| Message ID | 20170627173330.13804-1-opendmb@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jun 27, 2017 at 10:33:29AM -0700, Doug Berger wrote: > The pmd containing memblock_limit is cleared by prepare_page_table() > which creates the opportunity for early_alloc() to allocate unmapped > memory if memblock_limit is not pmd aligned causing a boot-time hang. > > Commit 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") > attempted to resolve this problem, but there is a path through the > adjust_lowmem_bounds() routine where if all memory regions start and > end on pmd-aligned addresses the memblock_limit will be set to > arm_lowmem_limit. > > Since arm_lowmem_limit can be affected by the vmalloc early parameter, > the value of arm_lowmem_limit may not be pmd-aligned. This commit > corrects this oversight such that memblock_limit is always rounded > down to pmd-alignment. > > Fixes: 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") > Signed-off-by: Doug Berger <opendmb@gmail.com> > Suggested-by: Mark Rutland <mark.rutland@arm.com> As a minor nit, it would be better for the title to be something like "ARM: ensure memblock-limit is pmd-aligned", but either way: Acked-by: Mark Rutland <mark.rutland@arm.com> Assuming Russell doesn't have any furhter comments, this looks good to drop into the patch system. See: http://www.arm.linux.org.uk/developer/patches/info.php ... for instructions on how to send patches there. Thanks, Mark. > --- > Changes for v2: > - Cleaner equivalent implementation suggested by Mark Rutland > - Revised description to better capture the history > > arch/arm/mm/mmu.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c > index 31af3cb59a60..e46a6a446cdd 100644 > --- a/arch/arm/mm/mmu.c > +++ b/arch/arm/mm/mmu.c > @@ -1218,15 +1218,15 @@ void __init adjust_lowmem_bounds(void) > > high_memory = __va(arm_lowmem_limit - 1) + 1; > > + if (!memblock_limit) > + memblock_limit = arm_lowmem_limit; > + > /* > * Round the memblock limit down to a pmd size. This > * helps to ensure that we will allocate memory from the > * last full pmd, which should be mapped. > */ > - if (memblock_limit) > - memblock_limit = round_down(memblock_limit, PMD_SIZE); > - if (!memblock_limit) > - memblock_limit = arm_lowmem_limit; > + memblock_limit = round_down(memblock_limit, PMD_SIZE); > > if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) { > if (memblock_end_of_DRAM() > arm_lowmem_limit) { > -- > 2.13.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On 06/29/2017 04:16 AM, Mark Rutland wrote: > On Tue, Jun 27, 2017 at 10:33:29AM -0700, Doug Berger wrote: >> The pmd containing memblock_limit is cleared by prepare_page_table() >> which creates the opportunity for early_alloc() to allocate unmapped >> memory if memblock_limit is not pmd aligned causing a boot-time hang. >> >> Commit 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") >> attempted to resolve this problem, but there is a path through the >> adjust_lowmem_bounds() routine where if all memory regions start and >> end on pmd-aligned addresses the memblock_limit will be set to >> arm_lowmem_limit. >> >> Since arm_lowmem_limit can be affected by the vmalloc early parameter, >> the value of arm_lowmem_limit may not be pmd-aligned. This commit >> corrects this oversight such that memblock_limit is always rounded >> down to pmd-alignment. >> >> Fixes: 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") >> Signed-off-by: Doug Berger <opendmb@gmail.com> >> Suggested-by: Mark Rutland <mark.rutland@arm.com> > > As a minor nit, it would be better for the title to be something like > "ARM: ensure memblock-limit is pmd-aligned", but either way: > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > Assuming Russell doesn't have any furhter comments, this looks good to > drop into the patch system. See: > > http://www.arm.linux.org.uk/developer/patches/info.php > > ... for instructions on how to send patches there. > > Thanks, > Mark. > I modified the title as suggested and it has been submitted as 8685/1. Thanks! >> --- >> Changes for v2: >> - Cleaner equivalent implementation suggested by Mark Rutland >> - Revised description to better capture the history >> >> arch/arm/mm/mmu.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c >> index 31af3cb59a60..e46a6a446cdd 100644 >> --- a/arch/arm/mm/mmu.c >> +++ b/arch/arm/mm/mmu.c >> @@ -1218,15 +1218,15 @@ void __init adjust_lowmem_bounds(void) >> >> high_memory = __va(arm_lowmem_limit - 1) + 1; >> >> + if (!memblock_limit) >> + memblock_limit = arm_lowmem_limit; >> + >> /* >> * Round the memblock limit down to a pmd size. This >> * helps to ensure that we will allocate memory from the >> * last full pmd, which should be mapped. >> */ >> - if (memblock_limit) >> - memblock_limit = round_down(memblock_limit, PMD_SIZE); >> - if (!memblock_limit) >> - memblock_limit = arm_lowmem_limit; >> + memblock_limit = round_down(memblock_limit, PMD_SIZE); >> >> if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) { >> if (memblock_end_of_DRAM() > arm_lowmem_limit) { >> -- >> 2.13.0 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 31af3cb59a60..e46a6a446cdd 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1218,15 +1218,15 @@ void __init adjust_lowmem_bounds(void) high_memory = __va(arm_lowmem_limit - 1) + 1; + if (!memblock_limit) + memblock_limit = arm_lowmem_limit; + /* * Round the memblock limit down to a pmd size. This * helps to ensure that we will allocate memory from the * last full pmd, which should be mapped. */ - if (memblock_limit) - memblock_limit = round_down(memblock_limit, PMD_SIZE); - if (!memblock_limit) - memblock_limit = arm_lowmem_limit; + memblock_limit = round_down(memblock_limit, PMD_SIZE); if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) { if (memblock_end_of_DRAM() > arm_lowmem_limit) {
The pmd containing memblock_limit is cleared by prepare_page_table() which creates the opportunity for early_alloc() to allocate unmapped memory if memblock_limit is not pmd aligned causing a boot-time hang. Commit 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") attempted to resolve this problem, but there is a path through the adjust_lowmem_bounds() routine where if all memory regions start and end on pmd-aligned addresses the memblock_limit will be set to arm_lowmem_limit. Since arm_lowmem_limit can be affected by the vmalloc early parameter, the value of arm_lowmem_limit may not be pmd-aligned. This commit corrects this oversight such that memblock_limit is always rounded down to pmd-alignment. Fixes: 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") Signed-off-by: Doug Berger <opendmb@gmail.com> Suggested-by: Mark Rutland <mark.rutland@arm.com> --- Changes for v2: - Cleaner equivalent implementation suggested by Mark Rutland - Revised description to better capture the history arch/arm/mm/mmu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)