Nicholas Piggin <npig...@gmail.com> writes:
> Radix VA space allocations test addresses against mm->task_size which is
> 512TB, even in cases where the intention is to limit allocation to below
> 128TB.
>
> This results in mmap with a hint address below 128TB but address + length
> above 128TB succeeding when it should fail (as hash does after the
> previous patch).
>
> Set the high address limit to be considered up front, and base subsequent
> allocation checks on that consistently.
>
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
> Cc: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com>
> Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> ---
> arch/powerpc/mm/hugetlbpage-radix.c | 26 ++++++++++++------
> arch/powerpc/mm/mmap.c | 55
> ++++++++++++++++++++++---------------
> 2 files changed, 50 insertions(+), 31 deletions(-)
>
> diff --git a/arch/powerpc/mm/hugetlbpage-radix.c
> b/arch/powerpc/mm/hugetlbpage-radix.c
> index 558e9d3891bf..bd022d16745c 100644
> --- a/arch/powerpc/mm/hugetlbpage-radix.c
> +++ b/arch/powerpc/mm/hugetlbpage-radix.c
> @@ -49,17 +49,28 @@ radix__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);
> + int fixed = (flags & MAP_FIXED);
> + unsigned long high_limit;
> struct vm_unmapped_area_info info;
>
> - if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE))
> - mm->context.addr_limit = TASK_SIZE;
> + high_limit = DEFAULT_MAP_WINDOW;
> + if (addr >= high_limit || (fixed && (addr + len > high_limit)))
> + high_limit = TASK_SIZE;
>
> if (len & ~huge_page_mask(h))
> return -EINVAL;
> - if (len > mm->task_size)
> + if (len > high_limit)
> return -ENOMEM;
> + if (fixed) {
> + if (addr > high_limit - len)
> + return -ENOMEM;
> + }
>
> - if (flags & MAP_FIXED) {
> + if (unlikely(addr > mm->context.addr_limit &&
> + mm->context.addr_limit != TASK_SIZE))
> + mm->context.addr_limit = TASK_SIZE;
> +
> + if (fixed) {
> if (prepare_hugepage_range(file, addr, len))
> return -EINVAL;
> return addr;
> @@ -68,7 +79,7 @@ radix__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 (mm->task_size - len >= addr &&
> + if (high_limit - len >= addr &&
> (!vma || addr + len <= vm_start_gap(vma)))
> return addr;
> }
> @@ -79,12 +90,9 @@ radix__hugetlb_get_unmapped_area(struct file *file,
> unsigned long addr,
> info.flags = VM_UNMAPPED_AREA_TOPDOWN;
> info.length = len;
> info.low_limit = PAGE_SIZE;
> - info.high_limit = current->mm->mmap_base;
> + info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
> info.align_mask = PAGE_MASK & ~huge_page_mask(h);
> info.align_offset = 0;
>
> - if (addr > DEFAULT_MAP_WINDOW)
> - info.high_limit += mm->context.addr_limit - DEFAULT_MAP_WINDOW;
> -
> return vm_unmapped_area(&info);
> }
> diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
> index 5d78b193fec4..6d476a7b5611 100644
> --- a/arch/powerpc/mm/mmap.c
> +++ b/arch/powerpc/mm/mmap.c
> @@ -106,22 +106,32 @@ radix__arch_get_unmapped_area(struct file *filp,
> unsigned long addr,
> {
> struct mm_struct *mm = current->mm;
> struct vm_area_struct *vma;
> + int fixed = (flags & MAP_FIXED);
> + unsigned long high_limit;
> struct vm_unmapped_area_info info;
>
> + high_limit = DEFAULT_MAP_WINDOW;
> + if (addr >= high_limit || (fixed && (addr + len > high_limit)))
> + high_limit = TASK_SIZE;
> +
> + if (len > high_limit)
> + return -ENOMEM;
> + if (fixed) {
> + if (addr > high_limit - len)
> + return -ENOMEM;
> + }
> +
> if (unlikely(addr > mm->context.addr_limit &&
> mm->context.addr_limit != TASK_SIZE))
> mm->context.addr_limit = TASK_SIZE;
>
> - if (len > mm->task_size - mmap_min_addr)
> - return -ENOMEM;
> -
> - if (flags & MAP_FIXED)
> + if (fixed)
> return addr;
>
> if (addr) {
> addr = PAGE_ALIGN(addr);
> vma = find_vma(mm, addr);
> - if (mm->task_size - len >= addr && addr >= mmap_min_addr &&
> + if (high_limit - len >= addr && addr >= mmap_min_addr &&
> (!vma || addr + len <= vm_start_gap(vma)))
> return addr;
> }
> @@ -129,13 +139,9 @@ radix__arch_get_unmapped_area(struct file *filp,
> unsigned long addr,
> info.flags = 0;
> info.length = len;
> info.low_limit = mm->mmap_base;
> + info.high_limit = high_limit;
> info.align_mask = 0;
>
> - if (unlikely(addr > DEFAULT_MAP_WINDOW))
> - info.high_limit = mm->context.addr_limit;
> - else
> - info.high_limit = DEFAULT_MAP_WINDOW;
> -
> return vm_unmapped_area(&info);
> }
>
> @@ -149,37 +155,42 @@ radix__arch_get_unmapped_area_topdown(struct file *filp,
> struct vm_area_struct *vma;
> struct mm_struct *mm = current->mm;
> unsigned long addr = addr0;
> + int fixed = (flags & MAP_FIXED);
> + unsigned long high_limit;
> struct vm_unmapped_area_info info;
>
> + high_limit = DEFAULT_MAP_WINDOW;
> + if (addr >= high_limit || (fixed && (addr + len > high_limit)))
> + high_limit = TASK_SIZE;
> +
> + if (len > high_limit)
> + return -ENOMEM;
> + if (fixed) {
> + if (addr > high_limit - len)
> + return -ENOMEM;
> + }
> +
> if (unlikely(addr > mm->context.addr_limit &&
> mm->context.addr_limit != TASK_SIZE))
> mm->context.addr_limit = TASK_SIZE;
>
> - /* requested length too big for entire address space */
> - if (len > mm->task_size - mmap_min_addr)
> - return -ENOMEM;
> -
> - if (flags & MAP_FIXED)
> + if (fixed)
> return addr;
>
> - /* requesting a specific address */
> if (addr) {
> addr = PAGE_ALIGN(addr);
> vma = find_vma(mm, addr);
> - if (mm->task_size - len >= addr && addr >= mmap_min_addr &&
> - (!vma || addr + len <= vm_start_gap(vma)))
> + if (high_limit - len >= addr && addr >= mmap_min_addr &&
> + (!vma || addr + len <= vm_start_gap(vma)))
> return addr;
> }
>
> info.flags = VM_UNMAPPED_AREA_TOPDOWN;
> info.length = len;
> info.low_limit = max(PAGE_SIZE, mmap_min_addr);
> - info.high_limit = mm->mmap_base;
> + info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
> info.align_mask = 0;
>
> - if (addr > DEFAULT_MAP_WINDOW)
> - info.high_limit += mm->context.addr_limit - DEFAULT_MAP_WINDOW;
> -
> addr = vm_unmapped_area(&info);
> if (!(addr & ~PAGE_MASK))
> return addr;
> --
> 2.15.0
