From: Brian Gerst Date: Thu, 16 Mar 2023 22:21:05 +0000 (+0000) Subject: x86/smpboot: Remove initial_gs X-Git-Tag: v6.4-rc1~172^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8f6be6d870e8a078fcc956fc2ff8d7cff67795ee;p=thirdparty%2Fkernel%2Flinux.git x86/smpboot: Remove initial_gs Given its CPU#, each CPU can find its own per-cpu offset, and directly set GSBASE accordingly. The global variable can be eliminated. Signed-off-by: Brian Gerst Signed-off-by: David Woodhouse Signed-off-by: Usama Arif Signed-off-by: Thomas Gleixner Tested-by: Usama Arif Tested-by: Guilherme G. Piccoli Reviewed-by: David Woodhouse Link: https://lore.kernel.org/r/20230316222109.1940300-9-usama.arif@bytedance.com --- diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h index a336feef0af14..f6a1737c77be2 100644 --- a/arch/x86/include/asm/realmode.h +++ b/arch/x86/include/asm/realmode.h @@ -59,7 +59,6 @@ extern struct real_mode_header *real_mode_header; extern unsigned char real_mode_blob_end[]; extern unsigned long initial_code; -extern unsigned long initial_gs; extern unsigned long initial_stack; #ifdef CONFIG_AMD_MEM_ENCRYPT extern unsigned long initial_vc_handler; diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index de89bb4719d06..1328c221af30e 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -127,7 +127,6 @@ int x86_acpi_suspend_lowlevel(void) * value is in the actual %rsp register. */ current->thread.sp = (unsigned long)temp_stack + sizeof(temp_stack); - initial_gs = per_cpu_offset(smp_processor_id()); smpboot_control = smp_processor_id(); #endif initial_code = (unsigned long)wakeup_long64; diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index a5b46c2fba05b..6a8238702eabb 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -66,18 +66,10 @@ SYM_CODE_START_NOALIGN(startup_64) leaq _text(%rip), %rdi - /* - * initial_gs points to initial fixed_percpu_data struct with storage for - * the stack protector canary. Global pointer fixups are needed at this - * stage, so apply them as is done in fixup_pointer(), and initialize %gs - * such that the canary can be accessed at %gs:40 for subsequent C calls. - */ + /* Setup GSBASE to allow stack canary access for C code */ movl $MSR_GS_BASE, %ecx - movq initial_gs(%rip), %rax - movq $_text, %rdx - subq %rdx, %rax - addq %rdi, %rax - movq %rax, %rdx + leaq INIT_PER_CPU_VAR(fixed_percpu_data)(%rip), %rdx + movl %edx, %eax shrq $32, %rdx wrmsr @@ -294,8 +286,11 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) * the per cpu areas are set up. */ movl $MSR_GS_BASE,%ecx - movl initial_gs(%rip),%eax - movl initial_gs+4(%rip),%edx +#ifndef CONFIG_SMP + leaq INIT_PER_CPU_VAR(fixed_percpu_data)(%rip), %rdx +#endif + movl %edx, %eax + shrq $32, %rdx wrmsr /* Setup and Load IDT */ @@ -437,7 +432,6 @@ SYM_CODE_END(vc_boot_ghcb) __REFDATA .balign 8 SYM_DATA(initial_code, .quad x86_64_start_kernel) -SYM_DATA(initial_gs, .quad INIT_PER_CPU_VAR(fixed_percpu_data)) #ifdef CONFIG_AMD_MEM_ENCRYPT SYM_DATA(initial_vc_handler, .quad handle_vc_boot_ghcb) #endif diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 94e6c54ddb70f..b7d478de79e54 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1059,8 +1059,6 @@ int common_cpu_up(unsigned int cpu, struct task_struct *idle) #ifdef CONFIG_X86_32 /* Stack for startup_32 can be just as for start_secondary onwards */ per_cpu(pcpu_hot.top_of_stack, cpu) = task_top_of_stack(idle); -#else - initial_gs = per_cpu_offset(cpu); #endif return 0; }