diff options
Diffstat (limited to 'arch/arm64/mm/mmu.c')
| -rw-r--r-- | arch/arm64/mm/mmu.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 267d2b79d52d..451f96f3377c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -117,6 +117,10 @@ static bool pgattr_change_is_safe(u64 old, u64 new) if ((old | new) & PTE_CONT) return false; + /* Transitioning from Global to Non-Global is safe */ + if (((old ^ new) == PTE_NG) && (new & PTE_NG)) + return true; + return ((old ^ new) & ~mask) == 0; } @@ -525,6 +529,37 @@ static int __init parse_rodata(char *arg) } early_param("rodata", parse_rodata); +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +static int __init map_entry_trampoline(void) +{ + extern char __entry_tramp_text_start[]; + + pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; + phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); + + /* The trampoline is always mapped and can therefore be global */ + pgprot_val(prot) &= ~PTE_NG; + + /* Map only the text into the trampoline page table */ + memset(tramp_pg_dir, 0, PGD_SIZE); + __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, + prot, pgd_pgtable_alloc, 0); + + /* Map both the text and data into the kernel page table */ + __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { + extern char __entry_tramp_data_start[]; + + __set_fixmap(FIX_ENTRY_TRAMP_DATA, + __pa_symbol(__entry_tramp_data_start), + PAGE_KERNEL_RO); + } + + return 0; +} +core_initcall(map_entry_trampoline); +#endif + /* * Create fine-grained mappings for the kernel. */ |