From 321f7d29e5163d7f1c9c0b705acc45bd1be34aa6 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 18 Apr 2017 12:31:27 +0530 Subject: [PATCH] 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 Signed-off-by: Michael Ellerman --- arch/powerpc/mm/mmap.c | 6 ++++-- arch/powerpc/mm/slice.c | 3 ++- 2 files changed, 6 insertions(+), 3 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 */ diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c index ade66c3ecdce..966b9fccfa66 100644 --- a/arch/powerpc/mm/slice.c +++ b/arch/powerpc/mm/slice.c @@ -419,7 +419,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len, /* * Check if we need to expland slice area. */ - 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; on_each_cpu(slice_flush_segments, mm, 1); } -- 2.45.2