Re: [PATCH v11 6/6] powerpc: Book3S 64-bit outline-only KASAN support
From: Christophe Leroy <hidden>
Date: 2021-04-21 12:29:43
Also in:
linux-mm, lkml
Le 19/03/2021 à 15:40, Daniel Axtens a écrit :
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index aca354fb670b..63672aa656e8 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c@@ -20,6 +20,7 @@ #include <linux/seq_file.h> #include <asm/fixmap.h> #include <linux/const.h> +#include <linux/kasan.h> #include <asm/page.h> #include <asm/hugetlb.h>@@ -317,6 +318,23 @@ static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start) unsigned long addr; unsigned int i; +#if defined(CONFIG_KASAN) && defined(CONFIG_PPC_BOOK3S_64) + /* + * On radix + KASAN, we want to check for the KASAN "early" shadow + * which covers huge quantities of memory with the same set of + * read-only PTEs. If it is, we want to note the first page (to see + * the status change), and then note the last page. This gives us good + * results without spending ages noting the exact same PTEs over 100s of + * terabytes of memory. + */ + if (p4d_page(*p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud))) { + walk_pmd(st, pud, start); + addr = start + (PTRS_PER_PUD - 1) * PUD_SIZE; + walk_pmd(st, pud, addr); + return; + } +#endif + for (i = 0; i < PTRS_PER_PUD; i++, pud++) { addr = start + i * PUD_SIZE; if (!pud_none(*pud) && !pud_is_leaf(*pud))
The above changes should not be necessary once PPC_PTDUMP is converted to GENERIC_PTDUMP. See https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=239795 Christophe