https://github.com/torvalds/linux
Revision 7a3136666bc0f0419f7aaa7b1fabb4b0e0a7fb76 authored by Kees Cook on 07 July 2011, 01:10:34 UTC, committed by H. Peter Anvin on 07 July 2011, 03:09:34 UTC
Some BIOSes will reset the Intel MISC_ENABLE MSR (specifically the XD_DISABLE bit) when resuming from S3, which can interact poorly with ebba638ae723d8a8fc2f7abce5ec18b688b791d7. In 32bit PAE mode, this can lead to a fault when EFER is restored by the kernel wakeup routines, due to it setting the NX bit for a CPU that (thanks to the BIOS reset) now incorrectly thinks it lacks the NX feature. (64bit is not affected because it uses a common CPU bring-up that specifically handles the XD_DISABLE bit.) The need for MISC_ENABLE being restored so early is specific to the S3 resume path. Normally, MISC_ENABLE is saved in save_processor_state(), but this happens after the resume header is created, so just reproduce the logic here. (acpi_suspend_lowlevel() creates the header, calls do_suspend_lowlevel, which calls save_processor_state(), so the saved processor context isn't available during resume header creation.) [ hpa: Consider for stable if OK in mainline ] Signed-off-by: Kees Cook <kees.cook@canonical.com> Link: http://lkml.kernel.org/r/20110707011034.GA8523@outflux.net Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: <stable@kernel.org> 2.6.38+
1 parent b49c78d
Tip revision: 7a3136666bc0f0419f7aaa7b1fabb4b0e0a7fb76 authored by Kees Cook on 07 July 2011, 01:10:34 UTC
x86, suspend: Restore MISC_ENABLE MSR in realmode wakeup
x86, suspend: Restore MISC_ENABLE MSR in realmode wakeup
Tip revision: 7a31366
scatterwalk.c
/*
* Cryptographic API.
*
* Cipher operations.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* 2002 Adam J. Richter <adam@yggdrasil.com>
* 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <crypto/scatterwalk.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/scatterlist.h>
static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
{
void *src = out ? buf : sgdata;
void *dst = out ? sgdata : buf;
memcpy(dst, src, nbytes);
}
void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
{
walk->sg = sg;
BUG_ON(!sg->length);
walk->offset = sg->offset;
}
EXPORT_SYMBOL_GPL(scatterwalk_start);
void *scatterwalk_map(struct scatter_walk *walk, int out)
{
return crypto_kmap(scatterwalk_page(walk), out) +
offset_in_page(walk->offset);
}
EXPORT_SYMBOL_GPL(scatterwalk_map);
static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
unsigned int more)
{
if (out) {
struct page *page;
page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
if (!PageSlab(page))
flush_dcache_page(page);
}
if (more) {
walk->offset += PAGE_SIZE - 1;
walk->offset &= PAGE_MASK;
if (walk->offset >= walk->sg->offset + walk->sg->length)
scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));
}
}
void scatterwalk_done(struct scatter_walk *walk, int out, int more)
{
if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
scatterwalk_pagedone(walk, out, more);
}
EXPORT_SYMBOL_GPL(scatterwalk_done);
void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
size_t nbytes, int out)
{
for (;;) {
unsigned int len_this_page = scatterwalk_pagelen(walk);
u8 *vaddr;
if (len_this_page > nbytes)
len_this_page = nbytes;
vaddr = scatterwalk_map(walk, out);
memcpy_dir(buf, vaddr, len_this_page, out);
scatterwalk_unmap(vaddr, out);
scatterwalk_advance(walk, len_this_page);
if (nbytes == len_this_page)
break;
buf += len_this_page;
nbytes -= len_this_page;
scatterwalk_pagedone(walk, out, 1);
}
}
EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
unsigned int start, unsigned int nbytes, int out)
{
struct scatter_walk walk;
unsigned int offset = 0;
if (!nbytes)
return;
for (;;) {
scatterwalk_start(&walk, sg);
if (start < offset + sg->length)
break;
offset += sg->length;
sg = scatterwalk_sg_next(sg);
}
scatterwalk_advance(&walk, start - offset);
scatterwalk_copychunks(buf, &walk, nbytes, out);
scatterwalk_done(&walk, out, 0);
}
EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
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