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SubjectRe: [PATCH 1/2] x86/boot/KASLR: Adapt process_e820_entry for all kinds of memory map
On Thu, Jun 15, 2017 at 03:52:48PM +0800, Baoquan He wrote:
>Now function process_e820_entry is only used to process e820 memory
>entry. Adapt it for memory region only, not just for e820. Later
>we will use it to process efi mirror regions.
>
>So rename the original process_e820_entry to process_mem_region, and
>extract and wrap the e820 specific processing code into process_e820_entry.
>
>Signed-off-by: Baoquan He <bhe@redhat.com>

Hi Bao,

Maybe some code annotations should be changed, for example:

/* Walk e820 and find a random address. */
random_addr = find_random_phys_addr(min_addr, output_size);

Cause you will walk efi map firstly, and then e820 map(or not).

Thanks,
Chao Fan

>---
> arch/x86/boot/compressed/kaslr.c | 60 ++++++++++++++++++++++------------------
> 1 file changed, 33 insertions(+), 27 deletions(-)
>
>diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
>index fe318b4..c2ed051 100644
>--- a/arch/x86/boot/compressed/kaslr.c
>+++ b/arch/x86/boot/compressed/kaslr.c
>@@ -479,35 +479,31 @@ static unsigned long slots_fetch_random(void)
> return 0;
> }
>
>-static void process_e820_entry(struct boot_e820_entry *entry,
>+static void process_mem_region(struct mem_vector *entry,
> unsigned long minimum,
> unsigned long image_size)
> {
> struct mem_vector region, overlap;
> struct slot_area slot_area;
> unsigned long start_orig, end;
>- struct boot_e820_entry cur_entry;
>-
>- /* Skip non-RAM entries. */
>- if (entry->type != E820_TYPE_RAM)
>- return;
>+ struct mem_vector cur_entry;
>
> /* On 32-bit, ignore entries entirely above our maximum. */
>- if (IS_ENABLED(CONFIG_X86_32) && entry->addr >= KERNEL_IMAGE_SIZE)
>+ if (IS_ENABLED(CONFIG_X86_32) && entry->start >= KERNEL_IMAGE_SIZE)
> return;
>
> /* Ignore entries entirely below our minimum. */
>- if (entry->addr + entry->size < minimum)
>+ if (entry->start + entry->size < minimum)
> return;
>
> /* Ignore entries above memory limit */
>- end = min(entry->size + entry->addr, mem_limit);
>- if (entry->addr >= end)
>+ end = min(entry->size + entry->start, mem_limit);
>+ if (entry->start >= end)
> return;
>- cur_entry.addr = entry->addr;
>- cur_entry.size = end - entry->addr;
>+ cur_entry.start = entry->start;
>+ cur_entry.size = end - entry->start;
>
>- region.start = cur_entry.addr;
>+ region.start = cur_entry.start;
> region.size = cur_entry.size;
>
> /* Give up if slot area array is full. */
>@@ -522,7 +518,7 @@ static void process_e820_entry(struct boot_e820_entry *entry,
> region.start = ALIGN(region.start, CONFIG_PHYSICAL_ALIGN);
>
> /* Did we raise the address above this e820 region? */
>- if (region.start > cur_entry.addr + cur_entry.size)
>+ if (region.start > cur_entry.start + cur_entry.size)
> return;
>
> /* Reduce size by any delta from the original address. */
>@@ -562,12 +558,31 @@ static void process_e820_entry(struct boot_e820_entry *entry,
> }
> }
>
>-static unsigned long find_random_phys_addr(unsigned long minimum,
>- unsigned long image_size)
>+static void process_e820_entry(unsigned long minimum,unsigned long image_size)
> {
> int i;
>- unsigned long addr;
>+ struct mem_vector region;
>+ struct boot_e820_entry *entry;
>+
>+ /* Verify potential e820 positions, appending to slots list. */
>+ for (i = 0; i < boot_params->e820_entries; i++) {
>+ entry = &boot_params->e820_table[i];
>+ /* Skip non-RAM entries. */
>+ if (entry->type != E820_TYPE_RAM)
>+ continue;
>+ region.start = entry->addr;
>+ region.size = entry->size;
>+ process_mem_region(&region, minimum, image_size);
>+ if (slot_area_index == MAX_SLOT_AREA) {
>+ debug_putstr("Aborted e820 scan (slot_areas full)!\n");
>+ break;
>+ }
>+ }
>+}
>
>+static unsigned long find_random_phys_addr(unsigned long minimum,
>+ unsigned long image_size)
>+{
> /* Check if we had too many memmaps. */
> if (memmap_too_large) {
> debug_putstr("Aborted e820 scan (more than 4 memmap= args)!\n");
>@@ -577,16 +592,7 @@ static unsigned long find_random_phys_addr(unsigned long minimum,
> /* Make sure minimum is aligned. */
> minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN);
>
>- /* Verify potential e820 positions, appending to slots list. */
>- for (i = 0; i < boot_params->e820_entries; i++) {
>- process_e820_entry(&boot_params->e820_table[i], minimum,
>- image_size);
>- if (slot_area_index == MAX_SLOT_AREA) {
>- debug_putstr("Aborted e820 scan (slot_areas full)!\n");
>- break;
>- }
>- }
>-
>+ process_e820_entry(minimum, image_size);
> return slots_fetch_random();
> }
>
>--
>2.5.5
>
>
>


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