MIPS: Shrink the size of tlb handler

By combining swapper_pg_dir and module_pg_dir, several if conditions
can be eliminated from the tlb exception handler. The reason they
can be combined is that, the effective virtual address of vmalloc
returned is at the bottom, and of module_alloc returned is at the
top. It also fixes the bug in vmalloc(), which happens when its
return address is not covered by the first pgd.

Signed-off-by: Wu Fei <at.wufei@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 3 insertions, 8 deletions

diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index 4ed9d1bba2ba..9cd508993956 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -109,13 +109,13 @@
 
 #define VMALLOC_START           MAP_BASE
 #define VMALLOC_END     \
-        (VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
+        (VMALLOC_START + \
+         PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE - (1UL << 32))
 #if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
         VMALLOC_START != CKSSEG
 /* Load modules into 32bit-compatible segment. */
 #define MODULE_START    CKSSEG
 #define MODULE_END      (FIXADDR_START-2*PAGE_SIZE)
-extern pgd_t module_pg_dir[PTRS_PER_PGD];
 #endif
 
 #define pte_ERROR(e) \
@@ -188,12 +188,7 @@ static inline void pud_clear(pud_t *pudp)
 #define __pmd_offset(address)   pmd_index(address)
 
 /* to find an entry in a kernel page-table-directory */
-#ifdef MODULE_START
-#define pgd_offset_k(address) \
-        ((address) >= MODULE_START ? module_pg_dir : pgd_offset(&init_mm, 0UL))
-#else
-#define pgd_offset_k(address) pgd_offset(&init_mm, 0UL)
-#endif
+#define pgd_offset_k(address) pgd_offset(&init_mm, address)
 
 #define pgd_index(address)      (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 #define pmd_index(address)      (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))