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>
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index d959273..73c0d45 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -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 { \
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index e971043..71350f7 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1592,7 +1592,6 @@
#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 @@
write_c0_wired(0);
}
#endif /* CONFIG_MIPS_MT_SMTC */
+ TLBMISS_HANDLER_SETUP();
}
/* Install CPU exception handler */
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index 93816f3..0bb4c3b 100644
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -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 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 @@
/* 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 @@
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 @@
}
#ifndef CONFIG_MIPS_PGD_C0_CONTEXT
+
+
/*
* R3000 style TLB load/store/modify handlers.
*/
@@ -1623,13 +1712,16 @@
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 @@
(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
}