[PATCH 3/8] arch/x86: Stop special-casing hugetlb mappings in arch_get_unmapped_area

[Oscar Salvador]

arch_get_unmapped_area* sets info.align_mask to make room for extra alignment,
so that is added on top of the length we request in unmapped_area{_topdown}.
hugetlb_get_unmapped_area() already adds this extra padding in the 'len'
parameter, and it also masks off the address it gets to properly align it to
the huge_page_size we are using.

So, stop special-casing hugetlb in arch_get_unmapped_area* functions.

Also, there is no need to worry about align_offset and start_gap because
the former will be masked off back in hugetlb_get_unmapped_area() and
the latter only applies to mappings created via vm_mmap_shadow_stack() which
do not involve hugetlb.

Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
 arch/x86/kernel/sys_x86_64.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 776ae6fa7f2d..1cf2dafd223b 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -18,7 +18,6 @@
 #include <linux/random.h>
 #include <linux/uaccess.h>
 #include <linux/elf.h>
-#include <linux/hugetlb.h>
 
 #include <asm/elf.h>
 #include <asm/ia32.h>
@@ -28,8 +27,6 @@
  */
 static unsigned long get_align_mask(struct file *filp)
 {
-	if (filp && is_file_hugepages(filp))
-		return huge_page_mask_align(filp);
 	/* handle 32- and 64-bit case with a single conditional */
 	if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
 		return 0;
@@ -151,10 +148,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len,
 	info.length = len;
 	info.low_limit = begin;
 	info.high_limit = end;
-	if (!(filp && is_file_hugepages(filp))) {
-		info.align_offset = pgoff << PAGE_SHIFT;
-		info.start_gap = stack_guard_placement(vm_flags);
-	}
+	info.align_offset = pgoff << PAGE_SHIFT;
+	info.start_gap = stack_guard_placement(vm_flags);
 	if (filp) {
 		info.align_mask = get_align_mask(filp);
 		info.align_offset += get_align_bits();
@@ -205,10 +200,8 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr0,
 		info.low_limit = PAGE_SIZE;
 
 	info.high_limit = get_mmap_base(0);
-	if (!(filp && is_file_hugepages(filp))) {
-		info.start_gap = stack_guard_placement(vm_flags);
-		info.align_offset = pgoff << PAGE_SHIFT;
-	}
+	info.start_gap = stack_guard_placement(vm_flags);
+	info.align_offset = pgoff << PAGE_SHIFT;
 
 	/*
 	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
-- 
2.35.3