diff options
Diffstat (limited to 'arch/csky/mm/highmem.c')
| -rw-r--r-- | arch/csky/mm/highmem.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/arch/csky/mm/highmem.c b/arch/csky/mm/highmem.c new file mode 100644 index 000000000000..e168ac087ccb --- /dev/null +++ b/arch/csky/mm/highmem.c @@ -0,0 +1,198 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. + +#include <linux/module.h> +#include <linux/highmem.h> +#include <linux/smp.h> +#include <linux/bootmem.h> +#include <asm/fixmap.h> +#include <asm/tlbflush.h> +#include <asm/cacheflush.h> + +static pte_t *kmap_pte; + +unsigned long highstart_pfn, highend_pfn; + +void *kmap(struct page *page) +{ + void *addr; + + might_sleep(); + if (!PageHighMem(page)) + return page_address(page); + addr = kmap_high(page); + flush_tlb_one((unsigned long)addr); + + return addr; +} +EXPORT_SYMBOL(kmap); + +void kunmap(struct page *page) +{ + BUG_ON(in_interrupt()); + if (!PageHighMem(page)) + return; + kunmap_high(page); +} +EXPORT_SYMBOL(kunmap); + +void *kmap_atomic(struct page *page) +{ + unsigned long vaddr; + int idx, type; + + preempt_disable(); + pagefault_disable(); + if (!PageHighMem(page)) + return page_address(page); + + type = kmap_atomic_idx_push(); + idx = type + KM_TYPE_NR*smp_processor_id(); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); +#ifdef CONFIG_DEBUG_HIGHMEM + BUG_ON(!pte_none(*(kmap_pte - idx))); +#endif + set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL)); + flush_tlb_one((unsigned long)vaddr); + + return (void *)vaddr; +} +EXPORT_SYMBOL(kmap_atomic); + +void __kunmap_atomic(void *kvaddr) +{ + unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; + int idx; + + if (vaddr < FIXADDR_START) + goto out; + +#ifdef CONFIG_DEBUG_HIGHMEM + idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx(); + + BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); + + pte_clear(&init_mm, vaddr, kmap_pte - idx); + flush_tlb_one(vaddr); +#else + (void) idx; /* to kill a warning */ +#endif + kmap_atomic_idx_pop(); +out: + pagefault_enable(); + preempt_enable(); +} +EXPORT_SYMBOL(__kunmap_atomic); + +/* + * This is the same as kmap_atomic() but can map memory that doesn't + * have a struct page associated with it. + */ +void *kmap_atomic_pfn(unsigned long pfn) +{ + unsigned long vaddr; + int idx, type; + + pagefault_disable(); + + type = kmap_atomic_idx_push(); + idx = type + KM_TYPE_NR*smp_processor_id(); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL)); + flush_tlb_one(vaddr); + + return (void *) vaddr; +} + +struct page *kmap_atomic_to_page(void *ptr) +{ + unsigned long idx, vaddr = (unsigned long)ptr; + pte_t *pte; + + if (vaddr < FIXADDR_START) + return virt_to_page(ptr); + + idx = virt_to_fix(vaddr); + pte = kmap_pte - (idx - FIX_KMAP_BEGIN); + return pte_page(*pte); +} + +static void __init fixrange_init(unsigned long start, unsigned long end, + pgd_t *pgd_base) +{ +#ifdef CONFIG_HIGHMEM + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + int i, j, k; + unsigned long vaddr; + + vaddr = start; + i = __pgd_offset(vaddr); + j = __pud_offset(vaddr); + k = __pmd_offset(vaddr); + pgd = pgd_base + i; + + for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) { + pud = (pud_t *)pgd; + for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) { + pmd = (pmd_t *)pud; + for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) { + if (pmd_none(*pmd)) { + pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE); + set_pmd(pmd, __pmd(__pa(pte))); + BUG_ON(pte != pte_offset_kernel(pmd, 0)); + } + vaddr += PMD_SIZE; + } + k = 0; + } + j = 0; + } +#endif +} + +void __init fixaddr_kmap_pages_init(void) +{ + unsigned long vaddr; + pgd_t *pgd_base; +#ifdef CONFIG_HIGHMEM + pgd_t *pgd; + pmd_t *pmd; + pud_t *pud; + pte_t *pte; +#endif + pgd_base = swapper_pg_dir; + + /* + * Fixed mappings: + */ + vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; + fixrange_init(vaddr, 0, pgd_base); + +#ifdef CONFIG_HIGHMEM + /* + * Permanent kmaps: + */ + vaddr = PKMAP_BASE; + fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); + + pgd = swapper_pg_dir + __pgd_offset(vaddr); + pud = (pud_t *)pgd; + pmd = pmd_offset(pud, vaddr); + pte = pte_offset_kernel(pmd, vaddr); + pkmap_page_table = pte; +#endif +} + +void __init kmap_init(void) +{ + unsigned long vaddr; + + fixaddr_kmap_pages_init(); + + vaddr = __fix_to_virt(FIX_KMAP_BEGIN); + + kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr); +} |