@@ -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);
}
Add support for MAP_BELOW_HINT to mmap by restricting high_limit to addr when the flag is enabled. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- arch/mips/mm/mmap.c | 9 +++++++++ 1 file changed, 9 insertions(+)