[PATCH 11/16] mips: mm: Support MAP_BELOW_HINT
Charlie Jenkins <[email protected]>
| Newsgroups | gmane.linux.ports.mips,gmane.linux.kernel.cross-arch,gmane.linux.kernel,gmane.linux.ports.riscv,gmane.linux.ports.arm.kernel,gmane.linux.ports.ppc64.devel,gmane.linux.kernel.mm,gmane.linux.ports.parisc,gmane.linux.ports.sh.devel,gmane.linux.ports.sparc |
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| Message-ID | <[email protected]> |
Add support for MAP_BELOW_HINT to mmap by restricting high_limit to addr when the flag is enabled. Signed-off-by: Charlie Jenkins <[email protected]> --- arch/mips/mm/mmap.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c index 7e11d7b58761..1595fda284cd 100644 --- a/arch/mips/mm/mmap.c +++ b/arch/mips/mm/mmap.c @@ -79,6 +79,13 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.low_limit = PAGE_SIZE; info.high_limit = mm->mmap_base; + if (flags & MAP_BELOW_HINT) + /* + * Subtract (STACK_TOP - mm->mmap_base) to get random + * offset defined in mmap_base() in mm/util.c + */ + info.high_limit = MIN(info.high_limit, + (addr + len) - (STACK_TOP - mm->mmap_base)); addr = vm_unmapped_area(&info); if (!(addr & ~PAGE_MASK)) @@ -94,6 +101,8 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, info.low_limit = mm->mmap_base; info.high_limit = TASK_SIZE; + if (flags & MAP_BELOW_HINT) + info.high_limit = MIN(info.high_limit, addr + len); return vm_unmapped_area(&info); } -- 2.45.0