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-rw-r--r--drivers/firmware/efi/libstub/Makefile3
-rw-r--r--drivers/firmware/efi/libstub/alignedmem.c7
-rw-r--r--drivers/firmware/efi/libstub/arm64-stub.c11
-rw-r--r--drivers/firmware/efi/libstub/efi-stub-helper.c2
-rw-r--r--drivers/firmware/efi/libstub/efistub.h32
-rw-r--r--drivers/firmware/efi/libstub/mem.c5
-rw-r--r--drivers/firmware/efi/libstub/randomalloc.c17
-rw-r--r--drivers/firmware/efi/libstub/x86-5lvl.c95
-rw-r--r--drivers/firmware/efi/libstub/x86-stub.c315
-rw-r--r--drivers/firmware/efi/libstub/x86-stub.h17
10 files changed, 358 insertions, 146 deletions
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index ef5045a53..473ef1842 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -25,7 +25,7 @@ cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
-fno-builtin -fpic \
$(call cc-option,-mno-single-pic-base)
cflags-$(CONFIG_RISCV) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
- -fpic
+ -fpic -mno-relax
cflags-$(CONFIG_LOONGARCH) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
-fpie
@@ -84,6 +84,7 @@ lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o
lib-$(CONFIG_ARM) += arm32-stub.o
lib-$(CONFIG_ARM64) += arm64-stub.o smbios.o
lib-$(CONFIG_X86) += x86-stub.o
+lib-$(CONFIG_X86_64) += x86-5lvl.o
lib-$(CONFIG_RISCV) += riscv-stub.o
lib-$(CONFIG_LOONGARCH) += loongarch-stub.o
diff --git a/drivers/firmware/efi/libstub/alignedmem.c b/drivers/firmware/efi/libstub/alignedmem.c
index 1de9878dd..6b83c492c 100644
--- a/drivers/firmware/efi/libstub/alignedmem.c
+++ b/drivers/firmware/efi/libstub/alignedmem.c
@@ -22,12 +22,15 @@
* Return: status code
*/
efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
- unsigned long max, unsigned long align)
+ unsigned long max, unsigned long align,
+ int memory_type)
{
efi_physical_addr_t alloc_addr;
efi_status_t status;
int slack;
+ max = min(max, EFI_ALLOC_LIMIT);
+
if (align < EFI_ALLOC_ALIGN)
align = EFI_ALLOC_ALIGN;
@@ -36,7 +39,7 @@ efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
slack = align / EFI_PAGE_SIZE - 1;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
- EFI_LOADER_DATA, size / EFI_PAGE_SIZE + slack,
+ memory_type, size / EFI_PAGE_SIZE + slack,
&alloc_addr);
if (status != EFI_SUCCESS)
return status;
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index e2f90566b..16f15e36f 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -180,7 +180,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
* locate the kernel at a randomized offset in physical memory.
*/
status = efi_random_alloc(*reserve_size, min_kimg_align,
- reserve_addr, phys_seed);
+ reserve_addr, phys_seed,
+ EFI_LOADER_CODE, 0, EFI_ALLOC_LIMIT);
if (status != EFI_SUCCESS)
efi_warn("efi_random_alloc() failed: 0x%lx\n", status);
} else {
@@ -190,10 +191,11 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
if (status != EFI_SUCCESS) {
if (!check_image_region((u64)_text, kernel_memsize)) {
efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");
- } else if (IS_ALIGNED((u64)_text, min_kimg_align)) {
+ } else if (IS_ALIGNED((u64)_text, min_kimg_align) &&
+ (u64)_end < EFI_ALLOC_LIMIT) {
/*
* Just execute from wherever we were loaded by the
- * UEFI PE/COFF loader if the alignment is suitable.
+ * UEFI PE/COFF loader if the placement is suitable.
*/
*image_addr = (u64)_text;
*reserve_size = 0;
@@ -201,7 +203,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
}
status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
- ULONG_MAX, min_kimg_align);
+ ULONG_MAX, min_kimg_align,
+ EFI_LOADER_CODE);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 3d9b2469a..97744822d 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -216,6 +216,8 @@ efi_status_t efi_parse_options(char const *cmdline)
efi_loglevel = CONSOLE_LOGLEVEL_QUIET;
} else if (!strcmp(param, "noinitrd")) {
efi_noinitrd = true;
+ } else if (IS_ENABLED(CONFIG_X86_64) && !strcmp(param, "no5lvl")) {
+ efi_no5lvl = true;
} else if (!strcmp(param, "efi") && val) {
efi_nochunk = parse_option_str(val, "nochunk");
efi_novamap |= parse_option_str(val, "novamap");
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 970e86e3a..6741f3d90 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -29,6 +29,11 @@
#define EFI_ALLOC_ALIGN EFI_PAGE_SIZE
#endif
+#ifndef EFI_ALLOC_LIMIT
+#define EFI_ALLOC_LIMIT ULONG_MAX
+#endif
+
+extern bool efi_no5lvl;
extern bool efi_nochunk;
extern bool efi_nokaslr;
extern int efi_loglevel;
@@ -415,6 +420,26 @@ union efi_dxe_services_table {
} mixed_mode;
};
+typedef union efi_memory_attribute_protocol efi_memory_attribute_protocol_t;
+
+union efi_memory_attribute_protocol {
+ struct {
+ efi_status_t (__efiapi *get_memory_attributes)(
+ efi_memory_attribute_protocol_t *, efi_physical_addr_t, u64, u64 *);
+
+ efi_status_t (__efiapi *set_memory_attributes)(
+ efi_memory_attribute_protocol_t *, efi_physical_addr_t, u64, u64);
+
+ efi_status_t (__efiapi *clear_memory_attributes)(
+ efi_memory_attribute_protocol_t *, efi_physical_addr_t, u64, u64);
+ };
+ struct {
+ u32 get_memory_attributes;
+ u32 set_memory_attributes;
+ u32 clear_memory_attributes;
+ } mixed_mode;
+};
+
typedef union efi_uga_draw_protocol efi_uga_draw_protocol_t;
union efi_uga_draw_protocol {
@@ -880,7 +905,9 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
efi_status_t efi_get_random_bytes(unsigned long size, u8 *out);
efi_status_t efi_random_alloc(unsigned long size, unsigned long align,
- unsigned long *addr, unsigned long random_seed);
+ unsigned long *addr, unsigned long random_seed,
+ int memory_type, unsigned long alloc_min,
+ unsigned long alloc_max);
efi_status_t efi_random_get_seed(void);
@@ -907,7 +934,8 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
unsigned long max);
efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
- unsigned long max, unsigned long align);
+ unsigned long max, unsigned long align,
+ int memory_type);
efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
unsigned long *addr, unsigned long min);
diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c
index 45841ef55..4f1fa3022 100644
--- a/drivers/firmware/efi/libstub/mem.c
+++ b/drivers/firmware/efi/libstub/mem.c
@@ -89,9 +89,12 @@ efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
efi_physical_addr_t alloc_addr;
efi_status_t status;
+ max = min(max, EFI_ALLOC_LIMIT);
+
if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
return efi_allocate_pages_aligned(size, addr, max,
- EFI_ALLOC_ALIGN);
+ EFI_ALLOC_ALIGN,
+ EFI_LOADER_DATA);
alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c
index 9fb586989..7ba05719a 100644
--- a/drivers/firmware/efi/libstub/randomalloc.c
+++ b/drivers/firmware/efi/libstub/randomalloc.c
@@ -16,7 +16,8 @@
*/
static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
unsigned long size,
- unsigned long align_shift)
+ unsigned long align_shift,
+ u64 alloc_min, u64 alloc_max)
{
unsigned long align = 1UL << align_shift;
u64 first_slot, last_slot, region_end;
@@ -29,11 +30,11 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
return 0;
region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1,
- (u64)ULONG_MAX);
+ alloc_max);
if (region_end < size)
return 0;
- first_slot = round_up(md->phys_addr, align);
+ first_slot = round_up(max(md->phys_addr, alloc_min), align);
last_slot = round_down(region_end - size + 1, align);
if (first_slot > last_slot)
@@ -53,7 +54,10 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md,
efi_status_t efi_random_alloc(unsigned long size,
unsigned long align,
unsigned long *addr,
- unsigned long random_seed)
+ unsigned long random_seed,
+ int memory_type,
+ unsigned long alloc_min,
+ unsigned long alloc_max)
{
unsigned long total_slots = 0, target_slot;
unsigned long total_mirrored_slots = 0;
@@ -75,7 +79,8 @@ efi_status_t efi_random_alloc(unsigned long size,
efi_memory_desc_t *md = (void *)map->map + map_offset;
unsigned long slots;
- slots = get_entry_num_slots(md, size, ilog2(align));
+ slots = get_entry_num_slots(md, size, ilog2(align), alloc_min,
+ alloc_max);
MD_NUM_SLOTS(md) = slots;
total_slots += slots;
if (md->attribute & EFI_MEMORY_MORE_RELIABLE)
@@ -118,7 +123,7 @@ efi_status_t efi_random_alloc(unsigned long size,
pages = size / EFI_PAGE_SIZE;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
- EFI_LOADER_DATA, pages, &target);
+ memory_type, pages, &target);
if (status == EFI_SUCCESS)
*addr = target;
break;
diff --git a/drivers/firmware/efi/libstub/x86-5lvl.c b/drivers/firmware/efi/libstub/x86-5lvl.c
new file mode 100644
index 000000000..479dd445a
--- /dev/null
+++ b/drivers/firmware/efi/libstub/x86-5lvl.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/efi.h>
+
+#include <asm/boot.h>
+#include <asm/desc.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+#include "x86-stub.h"
+
+bool efi_no5lvl;
+
+static void (*la57_toggle)(void *cr3);
+
+static const struct desc_struct gdt[] = {
+ [GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
+ [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
+};
+
+/*
+ * Enabling (or disabling) 5 level paging is tricky, because it can only be
+ * done from 32-bit mode with paging disabled. This means not only that the
+ * code itself must be running from 32-bit addressable physical memory, but
+ * also that the root page table must be 32-bit addressable, as programming
+ * a 64-bit value into CR3 when running in 32-bit mode is not supported.
+ */
+efi_status_t efi_setup_5level_paging(void)
+{
+ u8 tmpl_size = (u8 *)&trampoline_ljmp_imm_offset - (u8 *)&trampoline_32bit_src;
+ efi_status_t status;
+ u8 *la57_code;
+
+ if (!efi_is_64bit())
+ return EFI_SUCCESS;
+
+ /* check for 5 level paging support */
+ if (native_cpuid_eax(0) < 7 ||
+ !(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31))))
+ return EFI_SUCCESS;
+
+ /* allocate some 32-bit addressable memory for code and a page table */
+ status = efi_allocate_pages(2 * PAGE_SIZE, (unsigned long *)&la57_code,
+ U32_MAX);
+ if (status != EFI_SUCCESS)
+ return status;
+
+ la57_toggle = memcpy(la57_code, trampoline_32bit_src, tmpl_size);
+ memset(la57_code + tmpl_size, 0x90, PAGE_SIZE - tmpl_size);
+
+ /*
+ * To avoid the need to allocate a 32-bit addressable stack, the
+ * trampoline uses a LJMP instruction to switch back to long mode.
+ * LJMP takes an absolute destination address, which needs to be
+ * fixed up at runtime.
+ */
+ *(u32 *)&la57_code[trampoline_ljmp_imm_offset] += (unsigned long)la57_code;
+
+ efi_adjust_memory_range_protection((unsigned long)la57_toggle, PAGE_SIZE);
+
+ return EFI_SUCCESS;
+}
+
+void efi_5level_switch(void)
+{
+ bool want_la57 = IS_ENABLED(CONFIG_X86_5LEVEL) && !efi_no5lvl;
+ bool have_la57 = native_read_cr4() & X86_CR4_LA57;
+ bool need_toggle = want_la57 ^ have_la57;
+ u64 *pgt = (void *)la57_toggle + PAGE_SIZE;
+ u64 *cr3 = (u64 *)__native_read_cr3();
+ u64 *new_cr3;
+
+ if (!la57_toggle || !need_toggle)
+ return;
+
+ if (!have_la57) {
+ /*
+ * 5 level paging will be enabled, so a root level page needs
+ * to be allocated from the 32-bit addressable physical region,
+ * with its first entry referring to the existing hierarchy.
+ */
+ new_cr3 = memset(pgt, 0, PAGE_SIZE);
+ new_cr3[0] = (u64)cr3 | _PAGE_TABLE_NOENC;
+ } else {
+ /* take the new root table pointer from the current entry #0 */
+ new_cr3 = (u64 *)(cr3[0] & PAGE_MASK);
+
+ /* copy the new root table if it is not 32-bit addressable */
+ if ((u64)new_cr3 > U32_MAX)
+ new_cr3 = memcpy(pgt, new_cr3, PAGE_SIZE);
+ }
+
+ native_load_gdt(&(struct desc_ptr){ sizeof(gdt) - 1, (u64)gdt });
+
+ la57_toggle(new_cr3);
+}
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 4f0152b11..784e1b2ae 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -15,16 +15,16 @@
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/boot.h>
+#include <asm/kaslr.h>
+#include <asm/sev.h>
#include "efistub.h"
-
-/* Maximum physical address for 64-bit kernel with 4-level paging */
-#define MAXMEM_X86_64_4LEVEL (1ull << 46)
+#include "x86-stub.h"
const efi_system_table_t *efi_system_table;
const efi_dxe_services_table_t *efi_dxe_table;
-extern u32 image_offset;
static efi_loaded_image_t *image = NULL;
+static efi_memory_attribute_protocol_t *memattr;
static efi_status_t
preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
@@ -212,8 +212,8 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params)
}
}
-static void
-adjust_memory_range_protection(unsigned long start, unsigned long size)
+efi_status_t efi_adjust_memory_range_protection(unsigned long start,
+ unsigned long size)
{
efi_status_t status;
efi_gcd_memory_space_desc_t desc;
@@ -221,12 +221,22 @@ adjust_memory_range_protection(unsigned long start, unsigned long size)
unsigned long rounded_start, rounded_end;
unsigned long unprotect_start, unprotect_size;
- if (efi_dxe_table == NULL)
- return;
-
rounded_start = rounddown(start, EFI_PAGE_SIZE);
rounded_end = roundup(start + size, EFI_PAGE_SIZE);
+ if (memattr != NULL) {
+ status = efi_call_proto(memattr, clear_memory_attributes,
+ rounded_start,
+ rounded_end - rounded_start,
+ EFI_MEMORY_XP);
+ if (status != EFI_SUCCESS)
+ efi_warn("Failed to clear EFI_MEMORY_XP attribute\n");
+ return status;
+ }
+
+ if (efi_dxe_table == NULL)
+ return EFI_SUCCESS;
+
/*
* Don't modify memory region attributes, they are
* already suitable, to lower the possibility to
@@ -238,7 +248,7 @@ adjust_memory_range_protection(unsigned long start, unsigned long size)
status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
if (status != EFI_SUCCESS)
- return;
+ break;
next = desc.base_address + desc.length;
@@ -263,69 +273,26 @@ adjust_memory_range_protection(unsigned long start, unsigned long size)
unprotect_start,
unprotect_start + unprotect_size,
status);
+ break;
}
}
+ return EFI_SUCCESS;
}
-/*
- * Trampoline takes 2 pages and can be loaded in first megabyte of memory
- * with its end placed between 128k and 640k where BIOS might start.
- * (see arch/x86/boot/compressed/pgtable_64.c)
- *
- * We cannot find exact trampoline placement since memory map
- * can be modified by UEFI, and it can alter the computed address.
- */
-
-#define TRAMPOLINE_PLACEMENT_BASE ((128 - 8)*1024)
-#define TRAMPOLINE_PLACEMENT_SIZE (640*1024 - (128 - 8)*1024)
-
-void startup_32(struct boot_params *boot_params);
-
-static void
-setup_memory_protection(unsigned long image_base, unsigned long image_size)
+static efi_char16_t *efistub_fw_vendor(void)
{
- /*
- * Allow execution of possible trampoline used
- * for switching between 4- and 5-level page tables
- * and relocated kernel image.
- */
-
- adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE,
- TRAMPOLINE_PLACEMENT_SIZE);
+ unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);
-#ifdef CONFIG_64BIT
- if (image_base != (unsigned long)startup_32)
- adjust_memory_range_protection(image_base, image_size);
-#else
- /*
- * Clear protection flags on a whole range of possible
- * addresses used for KASLR. We don't need to do that
- * on x86_64, since KASLR/extraction is performed after
- * dedicated identity page tables are built and we only
- * need to remove possible protection on relocated image
- * itself disregarding further relocations.
- */
- adjust_memory_range_protection(LOAD_PHYSICAL_ADDR,
- KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR);
-#endif
+ return (efi_char16_t *)vendor;
}
static const efi_char16_t apple[] = L"Apple";
-static void setup_quirks(struct boot_params *boot_params,
- unsigned long image_base,
- unsigned long image_size)
+static void setup_quirks(struct boot_params *boot_params)
{
- efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
- efi_table_attr(efi_system_table, fw_vendor);
-
- if (!memcmp(fw_vendor, apple, sizeof(apple))) {
- if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
- retrieve_apple_device_properties(boot_params);
- }
-
- if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES))
- setup_memory_protection(image_base, image_size);
+ if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) &&
+ !memcmp(efistub_fw_vendor(), apple, sizeof(apple)))
+ retrieve_apple_device_properties(boot_params);
}
/*
@@ -478,7 +445,6 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
}
image_base = efi_table_attr(image, image_base);
- image_offset = (void *)startup_32 - image_base;
status = efi_allocate_pages(sizeof(struct boot_params),
(unsigned long *)&boot_params, ULONG_MAX);
@@ -760,85 +726,139 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
return EFI_SUCCESS;
}
+static bool have_unsupported_snp_features(void)
+{
+ u64 unsupported;
+
+ unsupported = snp_get_unsupported_features(sev_get_status());
+ if (unsupported) {
+ efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
+ unsupported);
+ return true;
+ }
+ return false;
+}
+
+static void efi_get_seed(void *seed, int size)
+{
+ efi_get_random_bytes(size, seed);
+
+ /*
+ * This only updates seed[0] when running on 32-bit, but in that case,
+ * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
+ */
+ *(unsigned long *)seed ^= kaslr_get_random_long("EFI");
+}
+
+static void error(char *str)
+{
+ efi_warn("Decompression failed: %s\n", str);
+}
+
+static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
+{
+ unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
+ unsigned long addr, alloc_size, entry;
+ efi_status_t status;
+ u32 seed[2] = {};
+
+ /* determine the required size of the allocation */
+ alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
+ MIN_KERNEL_ALIGN);
+
+ if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
+ u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
+ static const efi_char16_t ami[] = L"American Megatrends";
+
+ efi_get_seed(seed, sizeof(seed));
+
+ virt_addr += (range * seed[1]) >> 32;
+ virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
+
+ /*
+ * Older Dell systems with AMI UEFI firmware v2.0 may hang
+ * while decompressing the kernel if physical address
+ * randomization is enabled.
+ *
+ * https://bugzilla.kernel.org/show_bug.cgi?id=218173
+ */
+ if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
+ !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
+ efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
+ seed[0] = 0;
+ }
+
+ boot_params_ptr->hdr.loadflags |= KASLR_FLAG;
+ }
+
+ status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
+ seed[0], EFI_LOADER_CODE,
+ LOAD_PHYSICAL_ADDR,
+ EFI_X86_KERNEL_ALLOC_LIMIT);
+ if (status != EFI_SUCCESS)
+ return status;
+
+ entry = decompress_kernel((void *)addr, virt_addr, error);
+ if (entry == ULONG_MAX) {
+ efi_free(alloc_size, addr);
+ return EFI_LOAD_ERROR;
+ }
+
+ *kernel_entry = addr + entry;
+
+ return efi_adjust_memory_range_protection(addr, kernel_total_size);
+}
+
+static void __noreturn enter_kernel(unsigned long kernel_addr,
+ struct boot_params *boot_params)
+{
+ /* enter decompressed kernel with boot_params pointer in RSI/ESI */
+ asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
+
+ unreachable();
+}
+
/*
- * On success, we return the address of startup_32, which has potentially been
- * relocated by efi_relocate_kernel.
- * On failure, we exit to the firmware via efi_exit instead of returning.
+ * On success, this routine will jump to the relocated image directly and never
+ * return. On failure, it will exit to the firmware via efi_exit() instead of
+ * returning.
*/
-asmlinkage unsigned long efi_main(efi_handle_t handle,
- efi_system_table_t *sys_table_arg,
- struct boot_params *boot_params)
+void __noreturn efi_stub_entry(efi_handle_t handle,
+ efi_system_table_t *sys_table_arg,
+ struct boot_params *boot_params)
{
- unsigned long bzimage_addr = (unsigned long)startup_32;
- unsigned long buffer_start, buffer_end;
+ efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
struct setup_header *hdr = &boot_params->hdr;
const struct linux_efi_initrd *initrd = NULL;
+ unsigned long kernel_entry;
efi_status_t status;
+ boot_params_ptr = boot_params;
+
efi_system_table = sys_table_arg;
/* Check if we were booted by the EFI firmware */
if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
efi_exit(handle, EFI_INVALID_PARAMETER);
- efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
- if (efi_dxe_table &&
- efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
- efi_warn("Ignoring DXE services table: invalid signature\n");
- efi_dxe_table = NULL;
+ if (have_unsupported_snp_features())
+ efi_exit(handle, EFI_UNSUPPORTED);
+
+ if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
+ efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
+ if (efi_dxe_table &&
+ efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
+ efi_warn("Ignoring DXE services table: invalid signature\n");
+ efi_dxe_table = NULL;
+ }
}
- /*
- * If the kernel isn't already loaded at a suitable address,
- * relocate it.
- *
- * It must be loaded above LOAD_PHYSICAL_ADDR.
- *
- * The maximum address for 64-bit is 1 << 46 for 4-level paging. This
- * is defined as the macro MAXMEM, but unfortunately that is not a
- * compile-time constant if 5-level paging is configured, so we instead
- * define our own macro for use here.
- *
- * For 32-bit, the maximum address is complicated to figure out, for
- * now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
- * KASLR uses.
- *
- * Also relocate it if image_offset is zero, i.e. the kernel wasn't
- * loaded by LoadImage, but rather by a bootloader that called the
- * handover entry. The reason we must always relocate in this case is
- * to handle the case of systemd-boot booting a unified kernel image,
- * which is a PE executable that contains the bzImage and an initrd as
- * COFF sections. The initrd section is placed after the bzImage
- * without ensuring that there are at least init_size bytes available
- * for the bzImage, and thus the compressed kernel's startup code may
- * overwrite the initrd unless it is moved out of the way.
- */
+ /* grab the memory attributes protocol if it exists */
+ efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
- buffer_start = ALIGN(bzimage_addr - image_offset,
- hdr->kernel_alignment);
- buffer_end = buffer_start + hdr->init_size;
-
- if ((buffer_start < LOAD_PHYSICAL_ADDR) ||
- (IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE) ||
- (IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) ||
- (image_offset == 0)) {
- extern char _bss[];
-
- status = efi_relocate_kernel(&bzimage_addr,
- (unsigned long)_bss - bzimage_addr,
- hdr->init_size,
- hdr->pref_address,
- hdr->kernel_alignment,
- LOAD_PHYSICAL_ADDR);
- if (status != EFI_SUCCESS) {
- efi_err("efi_relocate_kernel() failed!\n");
- goto fail;
- }
- /*
- * Now that we've copied the kernel elsewhere, we no longer
- * have a set up block before startup_32(), so reset image_offset
- * to zero in case it was set earlier.
- */
- image_offset = 0;
+ status = efi_setup_5level_paging();
+ if (status != EFI_SUCCESS) {
+ efi_err("efi_setup_5level_paging() failed!\n");
+ goto fail;
}
#ifdef CONFIG_CMDLINE_BOOL
@@ -858,6 +878,12 @@ asmlinkage unsigned long efi_main(efi_handle_t handle,
}
}
+ status = efi_decompress_kernel(&kernel_entry);
+ if (status != EFI_SUCCESS) {
+ efi_err("Failed to decompress kernel\n");
+ goto fail;
+ }
+
/*
* At this point, an initrd may already have been loaded by the
* bootloader and passed via bootparams. We permit an initrd loaded
@@ -897,7 +923,7 @@ asmlinkage unsigned long efi_main(efi_handle_t handle,
setup_efi_pci(boot_params);
- setup_quirks(boot_params, bzimage_addr, buffer_end - buffer_start);
+ setup_quirks(boot_params);
status = exit_boot(boot_params, handle);
if (status != EFI_SUCCESS) {
@@ -905,9 +931,38 @@ asmlinkage unsigned long efi_main(efi_handle_t handle,
goto fail;
}
- return bzimage_addr;
+ /*
+ * Call the SEV init code while still running with the firmware's
+ * GDT/IDT, so #VC exceptions will be handled by EFI.
+ */
+ sev_enable(boot_params);
+
+ efi_5level_switch();
+
+ enter_kernel(kernel_entry, boot_params);
fail:
- efi_err("efi_main() failed!\n");
+ efi_err("efi_stub_entry() failed!\n");
efi_exit(handle, status);
}
+
+#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
+void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
+ struct boot_params *boot_params)
+{
+ extern char _bss[], _ebss[];
+
+ memset(_bss, 0, _ebss - _bss);
+ efi_stub_entry(handle, sys_table_arg, boot_params);
+}
+
+#ifndef CONFIG_EFI_MIXED
+extern __alias(efi_handover_entry)
+void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
+ struct boot_params *boot_params);
+
+extern __alias(efi_handover_entry)
+void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
+ struct boot_params *boot_params);
+#endif
+#endif
diff --git a/drivers/firmware/efi/libstub/x86-stub.h b/drivers/firmware/efi/libstub/x86-stub.h
new file mode 100644
index 000000000..1c20e99a6
--- /dev/null
+++ b/drivers/firmware/efi/libstub/x86-stub.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/efi.h>
+
+extern void trampoline_32bit_src(void *, bool);
+extern const u16 trampoline_ljmp_imm_offset;
+
+efi_status_t efi_adjust_memory_range_protection(unsigned long start,
+ unsigned long size);
+
+#ifdef CONFIG_X86_64
+efi_status_t efi_setup_5level_paging(void);
+void efi_5level_switch(void);
+#else
+static inline efi_status_t efi_setup_5level_paging(void) { return EFI_SUCCESS; }
+static inline void efi_5level_switch(void) {}
+#endif