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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2017-04-18 10:01:27 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2017-04-19 13:00:19 +0300
commit321f7d29e5163d7f1c9c0b705acc45bd1be34aa6 (patch)
treeccb80ac79e28a7b4fad3a2187dad26d571686e6e /arch/powerpc/mm/mmap.c
parent41e20d959e5919c70058369323cefa57428b7aaf (diff)
downloadlinux-321f7d29e5163d7f1c9c0b705acc45bd1be34aa6.tar.xz
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: f4ea6dcb08ea2c (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>
Diffstat (limited to 'arch/powerpc/mm/mmap.c')
-rw-r--r--arch/powerpc/mm/mmap.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
index 106a86406c77..82fc5762f971 100644
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -97,7 +97,8 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
struct vm_area_struct *vma;
struct vm_unmapped_area_info info;
- if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE))
+ 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)
@@ -139,7 +140,8 @@ radix__arch_get_unmapped_area_topdown(struct file *filp,
unsigned long addr = addr0;
struct vm_unmapped_area_info info;
- if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE))
+ 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 */