diff options
| author | Vasily Gorbik <gor@linux.ibm.com> | 2017-11-17 19:59:53 +0300 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-10-09 12:21:30 +0300 |
| commit | e006222b57508d58b55d36c6ae6663f5729dad2b (patch) | |
| tree | c1f3f2c83a80ea41fa9cb40ac77bb53ca07961cb /arch/s390/mm | |
| parent | 5dff03813f46f267bc1ecb334901e916346692ff (diff) | |
| download | linux-e006222b57508d58b55d36c6ae6663f5729dad2b.tar.xz | |
s390/mm: optimize debugfs ptdump kasan zero page walking
Kasan zero p4d/pud/pmd/pte are always filled in with corresponding
kasan zero entries. Walking kasan zero page backed area is time
consuming and unnecessary. When kasan zero p4d/pud/pmd is encountered,
it eventually points to the kasan zero page always with the same
attributes and nothing but it, therefore zero p4d/pud/pmd could
be jumped over.
Also adds a space between address range and pages number to separate
them from each other when pages number is huge.
0x0018000000000000-0x0018000010000000 256M PMD RW X
0x0018000010000000-0x001bfffff0000000 1073741312M PTE RO X
0x001bfffff0000000-0x001bfffff0001000 4K PTE RW X
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/dump_pagetables.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index 5139c24111bc..15ee7dc48215 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -3,6 +3,7 @@ #include <linux/debugfs.h> #include <linux/sched.h> #include <linux/mm.h> +#include <linux/kasan.h> #include <asm/kasan.h> #include <asm/sections.h> #include <asm/pgtable.h> @@ -89,7 +90,7 @@ static void note_page(struct seq_file *m, struct pg_state *st, } else if (prot != cur || level != st->level || st->current_address >= st->marker[1].start_address) { /* Print the actual finished series */ - seq_printf(m, "0x%0*lx-0x%0*lx", + seq_printf(m, "0x%0*lx-0x%0*lx ", width, st->start_address, width, st->current_address); delta = (st->current_address - st->start_address) >> 10; @@ -109,6 +110,17 @@ static void note_page(struct seq_file *m, struct pg_state *st, } } +#ifdef CONFIG_KASAN +static void note_kasan_zero_page(struct seq_file *m, struct pg_state *st) +{ + unsigned int prot; + + prot = pte_val(*kasan_zero_pte) & + (_PAGE_PROTECT | _PAGE_INVALID | _PAGE_NOEXEC); + note_page(m, st, prot, 4); +} +#endif + /* * The actual page table walker functions. In order to keep the * implementation of print_prot() short, we only check and pass @@ -141,6 +153,13 @@ static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pmd_t *pmd; int i; +#ifdef CONFIG_KASAN + if ((pud_val(*pud) & PAGE_MASK) == __pa(kasan_zero_pmd)) { + note_kasan_zero_page(m, st); + return; + } +#endif + for (i = 0; i < PTRS_PER_PMD && addr < max_addr; i++) { st->current_address = addr; pmd = pmd_offset(pud, addr); @@ -165,6 +184,13 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pud_t *pud; int i; +#ifdef CONFIG_KASAN + if ((p4d_val(*p4d) & PAGE_MASK) == __pa(kasan_zero_pud)) { + note_kasan_zero_page(m, st); + return; + } +#endif + for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++) { st->current_address = addr; pud = pud_offset(p4d, addr); @@ -188,6 +214,13 @@ static void walk_p4d_level(struct seq_file *m, struct pg_state *st, p4d_t *p4d; int i; +#ifdef CONFIG_KASAN + if ((pgd_val(*pgd) & PAGE_MASK) == __pa(kasan_zero_p4d)) { + note_kasan_zero_page(m, st); + return; + } +#endif + for (i = 0; i < PTRS_PER_P4D && addr < max_addr; i++) { st->current_address = addr; p4d = p4d_offset(pgd, addr); |