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authorMatt Fleming <matt.fleming@intel.com>2014-03-05 18:15:37 +0000
committerMatt Fleming <matt.fleming@intel.com>2014-03-05 18:15:37 +0000
commit994448f1afa6689bafbebaf7412b23b541b41ef5 (patch)
treeb7460c6a9bdadc6554ad7f0da52b5c60403164c1 /arch/x86/platform
parent4fd69331ad227a4d8de26592d017b73e00caca9f (diff)
parent18c46461d9e42d398536055f31f58cdcd2c6347e (diff)
Merge remote-tracking branch 'tip/x86/efi-mixed' into efi-for-mingo
Conflicts: arch/x86/kernel/setup.c arch/x86/platform/efi/efi.c arch/x86/platform/efi/efi_64.c
Diffstat (limited to 'arch/x86/platform')
-rw-r--r--arch/x86/platform/efi/Makefile1
-rw-r--r--arch/x86/platform/efi/efi.c158
-rw-r--r--arch/x86/platform/efi/efi_64.c327
-rw-r--r--arch/x86/platform/efi/efi_stub_64.S157
-rw-r--r--arch/x86/platform/efi/efi_thunk_64.S65
5 files changed, 651 insertions, 57 deletions
diff --git a/arch/x86/platform/efi/Makefile b/arch/x86/platform/efi/Makefile
index b7b0b35c198..d51045afcaa 100644
--- a/arch/x86/platform/efi/Makefile
+++ b/arch/x86/platform/efi/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_EFI) += efi.o efi_$(BITS).o efi_stub_$(BITS).o
obj-$(CONFIG_ACPI_BGRT) += efi-bgrt.o
obj-$(CONFIG_EARLY_PRINTK_EFI) += early_printk.o
+obj-$(CONFIG_EFI_MIXED) += efi_thunk_$(BITS).o
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 45d4f767467..43e7cf6c611 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -453,9 +453,6 @@ void __init efi_free_boot_services(void)
{
void *p;
- if (!efi_is_native())
- return;
-
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
efi_memory_desc_t *md = p;
unsigned long long start = md->phys_addr;
@@ -579,37 +576,85 @@ static int __init efi_systab_init(void *phys)
return 0;
}
-static int __init efi_runtime_init(void)
+static int __init efi_runtime_init32(void)
{
- efi_runtime_services_t *runtime;
+ efi_runtime_services_32_t *runtime;
+
+ runtime = early_ioremap((unsigned long)efi.systab->runtime,
+ sizeof(efi_runtime_services_32_t));
+ if (!runtime) {
+ pr_err("Could not map the runtime service table!\n");
+ return -ENOMEM;
+ }
/*
- * Check out the runtime services table. We need to map
- * the runtime services table so that we can grab the physical
- * address of several of the EFI runtime functions, needed to
- * set the firmware into virtual mode.
+ * We will only need *early* access to the following two
+ * EFI runtime services before set_virtual_address_map
+ * is invoked.
+ */
+ efi_phys.get_time = (efi_get_time_t *)
+ (unsigned long)runtime->get_time;
+ efi_phys.set_virtual_address_map =
+ (efi_set_virtual_address_map_t *)
+ (unsigned long)runtime->set_virtual_address_map;
+ /*
+ * Make efi_get_time can be called before entering
+ * virtual mode.
*/
+ efi.get_time = phys_efi_get_time;
+ early_iounmap(runtime, sizeof(efi_runtime_services_32_t));
+
+ return 0;
+}
+
+static int __init efi_runtime_init64(void)
+{
+ efi_runtime_services_64_t *runtime;
+
runtime = early_ioremap((unsigned long)efi.systab->runtime,
- sizeof(efi_runtime_services_t));
+ sizeof(efi_runtime_services_64_t));
if (!runtime) {
pr_err("Could not map the runtime service table!\n");
return -ENOMEM;
}
+
/*
- * We will only need *early* access to the following
- * two EFI runtime services before set_virtual_address_map
+ * We will only need *early* access to the following two
+ * EFI runtime services before set_virtual_address_map
* is invoked.
*/
- efi_phys.get_time = (efi_get_time_t *)runtime->get_time;
+ efi_phys.get_time = (efi_get_time_t *)
+ (unsigned long)runtime->get_time;
efi_phys.set_virtual_address_map =
- (efi_set_virtual_address_map_t *)
- runtime->set_virtual_address_map;
+ (efi_set_virtual_address_map_t *)
+ (unsigned long)runtime->set_virtual_address_map;
/*
* Make efi_get_time can be called before entering
* virtual mode.
*/
efi.get_time = phys_efi_get_time;
- early_iounmap(runtime, sizeof(efi_runtime_services_t));
+ early_iounmap(runtime, sizeof(efi_runtime_services_64_t));
+
+ return 0;
+}
+
+static int __init efi_runtime_init(void)
+{
+ int rv;
+
+ /*
+ * Check out the runtime services table. We need to map
+ * the runtime services table so that we can grab the physical
+ * address of several of the EFI runtime functions, needed to
+ * set the firmware into virtual mode.
+ */
+ if (efi_enabled(EFI_64BIT))
+ rv = efi_runtime_init64();
+ else
+ rv = efi_runtime_init32();
+
+ if (rv)
+ return rv;
set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
@@ -747,7 +792,7 @@ void __init efi_init(void)
* that doesn't match the kernel 32/64-bit mode.
*/
- if (!efi_is_native())
+ if (!efi_runtime_supported())
pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
else {
if (disable_runtime || efi_runtime_init())
@@ -833,6 +878,22 @@ void __init old_map_region(efi_memory_desc_t *md)
(unsigned long long)md->phys_addr);
}
+static void native_runtime_setup(void)
+{
+ efi.get_time = virt_efi_get_time;
+ efi.set_time = virt_efi_set_time;
+ efi.get_wakeup_time = virt_efi_get_wakeup_time;
+ efi.set_wakeup_time = virt_efi_set_wakeup_time;
+ efi.get_variable = virt_efi_get_variable;
+ efi.get_next_variable = virt_efi_get_next_variable;
+ efi.set_variable = virt_efi_set_variable;
+ efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
+ efi.reset_system = virt_efi_reset_system;
+ efi.query_variable_info = virt_efi_query_variable_info;
+ efi.update_capsule = virt_efi_update_capsule;
+ efi.query_capsule_caps = virt_efi_query_capsule_caps;
+}
+
/* Merge contiguous regions of the same type and attribute */
static void __init efi_merge_regions(void)
{
@@ -1015,19 +1076,10 @@ static void __init kexec_enter_virtual_mode(void)
* Call EFI services through wrapper functions.
*/
efi.runtime_version = efi_systab.hdr.revision;
- efi.get_time = virt_efi_get_time;
- efi.set_time = virt_efi_set_time;
- efi.get_wakeup_time = virt_efi_get_wakeup_time;
- efi.set_wakeup_time = virt_efi_set_wakeup_time;
- efi.get_variable = virt_efi_get_variable;
- efi.get_next_variable = virt_efi_get_next_variable;
- efi.set_variable = virt_efi_set_variable;
- efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
- efi.reset_system = virt_efi_reset_system;
+
+ native_runtime_setup();
+
efi.set_virtual_address_map = NULL;
- efi.query_variable_info = virt_efi_query_variable_info;
- efi.update_capsule = virt_efi_update_capsule;
- efi.query_capsule_caps = virt_efi_query_capsule_caps;
if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
runtime_code_page_mkexec();
@@ -1071,15 +1123,6 @@ static void __init __efi_enter_virtual_mode(void)
efi.systab = NULL;
- /*
- * We don't do virtual mode, since we don't do runtime services, on
- * non-native EFI
- */
- if (!efi_is_native()) {
- efi_unmap_memmap();
- return;
- }
-
efi_merge_regions();
new_memmap = efi_map_regions(&count, &pg_shift);
if (!new_memmap) {
@@ -1097,11 +1140,20 @@ static void __init __efi_enter_virtual_mode(void)
efi_sync_low_kernel_mappings();
efi_dump_pagetable();
- status = phys_efi_set_virtual_address_map(
- memmap.desc_size * count,
- memmap.desc_size,
- memmap.desc_version,
- (efi_memory_desc_t *)__pa(new_memmap));
+ if (efi_is_native()) {
+ status = phys_efi_set_virtual_address_map(
+ memmap.desc_size * count,
+ memmap.desc_size,
+ memmap.desc_version,
+ (efi_memory_desc_t *)__pa(new_memmap));
+ } else {
+ status = efi_thunk_set_virtual_address_map(
+ efi_phys.set_virtual_address_map,
+ memmap.desc_size * count,
+ memmap.desc_size,
+ memmap.desc_version,
+ (efi_memory_desc_t *)__pa(new_memmap));
+ }
if (status != EFI_SUCCESS) {
pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
@@ -1116,19 +1168,13 @@ static void __init __efi_enter_virtual_mode(void)
* Call EFI services through wrapper functions.
*/
efi.runtime_version = efi_systab.hdr.revision;
- efi.get_time = virt_efi_get_time;
- efi.set_time = virt_efi_set_time;
- efi.get_wakeup_time = virt_efi_get_wakeup_time;
- efi.set_wakeup_time = virt_efi_set_wakeup_time;
- efi.get_variable = virt_efi_get_variable;
- efi.get_next_variable = virt_efi_get_next_variable;
- efi.set_variable = virt_efi_set_variable;
- efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
- efi.reset_system = virt_efi_reset_system;
+
+ if (efi_is_native())
+ native_runtime_setup();
+ else
+ efi_thunk_runtime_setup();
+
efi.set_virtual_address_map = NULL;
- efi.query_variable_info = virt_efi_query_variable_info;
- efi.update_capsule = virt_efi_update_capsule;
- efi.query_capsule_caps = virt_efi_query_capsule_caps;
efi_runtime_mkexec();
@@ -1311,7 +1357,7 @@ void __init efi_apply_memmap_quirks(void)
* firmware/kernel architectures since there is no support for runtime
* services.
*/
- if (!efi_is_native()) {
+ if (!efi_runtime_supported()) {
pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n");
efi_unmap_memmap();
}
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 19280900ec2..7e7f195aa5c 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -39,6 +39,7 @@
#include <asm/cacheflush.h>
#include <asm/fixmap.h>
#include <asm/realmode.h>
+#include <asm/time.h>
static pgd_t *save_pgd __initdata;
static unsigned long efi_flags __initdata;
@@ -58,7 +59,8 @@ struct efi_scratch {
u64 prev_cr3;
pgd_t *efi_pgt;
bool use_pgd;
-};
+ u64 phys_stack;
+} __packed;
static void __init early_code_mapping_set_exec(int executable)
{
@@ -139,6 +141,9 @@ void efi_sync_low_kernel_mappings(void)
int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
+ unsigned long text;
+ struct page *page;
+ unsigned npages;
pgd_t *pgd;
if (efi_enabled(EFI_OLD_MEMMAP))
@@ -160,6 +165,29 @@ int efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
efi_scratch.use_pgd = true;
+ /*
+ * When making calls to the firmware everything needs to be 1:1
+ * mapped and addressable with 32-bit pointers. Map the kernel
+ * text and allocate a new stack because we can't rely on the
+ * stack pointer being < 4GB.
+ */
+ if (!IS_ENABLED(CONFIG_EFI_MIXED))
+ return 0;
+
+ page = alloc_page(GFP_KERNEL|__GFP_DMA32);
+ if (!page)
+ panic("Unable to allocate EFI runtime stack < 4GB\n");
+
+ efi_scratch.phys_stack = virt_to_phys(page_address(page));
+ efi_scratch.phys_stack += PAGE_SIZE; /* stack grows down */
+
+ npages = (_end - _text) >> PAGE_SHIFT;
+ text = __pa(_text);
+
+ if (kernel_map_pages_in_pgd(pgd, text >> PAGE_SHIFT, text, npages, 0)) {
+ pr_err("Failed to map kernel text 1:1\n");
+ return 1;
+ }
return 0;
}
@@ -199,6 +227,16 @@ void __init efi_map_region(efi_memory_desc_t *md)
*/
__map_region(md, md->phys_addr);
+ /*
+ * Enforce the 1:1 mapping as the default virtual address when
+ * booting in EFI mixed mode, because even though we may be
+ * running a 64-bit kernel, the firmware may only be 32-bit.
+ */
+ if (!efi_is_native () && IS_ENABLED(CONFIG_EFI_MIXED)) {
+ md->virt_addr = md->phys_addr;
+ return;
+ }
+
efi_va -= size;
/* Is PA 2M-aligned? */
@@ -277,3 +315,290 @@ void __init efi_dump_pagetable(void)
ptdump_walk_pgd_level(NULL, pgd);
#endif
}
+
+#ifdef CONFIG_EFI_MIXED
+extern efi_status_t efi64_thunk(u32, ...);
+
+#define runtime_service32(func) \
+({ \
+ u32 table = (u32)(unsigned long)efi.systab; \
+ u32 *rt, *___f; \
+ \
+ rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime)); \
+ ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
+ *___f; \
+})
+
+/*
+ * Switch to the EFI page tables early so that we can access the 1:1
+ * runtime services mappings which are not mapped in any other page
+ * tables. This function must be called before runtime_service32().
+ *
+ * Also, disable interrupts because the IDT points to 64-bit handlers,
+ * which aren't going to function correctly when we switch to 32-bit.
+ */
+#define efi_thunk(f, ...) \
+({ \
+ efi_status_t __s; \
+ unsigned long flags; \
+ u32 func; \
+ \
+ efi_sync_low_kernel_mappings(); \
+ local_irq_save(flags); \
+ \
+ efi_scratch.prev_cr3 = read_cr3(); \
+ write_cr3((unsigned long)efi_scratch.efi_pgt); \
+ __flush_tlb_all(); \
+ \
+ func = runtime_service32(f); \
+ __s = efi64_thunk(func, __VA_ARGS__); \
+ \
+ write_cr3(efi_scratch.prev_cr3); \
+ __flush_tlb_all(); \
+ local_irq_restore(flags); \
+ \
+ __s; \
+})
+
+efi_status_t efi_thunk_set_virtual_address_map(
+ void *phys_set_virtual_address_map,
+ unsigned long memory_map_size,
+ unsigned long descriptor_size,
+ u32 descriptor_version,
+ efi_memory_desc_t *virtual_map)
+{
+ efi_status_t status;
+ unsigned long flags;
+ u32 func;
+
+ efi_sync_low_kernel_mappings();
+ local_irq_save(flags);
+
+ efi_scratch.prev_cr3 = read_cr3();
+ write_cr3((unsigned long)efi_scratch.efi_pgt);
+ __flush_tlb_all();
+
+ func = (u32)(unsigned long)phys_set_virtual_address_map;
+ status = efi64_thunk(func, memory_map_size, descriptor_size,
+ descriptor_version, virtual_map);
+
+ write_cr3(efi_scratch.prev_cr3);
+ __flush_tlb_all();
+ local_irq_restore(flags);
+
+ return status;
+}
+
+static efi_status_t efi_thunk_get_time(efi_time_t *tm, efi_time_cap_t *tc)
+{
+ efi_status_t status;
+ u32 phys_tm, phys_tc;
+
+ spin_lock(&rtc_lock);
+
+ phys_tm = virt_to_phys(tm);
+ phys_tc = virt_to_phys(tc);
+
+ status = efi_thunk(get_time, phys_tm, phys_tc);
+
+ spin_unlock(&rtc_lock);
+
+ return status;
+}
+
+static efi_status_t efi_thunk_set_time(efi_time_t *tm)
+{
+ efi_status_t status;
+ u32 phys_tm;
+
+ spin_lock(&rtc_lock);
+
+ phys_tm = virt_to_phys(tm);
+
+ status = efi_thunk(set_time, phys_tm);
+
+ spin_unlock(&rtc_lock);
+
+ return status;
+}
+
+static efi_status_t
+efi_thunk_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending,
+ efi_time_t *tm)
+{
+ efi_status_t status;
+ u32 phys_enabled, phys_pending, phys_tm;
+
+ spin_lock(&rtc_lock);
+
+ phys_enabled = virt_to_phys(enabled);
+ phys_pending = virt_to_phys(pending);
+ phys_tm = virt_to_phys(tm);
+
+ status = efi_thunk(get_wakeup_time, phys_enabled,
+ phys_pending, phys_tm);
+
+ spin_unlock(&rtc_lock);
+
+ return status;
+}
+
+static efi_status_t
+efi_thunk_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
+{
+ efi_status_t status;
+ u32 phys_tm;
+
+ spin_lock(&rtc_lock);
+
+ phys_tm = virt_to_phys(tm);
+
+ status = efi_thunk(set_wakeup_time, enabled, phys_tm);
+
+ spin_unlock(&rtc_lock);
+
+ return status;
+}
+
+
+static efi_status_t
+efi_thunk_get_variable(efi_char16_t *name, efi_guid_t *vendor,
+ u32 *attr, unsigned long *data_size, void *data)
+{
+ efi_status_t status;
+ u32 phys_name, phys_vendor, phys_attr;
+ u32 phys_data_size, phys_data;
+
+ phys_data_size = virt_to_phys(data_size);
+ phys_vendor = virt_to_phys(vendor);
+ phys_name = virt_to_phys(name);
+ phys_attr = virt_to_phys(attr);
+ phys_data = virt_to_phys(data);
+
+ status = efi_thunk(get_variable, phys_name, phys_vendor,
+ phys_attr, phys_data_size, phys_data);
+
+ return status;
+}
+
+static efi_status_t
+efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
+ u32 attr, unsigned long data_size, void *data)
+{
+ u32 phys_name, phys_vendor, phys_data;
+ efi_status_t status;
+
+ phys_name = virt_to_phys(name);
+ phys_vendor = virt_to_phys(vendor);
+ phys_data = virt_to_phys(data);
+
+ /* If data_size is > sizeof(u32) we've got problems */
+ status = efi_thunk(set_variable, phys_name, phys_vendor,
+ attr, data_size, phys_data);
+
+ return status;
+}
+
+static efi_status_t
+efi_thunk_get_next_variable(unsigned long *name_size,
+ efi_char16_t *name,
+ efi_guid_t *vendor)
+{
+ efi_status_t status;
+ u32 phys_name_size, phys_name, phys_vendor;
+
+ phys_name_size = virt_to_phys(name_size);
+ phys_vendor = virt_to_phys(vendor);
+ phys_name = virt_to_phys(name);
+
+ status = efi_thunk(get_next_variable, phys_name_size,
+ phys_name, phys_vendor);
+
+ return status;
+}
+
+static efi_status_t
+efi_thunk_get_next_high_mono_count(u32 *count)
+{
+ efi_status_t status;
+ u32 phys_count;
+
+ phys_count = virt_to_phys(count);
+ status = efi_thunk(get_next_high_mono_count, phys_count);
+
+ return status;
+}
+
+static void
+efi_thunk_reset_system(int reset_type, efi_status_t status,
+ unsigned long data_size, efi_char16_t *data)
+{
+ u32 phys_data;
+
+ phys_data = virt_to_phys(data);
+
+ efi_thunk(reset_system, reset_type, status, data_size, phys_data);
+}
+
+static efi_status_t
+efi_thunk_update_capsule(efi_capsule_header_t **capsules,
+ unsigned long count, unsigned long sg_list)
+{
+ /*
+ * To properly support this function we would need to repackage
+ * 'capsules' because the firmware doesn't understand 64-bit
+ * pointers.
+ */
+ return EFI_UNSUPPORTED;
+}
+
+static efi_status_t
+efi_thunk_query_variable_info(u32 attr, u64 *storage_space,
+ u64 *remaining_space,
+ u64 *max_variable_size)
+{
+ efi_status_t status;
+ u32 phys_storage, phys_remaining, phys_max;
+
+ if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
+ return EFI_UNSUPPORTED;
+
+ phys_storage = virt_to_phys(storage_space);
+ phys_remaining = virt_to_phys(remaining_space);
+ phys_max = virt_to_phys(max_variable_size);
+
+ status = efi_thunk(query_variable_info, phys_storage,
+ phys_remaining, phys_max);
+
+ return status;
+}
+
+static efi_status_t
+efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
+ unsigned long count, u64 *max_size,
+ int *reset_type)
+{
+ /*
+ * To properly support this function we would need to repackage
+ * 'capsules' because the firmware doesn't understand 64-bit
+ * pointers.
+ */
+ return EFI_UNSUPPORTED;
+}
+
+void efi_thunk_runtime_setup(void)
+{
+ efi.get_time = efi_thunk_get_time;
+ efi.set_time = efi_thunk_set_time;
+ efi.get_wakeup_time = efi_thunk_get_wakeup_time;
+ efi.set_wakeup_time = efi_thunk_set_wakeup_time;
+ efi.get_variable = efi_thunk_get_variable;
+ efi.get_next_variable = efi_thunk_get_next_variable;
+ efi.set_variable = efi_thunk_set_variable;
+ efi.get_next_high_mono_count = efi_thunk_get_next_high_mono_count;
+ efi.reset_system = efi_thunk_reset_system;
+ efi.query_variable_info = efi_thunk_query_variable_info;
+ efi.update_capsule = efi_thunk_update_capsule;
+ efi.query_capsule_caps = efi_thunk_query_capsule_caps;
+}
+#endif /* CONFIG_EFI_MIXED */
diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S
index 88073b14029..65b787a9fc4 100644
--- a/arch/x86/platform/efi/efi_stub_64.S
+++ b/arch/x86/platform/efi/efi_stub_64.S
@@ -7,6 +7,10 @@
*/
#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/msr.h>
+#include <asm/processor-flags.h>
+#include <asm/page_types.h>
#define SAVE_XMM \
mov %rsp, %rax; \
@@ -164,7 +168,160 @@ ENTRY(efi_call6)
ret
ENDPROC(efi_call6)
+#ifdef CONFIG_EFI_MIXED
+
+/*
+ * We run this function from the 1:1 mapping.
+ *
+ * This function must be invoked with a 1:1 mapped stack.
+ */
+ENTRY(__efi64_thunk)
+ subq $32, %rsp
+ movl %esi, 0x0(%rsp)
+ movl %edx, 0x4(%rsp)
+ movl %ecx, 0x8(%rsp)
+ movq %r8, %rsi
+ movl %esi, 0xc(%rsp)
+ movq %r9, %rsi
+ movl %esi, 0x10(%rsp)
+
+ sgdt save_gdt(%rip)
+
+ leaq 1f(%rip), %rbx
+ movq %rbx, func_rt_ptr(%rip)
+
+ /* Switch to gdt with 32-bit segments */
+ movl 40(%rsp), %eax
+ lgdt (%rax)
+
+ leaq efi_enter32(%rip), %rax
+ pushq $__KERNEL_CS
+ pushq %rax
+ lretq
+
+1: addq $32, %rsp
+
+ lgdt save_gdt(%rip)
+
+ /*
+ * Convert 32-bit status code into 64-bit.
+ */
+ test %rax, %rax
+ jz 1f
+ movl %eax, %ecx
+ andl $0x0fffffff, %ecx
+ andl $0xf0000000, %eax
+ shl $32, %rax
+ or %rcx, %rax
+1:
+ ret
+ENDPROC(__efi64_thunk)
+
+ENTRY(efi_exit32)
+ xorq %rax, %rax
+ movl %eax, %ds
+ movl %eax, %es
+ movl %eax, %ss
+
+ movq func_rt_ptr(%rip), %rax
+ push %rax
+ mov %rdi, %rax
+ ret
+ENDPROC(efi_exit32)
+
+ .code32
+/*
+ * EFI service pointer must be in %edi.
+ *
+ * The stack should represent the 32-bit calling convention.
+ */
+ENTRY(efi_enter32)
+ movl $__KERNEL_DS, %eax
+ movl %eax, %ds
+ movl %eax, %es
+ movl %eax, %ss
+
+ /* Reload pgtables */
+ movl %cr3, %eax
+ movl %eax, %cr3
+
+ /* Disable paging */
+ movl %cr0, %eax
+ btrl $X86_CR0_PG_BIT, %eax
+ movl %eax, %cr0
+
+ /* Disable long mode via EFER */
+ movl $MSR_EFER, %ecx
+ rdmsr
+ btrl $_EFER_LME, %eax
+ wrmsr
+
+ call *%edi
+
+ /* We must preserve return value */
+ movl %eax, %edi
+
+ /*
+ * Some firmware will return with interrupts enabled. Be sure to
+ * disable them before we switch GDTs.
+ */
+ cli
+
+ movl 44(%esp), %eax
+ movl %eax, 2(%eax)
+ lgdtl (%eax)
+
+ movl %cr4, %eax
+ btsl $(X86_CR4_PAE_BIT), %eax
+ movl %eax, %cr4
+
+ movl %cr3, %eax
+ movl %eax, %cr3
+
+ movl $MSR_EFER, %ecx
+ rdmsr
+ btsl $_EFER_LME, %eax
+ wrmsr
+
+ xorl %eax, %eax
+ lldt %ax
+
+ movl 48(%esp), %eax
+ pushl $__KERNEL_CS
+ pushl %eax
+
+ /* Enable paging */
+ movl %cr0, %eax
+ btsl $X86_CR0_PG_BIT, %eax
+ movl %eax, %cr0
+ lret
+ENDPROC(efi_enter32)
+
+ .data
+ .balign 8
+ .global efi32_boot_gdt
+efi32_boot_gdt: .word 0
+ .quad 0
+
+save_gdt: .word 0
+ .quad 0
+func_rt_ptr: .quad 0
+
+ .global efi_gdt64
+efi_gdt64:
+ .word efi_gdt64_end - efi_gdt64
+ .long 0 /* Filled out by user */
+ .word 0
+ .quad 0x0000000000000000 /* NULL descriptor */
+ .quad 0x00af9a000000ffff /* __KERNEL_CS */
+ .quad 0x00cf92000000ffff /* __KERNEL_DS */
+ .quad 0x0080890000000000 /* TS descriptor */
+ .quad 0x0000000000000000 /* TS continued */
+efi_gdt64_end:
+#endif /* CONFIG_EFI_MIXED */
+
.data
ENTRY(efi_scratch)
.fill 3,8,0
.byte 0
+ .quad 0
diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S
new file mode 100644
index 00000000000..8806fa73e6e
--- /dev/null
+++ b/arch/x86/platform/efi/efi_thunk_64.S
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2014 Intel Corporation; author Matt Fleming
+ */
+
+#include <linux/linkage.h>
+#include <asm/page_types.h>
+
+ .text
+ .code64
+ENTRY(efi64_thunk)
+ push %rbp
+ push %rbx
+
+ /*
+ * Switch to 1:1 mapped 32-bit stack pointer.
+ */
+ movq %rsp, efi_saved_sp(%rip)
+ movq efi_scratch+25(%rip), %rsp
+
+ /*
+ * Calculate the physical address of the kernel text.
+ */
+ movq $__START_KERNEL_map, %rax
+ subq phys_base(%rip), %rax
+
+ /*
+ * Push some physical addresses onto the stack. This is easier
+ * to do now in a code64 section while the assembler can address
+ * 64-bit values. Note that all the addresses on the stack are
+ * 32-bit.
+ */
+ subq $16, %rsp
+ leaq efi_exit32(%rip), %rbx
+ subq %rax, %rbx
+ movl %ebx, 8(%rsp)
+ leaq efi_gdt64(%rip), %rbx
+ subq %rax, %rbx
+ movl %ebx, 2(%ebx)
+ movl %ebx, 4(%rsp)
+ leaq efi_gdt32(%rip), %rbx
+ subq %rax, %rbx
+ movl %ebx, 2(%ebx)
+ movl %ebx, (%rsp)
+
+ leaq __efi64_thunk(%rip), %rbx
+ subq %rax, %rbx
+ call *%rbx
+
+ movq efi_saved_sp(%rip), %rsp
+ pop %rbx
+ pop %rbp
+ retq
+ENDPROC(efi64_thunk)
+
+ .data
+efi_gdt32:
+ .word efi_gdt32_end - efi_gdt32
+ .long 0 /* Filled out above */
+ .word 0
+ .quad 0x0000000000000000 /* NULL descriptor */
+ .quad 0x00cf9a000000ffff /* __KERNEL_CS */
+ .quad 0x00cf93000000ffff /* __KERNEL_DS */
+efi_gdt32_end:
+
+efi_saved_sp: .quad 0