Created identiy mapped page table that maps 1 to 1 virtual to physical addresses.
Similarly to x86, this table can be used in kasan, hibernate, and kexec. Signed-off-by: Pavel Tatashin <[email protected]> --- arch/arm64/include/asm/ident_map.h | 26 ++++++++ arch/arm64/mm/Makefile | 1 + arch/arm64/mm/ident_map.c | 99 ++++++++++++++++++++++++++++++ 3 files changed, 126 insertions(+) create mode 100644 arch/arm64/include/asm/ident_map.h create mode 100644 arch/arm64/mm/ident_map.c diff --git a/arch/arm64/include/asm/ident_map.h b/arch/arm64/include/asm/ident_map.h new file mode 100644 index 000000000000..1bb9fcd27368 --- /dev/null +++ b/arch/arm64/include/asm/ident_map.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2019, Microsoft Corporation. + * Pavel Tatashin <[email protected]> + */ + +#ifndef _ASM_IDENT_MAP_H +#define _ASM_IDENT_MAP_H + +#include <linux/types.h> +#include <asm/pgtable.h> + +struct ident_map_info { + void * (*alloc_pgt_page)(void *); /* allocate a page */ + void *alloc_arg; /* arg. for alloc_pgt_page */ + unsigned long page_flags; /* PMD or PUD flags */ + unsigned long offset; /* ident mapping offset */ + bool pud_pages; /* PUD level huge pages */ +}; + +int ident_map_pgd_populate(struct ident_map_info *info, + phys_addr_t pgd_page, + phys_addr_t addr, + phys_addr_t end); + +#endif /* _ASM_ARM64_IDENT_MAP_H */ diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 849c1df3d214..dfa5a074a360 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -5,6 +5,7 @@ obj-y := dma-mapping.o extable.o fault.o init.o \ context.o proc.o pageattr.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_ARM64_PTDUMP_CORE) += dump.o +obj-$(CONFIG_KEXEC_CORE) += ident_map.o obj-$(CONFIG_ARM64_PTDUMP_DEBUGFS) += ptdump_debugfs.o obj-$(CONFIG_NUMA) += numa.o obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o diff --git a/arch/arm64/mm/ident_map.c b/arch/arm64/mm/ident_map.c new file mode 100644 index 000000000000..bcfff5e2573b --- /dev/null +++ b/arch/arm64/mm/ident_map.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019, Microsoft Corporation. + * Pavel Tatashin <[email protected]> + */ + +#include <asm/ident_map.h> +#include <asm/pgalloc.h> + +/* Initialize PMD size huge entries in page table */ +static void ident_map_pmd_init(struct ident_map_info *info, + phys_addr_t pmd_page, phys_addr_t addr, + phys_addr_t end) +{ + const unsigned long flags = info->page_flags; + const unsigned long offset = info->offset; + pmd_t *pmdp = (pmd_t *)__va(pmd_page) + pmd_index(addr); + + addr &= PMD_MASK; + for (; addr < end; addr += PMD_SIZE, pmdp++) { + set_pmd(pmdp, __pmd(__phys_to_pmd_val(addr - offset) | flags)); + } +} + +/* Initialize PUD size huge entries in page table */ +static void ident_map_pud_init(struct ident_map_info *info, + phys_addr_t pud_page, phys_addr_t addr, + phys_addr_t end) +{ + const unsigned long flags = info->page_flags; + const unsigned long offset = info->offset; + pud_t *pudp = (pud_t *)__va(pud_page) + pud_index(addr); + + addr &= PUD_MASK; + for (; addr < end; addr += PUD_SIZE, pudp++) { + set_pud(pudp, __pud(__phys_to_pud_val(addr - offset) | flags)); + } +} + +/* Populate PUD level with PMD entries */ +static int ident_map_pud_populate(struct ident_map_info *info, + phys_addr_t pud_page, phys_addr_t addr, + phys_addr_t end) +{ + pud_t *pudp = (pud_t *)__va(pud_page) + pud_index(addr); + phys_addr_t pmd_page, next; + + for (; addr < end; addr = next, pudp++) { + next = pud_addr_end(addr, end); + if (pud_none(*pudp)) { + void *pmd = info->alloc_pgt_page(info->alloc_arg); + + if (!pmd) + return -ENOMEM; + + clear_page(pmd); + __pud_populate(pudp, __pa(pmd), PUD_TYPE_TABLE); + } + pmd_page = __pud_to_phys(*pudp); + ident_map_pmd_init(info, pmd_page, addr, next); + } + + return 0; +} + +/* Populate identify mapped page table with physical range[addr, end) */ +int ident_map_pgd_populate(struct ident_map_info *info, + phys_addr_t pgd_page, phys_addr_t addr, + phys_addr_t end) +{ + const bool pud_pages = info->pud_pages; + pgd_t *pgdp = (pgd_t *)__va(pgd_page) + pgd_index(addr); + phys_addr_t pud_page, next; + + for (; addr < end; addr = next, pgdp++) { + next = pgd_addr_end(addr, end); + if (pgd_none(*pgdp)) { + void *pud = info->alloc_pgt_page(info->alloc_arg); + + if (!pud) + return -ENOMEM; + + clear_page(pud); + __pgd_populate(pgdp, __pa(pud), PUD_TYPE_TABLE); + } + pud_page = __pgd_to_phys(*pgdp); + if (pud_pages) { + ident_map_pud_init(info, pud_page, addr, next); + } else { + int rv = ident_map_pud_populate(info, pud_page, addr, + next); + + if (rv) + return rv; + } + } + + return 0; +} -- 2.22.0
