From: akpm@linux-foundation.org
To: akpm@linux-foundation.org, aryabinin@virtuozzo.com,
christophe.leroy@c-s.fr, dja@axtens.net, dvyukov@google.com,
glider@google.com, gor@linux.ibm.com, linux-mm@kvack.org,
mark.rutland@arm.com, mm-commits@vger.kernel.org,
torvalds@linux-foundation.org
Subject: [patch 096/158] x86/kasan: support KASAN_VMALLOC
Date: Sat, 30 Nov 2019 17:55:00 -0800 [thread overview]
Message-ID: <20191201015500.YucT296fu%akpm@linux-foundation.org> (raw)
From: Daniel Axtens <dja@axtens.net>
Subject: x86/kasan: support KASAN_VMALLOC
In the case where KASAN directly allocates memory to back vmalloc space,
don't map the early shadow page over it.
We prepopulate pgds/p4ds for the range that would otherwise be empty.
This is required to get it synced to hardware on boot, allowing the lower
levels of the page tables to be filled dynamically.
Link: http://lkml.kernel.org/r/20191031093909.9228-5-dja@axtens.net
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/x86/Kconfig | 1
arch/x86/mm/kasan_init_64.c | 61 ++++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+)
--- a/arch/x86/Kconfig~x86-kasan-support-kasan_vmalloc
+++ a/arch/x86/Kconfig
@@ -135,6 +135,7 @@ config X86
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN if X86_64
+ select HAVE_ARCH_KASAN_VMALLOC if X86_64
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
--- a/arch/x86/mm/kasan_init_64.c~x86-kasan-support-kasan_vmalloc
+++ a/arch/x86/mm/kasan_init_64.c
@@ -245,6 +245,49 @@ static void __init kasan_map_early_shado
} while (pgd++, addr = next, addr != end);
}
+static void __init kasan_shallow_populate_p4ds(pgd_t *pgd,
+ unsigned long addr,
+ unsigned long end)
+{
+ p4d_t *p4d;
+ unsigned long next;
+ void *p;
+
+ p4d = p4d_offset(pgd, addr);
+ do {
+ next = p4d_addr_end(addr, end);
+
+ if (p4d_none(*p4d)) {
+ p = early_alloc(PAGE_SIZE, NUMA_NO_NODE, true);
+ p4d_populate(&init_mm, p4d, p);
+ }
+ } while (p4d++, addr = next, addr != end);
+}
+
+static void __init kasan_shallow_populate_pgds(void *start, void *end)
+{
+ unsigned long addr, next;
+ pgd_t *pgd;
+ void *p;
+
+ addr = (unsigned long)start;
+ pgd = pgd_offset_k(addr);
+ do {
+ next = pgd_addr_end(addr, (unsigned long)end);
+
+ if (pgd_none(*pgd)) {
+ p = early_alloc(PAGE_SIZE, NUMA_NO_NODE, true);
+ pgd_populate(&init_mm, pgd, p);
+ }
+
+ /*
+ * we need to populate p4ds to be synced when running in
+ * four level mode - see sync_global_pgds_l4()
+ */
+ kasan_shallow_populate_p4ds(pgd, addr, next);
+ } while (pgd++, addr = next, addr != (unsigned long)end);
+}
+
#ifdef CONFIG_KASAN_INLINE
static int kasan_die_handler(struct notifier_block *self,
unsigned long val,
@@ -354,6 +397,24 @@ void __init kasan_init(void)
kasan_populate_early_shadow(
kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
+ kasan_mem_to_shadow((void *)VMALLOC_START));
+
+ /*
+ * If we're in full vmalloc mode, don't back vmalloc space with early
+ * shadow pages. Instead, prepopulate pgds/p4ds so they are synced to
+ * the global table and we can populate the lower levels on demand.
+ */
+ if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
+ kasan_shallow_populate_pgds(
+ kasan_mem_to_shadow((void *)VMALLOC_START),
+ kasan_mem_to_shadow((void *)VMALLOC_END));
+ else
+ kasan_populate_early_shadow(
+ kasan_mem_to_shadow((void *)VMALLOC_START),
+ kasan_mem_to_shadow((void *)VMALLOC_END));
+
+ kasan_populate_early_shadow(
+ kasan_mem_to_shadow((void *)VMALLOC_END + 1),
shadow_cpu_entry_begin);
kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
_
reply other threads:[~2019-12-01 1:55 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191201015500.YucT296fu%akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=aryabinin@virtuozzo.com \
--cc=christophe.leroy@c-s.fr \
--cc=dja@axtens.net \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=gor@linux.ibm.com \
--cc=linux-mm@kvack.org \
--cc=mark.rutland@arm.com \
--cc=mm-commits@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).