Le 09/04/2022 à 19:17, Christophe Leroy a écrit :
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.
From Catalin (ARM64): We should have fixed hugetlb_get_unmapped_area() as well when we added support for 52-bit VA. The reason for commit f6795053dac8 was to prevent normal mmap() from returning addresses above 48-bit by default as some user-space had hard assumptions about this.
It's a slight ABI change if you do this for hugetlb_get_unmapped_area() but I doubt anyone would notice. It's more likely that the current behaviour would cause issues, so I'd rather have them consistent.
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 Fixes: f6795053dac8 ("mm: mmap: Allow for "high" userspace addresses") Cc: stable@vger.kernel.org # 5.0.x Reviewed-by: Catalin Marinas catalin.marinas@arm.com Acked-by: Andrew Morton akpm@linux-foundation.org
This patch was merged in 5.18-rc4
See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
The rest of the series is to be merged via powerpc tree.
v10:
- Moved as first patch of the series so that it can be applied
separately as a flag and be easily applied back on stable.
- Added text from Catalin explaining why it is a fixup.
fs/hugetlbfs/inode.c | 9 +++++---- include/linux/sched/mm.h | 8 ++++++++ mm/mmap.c | 8 -------- 3 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 99c7477cee5c..dd3a088db11d 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -206,7 +206,7 @@ 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); info.align_mask = PAGE_MASK & ~huge_page_mask(h); info.align_offset = 0; return vm_unmapped_area(&info);
@@ -222,7 +222,7 @@ 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);
@@ -237,7 +237,7 @@ 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);@@ -251,6 +251,7 @@ 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);
if (len & ~huge_page_mask(h)) return -EINVAL; @@ -266,7 +267,7 @@ 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 &&diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index a80356e9dc69..1ad1f4bfa025 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -136,6 +136,14 @@ 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) (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 3aa839f81e63..313b57d55a63 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2117,14 +2117,6 @@ unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) return addr; } -#ifndef arch_get_mmap_end -#define arch_get_mmap_end(addr) (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.