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SubjectRe: [PATCH v4 3/4] x86/boot/KASLR: Walk srat tables to filter immovable memory
On Thu, Aug 02, 2018 at 11:47:13AM +0800, Dou Liyang wrote:
>Hi Fan,
>
>At 07/23/2018 05:29 PM, Chao Fan wrote:
>> If 'CONFIG_MEMORY_HOTREMOVE' specified, walk the acpi srat memory
>> tables, store the immovable memory regions, so that kaslr can get
>> the information abouth where can be selected or not.
>> If 'CONFIG_MEMORY_HOTREMOVE' not specified, go on the old code.
>>
>> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
>> ---
>> arch/x86/boot/compressed/kaslr.c | 55 ++++++++++++++++++++++++++++++++
>> 1 file changed, 55 insertions(+)
>>
>> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
>> index 531c9876f573..4705682caf1f 100644
>> --- a/arch/x86/boot/compressed/kaslr.c
>> +++ b/arch/x86/boot/compressed/kaslr.c
>> @@ -31,6 +31,7 @@
>> #include "misc.h"
>> #include "error.h"
>> +#include "acpitb.h"
>> #include "../string.h"
>> #include <generated/compile.h>
>> @@ -104,6 +105,14 @@ static bool memmap_too_large;
>> /* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */
>> unsigned long long mem_limit = ULLONG_MAX;
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +/* Store the immovable memory regions */
>> +struct mem_vector immovable_mem[];
>> +
>> +/* Store the amount of immovable memory regions */
>> +static int num_immovable_mem;
>> +#endif
>> +
>> enum mem_avoid_index {
>> MEM_AVOID_ZO_RANGE = 0,
>> @@ -298,6 +307,47 @@ static int handle_mem_options(void)
>> return 0;
>> }
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +/*
>> + * According to ACPI table, filter the immvoable memory regions
>> + * and store them in immovable_mem[].
>> + */
>> +static void handle_immovable_mem(void)
>> +{
>> + struct acpi_table_header *table_header;
>> + struct acpi_subtable_header *table;
>> + struct acpi_srat_mem_affinity *ma;
>> + unsigned long table_size;
>> + unsigned long table_end;
>> + int i = 0;
>> +
>> + table_header = get_acpi_srat_table();
>> +
>> + if (!table_header)
>> + return;
>> +
>> + table_end = (unsigned long)table_header + table_header->length;
>> +
>> + table = (struct acpi_subtable_header *)
>> + ((unsigned long)table_header + sizeof(struct acpi_table_srat));
>> +
>> + table_size = sizeof(struct acpi_subtable_header);
>
>table_size isn't used, can be remove.
>

Thank you very much, will update in next version.

Thanks,
Chao Fan

>> + while (((unsigned long)table) + table->length < table_end) {
>> + if (table->type == 1) {
>> + ma = (struct acpi_srat_mem_affinity *)table;
>> + if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)) {
>> + immovable_mem[i].start = ma->base_address;
>> + immovable_mem[i].size = ma->length;
>> + i++;
>
>need a check(i < MAX_NUMNODES*2) before doing that in case of
>__IndexOutOfBoundsException__ even if it may be impossible in ACPI.
>
>Thanks,
> dou
>> + }
>> + }
>> + table = (struct acpi_subtable_header *)
>> + ((unsigned long)table + table->length);
>> + }
>> + num_immovable_mem = i;
>> +}
>> +#endif
>> +
>> /*
>> * In theory, KASLR can put the kernel anywhere in the range of [16M, 64T).
>> * The mem_avoid array is used to store the ranges that need to be avoided
>> @@ -421,6 +471,11 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
>> /* Mark the memmap regions we need to avoid */
>> handle_mem_options();
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> + /* Mark the immovable regions we need to choose */
>> + handle_immovable_mem();
>> +#endif
>> +
>> #ifdef CONFIG_X86_VERBOSE_BOOTUP
>> /* Make sure video RAM can be used. */
>> add_identity_map(0, PMD_SIZE);
>>


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