diff options
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 165 |
1 files changed, 67 insertions, 98 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 97d37f0a34f5..9e46729cf162 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -40,11 +40,35 @@ */ .hidden _bss .hidden _ebss - .hidden _got - .hidden _egot .hidden _end __HEAD + +/* + * This macro gives the relative virtual address of X, i.e. the offset of X + * from startup_32. This is the same as the link-time virtual address of X, + * since startup_32 is at 0, but defining it this way tells the + * assembler/linker that we do not want the actual run-time address of X. This + * prevents the linker from trying to create unwanted run-time relocation + * entries for the reference when the compressed kernel is linked as PIE. + * + * A reference X(%reg) will result in the link-time VA of X being stored with + * the instruction, and a run-time R_X86_64_RELATIVE relocation entry that + * adds the 64-bit base address where the kernel is loaded. + * + * Replacing it with (X-startup_32)(%reg) results in the offset being stored, + * and no run-time relocation. + * + * The macro should be used as a displacement with a base register containing + * the run-time address of startup_32 [i.e. rva(X)(%reg)], or as an immediate + * [$ rva(X)]. + * + * This macro can only be used from within the .head.text section, since the + * expression requires startup_32 to be in the same section as the code being + * assembled. + */ +#define rva(X) ((X) - startup_32) + .code32 SYM_FUNC_START(startup_32) /* @@ -67,10 +91,10 @@ SYM_FUNC_START(startup_32) leal (BP_scratch+4)(%esi), %esp call 1f 1: popl %ebp - subl $1b, %ebp + subl $ rva(1b), %ebp /* Load new GDT with the 64bit segments using 32bit descriptor */ - leal gdt(%ebp), %eax + leal rva(gdt)(%ebp), %eax movl %eax, 2(%eax) lgdt (%eax) @@ -83,7 +107,7 @@ SYM_FUNC_START(startup_32) movl %eax, %ss /* setup a stack and make sure cpu supports long mode. */ - leal boot_stack_end(%ebp), %esp + leal rva(boot_stack_end)(%ebp), %esp call verify_cpu testl %eax, %eax @@ -110,7 +134,7 @@ SYM_FUNC_START(startup_32) * image_offset = startup_32 - image_base * Otherwise image_offset will be zero and has no effect on the calculations. */ - subl image_offset(%ebp), %ebx + subl rva(image_offset)(%ebp), %ebx #endif movl BP_kernel_alignment(%esi), %eax @@ -126,7 +150,7 @@ SYM_FUNC_START(startup_32) /* Target address to relocate to for decompression */ addl BP_init_size(%esi), %ebx - subl $_end, %ebx + subl $ rva(_end), %ebx /* * Prepare for entering 64 bit mode @@ -154,19 +178,19 @@ SYM_FUNC_START(startup_32) 1: /* Initialize Page tables to 0 */ - leal pgtable(%ebx), %edi + leal rva(pgtable)(%ebx), %edi xorl %eax, %eax movl $(BOOT_INIT_PGT_SIZE/4), %ecx rep stosl /* Build Level 4 */ - leal pgtable + 0(%ebx), %edi + leal rva(pgtable + 0)(%ebx), %edi leal 0x1007 (%edi), %eax movl %eax, 0(%edi) addl %edx, 4(%edi) /* Build Level 3 */ - leal pgtable + 0x1000(%ebx), %edi + leal rva(pgtable + 0x1000)(%ebx), %edi leal 0x1007(%edi), %eax movl $4, %ecx 1: movl %eax, 0x00(%edi) @@ -177,7 +201,7 @@ SYM_FUNC_START(startup_32) jnz 1b /* Build Level 2 */ - leal pgtable + 0x2000(%ebx), %edi + leal rva(pgtable + 0x2000)(%ebx), %edi movl $0x00000183, %eax movl $2048, %ecx 1: movl %eax, 0(%edi) @@ -188,7 +212,7 @@ SYM_FUNC_START(startup_32) jnz 1b /* Enable the boot page tables */ - leal pgtable(%ebx), %eax + leal rva(pgtable)(%ebx), %eax movl %eax, %cr3 /* Enable Long mode in EFER (Extended Feature Enable Register) */ @@ -213,14 +237,14 @@ SYM_FUNC_START(startup_32) * We place all of the values on our mini stack so lret can * used to perform that far jump. */ - leal startup_64(%ebp), %eax + leal rva(startup_64)(%ebp), %eax #ifdef CONFIG_EFI_MIXED - movl efi32_boot_args(%ebp), %edi + movl rva(efi32_boot_args)(%ebp), %edi cmp $0, %edi jz 1f - leal efi64_stub_entry(%ebp), %eax - movl efi32_boot_args+4(%ebp), %esi - movl efi32_boot_args+8(%ebp), %edx // saved bootparams pointer + leal rva(efi64_stub_entry)(%ebp), %eax + movl rva(efi32_boot_args+4)(%ebp), %esi + movl rva(efi32_boot_args+8)(%ebp), %edx // saved bootparams pointer cmpl $0, %edx jnz 1f /* @@ -231,7 +255,7 @@ SYM_FUNC_START(startup_32) * the correct stack alignment for entry. */ subl $40, %esp - leal efi_pe_entry(%ebp), %eax + leal rva(efi_pe_entry)(%ebp), %eax movl %edi, %ecx // MS calling convention movl %esi, %edx 1: @@ -257,18 +281,18 @@ SYM_FUNC_START(efi32_stub_entry) call 1f 1: pop %ebp - subl $1b, %ebp + subl $ rva(1b), %ebp - movl %esi, efi32_boot_args+8(%ebp) + movl %esi, rva(efi32_boot_args+8)(%ebp) SYM_INNER_LABEL(efi32_pe_stub_entry, SYM_L_LOCAL) - movl %ecx, efi32_boot_args(%ebp) - movl %edx, efi32_boot_args+4(%ebp) - movb $0, efi_is64(%ebp) + movl %ecx, rva(efi32_boot_args)(%ebp) + movl %edx, rva(efi32_boot_args+4)(%ebp) + movb $0, rva(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) + sgdtl rva(efi32_boot_gdt)(%ebp) + movw %cs, rva(efi32_boot_cs)(%ebp) + movw %ds, rva(efi32_boot_ds)(%ebp) /* Disable paging */ movl %cr0, %eax @@ -347,30 +371,11 @@ SYM_CODE_START(startup_64) /* Target address to relocate to for decompression */ movl BP_init_size(%rsi), %ebx - subl $_end, %ebx + subl $ rva(_end), %ebx addq %rbp, %rbx /* Set up the stack */ - leaq boot_stack_end(%rbx), %rsp - - /* - * paging_prepare() and cleanup_trampoline() below can have GOT - * references. Adjust the table with address we are running at. - * - * Zero RAX for adjust_got: the GOT was not adjusted before; - * there's no adjustment to undo. - */ - xorq %rax, %rax - - /* - * Calculate the address the binary is loaded at and use it as - * a GOT adjustment. - */ - call 1f -1: popq %rdi - subq $1b, %rdi - - call .Ladjust_got + leaq rva(boot_stack_end)(%rbx), %rsp /* * At this point we are in long mode with 4-level paging enabled, @@ -444,7 +449,7 @@ SYM_CODE_START(startup_64) lretq trampoline_return: /* Restore the stack, the 32-bit trampoline uses its own stack */ - leaq boot_stack_end(%rbx), %rsp + leaq rva(boot_stack_end)(%rbx), %rsp /* * cleanup_trampoline() would restore trampoline memory. @@ -456,7 +461,7 @@ trampoline_return: * this function call. */ pushq %rsi - leaq top_pgtable(%rbx), %rdi + leaq rva(top_pgtable)(%rbx), %rdi call cleanup_trampoline popq %rsi @@ -464,30 +469,15 @@ trampoline_return: pushq $0 popfq - /* - * Previously we've adjusted the GOT with address the binary was - * loaded at. Now we need to re-adjust for relocation address. - * - * Calculate the address the binary is loaded at, so that we can - * undo the previous GOT adjustment. - */ - call 1f -1: popq %rax - subq $1b, %rax - - /* The new adjustment is the relocation address */ - movq %rbx, %rdi - call .Ladjust_got - /* * Copy the compressed kernel to the end of our buffer * where decompression in place becomes safe. */ pushq %rsi leaq (_bss-8)(%rip), %rsi - leaq (_bss-8)(%rbx), %rdi - movq $_bss /* - $startup_32 */, %rcx - shrq $3, %rcx + leaq rva(_bss-8)(%rbx), %rdi + movl $(_bss - startup_32), %ecx + shrl $3, %ecx std rep movsq cld @@ -498,15 +488,15 @@ trampoline_return: * during extract_kernel below. To avoid any issues, repoint the GDTR * to the new copy of the GDT. */ - leaq gdt64(%rbx), %rax - leaq gdt(%rbx), %rdx + leaq rva(gdt64)(%rbx), %rax + leaq rva(gdt)(%rbx), %rdx movq %rdx, 2(%rax) lgdt (%rax) /* * Jump to the relocated address. */ - leaq .Lrelocated(%rbx), %rax + leaq rva(.Lrelocated)(%rbx), %rax jmp *%rax SYM_CODE_END(startup_64) @@ -518,7 +508,7 @@ SYM_FUNC_START_ALIAS(efi_stub_entry) movq %rdx, %rbx /* save boot_params pointer */ call efi_main movq %rbx,%rsi - leaq startup_64(%rax), %rax + leaq rva(startup_64)(%rax), %rax jmp *%rax SYM_FUNC_END(efi64_stub_entry) SYM_FUNC_END_ALIAS(efi_stub_entry) @@ -544,9 +534,9 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) movq %rsi, %rdi /* real mode address */ leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ leaq input_data(%rip), %rdx /* input_data */ - movl $z_input_len, %ecx /* input_len */ + movl input_len(%rip), %ecx /* input_len */ movq %rbp, %r8 /* output target address */ - movl $z_output_len, %r9d /* decompressed length, end of relocs */ + movl output_len(%rip), %r9d /* decompressed length, end of relocs */ call extract_kernel /* returns kernel location in %rax */ popq %rsi @@ -556,27 +546,6 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) jmp *%rax SYM_FUNC_END(.Lrelocated) -/* - * Adjust the global offset table - * - * RAX is the previous adjustment of the table to undo (use 0 if it's the - * first time we touch GOT). - * RDI is the new adjustment to apply. - */ -.Ladjust_got: - /* Walk through the GOT adding the address to the entries */ - leaq _got(%rip), %rdx - leaq _egot(%rip), %rcx -1: - cmpq %rcx, %rdx - jae 2f - subq %rax, (%rdx) /* Undo previous adjustment */ - addq %rdi, (%rdx) /* Apply the new adjustment */ - addq $8, %rdx - jmp 1b -2: - ret - .code32 /* * This is the 32-bit trampoline that will be copied over to low memory. @@ -702,7 +671,7 @@ SYM_DATA(efi_is64, .byte 1) #define BS32_handle_protocol 88 // offsetof(efi_boot_services_32_t, handle_protocol) #define LI32_image_base 32 // offsetof(efi_loaded_image_32_t, image_base) - .text + __HEAD .code32 SYM_FUNC_START(efi32_pe_entry) /* @@ -724,12 +693,12 @@ SYM_FUNC_START(efi32_pe_entry) call 1f 1: pop %ebx - subl $1b, %ebx + subl $ rva(1b), %ebx /* Get the loaded image protocol pointer from the image handle */ leal -4(%ebp), %eax pushl %eax // &loaded_image - leal loaded_image_proto(%ebx), %eax + leal rva(loaded_image_proto)(%ebx), %eax pushl %eax // pass the GUID address pushl 8(%ebp) // pass the image handle @@ -764,7 +733,7 @@ SYM_FUNC_START(efi32_pe_entry) * use it before we get to the 64-bit efi_pe_entry() in C code. */ subl %esi, %ebx - movl %ebx, image_offset(%ebp) // save image_offset + movl %ebx, rva(image_offset)(%ebp) // save image_offset jmp efi32_pe_stub_entry 2: popl %edi // restore callee-save registers |