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SubjectRe: [PATCH v3 2/4] kaslr: calculate the memory region in immovable node
On 12/05/17 at 11:40am, Kees Cook wrote:
> On Tue, Dec 5, 2017 at 12:51 AM, Chao Fan <fanc.fnst@cn.fujitsu.com> wrote:
> > If there is no immovable memory region specified, go on the old code.
> > There are several conditons:
> > 1. CONFIG_MEMORY_HOTPLUG is not specified to y.
> > 2. immovable_mem= is not specified.
> >
> > Otherwise, calculate the intersecting between memmap entry and
> > immovable memory.
>
> Instead of copy/pasting code between process_efi_entries() and
> process_e820_entries(), I'd rather that process_mem_region() is
> modified to deal with immovable regions.

If put it into process_mem_region(), one level of loop is added. How
about changing it like below. If no immovable_mem, just process the
region in process_immovable_mem(). This we don't need to touch
process_mem_region().


From 9ae3f5ab0e2f129757495af2412bd52dcf86aa46 Mon Sep 17 00:00:00 2001
From: Baoquan He <bhe@redhat.com>
Date: Wed, 6 Dec 2017 17:24:55 +0800
Subject: [PATCH] KASLR: change code

Signed-off-by: Baoquan He <bhe@redhat.com>
---
arch/x86/boot/compressed/kaslr.c | 32 ++++++++++++++------------------
1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 13d26b859c69..73b1562a7439 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -638,13 +638,23 @@ static bool process_immovable_mem(struct mem_vector region,
unsigned long long minimum,
unsigned long long image_size)
{
- int i;
+ /* If no immovable_mem stored, use region directly */
+ if (num_immovable_region == 0) {
+ process_mem_region(&entry, minimum, image_size);
+
+ if (slot_area_index == MAX_SLOT_AREA) {
+ debug_putstr("Aborted memmap scan (slot_areas full)!\n");
+ return 1;
+ }
+
+ return 0;
+ }

/*
* Walk all immovable regions, and filter the intersection
* to process_mem_region.
*/
- for (i = 0; i < num_immovable_region; i++) {
+ for (int i = 0; i < num_immovable_region; i++) {
struct mem_vector entry;
unsigned long long start, end, entry_end;

@@ -738,14 +748,7 @@ process_efi_entries(unsigned long minimum, unsigned long image_size)
region.start = md->phys_addr;
region.size = md->num_pages << EFI_PAGE_SHIFT;

- /* If no immovable_mem stored, use region directly */
- if (num_immovable_region == 0) {
- process_mem_region(&region, minimum, image_size);
- if (slot_area_index == MAX_SLOT_AREA) {
- debug_putstr("Aborted memmap scan (slot_areas full)!\n");
- break;
- }
- } else if (process_immovable_mem(region, minimum, image_size))
+ if (process_immovable_mem(region, minimum, image_size))
break;
}
return true;
@@ -774,14 +777,7 @@ static void process_e820_entries(unsigned long minimum,
region.start = entry->addr;
region.size = entry->size;

- /* If no immovable_mem stored, use region directly */
- if (num_immovable_region == 0) {
- process_mem_region(&region, minimum, image_size);
- if (slot_area_index == MAX_SLOT_AREA) {
- debug_putstr("Aborted memmap scan (slot_areas full)!\n");
- break;
- }
- } else if (process_immovable_mem(region, minimum, image_size))
+ if (process_immovable_mem(region, minimum, image_size))
break;
}
}
--
2.5.5
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