diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index cb08035b89a0..e7e9c6e057f9 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -164,12 +164,6 @@ extern void parse_efi_setup(u64 phys_addr, u32 data_len);
 extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
 
 extern void efi_thunk_runtime_setup(void);
-extern 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 efi_set_virtual_address_map(unsigned long memory_map_size,
 					 unsigned long descriptor_size,
 					 u32 descriptor_version,
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 50f8123e658a..e4d3afac7be3 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -1015,21 +1015,10 @@ static void __init __efi_enter_virtual_mode(void)
 
 	efi_sync_low_kernel_mappings();
 
-	if (!efi_is_mixed()) {
-		status = efi_set_virtual_address_map(
-				efi.memmap.desc_size * count,
-				efi.memmap.desc_size,
-				efi.memmap.desc_version,
-				(efi_memory_desc_t *)pa);
-	} else {
-		status = efi_thunk_set_virtual_address_map(
-				efi_phys.set_virtual_address_map,
-				efi.memmap.desc_size * count,
-				efi.memmap.desc_size,
-				efi.memmap.desc_version,
-				(efi_memory_desc_t *)pa);
-	}
-
+	status = efi_set_virtual_address_map(efi.memmap.desc_size * count,
+					     efi.memmap.desc_size,
+					     efi.memmap.desc_version,
+					     (efi_memory_desc_t *)pa);
 	if (status != EFI_SUCCESS) {
 		pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
 			 status);
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 03565dad0c4b..910e9ec03b09 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -626,61 +626,74 @@ void efi_switch_mm(struct mm_struct *mm)
 	switch_mm(efi_scratch.prev_mm, mm, NULL);
 }
 
-#ifdef CONFIG_EFI_MIXED
 static DEFINE_SPINLOCK(efi_runtime_lock);
 
-#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;								 \
+/*
+ * DS and ES contain user values.  We need to save them.
+ * The 32-bit EFI code needs a valid DS, ES, and SS.  There's no
+ * need to save the old SS: __KERNEL_DS is always acceptable.
+ */
+#define __efi_thunk(func, ...)						\
+({									\
+	efi_runtime_services_32_t *__rt;				\
+	unsigned short __ds, __es;					\
+	efi_status_t ____s;						\
+									\
+	__rt = (void *)(unsigned long)efi.systab->mixed_mode.runtime;	\
+									\
+	savesegment(ds, __ds);						\
+	savesegment(es, __es);						\
+									\
+	loadsegment(ss, __KERNEL_DS);					\
+	loadsegment(ds, __KERNEL_DS);					\
+	loadsegment(es, __KERNEL_DS);					\
+									\
+	____s = efi64_thunk(__rt->func, __VA_ARGS__);			\
+									\
+	loadsegment(ds, __ds);						\
+	loadsegment(es, __es);						\
+									\
+	____s ^= (____s & BIT(31)) | (____s & BIT_ULL(31)) << 32;	\
+	____s;								\
 })
 
 /*
  * 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().
+ * tables.
  *
  * 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, ...)						\
+#define efi_thunk(func...)						\
 ({									\
 	efi_status_t __s;						\
-	u32 __func;							\
 									\
 	arch_efi_call_virt_setup();					\
 									\
-	__func = runtime_service32(f);					\
-	__s = efi64_thunk(__func, __VA_ARGS__);				\
+	__s = __efi_thunk(func);					\
 									\
 	arch_efi_call_virt_teardown();					\
 									\
 	__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)
+static efi_status_t __init
+efi_thunk_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_switch_mm(&efi_mm);
 
-	func = (u32)(unsigned long)phys_set_virtual_address_map;
-	status = efi64_thunk(func, memory_map_size, descriptor_size,
-			     descriptor_version, virtual_map);
+	status = __efi_thunk(set_virtual_address_map, memory_map_size,
+			     descriptor_size, descriptor_version, virtual_map);
 
 	efi_switch_mm(efi_scratch.prev_mm);
 	local_irq_restore(flags);
@@ -983,8 +996,11 @@ efi_thunk_query_capsule_caps(efi_capsule_header_t **capsules,
 	return EFI_UNSUPPORTED;
 }
 
-void efi_thunk_runtime_setup(void)
+void __init efi_thunk_runtime_setup(void)
 {
+	if (!IS_ENABLED(CONFIG_EFI_MIXED))
+		return;
+
 	efi.get_time = efi_thunk_get_time;
 	efi.set_time = efi_thunk_set_time;
 	efi.get_wakeup_time = efi_thunk_get_wakeup_time;
@@ -1000,7 +1016,6 @@ void efi_thunk_runtime_setup(void)
 	efi.update_capsule = efi_thunk_update_capsule;
 	efi.query_capsule_caps = efi_thunk_query_capsule_caps;
 }
-#endif /* CONFIG_EFI_MIXED */
 
 efi_status_t __init efi_set_virtual_address_map(unsigned long memory_map_size,
 						unsigned long descriptor_size,
@@ -1011,6 +1026,12 @@ efi_status_t __init efi_set_virtual_address_map(unsigned long memory_map_size,
 	unsigned long flags;
 	pgd_t *save_pgd = NULL;
 
+	if (efi_is_mixed())
+		return efi_thunk_set_virtual_address_map(memory_map_size,
+							 descriptor_size,
+							 descriptor_version,
+							 virtual_map);
+
 	if (efi_enabled(EFI_OLD_MEMMAP)) {
 		save_pgd = efi_old_memmap_phys_prolog();
 		if (!save_pgd)
diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S
index 3189f1394701..162b35729633 100644
--- a/arch/x86/platform/efi/efi_thunk_64.S
+++ b/arch/x86/platform/efi/efi_thunk_64.S
@@ -25,15 +25,16 @@
 
 	.text
 	.code64
-SYM_FUNC_START(efi64_thunk)
+SYM_CODE_START(efi64_thunk)
 	push	%rbp
 	push	%rbx
 
 	/*
 	 * Switch to 1:1 mapped 32-bit stack pointer.
 	 */
-	movq	%rsp, efi_saved_sp(%rip)
+	movq	%rsp, %rax
 	movq	efi_scratch(%rip), %rsp
+	push	%rax
 
 	/*
 	 * Calculate the physical address of the kernel text.
@@ -41,113 +42,31 @@ SYM_FUNC_START(efi64_thunk)
 	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
+	leaq	1f(%rip), %rbp
+	leaq	2f(%rip), %rbx
+	subq	%rax, %rbp
 	subq	%rax, %rbx
-	movl	%ebx, 8(%rsp)
 
-	leaq	__efi64_thunk(%rip), %rbx
-	subq	%rax, %rbx
-	call	*%rbx
-
-	movq	efi_saved_sp(%rip), %rsp
-	pop	%rbx
-	pop	%rbp
-	retq
-SYM_FUNC_END(efi64_thunk)
-
-/*
- * We run this function from the 1:1 mapping.
- *
- * This function must be invoked with a 1:1 mapped stack.
- */
-SYM_FUNC_START_LOCAL(__efi64_thunk)
-	movl	%ds, %eax
-	push	%rax
-	movl	%es, %eax
-	push	%rax
-	movl	%ss, %eax
-	push	%rax
-
-	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)
-
-	leaq	1f(%rip), %rbx
-	movq	%rbx, func_rt_ptr(%rip)
+	subq	$28, %rsp
+	movl	%ebx, 0x0(%rsp)		/* return address */
+	movl	%esi, 0x4(%rsp)
+	movl	%edx, 0x8(%rsp)
+	movl	%ecx, 0xc(%rsp)
+	movl	%r8d, 0x10(%rsp)
+	movl	%r9d, 0x14(%rsp)
 
 	/* Switch to 32-bit descriptor */
 	pushq	$__KERNEL32_CS
-	leaq	efi_enter32(%rip), %rax
-	pushq	%rax
+	pushq	%rdi			/* EFI runtime service address */
 	lretq
 
-1:	addq	$32, %rsp
-
+1:	movq	24(%rsp), %rsp
 	pop	%rbx
-	movl	%ebx, %ss
-	pop	%rbx
-	movl	%ebx, %es
-	pop	%rbx
-	movl	%ebx, %ds
-
-	/*
-	 * 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
-SYM_FUNC_END(__efi64_thunk)
-
-SYM_FUNC_START_LOCAL(efi_exit32)
-	movq	func_rt_ptr(%rip), %rax
-	push	%rax
-	mov	%rdi, %rax
-	ret
-SYM_FUNC_END(efi_exit32)
+	pop	%rbp
+	retq
 
 	.code32
-/*
- * EFI service pointer must be in %edi.
- *
- * The stack should represent the 32-bit calling convention.
- */
-SYM_FUNC_START_LOCAL(efi_enter32)
-	movl	$__KERNEL_DS, %eax
-	movl	%eax, %ds
-	movl	%eax, %es
-	movl	%eax, %ss
-
-	call	*%edi
-
-	/* We must preserve return value */
-	movl	%eax, %edi
-
-	movl	72(%esp), %eax
-	pushl	$__KERNEL_CS
-	pushl	%eax
-
+2:	pushl	$__KERNEL_CS
+	pushl	%ebp
 	lret
-SYM_FUNC_END(efi_enter32)
-
-	.data
-	.balign	8
-func_rt_ptr:		.quad 0
-efi_saved_sp:		.quad 0
+SYM_CODE_END(efi64_thunk)