diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/boot/compressed/efi_thunk_64.S | 29 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 30 |
2 files changed, 42 insertions, 17 deletions
diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S index 8fb7f6799c52..2b2049259619 100644 --- a/arch/x86/boot/compressed/efi_thunk_64.S +++ b/arch/x86/boot/compressed/efi_thunk_64.S @@ -54,11 +54,16 @@ SYM_FUNC_START(__efi64_thunk) * Switch to gdt with 32-bit segments. This is the firmware GDT * that was installed when the kernel started executing. This * pointer was saved at the EFI stub entry point in head_64.S. + * + * Pass the saved DS selector to the 32-bit code, and use far return to + * restore the saved CS selector. */ leaq efi32_boot_gdt(%rip), %rax lgdt (%rax) - pushq $__KERNEL_CS + movzwl efi32_boot_ds(%rip), %edx + movzwq efi32_boot_cs(%rip), %rax + pushq %rax leaq efi_enter32(%rip), %rax pushq %rax lretq @@ -73,6 +78,10 @@ SYM_FUNC_START(__efi64_thunk) 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 /* * Convert 32-bit status code into 64-bit. @@ -92,10 +101,12 @@ SYM_FUNC_END(__efi64_thunk) * 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 + /* Load firmware selector into data and stack segment registers */ + movl %edx, %ds + movl %edx, %es + movl %edx, %fs + movl %edx, %gs + movl %edx, %ss /* Reload pgtables */ movl %cr3, %eax @@ -157,6 +168,14 @@ SYM_DATA_START(efi32_boot_gdt) .quad 0 SYM_DATA_END(efi32_boot_gdt) +SYM_DATA_START(efi32_boot_cs) + .word 0 +SYM_DATA_END(efi32_boot_cs) + +SYM_DATA_START(efi32_boot_ds) + .word 0 +SYM_DATA_END(efi32_boot_ds) + SYM_DATA_START(efi_gdt64) .word efi_gdt64_end - efi_gdt64 .long 0 /* Filled out by user */ diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index bd44d89540d3..c56b30bd9c7b 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -54,10 +54,6 @@ SYM_FUNC_START(startup_32) */ cld cli - movl $(__BOOT_DS), %eax - movl %eax, %ds - movl %eax, %es - movl %eax, %ss /* * Calculate the delta between where we were compiled to run @@ -72,10 +68,20 @@ SYM_FUNC_START(startup_32) 1: popl %ebp subl $1b, %ebp + /* Load new GDT with the 64bit segments using 32bit descriptor */ + addl %ebp, gdt+2(%ebp) + lgdt gdt(%ebp) + + /* Load segment registers with our descriptors */ + movl $__BOOT_DS, %eax + movl %eax, %ds + movl %eax, %es + movl %eax, %fs + movl %eax, %gs + movl %eax, %ss + /* setup a stack and make sure cpu supports long mode. */ - movl $boot_stack_end, %eax - addl %ebp, %eax - movl %eax, %esp + leal boot_stack_end(%ebp), %esp call verify_cpu testl %eax, %eax @@ -112,10 +118,6 @@ SYM_FUNC_START(startup_32) * Prepare for entering 64 bit mode */ - /* Load new GDT with the 64bit segments using 32bit descriptor */ - addl %ebp, gdt+2(%ebp) - lgdt gdt(%ebp) - /* Enable PAE mode */ movl %cr4, %eax orl $X86_CR4_PAE, %eax @@ -232,9 +234,13 @@ SYM_FUNC_START(efi32_stub_entry) movl %ecx, efi32_boot_args(%ebp) movl %edx, efi32_boot_args+4(%ebp) - sgdtl efi32_boot_gdt(%ebp) movb $0, efi_is64(%ebp) + /* Save firmware GDTR and code/data selectors */ + sgdtl efi32_boot_gdt(%ebp) + movw %cs, efi32_boot_cs(%ebp) + movw %ds, efi32_boot_ds(%ebp) + /* Disable paging */ movl %cr0, %eax btrl $X86_CR0_PG_BIT, %eax |