diff options
Diffstat (limited to 'arch/arm/mm/init.c')
| -rw-r--r-- | arch/arm/mm/init.c | 149 |
1 files changed, 147 insertions, 2 deletions
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 6ca53c338519..ba87b1b3565f 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -29,6 +29,7 @@ #include <asm/prom.h> #include <asm/sections.h> #include <asm/setup.h> +#include <asm/system_info.h> #include <asm/tlb.h> #include <asm/fixmap.h> @@ -570,7 +571,7 @@ void __init mem_init(void) MLK(DTCM_OFFSET, (unsigned long) dtcm_end), MLK(ITCM_OFFSET, (unsigned long) itcm_end), #endif - MLK(FIXADDR_START, FIXADDR_TOP), + MLK(FIXADDR_START, FIXADDR_END), MLM(VMALLOC_START, VMALLOC_END), MLM(PAGE_OFFSET, (unsigned long)high_memory), #ifdef CONFIG_HIGHMEM @@ -615,7 +616,145 @@ void __init mem_init(void) } } -void free_initmem(void) +#ifdef CONFIG_ARM_KERNMEM_PERMS +struct section_perm { + unsigned long start; + unsigned long end; + pmdval_t mask; + pmdval_t prot; + pmdval_t clear; +}; + +static struct section_perm nx_perms[] = { + /* Make pages tables, etc before _stext RW (set NX). */ + { + .start = PAGE_OFFSET, + .end = (unsigned long)_stext, + .mask = ~PMD_SECT_XN, + .prot = PMD_SECT_XN, + }, + /* Make init RW (set NX). */ + { + .start = (unsigned long)__init_begin, + .end = (unsigned long)_sdata, + .mask = ~PMD_SECT_XN, + .prot = PMD_SECT_XN, + }, +#ifdef CONFIG_DEBUG_RODATA + /* Make rodata NX (set RO in ro_perms below). */ + { + .start = (unsigned long)__start_rodata, + .end = (unsigned long)__init_begin, + .mask = ~PMD_SECT_XN, + .prot = PMD_SECT_XN, + }, +#endif +}; + +#ifdef CONFIG_DEBUG_RODATA +static struct section_perm ro_perms[] = { + /* Make kernel code and rodata RX (set RO). */ + { + .start = (unsigned long)_stext, + .end = (unsigned long)__init_begin, +#ifdef CONFIG_ARM_LPAE + .mask = ~PMD_SECT_RDONLY, + .prot = PMD_SECT_RDONLY, +#else + .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE), + .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE, + .clear = PMD_SECT_AP_WRITE, +#endif + }, +}; +#endif + +/* + * Updates section permissions only for the current mm (sections are + * copied into each mm). During startup, this is the init_mm. Is only + * safe to be called with preemption disabled, as under stop_machine(). + */ +static inline void section_update(unsigned long addr, pmdval_t mask, + pmdval_t prot) +{ + struct mm_struct *mm; + pmd_t *pmd; + + mm = current->active_mm; + pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr); + +#ifdef CONFIG_ARM_LPAE + pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot); +#else + if (addr & SECTION_SIZE) + pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot); + else + pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot); +#endif + flush_pmd_entry(pmd); + local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE); +} + +/* Make sure extended page tables are in use. */ +static inline bool arch_has_strict_perms(void) +{ + if (cpu_architecture() < CPU_ARCH_ARMv6) + return false; + + return !!(get_cr() & CR_XP); +} + +#define set_section_perms(perms, field) { \ + size_t i; \ + unsigned long addr; \ + \ + if (!arch_has_strict_perms()) \ + return; \ + \ + for (i = 0; i < ARRAY_SIZE(perms); i++) { \ + if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) || \ + !IS_ALIGNED(perms[i].end, SECTION_SIZE)) { \ + pr_err("BUG: section %lx-%lx not aligned to %lx\n", \ + perms[i].start, perms[i].end, \ + SECTION_SIZE); \ + continue; \ + } \ + \ + for (addr = perms[i].start; \ + addr < perms[i].end; \ + addr += SECTION_SIZE) \ + section_update(addr, perms[i].mask, \ + perms[i].field); \ + } \ +} + +static inline void fix_kernmem_perms(void) +{ + set_section_perms(nx_perms, prot); +} + +#ifdef CONFIG_DEBUG_RODATA +void mark_rodata_ro(void) +{ + set_section_perms(ro_perms, prot); +} + +void set_kernel_text_rw(void) +{ + set_section_perms(ro_perms, clear); +} + +void set_kernel_text_ro(void) +{ + set_section_perms(ro_perms, prot); +} +#endif /* CONFIG_DEBUG_RODATA */ + +#else +static inline void fix_kernmem_perms(void) { } +#endif /* CONFIG_ARM_KERNMEM_PERMS */ + +void free_tcmmem(void) { #ifdef CONFIG_HAVE_TCM extern char __tcm_start, __tcm_end; @@ -623,6 +762,12 @@ void free_initmem(void) poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start); free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link"); #endif +} + +void free_initmem(void) +{ + fix_kernmem_perms(); + free_tcmmem(); poison_init_mem(__init_begin, __init_end - __init_begin); if (!machine_is_integrator() && !machine_is_cintegrator()) |