Re: [PATCH v9 6/8] x86/boot: Dig out SRAT table from RSDP and find immovable memory

[Chao Fan]

On Wed, Oct 17, 2018 at 06:20:10PM +0800, Chao Fan wrote:
>Dig out SRAT table from RSDP, and then walk all memory to find
>the immovable memory regions, and fill in the immovable_mem[].
>So that we can use it to select memory for KASLR.
>
>Signed-off-by: Chao Fan <fanc.fnst@xxxxxxxxxxxxxx>
>---
> arch/x86/boot/compressed/Makefile |   4 +
> arch/x86/boot/compressed/acpitb.c | 129 ++++++++++++++++++++++++++++++
> arch/x86/boot/compressed/misc.h   |  10 +++
> 3 files changed, 143 insertions(+)
>
>diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
>index 28764dacf018..f67674d7d2bd 100644
>--- a/arch/x86/boot/compressed/Makefile
>+++ b/arch/x86/boot/compressed/Makefile
>@@ -83,6 +83,10 @@ ifdef CONFIG_X86_64
> 	vmlinux-objs-y += $(obj)/pgtable_64.o
> endif
> 
>+#ifdef CONFIG_MEMORY_HOTREMOVE && CONFIG_RANDOMIZE_BASE

Sorry for this, should be
#if (defined CONFIG_MEMORY_HOTREMOVE) && (defined CONFIG_RANDOMIZE_BASE)

I have change it in another file but forget here.

Thanks,
Chao Fan

>+vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/acpitb.o
>+#endif
>+
> $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone
> 
> vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \
>diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c
>index 37b1f4407be8..d119663c05bb 100644
>--- a/arch/x86/boot/compressed/acpitb.c
>+++ b/arch/x86/boot/compressed/acpitb.c
>@@ -11,6 +11,15 @@
> #define STATIC
> #include <linux/decompress/mm.h>
> 
>+#ifdef CONFIG_MEMORY_HOTREMOVE
>+struct mem_vector {
>+	unsigned long long start;
>+	unsigned long long size;
>+};
>+/* Store the immovable memory regions */
>+struct mem_vector immovable_mem[MAX_NUMNODES*2];
>+#endif
>+
> /* Search EFI table for RSDP table. */
> static void efi_get_rsdp_addr(acpi_physical_address *rsdp_addr)
> {
>@@ -223,3 +232,123 @@ static void get_acpi_rsdp(acpi_physical_address *rsdp_addr)
> 	}
> #endif
> }
>+
>+/*
>+ * Used to dig RSDP table from EFI table or BIOS.
>+ * If RSDP table found in EFI table, use it. Or search BIOS.
>+ * Based on acpi_os_get_root_pointer().
>+ */
>+static acpi_physical_address get_rsdp_addr(void)
>+{
>+	acpi_physical_address pa = 0;
>+
>+	get_acpi_rsdp(&pa);
>+
>+	if (!pa)
>+		efi_get_rsdp_addr(&pa);
>+
>+	if (!pa)
>+		bios_get_rsdp_addr(&pa);
>+
>+	return pa;
>+}
>+
>+static struct acpi_table_header *get_acpi_srat_table(void)
>+{
>+	acpi_physical_address acpi_table;
>+	acpi_physical_address root_table;
>+	struct acpi_table_header *header;
>+	struct acpi_table_rsdp *rsdp;
>+	char *signature;
>+	u8 *entry;
>+	u32 count;
>+	u32 size;
>+	int i, j;
>+	u32 len;
>+
>+	rsdp = (struct acpi_table_rsdp *)get_rsdp_addr();
>+	if (!rsdp)
>+		return NULL;
>+
>+	/* Get RSDT or XSDT from RSDP. */
>+	if (!cmdline_find_option_arg("acpi", "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;
>+	}
>+
>+	/* Get ACPI root table from RSDT or XSDT.*/
>+	header = (struct acpi_table_header *)root_table;
>+	len = header->length;
>+	count = (u32)((len - sizeof(struct acpi_table_header)) / size);
>+	entry = ACPI_ADD_PTR(u8, header, sizeof(struct acpi_table_header));
>+
>+	for (i = 0; i < count; i++) {
>+		u64 address64;
>+
>+		if (size == ACPI_RSDT_ENTRY_SIZE)
>+			acpi_table = ((acpi_physical_address)
>+				      (*ACPI_CAST_PTR(u32, entry)));
>+		else {
>+			*(u64 *)(void *)&address64 = *(u64 *)(void *)entry;
>+			acpi_table = (acpi_physical_address) address64;
>+		}
>+
>+		if (acpi_table) {
>+			header = (struct acpi_table_header *)acpi_table;
>+			signature = header->signature;
>+
>+			if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_SRAT))
>+				return header;
>+		}
>+		entry += size;
>+	}
>+	return NULL;
>+}
>+
>+/*
>+ * According to ACPI table, filter the immvoable memory regions
>+ * and store them in immovable_mem[].
>+ */
>+void get_immovable_mem(void)
>+{
>+	struct acpi_table_header *table_header;
>+	struct acpi_subtable_header *table;
>+	struct acpi_srat_mem_affinity *ma;
>+	unsigned long table_end;
>+	int i = 0;
>+
>+	if (!cmdline_find_option_bool("movable_node") ||
>+	    cmdline_find_option_arg("acpi", "off", 3))
>+		return;
>+
>+	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));
>+
>+	while (((unsigned long)table) +
>+		       sizeof(struct acpi_subtable_header) < table_end) {
>+		if (table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) {
>+			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++;
>+			}
>+
>+			if (i >= MAX_NUMNODES*2)
>+				break;
>+		}
>+		table = (struct acpi_subtable_header *)
>+			((unsigned long)table + table->length);
>+	}
>+	num_immovable_mem = i;
>+}
>diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
>index 40378408d980..70c403e1444c 100644
>--- a/arch/x86/boot/compressed/misc.h
>+++ b/arch/x86/boot/compressed/misc.h
>@@ -121,3 +121,13 @@ static inline void console_init(void)
> void set_sev_encryption_mask(void);
> 
> #endif
>+
>+/* acpitb.c */
>+#ifdef CONFIG_RANDOMIZE_BASE
>+int num_immovable_mem;
>+#ifdef CONFIG_MEMORY_HOTREMOVE
>+/* Store the amount of immovable memory regions */
>+#define ACPI_MAX_TABLES                128
>+void get_immovable_mem(void);
>+#endif
>+#endif
>-- 
>2.17.2
>