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author | Santosh Shilimkar <santosh.shilimkar@ti.com> | 2013-07-31 12:44:46 -0400 |
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committer | Santosh Shilimkar <santosh.shilimkar@ti.com> | 2013-10-10 20:28:19 -0400 |
commit | a77e0c7b2774fd52ce6bf25c2c3ffdccb7b110ff (patch) | |
tree | 38b955dc032421ee71aa09c6e0bd18b31a7b3dc2 /arch/arm/mm | |
parent | f52bb722547f43caeaecbcc62db9f3c3b80ead9b (diff) | |
download | linux-a77e0c7b2774fd52ce6bf25c2c3ffdccb7b110ff.tar.gz linux-a77e0c7b2774fd52ce6bf25c2c3ffdccb7b110ff.tar.bz2 linux-a77e0c7b2774fd52ce6bf25c2c3ffdccb7b110ff.zip |
ARM: mm: Recreate kernel mappings in early_paging_init()
This patch adds a step in the init sequence, in order to recreate
the kernel code/data page table mappings prior to full paging
initialization. This is necessary on LPAE systems that run out of
a physical address space outside the 4G limit. On these systems,
this implementation provides a machine descriptor hook that allows
the PHYS_OFFSET to be overridden in a machine specific fashion.
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: R Sricharan <r.sricharan@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r-- | arch/arm/mm/mmu.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index b1d17eeb59b8..78eeeca78f5a 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -28,6 +28,8 @@ #include <asm/highmem.h> #include <asm/system_info.h> #include <asm/traps.h> +#include <asm/procinfo.h> +#include <asm/memory.h> #include <asm/mach/arch.h> #include <asm/mach/map.h> @@ -1315,6 +1317,86 @@ static void __init map_lowmem(void) } } +#ifdef CONFIG_ARM_LPAE +/* + * early_paging_init() recreates boot time page table setup, allowing machines + * to switch over to a high (>4G) address space on LPAE systems + */ +void __init early_paging_init(const struct machine_desc *mdesc, + struct proc_info_list *procinfo) +{ + pmdval_t pmdprot = procinfo->__cpu_mm_mmu_flags; + unsigned long map_start, map_end; + pgd_t *pgd0, *pgdk; + pud_t *pud0, *pudk, *pud_start; + pmd_t *pmd0, *pmdk; + phys_addr_t phys; + int i; + + if (!(mdesc->init_meminfo)) + return; + + /* remap kernel code and data */ + map_start = init_mm.start_code; + map_end = init_mm.brk; + + /* get a handle on things... */ + pgd0 = pgd_offset_k(0); + pud_start = pud0 = pud_offset(pgd0, 0); + pmd0 = pmd_offset(pud0, 0); + + pgdk = pgd_offset_k(map_start); + pudk = pud_offset(pgdk, map_start); + pmdk = pmd_offset(pudk, map_start); + + mdesc->init_meminfo(); + + /* Run the patch stub to update the constants */ + fixup_pv_table(&__pv_table_begin, + (&__pv_table_end - &__pv_table_begin) << 2); + + /* + * Cache cleaning operations for self-modifying code + * We should clean the entries by MVA but running a + * for loop over every pv_table entry pointer would + * just complicate the code. + */ + flush_cache_louis(); + dsb(); + isb(); + + /* remap level 1 table */ + for (i = 0; i < PTRS_PER_PGD; pud0++, i++) { + set_pud(pud0, + __pud(__pa(pmd0) | PMD_TYPE_TABLE | L_PGD_SWAPPER)); + pmd0 += PTRS_PER_PMD; + } + + /* remap pmds for kernel mapping */ + phys = __pa(map_start) & PMD_MASK; + do { + *pmdk++ = __pmd(phys | pmdprot); + phys += PMD_SIZE; + } while (phys < map_end); + + flush_cache_all(); + cpu_switch_mm(pgd0, &init_mm); + cpu_set_ttbr(1, __pa(pgd0) + TTBR1_OFFSET); + local_flush_bp_all(); + local_flush_tlb_all(); +} + +#else + +void __init early_paging_init(const struct machine_desc *mdesc, + struct proc_info_list *procinfo) +{ + if (mdesc->init_meminfo) + mdesc->init_meminfo(); +} + +#endif + /* * paging_init() sets up the page tables, initialises the zone memory * maps, and sets up the zero page, bad page and bad page tables. |