| Message ID | db238c1ca2d46e33c57328f8d450f2563e92f8c2.1639736449.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Convert powerpc to default topdown mmap layout | expand |
On Fri, Dec 17, 2021 at 10:27:28AM +0000, Christophe Leroy wrote: > This is a complement of f6795053dac8 ("mm: mmap: Allow for "high" > userspace addresses") for hugetlb. > > This patch adds support for "high" userspace addresses that are > optionally supported on the system and have to be requested via a hint > mechanism ("high" addr parameter to mmap). > > Architectures such as powerpc and x86 achieve this by making changes to > their architectural versions of hugetlb_get_unmapped_area() function. > However, arm64 uses the generic version of that function. > > So take into account arch_get_mmap_base() and arch_get_mmap_end() in > hugetlb_get_unmapped_area(). To allow that, move those two macros > out of mm/mmap.c into include/linux/sched/mm.h > > If these macros are not defined in architectural code then they default > to (TASK_SIZE) and (base) so should not introduce any behavioural > changes to architectures that do not define them. > > For the time being, only ARM64 is affected by this change. > > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: Steve Capper <steve.capper@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > --- > fs/hugetlbfs/inode.c | 9 +++++---- > include/linux/sched/mm.h | 8 ++++++++ > mm/mmap.c | 8 -------- > 3 files changed, 13 insertions(+), 12 deletions(-) This would be an ABI change but I'm fine with it. Basically with this patch, getting hugetblfs addresses above 48-bit require explicit hint passed to mmap(). I wonder whether we should add a fixes tag (or at least the cc stable): Fixes: f6795053dac8 ("mm: mmap: Allow for "high" userspace addresses") Cc: <stable@vger.kernel.org> # 5.0.x I think the original commit should have changed hugetlb_get_unmapped_area() to have the same behaviour as arch_get_unmapped_area(). Steve, any thoughts? FWIW, Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index c7cde4e5924d..a8d3b0899b60 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -205,7 +205,7 @@ hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr, info.flags = 0; info.length = len; info.low_limit = current->mm->mmap_base; - info.high_limit = TASK_SIZE; + info.high_limit = arch_get_mmap_end(addr, len, flags); info.align_mask = PAGE_MASK & ~huge_page_mask(h); info.align_offset = 0; return vm_unmapped_area(&info); @@ -221,7 +221,7 @@ hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr, info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.length = len; info.low_limit = max(PAGE_SIZE, mmap_min_addr); - info.high_limit = current->mm->mmap_base; + info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base); info.align_mask = PAGE_MASK & ~huge_page_mask(h); info.align_offset = 0; addr = vm_unmapped_area(&info); @@ -236,7 +236,7 @@ hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr, VM_BUG_ON(addr != -ENOMEM); info.flags = 0; info.low_limit = current->mm->mmap_base; - info.high_limit = TASK_SIZE; + info.high_limit = arch_get_mmap_end(addr, len, flags); addr = vm_unmapped_area(&info); } @@ -251,6 +251,7 @@ generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr, struct mm_struct *mm = current->mm; struct vm_area_struct *vma; struct hstate *h = hstate_file(file); + const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); if (len & ~huge_page_mask(h)) return -EINVAL; @@ -266,7 +267,7 @@ generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr, if (addr) { addr = ALIGN(addr, huge_page_size(h)); vma = find_vma(mm, addr); - if (TASK_SIZE - len >= addr && + if (mmap_end - len >= addr && (!vma || addr + len <= vm_start_gap(vma))) return addr; } diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 2584f7c13f69..cc9d80bd36d5 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -135,6 +135,14 @@ static inline void mm_update_next_owner(struct mm_struct *mm) #endif /* CONFIG_MEMCG */ #ifdef CONFIG_MMU +#ifndef arch_get_mmap_end +#define arch_get_mmap_end(addr, len, flags) (TASK_SIZE) +#endif + +#ifndef arch_get_mmap_base +#define arch_get_mmap_base(addr, base) (base) +#endif + extern void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack); extern unsigned long diff --git a/mm/mmap.c b/mm/mmap.c index ad48f7af7511..c773b5ad9a11 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2112,14 +2112,6 @@ unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) return addr; } -#ifndef arch_get_mmap_end -#define arch_get_mmap_end(addr, len, flags) (TASK_SIZE) -#endif - -#ifndef arch_get_mmap_base -#define arch_get_mmap_base(addr, base) (base) -#endif - /* Get an address range which is currently unmapped. * For shmat() with addr=0. *
This is a complement of f6795053dac8 ("mm: mmap: Allow for "high" userspace addresses") for hugetlb. This patch adds support for "high" userspace addresses that are optionally supported on the system and have to be requested via a hint mechanism ("high" addr parameter to mmap). Architectures such as powerpc and x86 achieve this by making changes to their architectural versions of hugetlb_get_unmapped_area() function. However, arm64 uses the generic version of that function. So take into account arch_get_mmap_base() and arch_get_mmap_end() in hugetlb_get_unmapped_area(). To allow that, move those two macros out of mm/mmap.c into include/linux/sched/mm.h If these macros are not defined in architectural code then they default to (TASK_SIZE) and (base) so should not introduce any behavioural changes to architectures that do not define them. For the time being, only ARM64 is affected by this change. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Steve Capper <steve.capper@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> --- fs/hugetlbfs/inode.c | 9 +++++---- include/linux/sched/mm.h | 8 ++++++++ mm/mmap.c | 8 -------- 3 files changed, 13 insertions(+), 12 deletions(-)