Replace a couple of occurrences of absolute references with RIP-relative ones. This removes the need for boot-time fixups. This is a prerequisite for PIE linking, which only permits 64-bit wide loader-visible absolute references.
Signed-off-by: Ard Biesheuvel <[email protected]> --- arch/x86/kernel/head_64.S | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 21816b48537c..2c666c8c4519 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -179,8 +179,9 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) xorl %r15d, %r15d /* Derive the runtime physical address of init_top_pgt[] */ - movq phys_base(%rip), %rax - addq $(init_top_pgt - __START_KERNEL_map), %rax + leaq init_top_pgt(%rip), %rax + subq $__START_KERNEL_map, %rax + addq phys_base(%rip), %rax /* * Retrieve the modifier (SME encryption mask if SME is active) to be @@ -232,6 +233,9 @@ SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL) btsl $X86_CR4_PGE_BIT, %ecx movq %rcx, %cr4 + /* Use .text as an anchor to emit PC-relative symbol references */ + leaq .text(%rip), %rbx + #ifdef CONFIG_SMP /* * For parallel boot, the APIC ID is read from the APIC, and then @@ -288,10 +292,9 @@ SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL) .Llookup_AP: /* EAX contains the APIC ID of the current CPU */ xorl %ecx, %ecx - leaq cpuid_to_apicid(%rip), %rbx .Lfind_cpunr: - cmpl (%rbx,%rcx,4), %eax + cmpl cpuid_to_apicid - .text(%rbx,%rcx,4), %eax jz .Lsetup_cpu inc %ecx #ifdef CONFIG_FORCE_NR_CPUS @@ -311,7 +314,7 @@ SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL) .Lsetup_cpu: /* Get the per cpu offset for the given CPU# which is in ECX */ - movq __per_cpu_offset(,%rcx,8), %rdx + movq __per_cpu_offset - .text(%rbx,%rcx,8), %rdx #else xorl %edx, %edx /* zero-extended to clear all of RDX */ #endif /* CONFIG_SMP */ @@ -322,7 +325,7 @@ SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL) * * RDX contains the per-cpu offset */ - movq current_task(%rdx), %rax + movq current_task - .text(%rbx,%rdx), %rax movq TASK_threadsp(%rax), %rsp /* @@ -343,7 +346,7 @@ SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL) */ subq $16, %rsp movw $(GDT_SIZE-1), (%rsp) - leaq gdt_page(%rdx), %rax + leaq gdt_page - .text(%rbx,%rdx), %rax movq %rax, 2(%rsp) lgdt (%rsp) addq $16, %rsp -- 2.47.3
