return early_alloc_aligned(sz, sz);
}
-static pte_t * __init early_pte_alloc(pmd_t *pmd, unsigned long addr, unsigned long prot)
+static pte_t * __init early_pte_alloc(pmd_t *pmd)
+{
+ if (pmd_none(*pmd) || pmd_bad(*pmd))
+ return early_alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
+ return pmd_page_vaddr(*pmd);
+}
+
+static void __init early_pte_install(pmd_t *pmd, pte_t *pte, unsigned long prot)
+{
+ __pmd_populate(pmd, __pa(pte), prot);
+ BUG_ON(pmd_bad(*pmd));
+}
+
+static pte_t * __init early_pte_alloc_and_install(pmd_t *pmd,
+ unsigned long addr, unsigned long prot)
{
if (pmd_none(*pmd)) {
- pte_t *pte = early_alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
- __pmd_populate(pmd, __pa(pte), prot);
+ pte_t *pte = early_pte_alloc(pmd);
+ early_pte_install(pmd, pte, prot);
}
BUG_ON(pmd_bad(*pmd));
return pte_offset_kernel(pmd, addr);
unsigned long end, unsigned long pfn,
const struct mem_type *type)
{
- pte_t *pte = early_pte_alloc(pmd, addr, type->prot_l1);
+ pte_t *start_pte = early_pte_alloc(pmd);
+ pte_t *pte = start_pte + pte_index(addr);
+
+ /* If replacing a section mapping, the whole section must be replaced */
+ BUG_ON(pmd_bad(*pmd) && ((addr | end) & ~PMD_MASK));
+
do {
set_pte_ext(pte, pfn_pte(pfn, __pgprot(type->prot_pte)), 0);
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
+ early_pte_install(pmd, start_pte, type->prot_l1);
}
static void __init __map_init_section(pmd_t *pmd, unsigned long addr,
static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
unsigned long end, phys_addr_t phys,
- const struct mem_type *type)
+ const struct mem_type *type,
+ bool force_pages)
{
pmd_t *pmd = pmd_offset(pud, addr);
unsigned long next;
* aligned to a section boundary.
*/
if (type->prot_sect &&
- ((addr | next | phys) & ~SECTION_MASK) == 0) {
+ ((addr | next | phys) & ~SECTION_MASK) == 0 &&
+ !force_pages) {
__map_init_section(pmd, addr, next, phys, type);
} else {
alloc_init_pte(pmd, addr, next,
}
static void __init alloc_init_pud(pgd_t *pgd, unsigned long addr,
- unsigned long end, unsigned long phys, const struct mem_type *type)
+ unsigned long end, unsigned long phys, const struct mem_type *type,
+ bool force_pages)
{
pud_t *pud = pud_offset(pgd, addr);
unsigned long next;
do {
next = pud_addr_end(addr, end);
- alloc_init_pmd(pud, addr, next, phys, type);
+ alloc_init_pmd(pud, addr, next, phys, type, force_pages);
phys += next - addr;
} while (pud++, addr = next, addr != end);
}
* offsets, and we take full advantage of sections and
* supersections.
*/
-static void __init create_mapping(struct map_desc *md)
+static void __init create_mapping(struct map_desc *md, bool force_pages)
{
unsigned long addr, length, end;
phys_addr_t phys;
do {
unsigned long next = pgd_addr_end(addr, end);
- alloc_init_pud(pgd, addr, next, phys, type);
+ alloc_init_pud(pgd, addr, next, phys, type, force_pages);
phys += next - addr;
addr = next;
svm = early_alloc_aligned(sizeof(*svm) * nr, __alignof__(*svm));
for (md = io_desc; nr; md++, nr--) {
- create_mapping(md);
+ create_mapping(md, false);
vm = &svm->vm;
vm->addr = (void *)(md->virtual & PAGE_MASK);
map.virtual &= PAGE_MASK;
map.length = PAGE_SIZE;
map.type = MT_DEVICE;
- create_mapping(&map);
+ create_mapping(&map, false);
}
#endif
map.virtual = MODULES_VADDR;
map.length = ((unsigned long)_etext - map.virtual + ~SECTION_MASK) & SECTION_MASK;
map.type = MT_ROM;
- create_mapping(&map);
+ create_mapping(&map, false);
#endif
/*
map.virtual = FLUSH_BASE;
map.length = SZ_1M;
map.type = MT_CACHECLEAN;
- create_mapping(&map);
+ create_mapping(&map, false);
#endif
#ifdef FLUSH_BASE_MINICACHE
map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + SZ_1M);
map.virtual = FLUSH_BASE_MINICACHE;
map.length = SZ_1M;
map.type = MT_MINICLEAN;
- create_mapping(&map);
+ create_mapping(&map, false);
#endif
/*
map.virtual = 0xffff0000;
map.length = PAGE_SIZE;
map.type = MT_HIGH_VECTORS;
- create_mapping(&map);
+ create_mapping(&map, false);
if (!vectors_high()) {
map.virtual = 0;
map.type = MT_LOW_VECTORS;
- create_mapping(&map);
+ create_mapping(&map, false);
}
/*
static void __init kmap_init(void)
{
#ifdef CONFIG_HIGHMEM
- pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE),
+ pkmap_page_table = early_pte_alloc_and_install(pmd_off_k(PKMAP_BASE),
PKMAP_BASE, _PAGE_KERNEL_TABLE);
#endif
}
+
static void __init map_lowmem(void)
{
struct memblock_region *reg;
+ phys_addr_t start;
+ phys_addr_t end;
+ struct map_desc map;
/* Map all the lowmem memory banks. */
for_each_memblock(memory, reg) {
- phys_addr_t start = reg->base;
- phys_addr_t end = start + reg->size;
- struct map_desc map;
+ start = reg->base;
+ end = start + reg->size;
if (end > arm_lowmem_limit)
end = arm_lowmem_limit;
map.length = end - start;
map.type = MT_MEMORY;
- create_mapping(&map);
+ create_mapping(&map, false);
}
+
+#ifdef CONFIG_DEBUG_RODATA
+ start = __pa(_stext) & PMD_MASK;
+ end = ALIGN(__pa(__end_rodata), PMD_SIZE);
+
+ map.pfn = __phys_to_pfn(start);
+ map.virtual = __phys_to_virt(start);
+ map.length = end - start;
+ map.type = MT_MEMORY;
+
+ create_mapping(&map, true);
+#endif
}
/*
--- /dev/null
+/*
+ * linux/arch/arm/mm/rodata.c
+ *
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author: Colin Cross <ccross@android.com>
+ *
+ * Based on x86 implementation in arch/x86/mm/init_32.c
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+
+#include <asm/cache.h>
+#include <asm/pgtable.h>
+#include <asm/rodata.h>
+#include <asm/sections.h>
+#include <asm/tlbflush.h>
+
+#include "mm.h"
+
+static int kernel_set_to_readonly __read_mostly;
+
+#ifdef CONFIG_DEBUG_RODATA_TEST
+static const int rodata_test_data = 0xC3;
+
+static noinline void rodata_test(void)
+{
+ int result;
+
+ pr_info("%s: attempting to write to read-only section:\n", __func__);
+
+ if (*(volatile int *)&rodata_test_data != 0xC3) {
+ pr_err("read only data changed before test\n");
+ return;
+ }
+
+ /*
+ * Attempt to to write to rodata_test_data, trapping the expected
+ * data abort. If the trap executed, result will be 1. If it didn't,
+ * result will be 0xFF.
+ */
+ asm volatile(
+ "0: str %[zero], [%[rodata_test_data]]\n"
+ " mov %[result], #0xFF\n"
+ " b 2f\n"
+ "1: mov %[result], #1\n"
+ "2:\n"
+
+ /* Exception fixup - if store at label 0 faults, jumps to 1 */
+ ".pushsection __ex_table, \"a\"\n"
+ " .long 0b, 1b\n"
+ ".popsection\n"
+
+ : [result] "=r" (result)
+ : [rodata_test_data] "r" (&rodata_test_data), [zero] "r" (0)
+ : "memory"
+ );
+
+ if (result == 1)
+ pr_info("write to read-only section trapped, success\n");
+ else
+ pr_err("write to read-only section NOT trapped, test failed\n");
+
+ if (*(volatile int *)&rodata_test_data != 0xC3)
+ pr_err("read only data changed during write\n");
+}
+#else
+static inline void rodata_test(void) { }
+#endif
+
+static int set_page_attributes(unsigned long virt, int numpages,
+ pte_t (*f)(pte_t))
+{
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long start = virt;
+ unsigned long end = virt + (numpages << PAGE_SHIFT);
+ unsigned long pmd_end;
+
+ while (virt < end) {
+ pmd = pmd_off_k(virt);
+ pmd_end = min(ALIGN(virt + 1, PMD_SIZE), end);
+
+ if ((pmd_val(*pmd) & PMD_TYPE_MASK) != PMD_TYPE_TABLE) {
+ pr_err("%s: pmd %p=%08lx for %08lx not page table\n",
+ __func__, pmd, pmd_val(*pmd), virt);
+ virt = pmd_end;
+ continue;
+ }
+
+ while (virt < pmd_end) {
+ pte = pte_offset_kernel(pmd, virt);
+ set_pte_ext(pte, f(*pte), 0);
+ virt += PAGE_SIZE;
+ }
+ }
+
+ flush_tlb_kernel_range(start, end);
+
+ return 0;
+}
+
+int set_memory_ro(unsigned long virt, int numpages)
+{
+ return set_page_attributes(virt, numpages, pte_wrprotect);
+}
+EXPORT_SYMBOL(set_memory_ro);
+
+int set_memory_rw(unsigned long virt, int numpages)
+{
+ return set_page_attributes(virt, numpages, pte_mkwrite);
+}
+EXPORT_SYMBOL(set_memory_rw);
+
+void set_kernel_text_rw(void)
+{
+ unsigned long start = PAGE_ALIGN((unsigned long)_text);
+ unsigned long size = PAGE_ALIGN((unsigned long)__end_rodata) - start;
+
+ if (!kernel_set_to_readonly)
+ return;
+
+ pr_debug("Set kernel text: %lx - %lx to read-write\n",
+ start, start + size);
+
+ set_memory_rw(start, size >> PAGE_SHIFT);
+}
+
+void set_kernel_text_ro(void)
+{
+ unsigned long start = PAGE_ALIGN((unsigned long)_text);
+ unsigned long size = PAGE_ALIGN((unsigned long)__end_rodata) - start;
+
+ if (!kernel_set_to_readonly)
+ return;
+
+ pr_info_once("Write protecting the kernel text section %lx - %lx\n",
+ start, start + size);
+
+ pr_debug("Set kernel text: %lx - %lx to read only\n",
+ start, start + size);
+
+ set_memory_ro(start, size >> PAGE_SHIFT);
+}
+
+void mark_rodata_ro(void)
+{
+ kernel_set_to_readonly = 1;
+
+ set_kernel_text_ro();
+
+ rodata_test();
+}
projects / firefly-linux-kernel-4.4.55.git / commitdiff