| Message ID | 20180202151619.11126-1-kleber.souza@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [SRU,Artful] x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAP | expand |
On 02/02/18 15:16, Kleber Sacilotto de Souza wrote: > From: William Grant <william.grant@canonical.com> > > BugLink: http://bugs.launchpad.net/bugs/1745118 > > Since commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the > fixmap"), i386's CPU_ENTRY_AREA has been mapped to the memory area just > below FIXADDR_START. But already immediately before FIXADDR_START is the > FIX_BTMAP area, which means that early_ioremap can collide with the entry > area. > > It's especially bad on PAE where FIX_BTMAP_BEGIN gets aligned to exactly > match CPU_ENTRY_AREA_BASE, so the first early_ioremap slot clobbers the > IDT and causes interrupts during early boot to reset the system. > > The overlap wasn't a problem before the CPU entry area was introduced, > as the fixmap has classically been preceded by the pkmap or vmalloc > areas, neither of which is used until early_ioremap is out of the > picture. > > Relocate CPU_ENTRY_AREA to below FIX_BTMAP, not just below the permanent > fixmap area. > > Fixes: commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap") > Signed-off-by: William Grant <william.grant@canonical.com> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: stable@vger.kernel.org > Link: https://lkml.kernel.org/r/7041d181-a019-e8b9-4e4e-48215f841e2c@canonical.com > (cherry picked from commit 55f49fcb879fbeebf2a8c1ac7c9e6d90df55f798 git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git) > Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> > --- > arch/x86/include/asm/fixmap.h | 6 ++++-- > arch/x86/include/asm/pgtable_32_types.h | 5 +++-- > 2 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h > index a6ff9e1a6189..75d9ea3fedcd 100644 > --- a/arch/x86/include/asm/fixmap.h > +++ b/arch/x86/include/asm/fixmap.h > @@ -137,8 +137,10 @@ enum fixed_addresses { > > extern void reserve_top_address(unsigned long reserve); > > -#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) > -#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > +#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) > +#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > +#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) > +#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE) > > extern int fixmaps_set; > > diff --git a/arch/x86/include/asm/pgtable_32_types.h b/arch/x86/include/asm/pgtable_32_types.h > index 67b60e11b70d..5b8e9f1d61d8 100644 > --- a/arch/x86/include/asm/pgtable_32_types.h > +++ b/arch/x86/include/asm/pgtable_32_types.h > @@ -43,8 +43,9 @@ extern bool __vmalloc_start_set; /* set once high_memory is set */ > */ > #define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40) > > -#define CPU_ENTRY_AREA_BASE \ > - ((FIXADDR_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) & PMD_MASK) > +#define CPU_ENTRY_AREA_BASE \ > + ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) \ > + & PMD_MASK) > > #define PKMAP_BASE \ > ((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK) > Positive test results and I'm happy it's been signed off by Thomas Gleixner too, so.. Acked-by: Colin Ian King <colin.king@canonical.com>
On 02/02/18 16:16, Kleber Sacilotto de Souza wrote: > From: William Grant <william.grant@canonical.com> > > BugLink: http://bugs.launchpad.net/bugs/1745118 > > Since commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the > fixmap"), i386's CPU_ENTRY_AREA has been mapped to the memory area just > below FIXADDR_START. But already immediately before FIXADDR_START is the > FIX_BTMAP area, which means that early_ioremap can collide with the entry > area. > > It's especially bad on PAE where FIX_BTMAP_BEGIN gets aligned to exactly > match CPU_ENTRY_AREA_BASE, so the first early_ioremap slot clobbers the > IDT and causes interrupts during early boot to reset the system. > > The overlap wasn't a problem before the CPU entry area was introduced, > as the fixmap has classically been preceded by the pkmap or vmalloc > areas, neither of which is used until early_ioremap is out of the > picture. > > Relocate CPU_ENTRY_AREA to below FIX_BTMAP, not just below the permanent > fixmap area. > > Fixes: commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap") > Signed-off-by: William Grant <william.grant@canonical.com> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: stable@vger.kernel.org > Link: https://lkml.kernel.org/r/7041d181-a019-e8b9-4e4e-48215f841e2c@canonical.com > (cherry picked from commit 55f49fcb879fbeebf2a8c1ac7c9e6d90df55f798 git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git) > Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> > --- > arch/x86/include/asm/fixmap.h | 6 ++++-- > arch/x86/include/asm/pgtable_32_types.h | 5 +++-- > 2 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h > index a6ff9e1a6189..75d9ea3fedcd 100644 > --- a/arch/x86/include/asm/fixmap.h > +++ b/arch/x86/include/asm/fixmap.h > @@ -137,8 +137,10 @@ enum fixed_addresses { > > extern void reserve_top_address(unsigned long reserve); > > -#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) > -#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > +#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) > +#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > +#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) > +#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE) > > extern int fixmaps_set; > > diff --git a/arch/x86/include/asm/pgtable_32_types.h b/arch/x86/include/asm/pgtable_32_types.h > index 67b60e11b70d..5b8e9f1d61d8 100644 > --- a/arch/x86/include/asm/pgtable_32_types.h > +++ b/arch/x86/include/asm/pgtable_32_types.h > @@ -43,8 +43,9 @@ extern bool __vmalloc_start_set; /* set once high_memory is set */ > */ > #define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40) > > -#define CPU_ENTRY_AREA_BASE \ > - ((FIXADDR_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) & PMD_MASK) > +#define CPU_ENTRY_AREA_BASE \ > + ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) \ > + & PMD_MASK) > > #define PKMAP_BASE \ > ((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK) > Applied to artful/master-next branch. Thanks, Kleber
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index a6ff9e1a6189..75d9ea3fedcd 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -137,8 +137,10 @@ enum fixed_addresses { extern void reserve_top_address(unsigned long reserve); -#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) -#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) +#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) +#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) +#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) +#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE) extern int fixmaps_set; diff --git a/arch/x86/include/asm/pgtable_32_types.h b/arch/x86/include/asm/pgtable_32_types.h index 67b60e11b70d..5b8e9f1d61d8 100644 --- a/arch/x86/include/asm/pgtable_32_types.h +++ b/arch/x86/include/asm/pgtable_32_types.h @@ -43,8 +43,9 @@ extern bool __vmalloc_start_set; /* set once high_memory is set */ */ #define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40) -#define CPU_ENTRY_AREA_BASE \ - ((FIXADDR_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) & PMD_MASK) +#define CPU_ENTRY_AREA_BASE \ + ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) \ + & PMD_MASK) #define PKMAP_BASE \ ((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)