*/
#include <linux/linkage.h>
-#include <asm/asm-offsets.h>
+#include <asm/desc_defs.h>
#include <asm/msr.h>
#include <asm/page_types.h>
#include <asm/pgtable_types.h>
#include <asm/processor-flags.h>
#include <asm/segment.h>
-#include <asm/setup.h>
.code64
.text
-/*
- * When booting in 64-bit mode on 32-bit EFI firmware, startup_64_mixed_mode()
- * is the first thing that runs after switching to long mode. Depending on
- * whether the EFI handover protocol or the compat entry point was used to
- * enter the kernel, it will either branch to the common 64-bit EFI stub
- * entrypoint efi_stub_entry() directly, or via the 64-bit EFI PE/COFF
- * entrypoint efi_pe_entry(). In the former case, the bootloader must provide a
- * struct bootparams pointer as the third argument, so the presence of such a
- * pointer is used to disambiguate.
- *
- * +--------------+
- * +------------------+ +------------+ +------>| efi_pe_entry |
- * | efi32_pe_entry |---->| | | +-----------+--+
- * +------------------+ | | +------+----------------+ |
- * | startup_32 |---->| startup_64_mixed_mode | |
- * +------------------+ | | +------+----------------+ |
- * | efi32_stub_entry |---->| | | |
- * +------------------+ +------------+ | |
- * V |
- * +------------+ +----------------+ |
- * | startup_64 |<----| efi_stub_entry |<--------+
- * +------------+ +----------------+
- */
-SYM_FUNC_START(startup_64_mixed_mode)
- lea efi32_boot_args(%rip), %rdx
- mov 0(%rdx), %edi
- mov 4(%rdx), %esi
-
- leaq (pte + 5 * PAGE_SIZE)(%rip), %rax
- movq %rax, %cr3 // reload after startup_32
-
- /* Switch to the firmware's stack */
- movl efi32_boot_sp(%rip), %esp
- andl $~7, %esp
-
- mov 8(%rdx), %edx // saved bootparams pointer
- call efi_stub_entry
-SYM_FUNC_END(startup_64_mixed_mode)
-
SYM_FUNC_START(__efi64_thunk)
push %rbp
push %rbx
- movl %ds, %eax
- push %rax
- movl %es, %eax
- push %rax
- movl %ss, %eax
- push %rax
-
/* Copy args passed on stack */
- movq 0x30(%rsp), %rbp
- movq 0x38(%rsp), %rbx
- movq 0x40(%rsp), %rax
+ movq 0x18(%rsp), %rbp
+ movq 0x20(%rsp), %rbx
+ movq 0x28(%rsp), %rax
/*
* Convert x86-64 ABI params to i386 ABI
movl %ebx, 0x18(%rsp)
movl %eax, 0x1c(%rsp)
- leaq 0x20(%rsp), %rbx
- sgdt (%rbx)
- sidt 16(%rbx)
-
leaq 1f(%rip), %rbp
+ movl %cs, %ebx
- /*
- * Switch to IDT and GDT with 32-bit segments. These are the firmware
- * GDT and IDT that were installed when the kernel started executing.
- * The pointers were saved by the efi32_entry() routine below.
- *
- * Pass the saved DS selector to the 32-bit code, and use far return to
- * restore the saved CS selector.
- */
- lidt efi32_boot_idt(%rip)
- lgdt efi32_boot_gdt(%rip)
-
- movzwl efi32_boot_ds(%rip), %edx
- movzwq efi32_boot_cs(%rip), %rax
- pushq %rax
- leaq efi_enter32(%rip), %rax
- pushq %rax
- lretq
+ ljmpl *efi32_call(%rip)
1: addq $64, %rsp
movq %rdi, %rax
- pop %rbx
- movl %ebx, %ss
- pop %rbx
- movl %ebx, %es
- pop %rbx
- movl %ebx, %ds
- /* Clear out 32-bit selector from FS and GS */
- xorl %ebx, %ebx
- movl %ebx, %fs
- movl %ebx, %gs
-
pop %rbx
pop %rbp
RET
SYM_FUNC_START(efi32_stub_entry)
call 1f
1: popl %ecx
- leal (efi32_boot_args - 1b)(%ecx), %ebx
/* Clear BSS */
xorl %eax, %eax
rep stosl
add $0x4, %esp /* Discard return address */
- popl %ecx
- popl %edx
- popl %esi
- movl %esi, 8(%ebx)
- jmp efi32_entry
+ movl 8(%esp), %ebx /* struct boot_params pointer */
+ jmp efi32_startup
SYM_FUNC_END(efi32_stub_entry)
#endif
* The stack should represent the 32-bit calling convention.
*/
SYM_FUNC_START_LOCAL(efi_enter32)
- /* Load firmware selector into data and stack segment registers */
- movl %edx, %ds
- movl %edx, %es
- movl %edx, %fs
- movl %edx, %gs
- movl %edx, %ss
-
/* Disable paging */
movl %cr0, %eax
btrl $X86_CR0_PG_BIT, %eax
/* We must preserve return value */
movl %eax, %edi
- /*
- * Some firmware will return with interrupts enabled. Be sure to
- * disable them before we switch GDTs and IDTs.
- */
- cli
-
- lidtl 16(%ebx)
- lgdtl (%ebx)
-
- xorl %eax, %eax
- lldt %ax
-
call efi32_enable_long_mode
- pushl $__KERNEL_CS
+ pushl %ebx
pushl %ebp
lret
SYM_FUNC_END(efi_enter32)
SYM_FUNC_END(efi32_enable_long_mode)
/*
- * This is the common EFI stub entry point for mixed mode.
+ * This is the common EFI stub entry point for mixed mode. It sets up the GDT
+ * and page tables needed for 64-bit execution, after which it calls the
+ * common 64-bit EFI entrypoint efi_stub_entry().
*
- * Arguments: %ecx image handle
- * %edx EFI system table pointer
+ * Arguments: 0(%esp) image handle
+ * 4(%esp) EFI system table pointer
+ * %ebx struct boot_params pointer (or NULL)
*
* Since this is the point of no return for ordinary execution, no registers
* are considered live except for the function parameters. [Note that the EFI
* stub may still exit and return to the firmware using the Exit() EFI boot
* service.]
*/
-SYM_FUNC_START_LOCAL(efi32_entry)
- call 1f
-1: pop %ebx
-
- /* Save firmware GDTR and code/data selectors */
- sgdtl (efi32_boot_gdt - 1b)(%ebx)
- movw %cs, (efi32_boot_cs - 1b)(%ebx)
- movw %ds, (efi32_boot_ds - 1b)(%ebx)
-
- /* Store firmware IDT descriptor */
- sidtl (efi32_boot_idt - 1b)(%ebx)
-
- /* Store firmware stack pointer */
- movl %esp, (efi32_boot_sp - 1b)(%ebx)
-
- /* Store boot arguments */
- leal (efi32_boot_args - 1b)(%ebx), %ebx
- movl %ecx, 0(%ebx)
- movl %edx, 4(%ebx)
- movb $0x0, 12(%ebx) // efi_is64
-
- /*
- * Allocate some memory for a temporary struct boot_params, which only
- * needs the minimal pieces that startup_32() relies on.
- */
- subl $PARAM_SIZE, %esp
- movl %esp, %esi
- movl $PAGE_SIZE, BP_kernel_alignment(%esi)
- movl $_end - 1b, BP_init_size(%esi)
- subl $startup_32 - 1b, BP_init_size(%esi)
+SYM_FUNC_START_LOCAL(efi32_startup)
+ movl %esp, %ebp
+
+ subl $8, %esp
+ sgdtl (%esp) /* Save GDT descriptor to the stack */
+ movl 2(%esp), %esi /* Existing GDT pointer */
+ movzwl (%esp), %ecx /* Existing GDT limit */
+ inc %ecx /* Existing GDT size */
+ andl $~7, %ecx /* Ensure size is multiple of 8 */
+
+ subl %ecx, %esp /* Allocate new GDT */
+ andl $~15, %esp /* Realign the stack */
+ movl %esp, %edi /* New GDT address */
+ leal 7(%ecx), %eax /* New GDT limit */
+ pushw %cx /* Push 64-bit CS (for LJMP below) */
+ pushl %edi /* Push new GDT address */
+ pushw %ax /* Push new GDT limit */
+
+ /* Copy GDT to the stack and add a 64-bit code segment at the end */
+ movl $GDT_ENTRY(DESC_CODE64, 0, 0xfffff) & 0xffffffff, (%edi,%ecx)
+ movl $GDT_ENTRY(DESC_CODE64, 0, 0xfffff) >> 32, 4(%edi,%ecx)
+ shrl $2, %ecx
+ cld
+ rep movsl /* Copy the firmware GDT */
+ lgdtl (%esp) /* Switch to the new GDT */
call 1f
1: pop %edi
+ /* Record mixed mode entry */
+ movb $0x0, (efi_is64 - 1b)(%edi)
+
+ /* Set up indirect far call to re-enter 32-bit mode */
+ leal (efi32_call - 1b)(%edi), %eax
+ addl %eax, (%eax)
+ movw %cs, 4(%eax)
+
/* Disable paging */
movl %cr0, %eax
btrl $X86_CR0_PG_BIT, %eax
movl %edx, (%eax)
movl %eax, %cr3
- jmp startup_32
-SYM_FUNC_END(efi32_entry)
+ call efi32_enable_long_mode
+
+ /* Set up far jump to 64-bit mode (CS is already on the stack) */
+ leal (efi_stub_entry - 1b)(%edi), %eax
+ movl %eax, 2(%esp)
+
+ movl 0(%ebp), %edi
+ movl 4(%ebp), %esi
+ movl %ebx, %edx
+ ljmpl *2(%esp)
+SYM_FUNC_END(efi32_startup)
/*
* efi_status_t efi32_pe_entry(efi_handle_t image_handle,
btl $29, %edx // check long mode bit
jnc 1f
leal 8(%esp), %esp // preserve stack alignment
- movl (%esp), %ecx // image_handle
- movl 4(%esp), %edx // sys_table
- jmp efi32_entry // pass %ecx, %edx
- // no other registers remain live
+ xor %ebx, %ebx // no struct boot_params pointer
+ jmp efi32_startup // only ESP and EBX remain live
1: movl $0x80000003, %eax // EFI_UNSUPPORTED
popl %ebx
RET
.data
.balign 8
-SYM_DATA_START_LOCAL(efi32_boot_gdt)
- .word 0
- .quad 0
-SYM_DATA_END(efi32_boot_gdt)
-
-SYM_DATA_START_LOCAL(efi32_boot_idt)
- .word 0
- .quad 0
-SYM_DATA_END(efi32_boot_idt)
-
-SYM_DATA_LOCAL(efi32_boot_cs, .word 0)
-SYM_DATA_LOCAL(efi32_boot_ds, .word 0)
-SYM_DATA_LOCAL(efi32_boot_sp, .long 0)
-SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0)
+SYM_DATA_START_LOCAL(efi32_call)
+ .long efi_enter32 - .
+ .word 0x0
+SYM_DATA_END(efi32_call)
SYM_DATA(efi_is64, .byte 1)
.bss
projects / thirdparty / kernel / linux.git / commitdiff
