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Peter Anvin" , Mukesh Ojha , Matteo Croce , Len Brown , Pu Wen , Nicolai Stange , Hui Wang , linux-kernel@vger.kernel.org Subject: [PATCH] x86/realmode: remove trampoline_status flag Date: Tue, 16 Jul 2019 16:40:24 +0800 Message-Id: <1563266424-3472-1-git-send-email-kernelfans@gmail.com> X-Mailer: git-send-email 2.7.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In current code, there is no reader of trampoline_status. It turns out that after commit ce4b1b16502b ("x86/smpboot: Initialize secondary CPU only if master CPU will wait for it"), trampoline_status is not needed any more. Signed-off-by: Pingfan Liu Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Mukesh Ojha Cc: Matteo Croce Cc: Len Brown Cc: Pu Wen Cc: Nicolai Stange Cc: Hui Wang Cc: linux-kernel@vger.kernel.org --- arch/x86/include/asm/realmode.h | 1 - arch/x86/kernel/smpboot.c | 5 ----- arch/x86/realmode/rm/header.S | 1 - arch/x86/realmode/rm/trampoline_32.S | 3 --- arch/x86/realmode/rm/trampoline_64.S | 3 --- arch/x86/realmode/rm/trampoline_common.S | 4 ---- 6 files changed, 17 deletions(-) diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h index c536823..09ecc32 100644 --- a/arch/x86/include/asm/realmode.h +++ b/arch/x86/include/asm/realmode.h @@ -20,7 +20,6 @@ struct real_mode_header { u32 ro_end; /* SMP trampoline */ u32 trampoline_start; - u32 trampoline_status; u32 trampoline_header; #ifdef CONFIG_X86_64 u32 trampoline_pgd; diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 362dd89..2ef10d9 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -965,8 +965,6 @@ int common_cpu_up(unsigned int cpu, struct task_struct *idle) static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, int *cpu0_nmi_registered) { - volatile u32 *trampoline_status = - (volatile u32 *) __va(real_mode_header->trampoline_status); /* start_ip had better be page-aligned! */ unsigned long start_ip = real_mode_header->trampoline_start; @@ -1058,9 +1056,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, } } - /* mark "stuck" area as not stuck */ - *trampoline_status = 0; - if (x86_platform.legacy.warm_reset) { /* * Cleanup possible dangling ends... diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S index 30b0d30..6363761 100644 --- a/arch/x86/realmode/rm/header.S +++ b/arch/x86/realmode/rm/header.S @@ -19,7 +19,6 @@ GLOBAL(real_mode_header) .long pa_ro_end /* SMP trampoline */ .long pa_trampoline_start - .long pa_trampoline_status .long pa_trampoline_header #ifdef CONFIG_X86_64 .long pa_trampoline_pgd; diff --git a/arch/x86/realmode/rm/trampoline_32.S b/arch/x86/realmode/rm/trampoline_32.S index 2dd866c..1868b15 100644 --- a/arch/x86/realmode/rm/trampoline_32.S +++ b/arch/x86/realmode/rm/trampoline_32.S @@ -41,9 +41,6 @@ ENTRY(trampoline_start) movl tr_start, %eax # where we need to go - movl $0xA5A5A5A5, trampoline_status - # write marker for master knows we're running - /* * GDT tables in non default location kernel can be beyond 16MB and * lgdt will not be able to load the address as in real mode default diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S index 24bb759..aee2b45 100644 --- a/arch/x86/realmode/rm/trampoline_64.S +++ b/arch/x86/realmode/rm/trampoline_64.S @@ -49,9 +49,6 @@ ENTRY(trampoline_start) mov %ax, %es mov %ax, %ss - movl $0xA5A5A5A5, trampoline_status - # write marker for master knows we're running - # Setup stack movl $rm_stack_end, %esp diff --git a/arch/x86/realmode/rm/trampoline_common.S b/arch/x86/realmode/rm/trampoline_common.S index 7c70677..8d8208d 100644 --- a/arch/x86/realmode/rm/trampoline_common.S +++ b/arch/x86/realmode/rm/trampoline_common.S @@ -2,7 +2,3 @@ .section ".rodata","a" .balign 16 tr_idt: .fill 1, 6, 0 - - .bss - .balign 4 -GLOBAL(trampoline_status) .space 4 -- 2.7.5