To avoid KASLR extracting kernel on movable memory, and slove the conflict between KASLR and movable_node feature, dig the SRAT tables from RSDP pointer. Walk the SRAT tables and store the immovable memory regions in immovable_mem[]. The code is imitated from ACPI code, based on acpi_os_get_root_pointer(). Process: RSDP->RSDT/XSDT->ACPI root table->SRAT. Signed-off-by: Chao Fan <fanc.fnst@xxxxxxxxxxxxxx> --- arch/x86/boot/compressed/Makefile | 4 + arch/x86/boot/compressed/acpitb.c | 127 ++++++++++++++++++++++++++++++ arch/x86/boot/compressed/kaslr.c | 4 - arch/x86/boot/compressed/misc.h | 15 ++++ 4 files changed, 146 insertions(+), 4 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 28764dacf018..0f631c5613d7 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -83,6 +83,10 @@ ifdef CONFIG_X86_64 vmlinux-objs-y += $(obj)/pgtable_64.o endif +#if (defined CONFIG_MEMORY_HOTREMOVE) && (defined CONFIG_RANDOMIZE_BASE) +vmlinux-objs-$(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 fa63a584d7ec..a9dbd42e5ab9 100644 --- a/arch/x86/boot/compressed/acpitb.c +++ b/arch/x86/boot/compressed/acpitb.c @@ -11,6 +11,11 @@ #define STATIC #include <linux/decompress/mm.h> +#ifdef CONFIG_MEMORY_HOTREMOVE +/* 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 +228,125 @@ 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) { + debug_putstr("Too many immovable memory regions, aborted.\n"); + break; + } + } + table = (struct acpi_subtable_header *) + ((unsigned long)table + table->length); + } + num_immovable_mem = i; +} diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 9ed9709d9947..b251572e77af 100644 --- 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 index 40378408d980..83075b9c6eea 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -82,6 +82,11 @@ void choose_random_location(unsigned long input, unsigned long *output, unsigned long output_size, unsigned long *virt_addr); +struct mem_vector { + unsigned long long start; + unsigned long long size; +}; + /* cpuflags.c */ bool has_cpuflag(int flag); #else @@ -121,3 +126,13 @@ 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