From a7761fe48993f103d6deac6037bf786bd1db0501 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 9 Feb 2016 17:08:18 +0100 Subject: powerpc/8xx: rewrite set_context() in C 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 Signed-off-by: Scott Wood --- arch/powerpc/mm/8xx_mmu.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'arch/powerpc/mm/8xx_mmu.c') diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c index a84f5ebed1c1..606d2319a44f 100644 --- a/arch/powerpc/mm/8xx_mmu.c +++ b/arch/powerpc/mm/8xx_mmu.c @@ -98,3 +98,37 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base, memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000)); #endif } + +/* + * 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(); +} -- cgit