(&l, p);
UASM_i_SLL(&p, a0, a0, 11);
uasm_i_jr(&p, 31);
UASM_i_MTC0(&p, a0, C0_CONTEXT);
} else {
/* PGD in c0_KScratch */
uasm_i_jr(&p, 31);
UASM_i_MTC0(&p, a0, 31, pgd_reg);
}
if (p - tlbmiss_handler_setup_pgd > ARRAY_SIZE(tlbmiss_handler_setup_pgd))
panic("tlbmiss_handler_setup_pgd space exceeded");
uasm_resolve_relocs(relocs, labels);
pr_debug("Wrote tlbmiss_handler_setup_pgd (%u instructions).\n",
(unsigned int)(p - tlbmiss_handler_setup_pgd));
dump_handler(tlbmiss_handler_setup_pgd,
ARRAY_SIZE(tlbmiss_handler_setup_pgd));
}
#endif
static void __cpuinit
iPTE_LW(u32 **p, unsigned int pte, unsigned int ptr)
@ -1161,6 +1248,8 @@ build_pte_modifiable(u32 **p, struct uasm_reloc **r,
}
#ifndef CONFIG_MIPS_PGD_C0_CONTEXT
/*
* R3000 style TLB load/store/modify handlers.
*/
@ -1623,13 +1712,16 @@ void __cpuinit build_tlb_refill_handler(void)
break;
default:
build_r4000_tlb_refill_handler();
if (!run_once) {
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
build_r4000_setup_pgd();
#endif
build_r4000_tlb_load_handler();
build_r4000_tlb_store_handler();
build_r4000_tlb_modify_handler();
run_once++;
}
build_r4000_tlb_refill_handler();
}
}
@ -1641,4 +1733,8 @@ void __cpuinit flush_tlb_handlers(void)
(unsigned long)handle_tlbs + sizeof(handle_tlbs));
local_flush_icache_range((unsigned long)handle_tlbm,
(unsigned long)handle_tlbm + sizeof(handle_tlbm));
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
local_flush_icache_range((unsigned long)tlbmiss_handler_setup_pgd,
(unsigned long)tlbmiss_handler_setup_pgd + sizeof(handle_tlbm));
#endif
}