diff options
| author | Toshi Kani <toshi.kani@hpe.com> | 2018-06-27 08:13:46 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-17 20:59:28 +0200 |
| commit | 2130e543ff1aa0885ac4fc5f4ecd98cfccdeed00 (patch) | |
| tree | bc280f650fbacc47a45a783e7497c81d6b51a66d | |
| parent | cc83ba490ddae49dc2c8ccdf2f32ae2ac4aeb562 (diff) | |
x86/mm: Disable ioremap free page handling on x86-PAE
commit f967db0b9ed44ec3057a28f3b28efc51df51b835 upstream.
ioremap() supports pmd mappings on x86-PAE. However, kernel's pmd
tables are not shared among processes on x86-PAE. Therefore, any
update to sync'd pmd entries need re-syncing. Freeing a pte page
also leads to a vmalloc fault and hits the BUG_ON in vmalloc_sync_one().
Disable free page handling on x86-PAE. pud_free_pmd_page() and
pmd_free_pte_page() simply return 0 if a given pud/pmd entry is present.
This assures that ioremap() does not update sync'd pmd entries at the
cost of falling back to pte mappings.
Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces")
Reported-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: mhocko@suse.com
Cc: akpm@linux-foundation.org
Cc: hpa@zytor.com
Cc: cpandya@codeaurora.org
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20180627141348.21777-2-toshi.kani@hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/mm/pgtable.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index a3b63e5a527c..36d0b81933f8 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -653,6 +653,7 @@ int pmd_clear_huge(pmd_t *pmd) return 0; } +#ifdef CONFIG_X86_64 /** * pud_free_pmd_page - Clear pud entry and free pmd page. * @pud: Pointer to a PUD. @@ -700,4 +701,22 @@ int pmd_free_pte_page(pmd_t *pmd) return 1; } + +#else /* !CONFIG_X86_64 */ + +int pud_free_pmd_page(pud_t *pud) +{ + return pud_none(*pud); +} + +/* + * Disable free page handling on x86-PAE. This assures that ioremap() + * does not update sync'd pmd entries. See vmalloc_sync_one(). + */ +int pmd_free_pte_page(pmd_t *pmd) +{ + return pmd_none(*pmd); +} + +#endif /* CONFIG_X86_64 */ #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ |