Re: [PATCH 2/4] kaslr: select the memory region in immovable node to process

Dou Liyang
2017-10-20T03:17:34Z

Hi Chao

At 10/19/2017 06:02 PM, Chao Fan wrote:
> Since the interrelationship between e820 or efi entries and memory
> region in immovable_mem is different:
> One memory region in one node may contain several entries of e820 or
> efi sometimes, and one entry of e820 or efi may contain the memory in
> different nodes sometimes. So select the intersection as a region to
> process_mem_region. It may split one node or one entry to several regions.
>
> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
> ---
> arch/x86/boot/compressed/kaslr.c | 72 ++++++++++++++++++++++++++++++++--------
> 1 file changed, 58 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index 3c1f5204693b..22330cbe8515 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -563,6 +563,7 @@ static void process_mem_region(struct mem_vector *entry,
> end = min(entry->size + entry->start, mem_limit);
> if (entry->start >= end)
> return;
> +
> cur_entry.start = entry->start;
> cur_entry.size = end - entry->start;

Above code has nothing to do with this patch. remove it.

>
> @@ -621,6 +622,52 @@ static void process_mem_region(struct mem_vector *entry,
> }
> }
>
> +static bool select_immovable_node(unsigned long long start,
> + unsigned long long size,
> + unsigned long long minimum,
> + unsigned long long image_size)
> +{
> + struct mem_vector region;
> + int i;
> +
> + if (num_immovable_region == 0) {

Seems it more better:

#ifdef CONFIG_MEMORY_HOTPLUG
for (i = 0; i < num_immovable_region; i++) {
...
}
#else
...
process_mem_region(&region, minimum, image_size);
...
#endif

> + region.start = start;
> + region.size = size;
> + process_mem_region(&region, minimum, image_size);
> +
> + if (slot_area_index == MAX_SLOT_AREA) {
> + debug_putstr("Aborted memmap scan (slot_areas full)!\n");
> + return 1;
> + }
> + } else {
> + for (i = 0; i < num_immovable_region; i++) {
> + unsigned long long end, select_end;
> + unsigned long long region_start, region_end;
> +
> + end = start + size - 1;
> + region_start = immovable_mem[i].start;
> + region_end = region_start + immovable_mem[i].size - 1;
> +
> + if (end < region_start || start > region_end)
> + continue;
> +
> + region.start = start > region_start ?
> + start : region_start;
> + select_end = end > region_end ? region_end : end;
> +
> + region.size = select_end - region.start + 1;
> +
> + process_mem_region(&region, minimum, image_size);
> +
> + if (slot_area_index == MAX_SLOT_AREA) {
> + debug_putstr("Aborted memmap scan (slot_areas full)!\n");
> + return 1;
> + }
> + }
> + }
> + return 0;
> +}
> +
> #ifdef CONFIG_EFI
> /*
> * Returns true if mirror region found (and must have been processed
> @@ -631,7 +678,6 @@ process_efi_entries(unsigned long minimum, unsigned long image_size)
> {
> struct efi_info *e = &boot_params->efi_info;
> bool efi_mirror_found = false;
> - struct mem_vector region;
> efi_memory_desc_t *md;
> unsigned long pmap;
> char *signature;
> @@ -664,6 +710,8 @@ process_efi_entries(unsigned long minimum, unsigned long image_size)
> }
>
> for (i = 0; i < nr_desc; i++) {
> + unsigned long long start, size;
> +
> md = efi_early_memdesc_ptr(pmap, e->efi_memdesc_size, i);
>
> /*
> @@ -684,13 +732,11 @@ process_efi_entries(unsigned long minimum, unsigned long image_size)
> !(md->attribute & EFI_MEMORY_MORE_RELIABLE))
> continue;
>
> - region.start = md->phys_addr;
> - region.size = md->num_pages << EFI_PAGE_SHIFT;
> - process_mem_region(&region, minimum, image_size);
> - if (slot_area_index == MAX_SLOT_AREA) {
> - debug_putstr("Aborted EFI scan (slot_areas full)!\n");
> + start = md->phys_addr;
> + size = md->num_pages << EFI_PAGE_SHIFT;
> +
> + if (select_immovable_node(start, size, minimum, image_size))

Why you replace the region with two parameters? Just use region.

> break;
> - }
> }
> return true;
> }
> @@ -706,22 +752,20 @@ static void process_e820_entries(unsigned long minimum,
> unsigned long image_size)
> {
> int i;
> - 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++) {
> + unsigned long long start, size;
> 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");
> + start = entry->addr;
> + size = entry->size;
> +
> + if (select_immovable_node(start, size, minimum, image_size))
ditto

Thanks,
dou.
> break;
> - }
> }
> }
>
>