When using KASAN, there are parts of the shadow area where all pages are mapped to the kasan_early_shadow_page. It is pointless to dump one line for each of those pages (in the example below there are 7168 entries pointing to the same physical page).
~# cat /sys/kernel/debug/kernel_page_tables ... ---[ kasan shadow mem start ]--- 0xf7c00000-0xf8bfffff 0x06fac000 16M rw present dirty accessed 0xf8c00000-0xf8c03fff 0x00cd0000 16K r present dirty accessed 0xf8c04000-0xf8c07fff 0x00cd0000 16K r present dirty accessed 0xf8c08000-0xf8c0bfff 0x00cd0000 16K r present dirty accessed 0xf8c0c000-0xf8c0ffff 0x00cd0000 16K r present dirty accessed 0xf8c10000-0xf8c13fff 0x00cd0000 16K r present dirty accessed ... 7168 identical lines 0xffbfc000-0xffbfffff 0x00cd0000 16K r present dirty accessed ---[ kasan shadow mem end ]--- ... This patch modifies linux table dump to dump as a single line areas where all addresses points to the same physical page. That physical address is put inside [] to show that all virt pages points to the same phys page. ~# cat /sys/kernel/debug/kernel_page_tables ... ---[ kasan shadow mem start ]--- 0xf7c00000-0xf8bfffff 0x06fac000 16M rw present dirty accessed 0xf8c00000-0xffbfffff [0x00cd0000] 16K r present dirty accessed ---[ kasan shadow mem end ]--- ... Signed-off-by: Christophe Leroy <[email protected]> Signed-off-by: Christophe Leroy <[email protected]> --- arch/powerpc/mm/dump_linuxpagetables.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c index 6aa41669ac1a..b0da447197d4 100644 --- a/arch/powerpc/mm/dump_linuxpagetables.c +++ b/arch/powerpc/mm/dump_linuxpagetables.c @@ -143,14 +143,19 @@ static void dump_addr(struct pg_state *st, unsigned long addr) unsigned long delta; #ifdef CONFIG_PPC64 - seq_printf(st->seq, "0x%016lx-0x%016lx ", st->start_address, addr-1); - seq_printf(st->seq, "0x%016lx ", st->start_pa); +#define REG "0x%016lx" #else - seq_printf(st->seq, "0x%08lx-0x%08lx ", st->start_address, addr - 1); - seq_printf(st->seq, "0x%08lx ", st->start_pa); +#define REG "0x%08lx" #endif - delta = (addr - st->start_address) >> 10; + seq_printf(st->seq, REG "-" REG " ", st->start_address, addr - 1); + if (st->start_pa == st->last_pa && st->start_address + PAGE_SIZE != addr) { + seq_printf(st->seq, "[" REG "]", st->start_pa); + delta = PAGE_SIZE >> 10; + } else { + seq_printf(st->seq, " " REG " ", st->start_pa); + delta = (addr - st->start_address) >> 10; + } /* Work out what appropriate unit to use */ while (!(delta & 1023) && unit[1]) { delta >>= 10; @@ -184,7 +189,8 @@ static void note_page(struct pg_state *st, unsigned long addr, */ } else if (flag != st->current_flags || level != st->level || addr >= st->marker[1].start_address || - pa != st->last_pa + PAGE_SIZE) { + (pa != st->last_pa + PAGE_SIZE && + (pa != st->start_pa || st->start_pa != st->last_pa))) { /* Check the PTE flags */ if (st->current_flags) { -- 2.13.3
