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Subject[PATCH] x86/realmode: remove trampoline_status flag
Date
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 <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mukesh Ojha <mojha@codeaurora.org>
Cc: Matteo Croce <mcroce@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pu Wen <puwen@hygon.cn>
Cc: Nicolai Stange <nstange@suse.de>
Cc: Hui Wang <john.wanghui@huawei.com>
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
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