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

Chao Fan
2018-10-18T06:12:33Z

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@cn.fujitsu.com>
>---
> 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
>