If you are unsure, say N.
-config PPC_PTDUMP
- bool "Export kernel pagetable layout to userspace via debugfs"
- depends on DEBUG_KERNEL && DEBUG_FS
- help
- This option exports the state of the kernel pagetables to a
- debugfs file. This is only useful for kernel developers who are
- working in architecture specific areas of the kernel - probably
- not a good idea to enable this feature in a production kernel.
-
- If you are unsure, say N.
-
-config PPC_DEBUG_WX
- bool "Warn on W+X mappings at boot"
- depends on PPC_PTDUMP && STRICT_KERNEL_RWX
- help
- Generate a warning if any W+X mappings are found at boot.
-
- This is useful for discovering cases where the kernel is leaving
- W+X mappings after applying NX, as such mappings are a security risk.
-
- Note that even if the check fails, your kernel is possibly
- still fine, as W+X mappings are not a security hole in
- themselves, what they do is that they make the exploitation
- of other unfixed kernel bugs easier.
-
- There is no runtime or memory usage effect of this option
- once the kernel has booted up - it's a one time check.
-
- If in doubt, say "Y".
-
config PPC_FAST_ENDIAN_SWITCH
bool "Deprecated fast endian-switch syscall"
depends on DEBUG_KERNEL && PPC_BOOK3S_64
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/highmem.h>
+#include <linux/ptdump.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <asm/fixmap.h>
*
*/
struct pg_state {
+ struct ptdump_state ptdump;
struct seq_file *seq;
const struct addr_marker *marker;
unsigned long start_address;
{ -1, NULL },
};
+static struct ptdump_range ptdump_range[] __ro_after_init = {
+ {TASK_SIZE_MAX, ~0UL},
+ {0, 0}
+};
+
#define pt_dump_seq_printf(m, fmt, args...) \
({ \
if (m) \
}
}
-static void note_page(struct pg_state *st, unsigned long addr,
- int level, u64 val, unsigned long page_size)
+static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, u64 val)
{
u64 flag = level >= 0 ? val & pg_level[level].mask : 0;
+ struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
/* At first no level is set */
if (st->level == -1) {
}
}
-static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
-{
- pte_t *pte = pte_offset_kernel(pmd, 0);
- unsigned long addr;
- unsigned int i;
-
- for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
- addr = start + i * PAGE_SIZE;
- note_page(st, addr, 4, pte_val(*pte), PAGE_SIZE);
-
- }
-}
-
-static void walk_hugepd(struct pg_state *st, hugepd_t *phpd, unsigned long start,
- int pdshift, int level)
-{
-#ifdef CONFIG_ARCH_HAS_HUGEPD
- unsigned int i;
- int shift = hugepd_shift(*phpd);
- int ptrs_per_hpd = pdshift - shift > 0 ? 1 << (pdshift - shift) : 1;
-
- if (start & ((1 << shift) - 1))
- return;
-
- for (i = 0; i < ptrs_per_hpd; i++) {
- unsigned long addr = start + (i << shift);
- pte_t *pte = hugepte_offset(*phpd, addr, pdshift);
-
- note_page(st, addr, level + 1, pte_val(*pte), 1 << shift);
- }
-#endif
-}
-
-static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
-{
- pmd_t *pmd = pmd_offset(pud, 0);
- unsigned long addr;
- unsigned int i;
-
- for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
- addr = start + i * PMD_SIZE;
- if (!pmd_none(*pmd) && !pmd_is_leaf(*pmd))
- /* pmd exists */
- walk_pte(st, pmd, addr);
- else
- note_page(st, addr, 3, pmd_val(*pmd), PMD_SIZE);
- }
-}
-
-static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
-{
- pud_t *pud = pud_offset(p4d, 0);
- unsigned long addr;
- unsigned int i;
-
- for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
- addr = start + i * PUD_SIZE;
- if (!pud_none(*pud) && !pud_is_leaf(*pud))
- /* pud exists */
- walk_pmd(st, pud, addr);
- else
- note_page(st, addr, 2, pud_val(*pud), PUD_SIZE);
- }
-}
-
-static void walk_pagetables(struct pg_state *st)
-{
- unsigned int i;
- unsigned long addr = st->start_address & PGDIR_MASK;
- pgd_t *pgd = pgd_offset_k(addr);
-
- /*
- * Traverse the linux pagetable structure and dump pages that are in
- * the hash pagetable.
- */
- for (i = pgd_index(addr); i < PTRS_PER_PGD; i++, pgd++, addr += PGDIR_SIZE) {
- p4d_t *p4d = p4d_offset(pgd, 0);
-
- if (p4d_none(*p4d) || p4d_is_leaf(*p4d))
- note_page(st, addr, 1, p4d_val(*p4d), PGDIR_SIZE);
- else if (is_hugepd(__hugepd(p4d_val(*p4d))))
- walk_hugepd(st, (hugepd_t *)p4d, addr, PGDIR_SHIFT, 1);
- else
- /* p4d exists */
- walk_pud(st, p4d, addr);
- }
-}
-
static void populate_markers(void)
{
int i = 0;
.seq = m,
.marker = address_markers,
.level = -1,
- .start_address = IS_ENABLED(CONFIG_PPC64) ? PAGE_OFFSET : TASK_SIZE,
+ .ptdump = {
+ .note_page = note_page,
+ .range = ptdump_range,
+ }
};
-#ifdef CONFIG_PPC64
- if (!radix_enabled())
- st.start_address = KERN_VIRT_START;
-#endif
-
/* Traverse kernel page tables */
- walk_pagetables(&st);
- note_page(&st, 0, -1, 0, 0);
+ ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
return 0;
}
pg_level[i].mask |= pg_level[i].flag[j].mask;
}
-#ifdef CONFIG_PPC_DEBUG_WX
+#ifdef CONFIG_DEBUG_WX
void ptdump_check_wx(void)
{
struct pg_state st = {
.seq = NULL,
- .marker = address_markers,
+ .marker = (struct addr_marker[]) {
+ { 0, NULL},
+ { -1, NULL},
+ },
.level = -1,
.check_wx = true,
- .start_address = IS_ENABLED(CONFIG_PPC64) ? PAGE_OFFSET : TASK_SIZE,
+ .ptdump = {
+ .note_page = note_page,
+ .range = ptdump_range,
+ }
};
-#ifdef CONFIG_PPC64
- if (!radix_enabled())
- st.start_address = KERN_VIRT_START;
-#endif
-
- walk_pagetables(&st);
+ ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
if (st.wx_pages)
pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found\n",
}
#endif
-static int ptdump_init(void)
+static int __init ptdump_init(void)
{
+#ifdef CONFIG_PPC64
+ if (!radix_enabled())
+ ptdump_range[0].start = KERN_VIRT_START;
+ else
+ ptdump_range[0].start = PAGE_OFFSET;
+#endif
+
populate_markers();
build_pgtable_complete_mask();
- debugfs_create_file("kernel_page_tables", 0400, NULL, NULL,
- &ptdump_fops);
+
+ if (IS_ENABLED(CONFIG_PTDUMP_DEBUGFS))
+ debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops);
+
return 0;
}
device_initcall(ptdump_init);
projects / kernel.git / commitdiff