From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
Tony Luck <tony.luck@intel.com>,
x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Dave Hansen <dave.hansen@intel.com>,
stable@vger.kernel.org
Subject: [PATCHv2 2/2] x86/boot/KASLR: Fix boot with some memory above MAXMEM
Date: Mon, 8 Jun 2020 15:54:24 +0300 [thread overview]
Message-ID: <20200608125424.70198-3-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20200608125424.70198-1-kirill.shutemov@linux.intel.com>
A 5-level paging capable machine can have memory above 46-bit in the
physical address space. This memory is only addressable in the 5-level
paging mode: we don't have enough virtual address space to create direct
mapping for such memory in the 4-level paging mode
Teach KASLR to avoid memory regions above MAXMEM or truncate the region
if the end is above MAXMEM.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: stable@vger.kernel.org # v4.14
---
arch/x86/boot/compressed/kaslr.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index d7408af55738..99db18eeb40e 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -695,7 +695,18 @@ static bool process_mem_region(struct mem_vector *region,
unsigned long long minimum,
unsigned long long image_size)
{
+ unsigned long long end;
int i;
+
+ /* Cannot access memory region above MAXMEM: skip it. */
+ if (region->start >= MAXMEM)
+ return 0;
+
+ /* Truncate the region if the end is above MAXMEM */
+ end = region->start + region->size;
+ end = min_t(unsigned long long, end, MAXMEM - 1);
+ region->size = end - region->start;
+
/*
* If no immovable memory found, or MEMORY_HOTREMOVE disabled,
* use @region directly.
--
2.26.2
next prev parent reply other threads:[~2020-06-08 12:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 12:54 [PATCHv2 0/2] x86: Fix boot with some memory above MAXMEM Kirill A. Shutemov
2020-06-08 12:54 ` [PATCHv2 1/2] x86/mm: " Kirill A. Shutemov
2020-06-10 8:41 ` Mike Rapoport
2020-06-11 2:17 ` [x86/mm] c7b2a6d1af: kernel_BUG_at_arch/x86/mm/physaddr.c kernel test robot
2020-06-08 12:54 ` Kirill A. Shutemov [this message]
2020-06-10 8:42 ` [PATCHv2 2/2] x86/boot/KASLR: Fix boot with some memory above MAXMEM Mike Rapoport
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=20200608125424.70198-3-kirill.shutemov@linux.intel.com \
--to=kirill.shutemov@linux.intel.com \
--cc=bp@alien8.de \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=x86@kernel.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).