x86/boot: Parse SRAT table and count immovable memory regions

Vidos · suryasaimadhu · commit 02a3e3cdb7f1 · 2019-02-01T11:52:55.000+01:00
Parse SRAT for the immovable memory regions and use that information to control which offset KASLR selects so that it doesn't overlap with any movable region. [ bp: - Move struct mem_vector where it is visible so that it builds. - Correct comments. - Rewrite commit message. ] Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Baoquan He <bhe@redhat.com> Cc: <caoj.fnst@cn.fujitsu.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <indou.takao@jp.fujitsu.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: <kasong@redhat.com> Cc: <keescook@chromium.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: <msys.mizuma@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190123110850.12433-7-fanc.fnst@cn.fujitsu.com
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
@@ -4,9 +4,22 @@
 #include "error.h"
 #include "../string.h"
 
+#include <linux/numa.h>
 #include <linux/efi.h>
 #include <asm/efi.h>
 
+/*
+ * Longest parameter of 'acpi=' is 'copy_dsdt', plus an extra '\0'
+ * for termination.
+ */
+#define MAX_ACPI_ARG_LENGTH 10
+
+/*
+ * Immovable memory regions representation. Max amount of memory regions is
+ * MAX_NUMNODES*2.
+ */
+struct mem_vector immovable_mem[MAX_NUMNODES*2];
+
 /*
  * Max length of 64-bit hex address string is 19, prefix "0x" + 16 hex
  * digits, and '\0' for termination.
@@ -203,3 +216,111 @@ acpi_physical_address get_rsdp_addr(void)
 
 	return pa;
 }
+
+#if defined(CONFIG_RANDOMIZE_BASE) && defined(CONFIG_MEMORY_HOTREMOVE)
+/* Compute SRAT address from RSDP. */
+static unsigned long get_acpi_srat_table(void)
+{
+	unsigned long root_table, acpi_table;
+	struct acpi_table_header *header;
+	struct acpi_table_rsdp *rsdp;
+	u32 num_entries, size, len;
+	char arg[10];
+	u8 *entry;
+
+	rsdp = (struct acpi_table_rsdp *)(long)boot_params->acpi_rsdp_addr;
+	if (!rsdp)
+		return 0;
+
+	/* Get ACPI root table from RSDP.*/
+	if (!(cmdline_find_option("acpi", arg, sizeof(arg)) == 4 &&
+	    !strncmp(arg, "rsdt", 4)) &&
+	    rsdp->xsdt_physical_address &&
+	    rsdp->revision > 1) {
+		root_table = rsdp->xsdt_physical_address;
+		size = ACPI_XSDT_ENTRY_SIZE;
+	} else {
+		root_table = rsdp->rsdt_physical_address;
+		size = ACPI_RSDT_ENTRY_SIZE;
+	}
+
+	if (!root_table)
+		return 0;
+
+	header = (struct acpi_table_header *)root_table;
+	len = header->length;
+	if (len < sizeof(struct acpi_table_header) + size)
+		return 0;
+
+	num_entries = (len - sizeof(struct acpi_table_header)) / size;
+	entry = (u8 *)(root_table + sizeof(struct acpi_table_header));
+
+	while (num_entries--) {
+		if (size == ACPI_RSDT_ENTRY_SIZE)
+			acpi_table = *(u32 *)entry;
+		else
+			acpi_table = *(u64 *)entry;
+
+		if (acpi_table) {
+			header = (struct acpi_table_header *)acpi_table;
+
+			if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_SRAT))
+				return acpi_table;
+		}
+		entry += size;
+	}
+	return 0;
+}
+
+/**
+ * count_immovable_mem_regions - Parse SRAT and cache the immovable
+ * memory regions into the immovable_mem array.
+ *
+ * Return the number of immovable memory regions on success, 0 on failure:
+ *
+ * - Too many immovable memory regions
+ * - ACPI off or no SRAT found
+ * - No immovable memory region found.
+ */
+int count_immovable_mem_regions(void)
+{
+	unsigned long table_addr, table_end, table;
+	struct acpi_subtable_header *sub_table;
+	struct acpi_table_header *table_header;
+	char arg[MAX_ACPI_ARG_LENGTH];
+	int num = 0;
+
+	if (cmdline_find_option("acpi", arg, sizeof(arg)) == 3 &&
+	    !strncmp(arg, "off", 3))
+		return 0;
+
+	table_addr = get_acpi_srat_table();
+	if (!table_addr)
+		return 0;
+
+	table_header = (struct acpi_table_header *)table_addr;
+	table_end = table_addr + table_header->length;
+	table = table_addr + sizeof(struct acpi_table_srat);
+
+	while (table + sizeof(struct acpi_subtable_header) < table_end) {
+		sub_table = (struct acpi_subtable_header *)table;
+		if (sub_table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) {
+			struct acpi_srat_mem_affinity *ma;
+
+			ma = (struct acpi_srat_mem_affinity *)sub_table;
+			if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) && ma->length) {
+				immovable_mem[num].start = ma->base_address;
+				immovable_mem[num].size = ma->length;
+				num++;
+			}
+
+			if (num >= MAX_NUMNODES*2) {
+				debug_putstr("Too many immovable memory regions, aborting.\n");
+				return 0;
+			}
+		}
+		table += sub_table->length;
+	}
+	return num;
+}
+#endif /* CONFIG_RANDOMIZE_BASE && CONFIG_MEMORY_HOTREMOVE */
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
@@ -87,10 +87,6 @@ static unsigned long get_boot_seed(void)
 #define KASLR_COMPRESSED_BOOT
 #include "../../lib/kaslr.c"
 
-struct mem_vector {
-	unsigned long long start;
-	unsigned long long size;
-};
 
 /* Only supporting at most 4 unusable memmap regions with kaslr */
 #define MAX_MEMMAP_REGIONS	4
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
@@ -72,6 +72,10 @@ int cmdline_find_option(const char *option, char *buffer, int bufsize);
 int cmdline_find_option_bool(const char *option);
 #endif
 
+struct mem_vector {
+	unsigned long long start;
+	unsigned long long size;
+};
 
 #if CONFIG_RANDOMIZE_BASE
 /* kaslr.c */
@@ -126,3 +130,9 @@ acpi_physical_address get_rsdp_addr(void);
 #else
 static inline acpi_physical_address get_rsdp_addr(void) { return 0; }
 #endif
+
+#if defined(CONFIG_RANDOMIZE_BASE) && defined(CONFIG_MEMORY_HOTREMOVE)
+int count_immovable_mem_regions(void);
+#else
+static inline int count_immovable_mem_regions(void) { return 0; }
+#endif
