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/*
* 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)
#define BP_HARDEN_EL2_SLOTS 4
#ifndef __ASSEMBLY__
typedef struct {
atomic64_t id;
void *vdso;
unsigned long flags;
} 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.
*/
#define ASID(mm) ((mm)->context.id.counter & 0xffff)
static inline bool arm64_kernel_unmapped_at_el0(void)
{
return IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) &&
cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0);
}
static inline bool arm64_kernel_use_ng_mappings(void)
{
bool tx1_bug;
/* What's a kpti? Use global mappings if we don't know. */
if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0))
return false;
/*
* Note: this function is called before the CPU capabilities have
* been configured, so our early mappings will be global. If we
* later determine that kpti is required, then
* kpti_install_ng_mappings() will make them non-global.
*/
if (arm64_kernel_unmapped_at_el0())
return true;
if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
return false;
/*
* KASLR is enabled so we're going to be enabling kpti on non-broken
* CPUs regardless of their susceptibility to Meltdown. Rather
* than force everybody to go through the G -> nG dance later on,
* just put down non-global mappings from the beginning.
*/
if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
tx1_bug = false;
#ifndef MODULE
} else if (!static_branch_likely(&arm64_const_caps_ready)) {
extern const struct midr_range cavium_erratum_27456_cpus[];
tx1_bug = is_midr_in_range_list(read_cpuid_id(),
cavium_erratum_27456_cpus);
#endif
} else {
tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456);
}
return !tx1_bug && kaslr_offset() > 0;
}
typedef void (*bp_hardening_cb_t)(void);
struct bp_hardening_data {
int hyp_vectors_slot;
bp_hardening_cb_t fn;
};
#if (defined(CONFIG_HARDEN_BRANCH_PREDICTOR) || \
defined(CONFIG_HARDEN_EL2_VECTORS))
extern char __bp_harden_hyp_vecs_start[], __bp_harden_hyp_vecs_end[];
extern atomic_t arm64_el2_vector_last_slot;
#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR || CONFIG_HARDEN_EL2_VECTORS */
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void)
{
return this_cpu_ptr(&bp_hardening_data);
}
static inline void arm64_apply_bp_hardening(void)
{
struct bp_hardening_data *d;
if (!cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR))
return;
d = arm64_get_bp_hardening_data();
if (d->fn)
d->fn();
}
#else
static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void)
{
return NULL;
}
static inline void arm64_apply_bp_hardening(void) { }
#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
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_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 mark_linear_text_alias_ro(void);
#define INIT_MM_CONTEXT(name) \
.pgd = init_pg_dir,
#endif /* !__ASSEMBLY__ */
#endif
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