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powerpc/mmap: Any hint > 128TB searches the full VA space
As part of the new large address space support, processes start out life with a
128TB virtual address space. However when calling mmap() a process can pass a
hint address, and if that hint is > 128TB the kernel will use the full 512TB
address space to try and satisfy the mmap() request.
Currently we have a check that the hint is > 128TB and < 512TB (TASK_SIZE),
which was added as an optimisation to avoid updating addr_limit unnecessarily
and also to avoid calling slice_flush_segments() on all CPUs more than
necessary.
However this has the user-visible side effect that an mmap() hint above 512TB
does not search the full address space unless a preceding mmap() used a hint
value > 128TB && < 512TB.
So fix it to treat any hint above 128TB as a hint to search the full address
space, instead of checking the hint against TASK_SIZE, we instead check if the
addr_limit is already == TASK_SIZE.
This also brings the ABI in-line with what is proposed on x86. ie, that a hint
address above 128TB up to and including (2^64)-1 is an indication to search the
full address space.
Fixes: f4ea6dcb08
(powerpc/mm: Enable mappings above 128TB)
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
parent
41e20d959e
commit
321f7d29e5
2 changed files with 6 additions and 3 deletions
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@ -97,7 +97,8 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
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struct vm_area_struct *vma;
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struct vm_unmapped_area_info info;
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if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE))
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if (unlikely(addr > mm->context.addr_limit &&
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mm->context.addr_limit != TASK_SIZE))
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mm->context.addr_limit = TASK_SIZE;
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if (len > mm->task_size - mmap_min_addr)
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@ -139,7 +140,8 @@ radix__arch_get_unmapped_area_topdown(struct file *filp,
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unsigned long addr = addr0;
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struct vm_unmapped_area_info info;
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if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE))
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if (unlikely(addr > mm->context.addr_limit &&
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mm->context.addr_limit != TASK_SIZE))
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mm->context.addr_limit = TASK_SIZE;
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/* requested length too big for entire address space */
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@ -419,7 +419,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
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/*
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* Check if we need to expland slice area.
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*/
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if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE)) {
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if (unlikely(addr > mm->context.addr_limit &&
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mm->context.addr_limit != TASK_SIZE)) {
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mm->context.addr_limit = TASK_SIZE;
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on_each_cpu(slice_flush_segments, mm, 1);
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}
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