mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-04 16:25:34 +00:00
fd28f5d439
The current pmd_huge() and pud_huge() functions simply check if the table
bit is not set and reports the entries as huge in that case. This is
counter-intuitive as a clear pmd/pud cannot also be a huge pmd/pud, and
it is inconsistent with at least arm and x86.
To prevent others from making the same mistake as me in looking at code
that calls these functions and to fix an issue with KVM on arm64 that
causes memory corruption due to incorrect page reference counting
resulting from this mistake, let's change the behavior.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Fixes: 084bd29810 ("ARM64: mm: HugeTLB support.")
Cc: <stable@vger.kernel.org> # 3.11+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
/*
|
|
* arch/arm64/mm/hugetlbpage.c
|
|
*
|
|
* Copyright (C) 2013 Linaro Ltd.
|
|
*
|
|
* Based on arch/x86/mm/hugetlbpage.c.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/err.h>
|
|
#include <linux/sysctl.h>
|
|
#include <asm/mman.h>
|
|
#include <asm/tlb.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <asm/pgalloc.h>
|
|
|
|
#ifndef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
|
|
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
int pmd_huge(pmd_t pmd)
|
|
{
|
|
return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
|
|
}
|
|
|
|
int pud_huge(pud_t pud)
|
|
{
|
|
#ifndef __PAGETABLE_PMD_FOLDED
|
|
return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT);
|
|
#else
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
static __init int setup_hugepagesz(char *opt)
|
|
{
|
|
unsigned long ps = memparse(opt, &opt);
|
|
if (ps == PMD_SIZE) {
|
|
hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
|
|
} else if (ps == PUD_SIZE) {
|
|
hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
|
|
} else {
|
|
pr_err("hugepagesz: Unsupported page size %lu M\n", ps >> 20);
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
__setup("hugepagesz=", setup_hugepagesz);
|