diff options
Diffstat (limited to 'arch/arm64/include/asm/mmu.h')
| -rw-r--r-- | arch/arm64/include/asm/mmu.h | 112 |
1 files changed, 93 insertions, 19 deletions
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 5468c834b072..137a173df1ff 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -1,42 +1,116 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2012 ARM Ltd. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #ifndef __ASM_MMU_H #define __ASM_MMU_H +#include <asm/cputype.h> + +#define MMCF_AARCH32 0x1 /* mm context flag for AArch32 executables */ +#define USER_ASID_BIT 48 +#define USER_ASID_FLAG (UL(1) << USER_ASID_BIT) +#define TTBR_ASID_MASK (UL(0xffff) << 48) + +#ifndef __ASSEMBLER__ + +#include <linux/refcount.h> +#include <asm/cpufeature.h> + +enum pgtable_type { + TABLE_PTE, + TABLE_PMD, + TABLE_PUD, + TABLE_P4D, +}; + typedef struct { atomic64_t id; +#ifdef CONFIG_COMPAT + void *sigpage; +#endif + refcount_t pinned; void *vdso; unsigned long flags; + u8 pkey_allocation_map; } mm_context_t; /* - * This macro is only used by the TLBI code, which cannot race with an - * ASID change and therefore doesn't need to reload the counter using - * atomic64_read. + * We use atomic64_read() here because the ASID for an 'mm_struct' can + * be reallocated when scheduling one of its threads following a + * rollover event (see new_context() and flush_context()). In this case, + * a concurrent TLBI (e.g. via try_to_unmap_one() and ptep_clear_flush()) + * may use a stale ASID. This is fine in principle as the new ASID is + * guaranteed to be clean in the TLB, but the TLBI routines have to take + * care to handle the following race: + * + * CPU 0 CPU 1 CPU 2 + * + * // ptep_clear_flush(mm) + * xchg_relaxed(pte, 0) + * DSB ISHST + * old = ASID(mm) + * | <rollover> + * | new = new_context(mm) + * \-----------------> atomic_set(mm->context.id, new) + * cpu_switch_mm(mm) + * // Hardware walk of pte using new ASID + * TLBI(old) + * + * In this scenario, the barrier on CPU 0 and the dependency on CPU 1 + * ensure that the page-table walker on CPU 1 *must* see the invalid PTE + * written by CPU 0. */ -#define ASID(mm) ((mm)->context.id.counter & 0xffff) +#define ASID(mm) (atomic64_read(&(mm)->context.id) & 0xffff) + +static inline bool arm64_kernel_unmapped_at_el0(void) +{ + return alternative_has_cap_unlikely(ARM64_UNMAP_KERNEL_AT_EL0); +} +extern void arm64_memblock_init(void); extern void paging_init(void); extern void bootmem_init(void); -extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt); -extern void init_mem_pgprot(void); +extern void create_mapping_noalloc(phys_addr_t phys, unsigned long virt, + phys_addr_t size, pgprot_t prot); extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, bool page_mappings_only); -extern void *fixmap_remap_fdt(phys_addr_t dt_phys); +extern void *fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot); extern void mark_linear_text_alias_ro(void); +extern int split_kernel_leaf_mapping(unsigned long start, unsigned long end); +extern void linear_map_maybe_split_to_ptes(void); + +/* + * This check is triggered during the early boot before the cpufeature + * is initialised. Checking the status on the local CPU allows the boot + * CPU to detect the need for non-global mappings and thus avoiding a + * pagetable re-write after all the CPUs are booted. This check will be + * anyway run on individual CPUs, allowing us to get the consistent + * state once the SMP CPUs are up and thus make the switch to non-global + * mappings if required. + */ +static inline bool kaslr_requires_kpti(void) +{ + /* + * E0PD does a similar job to KPTI so can be used instead + * where available. + */ + if (IS_ENABLED(CONFIG_ARM64_E0PD)) { + u64 mmfr2 = read_sysreg_s(SYS_ID_AA64MMFR2_EL1); + if (cpuid_feature_extract_unsigned_field(mmfr2, + ID_AA64MMFR2_EL1_E0PD_SHIFT)) + return false; + } + + return true; +} + +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +void kpti_install_ng_mappings(void); +#else +static inline void kpti_install_ng_mappings(void) {} +#endif +#endif /* !__ASSEMBLER__ */ #endif |