There is no reason to re-read each time the pointer at
location 0xf0 as it is fixed and known.

Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
 arch/powerpc/include/asm/mmu.h | 2 ++
 arch/powerpc/kernel/head_32.S  | 5 ++---
 arch/powerpc/kernel/head_40x.S | 5 ++---
 arch/powerpc/kernel/head_8xx.S | 1 +
 arch/powerpc/mm/8xx_mmu.c      | 7 ++-----
 5 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 25607604a7a5..6d22a8e78fe2 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -356,6 +356,8 @@ extern void early_init_mmu_secondary(void);
 extern void setup_initial_memory_limit(phys_addr_t first_memblock_base,
                                       phys_addr_t first_memblock_size);
 static inline void mmu_early_init_devtree(void) { }
+
+extern void *abatron_pteptrs[2];
 #endif /* __ASSEMBLY__ */
 #endif
 
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 05b08db3901d..c2f564690778 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -1027,9 +1027,8 @@ _ENTRY(switch_mmu_context)
         * The PGDIR is passed as second argument.
         */
        lwz     r4,MM_PGD(r4)
-       lis     r5, KERNELBASE@h
-       lwz     r5, 0xf0(r5)
-       stw     r4, 0x4(r5)
+       lis     r5, abatron_pteptrs@ha
+       stw     r4, abatron_pteptrs@l + 0x4(r5)
 #endif
        li      r4,0
        isync
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index b19d78410511..11dd09d0ce1a 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -953,9 +953,8 @@ _GLOBAL(set_context)
        /* Context switch the PTE pointer for the Abatron BDI2000.
         * The PGDIR is the second parameter.
         */
-       lis     r5, KERNELBASE@h
-       lwz     r5, 0xf0(r5)
-       stw     r4, 0x4(r5)
+       lis     r5, abatron_pteptrs@ha
+       stw     r4, abatron_pteptrs@l + 0x4(r5)
 #endif
        sync
        mtspr   SPRN_PID,r3
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index c3f776fda984..4a2e3ffdb5bb 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -1012,5 +1012,6 @@ swapper_pg_dir:
 /* Room for two PTE table poiners, usually the kernel and current user
  * pointer to their respective root page table (pgdir).
  */
+       .globl  abatron_pteptrs
 abatron_pteptrs:
        .space  8
diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c
index b5f6d794281d..e2c32bdb6023 100644
--- a/arch/powerpc/mm/8xx_mmu.c
+++ b/arch/powerpc/mm/8xx_mmu.c
@@ -159,14 +159,11 @@ void set_context(unsigned long id, pgd_t *pgd)
 {
        s16 offset = (s16)(__pa(swapper_pg_dir));
 
-#ifdef CONFIG_BDI_SWITCH
-       pgd_t   **ptr = *(pgd_t ***)(KERNELBASE + 0xf0);
-
        /* Context switch the PTE pointer for the Abatron BDI2000.
         * The PGDIR is passed as second argument.
         */
-       *(ptr + 1) = pgd;
-#endif
+       if (IS_ENABLED(CONFIG_BDI_SWITCH))
+               abatron_pteptrs[1] = pgd;
 
        /* Register M_TWB will contain base address of level 1 table minus the
         * lower part of the kernel PGDIR base address, so that all accesses to
-- 
2.13.3

Reply via email to