diff options
Diffstat (limited to 'arch/s390/boot/vmem.c')
| -rw-r--r-- | arch/s390/boot/vmem.c | 458 |
1 files changed, 458 insertions, 0 deletions
diff --git a/arch/s390/boot/vmem.c b/arch/s390/boot/vmem.c new file mode 100644 index 0000000000..442a74f113 --- /dev/null +++ b/arch/s390/boot/vmem.c @@ -0,0 +1,458 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/sched/task.h> +#include <linux/pgtable.h> +#include <linux/kasan.h> +#include <asm/pgalloc.h> +#include <asm/facility.h> +#include <asm/sections.h> +#include <asm/physmem_info.h> +#include <asm/maccess.h> +#include <asm/abs_lowcore.h> +#include "decompressor.h" +#include "boot.h" + +unsigned long __bootdata_preserved(s390_invalid_asce); + +#ifdef CONFIG_PROC_FS +atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]); +#endif + +#define init_mm (*(struct mm_struct *)vmlinux.init_mm_off) +#define swapper_pg_dir vmlinux.swapper_pg_dir_off +#define invalid_pg_dir vmlinux.invalid_pg_dir_off + +enum populate_mode { + POPULATE_NONE, + POPULATE_DIRECT, + POPULATE_ABS_LOWCORE, +#ifdef CONFIG_KASAN + POPULATE_KASAN_MAP_SHADOW, + POPULATE_KASAN_ZERO_SHADOW, + POPULATE_KASAN_SHALLOW +#endif +}; + +static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode); + +#ifdef CONFIG_KASAN + +#define kasan_early_shadow_page vmlinux.kasan_early_shadow_page_off +#define kasan_early_shadow_pte ((pte_t *)vmlinux.kasan_early_shadow_pte_off) +#define kasan_early_shadow_pmd ((pmd_t *)vmlinux.kasan_early_shadow_pmd_off) +#define kasan_early_shadow_pud ((pud_t *)vmlinux.kasan_early_shadow_pud_off) +#define kasan_early_shadow_p4d ((p4d_t *)vmlinux.kasan_early_shadow_p4d_off) +#define __sha(x) ((unsigned long)kasan_mem_to_shadow((void *)x)) + +static pte_t pte_z; + +static inline void kasan_populate(unsigned long start, unsigned long end, enum populate_mode mode) +{ + start = PAGE_ALIGN_DOWN(__sha(start)); + end = PAGE_ALIGN(__sha(end)); + pgtable_populate(start, end, mode); +} + +static void kasan_populate_shadow(void) +{ + pmd_t pmd_z = __pmd(__pa(kasan_early_shadow_pte) | _SEGMENT_ENTRY); + pud_t pud_z = __pud(__pa(kasan_early_shadow_pmd) | _REGION3_ENTRY); + p4d_t p4d_z = __p4d(__pa(kasan_early_shadow_pud) | _REGION2_ENTRY); + unsigned long memgap_start = 0; + unsigned long untracked_end; + unsigned long start, end; + int i; + + pte_z = __pte(__pa(kasan_early_shadow_page) | pgprot_val(PAGE_KERNEL_RO)); + if (!machine.has_nx) + pte_z = clear_pte_bit(pte_z, __pgprot(_PAGE_NOEXEC)); + crst_table_init((unsigned long *)kasan_early_shadow_p4d, p4d_val(p4d_z)); + crst_table_init((unsigned long *)kasan_early_shadow_pud, pud_val(pud_z)); + crst_table_init((unsigned long *)kasan_early_shadow_pmd, pmd_val(pmd_z)); + memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE); + + /* + * Current memory layout: + * +- 0 -------------+ +- shadow start -+ + * |1:1 ident mapping| /|1/8 of ident map| + * | | / | | + * +-end of ident map+ / +----------------+ + * | ... gap ... | / | kasan | + * | | / | zero page | + * +- vmalloc area -+ / | mapping | + * | vmalloc_size | / | (untracked) | + * +- modules vaddr -+ / +----------------+ + * | 2Gb |/ | unmapped | allocated per module + * +- shadow start -+ +----------------+ + * | 1/8 addr space | | zero pg mapping| (untracked) + * +- shadow end ----+---------+- shadow end ---+ + * + * Current memory layout (KASAN_VMALLOC): + * +- 0 -------------+ +- shadow start -+ + * |1:1 ident mapping| /|1/8 of ident map| + * | | / | | + * +-end of ident map+ / +----------------+ + * | ... gap ... | / | kasan zero page| (untracked) + * | | / | mapping | + * +- vmalloc area -+ / +----------------+ + * | vmalloc_size | / |shallow populate| + * +- modules vaddr -+ / +----------------+ + * | 2Gb |/ |shallow populate| + * +- shadow start -+ +----------------+ + * | 1/8 addr space | | zero pg mapping| (untracked) + * +- shadow end ----+---------+- shadow end ---+ + */ + + for_each_physmem_usable_range(i, &start, &end) { + kasan_populate(start, end, POPULATE_KASAN_MAP_SHADOW); + if (memgap_start && physmem_info.info_source == MEM_DETECT_DIAG260) + kasan_populate(memgap_start, start, POPULATE_KASAN_ZERO_SHADOW); + memgap_start = end; + } + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { + untracked_end = VMALLOC_START; + /* shallowly populate kasan shadow for vmalloc and modules */ + kasan_populate(VMALLOC_START, MODULES_END, POPULATE_KASAN_SHALLOW); + } else { + untracked_end = MODULES_VADDR; + } + /* populate kasan shadow for untracked memory */ + kasan_populate(ident_map_size, untracked_end, POPULATE_KASAN_ZERO_SHADOW); + kasan_populate(MODULES_END, _REGION1_SIZE, POPULATE_KASAN_ZERO_SHADOW); +} + +static bool kasan_pgd_populate_zero_shadow(pgd_t *pgd, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + if (mode == POPULATE_KASAN_ZERO_SHADOW && + IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { + pgd_populate(&init_mm, pgd, kasan_early_shadow_p4d); + return true; + } + return false; +} + +static bool kasan_p4d_populate_zero_shadow(p4d_t *p4d, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + if (mode == POPULATE_KASAN_ZERO_SHADOW && + IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { + p4d_populate(&init_mm, p4d, kasan_early_shadow_pud); + return true; + } + return false; +} + +static bool kasan_pud_populate_zero_shadow(pud_t *pud, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + if (mode == POPULATE_KASAN_ZERO_SHADOW && + IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { + pud_populate(&init_mm, pud, kasan_early_shadow_pmd); + return true; + } + return false; +} + +static bool kasan_pmd_populate_zero_shadow(pmd_t *pmd, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + if (mode == POPULATE_KASAN_ZERO_SHADOW && + IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { + pmd_populate(&init_mm, pmd, kasan_early_shadow_pte); + return true; + } + return false; +} + +static bool kasan_pte_populate_zero_shadow(pte_t *pte, enum populate_mode mode) +{ + pte_t entry; + + if (mode == POPULATE_KASAN_ZERO_SHADOW) { + set_pte(pte, pte_z); + return true; + } + return false; +} +#else + +static inline void kasan_populate_shadow(void) {} + +static inline bool kasan_pgd_populate_zero_shadow(pgd_t *pgd, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + return false; +} + +static inline bool kasan_p4d_populate_zero_shadow(p4d_t *p4d, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + return false; +} + +static inline bool kasan_pud_populate_zero_shadow(pud_t *pud, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + return false; +} + +static inline bool kasan_pmd_populate_zero_shadow(pmd_t *pmd, unsigned long addr, + unsigned long end, enum populate_mode mode) +{ + return false; +} + +static bool kasan_pte_populate_zero_shadow(pte_t *pte, enum populate_mode mode) +{ + return false; +} + +#endif + +/* + * Mimic virt_to_kpte() in lack of init_mm symbol. Skip pmd NULL check though. + */ +static inline pte_t *__virt_to_kpte(unsigned long va) +{ + return pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va), va); +} + +static void *boot_crst_alloc(unsigned long val) +{ + unsigned long size = PAGE_SIZE << CRST_ALLOC_ORDER; + unsigned long *table; + + table = (unsigned long *)physmem_alloc_top_down(RR_VMEM, size, size); + crst_table_init(table, val); + return table; +} + +static pte_t *boot_pte_alloc(void) +{ + static void *pte_leftover; + pte_t *pte; + + /* + * handling pte_leftovers this way helps to avoid memory fragmentation + * during POPULATE_KASAN_MAP_SHADOW when EDAT is off + */ + if (!pte_leftover) { + pte_leftover = (void *)physmem_alloc_top_down(RR_VMEM, PAGE_SIZE, PAGE_SIZE); + pte = pte_leftover + _PAGE_TABLE_SIZE; + } else { + pte = pte_leftover; + pte_leftover = NULL; + } + + memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE); + return pte; +} + +static unsigned long _pa(unsigned long addr, unsigned long size, enum populate_mode mode) +{ + switch (mode) { + case POPULATE_NONE: + return -1; + case POPULATE_DIRECT: + return addr; + case POPULATE_ABS_LOWCORE: + return __abs_lowcore_pa(addr); +#ifdef CONFIG_KASAN + case POPULATE_KASAN_MAP_SHADOW: + addr = physmem_alloc_top_down(RR_VMEM, size, size); + memset((void *)addr, 0, size); + return addr; +#endif + default: + return -1; + } +} + +static bool can_large_pud(pud_t *pu_dir, unsigned long addr, unsigned long end) +{ + return machine.has_edat2 && + IS_ALIGNED(addr, PUD_SIZE) && (end - addr) >= PUD_SIZE; +} + +static bool can_large_pmd(pmd_t *pm_dir, unsigned long addr, unsigned long end) +{ + return machine.has_edat1 && + IS_ALIGNED(addr, PMD_SIZE) && (end - addr) >= PMD_SIZE; +} + +static void pgtable_pte_populate(pmd_t *pmd, unsigned long addr, unsigned long end, + enum populate_mode mode) +{ + unsigned long pages = 0; + pte_t *pte, entry; + + pte = pte_offset_kernel(pmd, addr); + for (; addr < end; addr += PAGE_SIZE, pte++) { + if (pte_none(*pte)) { + if (kasan_pte_populate_zero_shadow(pte, mode)) + continue; + entry = __pte(_pa(addr, PAGE_SIZE, mode)); + entry = set_pte_bit(entry, PAGE_KERNEL); + if (!machine.has_nx) + entry = clear_pte_bit(entry, __pgprot(_PAGE_NOEXEC)); + set_pte(pte, entry); + pages++; + } + } + if (mode == POPULATE_DIRECT) + update_page_count(PG_DIRECT_MAP_4K, pages); +} + +static void pgtable_pmd_populate(pud_t *pud, unsigned long addr, unsigned long end, + enum populate_mode mode) +{ + unsigned long next, pages = 0; + pmd_t *pmd, entry; + pte_t *pte; + + pmd = pmd_offset(pud, addr); + for (; addr < end; addr = next, pmd++) { + next = pmd_addr_end(addr, end); + if (pmd_none(*pmd)) { + if (kasan_pmd_populate_zero_shadow(pmd, addr, next, mode)) + continue; + if (can_large_pmd(pmd, addr, next)) { + entry = __pmd(_pa(addr, _SEGMENT_SIZE, mode)); + entry = set_pmd_bit(entry, SEGMENT_KERNEL); + if (!machine.has_nx) + entry = clear_pmd_bit(entry, __pgprot(_SEGMENT_ENTRY_NOEXEC)); + set_pmd(pmd, entry); + pages++; + continue; + } + pte = boot_pte_alloc(); + pmd_populate(&init_mm, pmd, pte); + } else if (pmd_large(*pmd)) { + continue; + } + pgtable_pte_populate(pmd, addr, next, mode); + } + if (mode == POPULATE_DIRECT) + update_page_count(PG_DIRECT_MAP_1M, pages); +} + +static void pgtable_pud_populate(p4d_t *p4d, unsigned long addr, unsigned long end, + enum populate_mode mode) +{ + unsigned long next, pages = 0; + pud_t *pud, entry; + pmd_t *pmd; + + pud = pud_offset(p4d, addr); + for (; addr < end; addr = next, pud++) { + next = pud_addr_end(addr, end); + if (pud_none(*pud)) { + if (kasan_pud_populate_zero_shadow(pud, addr, next, mode)) + continue; + if (can_large_pud(pud, addr, next)) { + entry = __pud(_pa(addr, _REGION3_SIZE, mode)); + entry = set_pud_bit(entry, REGION3_KERNEL); + if (!machine.has_nx) + entry = clear_pud_bit(entry, __pgprot(_REGION_ENTRY_NOEXEC)); + set_pud(pud, entry); + pages++; + continue; + } + pmd = boot_crst_alloc(_SEGMENT_ENTRY_EMPTY); + pud_populate(&init_mm, pud, pmd); + } else if (pud_large(*pud)) { + continue; + } + pgtable_pmd_populate(pud, addr, next, mode); + } + if (mode == POPULATE_DIRECT) + update_page_count(PG_DIRECT_MAP_2G, pages); +} + +static void pgtable_p4d_populate(pgd_t *pgd, unsigned long addr, unsigned long end, + enum populate_mode mode) +{ + unsigned long next; + p4d_t *p4d; + pud_t *pud; + + p4d = p4d_offset(pgd, addr); + for (; addr < end; addr = next, p4d++) { + next = p4d_addr_end(addr, end); + if (p4d_none(*p4d)) { + if (kasan_p4d_populate_zero_shadow(p4d, addr, next, mode)) + continue; + pud = boot_crst_alloc(_REGION3_ENTRY_EMPTY); + p4d_populate(&init_mm, p4d, pud); + } + pgtable_pud_populate(p4d, addr, next, mode); + } +} + +static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode) +{ + unsigned long next; + pgd_t *pgd; + p4d_t *p4d; + + pgd = pgd_offset(&init_mm, addr); + for (; addr < end; addr = next, pgd++) { + next = pgd_addr_end(addr, end); + if (pgd_none(*pgd)) { + if (kasan_pgd_populate_zero_shadow(pgd, addr, next, mode)) + continue; + p4d = boot_crst_alloc(_REGION2_ENTRY_EMPTY); + pgd_populate(&init_mm, pgd, p4d); + } +#ifdef CONFIG_KASAN + if (mode == POPULATE_KASAN_SHALLOW) + continue; +#endif + pgtable_p4d_populate(pgd, addr, next, mode); + } +} + +void setup_vmem(unsigned long asce_limit) +{ + unsigned long start, end; + unsigned long asce_type; + unsigned long asce_bits; + int i; + + if (asce_limit == _REGION1_SIZE) { + asce_type = _REGION2_ENTRY_EMPTY; + asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH; + } else { + asce_type = _REGION3_ENTRY_EMPTY; + asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH; + } + s390_invalid_asce = invalid_pg_dir | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH; + + crst_table_init((unsigned long *)swapper_pg_dir, asce_type); + crst_table_init((unsigned long *)invalid_pg_dir, _REGION3_ENTRY_EMPTY); + + /* + * To allow prefixing the lowcore must be mapped with 4KB pages. + * To prevent creation of a large page at address 0 first map + * the lowcore and create the identity mapping only afterwards. + */ + pgtable_populate(0, sizeof(struct lowcore), POPULATE_DIRECT); + for_each_physmem_usable_range(i, &start, &end) + pgtable_populate(start, end, POPULATE_DIRECT); + pgtable_populate(__abs_lowcore, __abs_lowcore + sizeof(struct lowcore), + POPULATE_ABS_LOWCORE); + pgtable_populate(__memcpy_real_area, __memcpy_real_area + PAGE_SIZE, + POPULATE_NONE); + memcpy_real_ptep = __virt_to_kpte(__memcpy_real_area); + + kasan_populate_shadow(); + + S390_lowcore.kernel_asce = swapper_pg_dir | asce_bits; + S390_lowcore.user_asce = s390_invalid_asce; + + __ctl_load(S390_lowcore.kernel_asce, 1, 1); + __ctl_load(S390_lowcore.user_asce, 7, 7); + __ctl_load(S390_lowcore.kernel_asce, 13, 13); + + init_mm.context.asce = S390_lowcore.kernel_asce; +} |