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Subject[RFC PATCH 3/4] x86/boot/KASLR: Walk srat tables to filter immovable memory
Date
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.

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 b87a7582853d..4edff0501540 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 +105,17 @@ static bool memmap_too_large;
/* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */
unsigned long long mem_limit = ULLONG_MAX;

+/* Store the max numbers of acpi tables */
+#define ACPI_MAX_TABLES 128
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/* Store the movable memory */
+struct mem_vector immovable_mem[MAX_NUMNODES*2];
+
+/* Store the num of movable mem regions */
+static int num_immovable_mem;
+#endif
+

enum mem_avoid_index {
MEM_AVOID_ZO_RANGE = 0,
@@ -266,6 +278,44 @@ static int handle_mem_memmap(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_movable_mem(void)
+{
+ struct acpi_table_header *table_header;
+ struct acpi_subtable_header *asth;
+ struct acpi_srat_mem_affinity *ma;
+ unsigned long table_size;
+ unsigned long table_end;
+ int i = 0;
+
+ table_header = get_acpi_srat_table();
+
+ table_size = sizeof(struct acpi_table_srat);
+ table_end = (unsigned long)table_header + table_header->length;
+ asth = (struct acpi_subtable_header *)
+ ((unsigned long)table_header + table_size);
+
+ while (((unsigned long)asth) +
+ sizeof(struct acpi_subtable_header) < table_end) {
+ if (asth->type == 1) {
+ ma = (struct acpi_srat_mem_affinity *)asth;
+ if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)) {
+ immovable_mem[i].start = ma->base_address;
+ immovable_mem[i].size = ma->length;
+ i++;
+ }
+ }
+ asth = (struct acpi_subtable_header *)
+ ((unsigned long)asth + asth->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
@@ -389,6 +439,11 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
/* Mark the memmap regions we need to avoid */
handle_mem_memmap();

+#ifdef CONFIG_MEMORY_HOTREMOVE
+ /* Mark the hotplug SB regions we need choose */
+ handle_movable_mem();
+#endif
+
#ifdef CONFIG_X86_VERBOSE_BOOTUP
/* Make sure video RAM can be used. */
add_identity_map(0, PMD_SIZE);
--
2.17.0


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