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Subject[PATCH v7 16/23] powerpc/8xx: rewrite set_context() in C
Date
There is no real need to have set_context() in assembly.
Now that we have mtspr() handling CPU6 ERRATA directly, we
can rewrite set_context() in C language for easier maintenance.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
v2: no change
v3: no change
v4: no change
v5: no change
v6: no change
v7: no change

arch/powerpc/kernel/head_8xx.S | 44 ------------------------------------------
arch/powerpc/mm/8xx_mmu.c | 34 ++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+), 44 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 637f8e9..bb2b657 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -968,50 +968,6 @@ initial_mmu:


/*
- * Set up to use a given MMU context.
- * r3 is context number, r4 is PGD pointer.
- *
- * We place the physical address of the new task page directory loaded
- * into the MMU base register, and set the ASID compare register with
- * the new "context."
- */
-_GLOBAL(set_context)
-
-#ifdef CONFIG_BDI_SWITCH
- /* Context switch the PTE pointer for the Abatron BDI2000.
- * The PGDIR is passed as second argument.
- */
- lis r5, KERNELBASE@h
- lwz r5, 0xf0(r5)
- stw r4, 0x4(r5)
-#endif
-
- /* Register M_TW will contain base address of level 1 table minus the
- * lower part of the kernel PGDIR base address, so that all accesses to
- * level 1 table are done relative to lower part of kernel PGDIR base
- * address.
- */
- li r5, (swapper_pg_dir-PAGE_OFFSET)@l
- sub r4, r4, r5
- tophys (r4, r4)
-#ifdef CONFIG_8xx_CPU6
- lis r6, cpu6_errata_word@h
- ori r6, r6, cpu6_errata_word@l
- li r7, 0x3f80
- stw r7, 12(r6)
- lwz r7, 12(r6)
-#endif
- mtspr SPRN_M_TW, r4 /* Update pointeur to level 1 table */
-#ifdef CONFIG_8xx_CPU6
- li r7, 0x3380
- stw r7, 12(r6)
- lwz r7, 12(r6)
-#endif
- mtspr SPRN_M_CASID, r3 /* Update context */
- SYNC
- blr
-
-/*
* We put a few things here that have to be page-aligned.
* This stuff goes at the beginning of the data segment,
* which is page-aligned.
diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c
index 50f17d2..b75c461 100644
--- a/arch/powerpc/mm/8xx_mmu.c
+++ b/arch/powerpc/mm/8xx_mmu.c
@@ -147,3 +147,37 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
memblock_set_current_limit(min_t(u64, first_memblock_size,
initial_memory_size));
}
+
+/*
+ * Set up to use a given MMU context.
+ * id is context number, pgd is PGD pointer.
+ *
+ * We place the physical address of the new task page directory loaded
+ * into the MMU base register, and set the ASID compare register with
+ * the new "context."
+ */
+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
+
+ /* Register M_TW will contain base address of level 1 table minus the
+ * lower part of the kernel PGDIR base address, so that all accesses to
+ * level 1 table are done relative to lower part of kernel PGDIR base
+ * address.
+ */
+ mtspr(SPRN_M_TW, __pa(pgd) - offset);
+
+ /* Update context */
+ mtspr(SPRN_M_CASID, id);
+ /* sync */
+ mb();
+}
--
2.1.0
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