* [PATCH 2/3] x86: Remove unused kernel_stack per-cpu variable
2015-04-24 15:31 [PATCH 1/3] x86: Stop using PER_CPU_VAR(kernel_stack) Denys Vlasenko
@ 2015-04-24 15:31 ` Denys Vlasenko
2015-05-01 0:19 ` Andy Lutomirski
2015-05-08 13:30 ` [tip:x86/asm] x86/entry: Remove unused 'kernel_stack' " tip-bot for Denys Vlasenko
2015-04-24 15:31 ` [PATCH 3/3] x86: Define cpu_current_top_of_stack for 64-bit code Denys Vlasenko
2015-05-08 13:30 ` [tip:x86/asm] x86/entry: Stop using PER_CPU_VAR(kernel_stack) tip-bot for Denys Vlasenko
2 siblings, 2 replies; 8+ messages in thread
From: Denys Vlasenko @ 2015-04-24 15:31 UTC (permalink / raw)
To: Ingo Molnar
Cc: Denys Vlasenko, Linus Torvalds, Steven Rostedt, Borislav Petkov,
H. Peter Anvin, Andy Lutomirski, Oleg Nesterov,
Frederic Weisbecker, Alexei Starovoitov, Will Drewry, Kees Cook,
x86, linux-kernel
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: Will Drewry <wad@chromium.org>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
arch/x86/include/asm/thread_info.h | 2 --
arch/x86/kernel/cpu/common.c | 4 ----
arch/x86/kernel/process_32.c | 5 +----
arch/x86/kernel/process_64.c | 3 ---
arch/x86/kernel/smpboot.c | 2 --
5 files changed, 1 insertion(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index d656a36..4722889 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -177,8 +177,6 @@ struct thread_info {
*/
#ifndef __ASSEMBLY__
-DECLARE_PER_CPU(unsigned long, kernel_stack);
-
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a62cf04..6bec0b5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1155,10 +1155,6 @@ static __init int setup_disablecpuid(char *arg)
}
__setup("clearcpuid=", setup_disablecpuid);
-DEFINE_PER_CPU(unsigned long, kernel_stack) =
- (unsigned long)&init_thread_union + THREAD_SIZE;
-EXPORT_PER_CPU_SYMBOL(kernel_stack);
-
#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8ed2106..a99900c 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -302,13 +302,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
arch_end_context_switch(next_p);
/*
- * Reload esp0, kernel_stack, and current_top_of_stack. This changes
+ * Reload esp0 and cpu_current_top_of_stack. This changes
* current_thread_info().
*/
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) +
- THREAD_SIZE);
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +
THREAD_SIZE);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4baaa97..342257c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -409,9 +409,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/* Reload esp0 and ss1. This changes current_thread_info(). */
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
-
/*
* Now maybe reload the debug registers and handle I/O bitmaps
*/
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 50e547e..023cccf 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -792,8 +792,6 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
clear_tsk_thread_flag(idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
#endif
- per_cpu(kernel_stack, cpu) =
- (unsigned long)task_stack_page(idle) + THREAD_SIZE;
}
/*
--
1.8.1.4
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 2/3] x86: Remove unused kernel_stack per-cpu variable
2015-04-24 15:31 ` [PATCH 2/3] x86: Remove unused kernel_stack per-cpu variable Denys Vlasenko
@ 2015-05-01 0:19 ` Andy Lutomirski
2015-05-08 13:30 ` [tip:x86/asm] x86/entry: Remove unused 'kernel_stack' " tip-bot for Denys Vlasenko
1 sibling, 0 replies; 8+ messages in thread
From: Andy Lutomirski @ 2015-05-01 0:19 UTC (permalink / raw)
To: Denys Vlasenko
Cc: Ingo Molnar, Linus Torvalds, Steven Rostedt, Borislav Petkov,
H. Peter Anvin, Oleg Nesterov, Frederic Weisbecker,
Alexei Starovoitov, Will Drewry, Kees Cook, X86 ML, linux-kernel
On Fri, Apr 24, 2015 at 8:31 AM, Denys Vlasenko <dvlasenk@redhat.com> wrote:
> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
> CC: Linus Torvalds <torvalds@linux-foundation.org>
> CC: Steven Rostedt <rostedt@goodmis.org>
> CC: Ingo Molnar <mingo@kernel.org>
> CC: Borislav Petkov <bp@alien8.de>
> CC: "H. Peter Anvin" <hpa@zytor.com>
> CC: Andy Lutomirski <luto@amacapital.net>
> CC: Oleg Nesterov <oleg@redhat.com>
> CC: Frederic Weisbecker <fweisbec@gmail.com>
> CC: Alexei Starovoitov <ast@plumgrid.com>
> CC: Will Drewry <wad@chromium.org>
> CC: Kees Cook <keescook@chromium.org>
> CC: x86@kernel.org
> CC: linux-kernel@vger.kernel.org
Acked-by: Andy Lutomirski <luto@kernel.org>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:x86/asm] x86/entry: Remove unused 'kernel_stack' per-cpu variable
2015-04-24 15:31 ` [PATCH 2/3] x86: Remove unused kernel_stack per-cpu variable Denys Vlasenko
2015-05-01 0:19 ` Andy Lutomirski
@ 2015-05-08 13:30 ` tip-bot for Denys Vlasenko
1 sibling, 0 replies; 8+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-05-08 13:30 UTC (permalink / raw)
To: linux-tip-commits
Cc: bp, wad, oleg, hpa, luto, torvalds, peterz, dvlasenk, keescook,
rostedt, mingo, fweisbec, linux-kernel, akpm, tglx, ast
Commit-ID: fed7c3f0f750f225317828d691e9eb76eec887b3
Gitweb: http://git.kernel.org/tip/fed7c3f0f750f225317828d691e9eb76eec887b3
Author: Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Fri, 24 Apr 2015 17:31:34 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 May 2015 13:49:43 +0200
x86/entry: Remove unused 'kernel_stack' per-cpu variable
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/thread_info.h | 2 --
arch/x86/kernel/cpu/common.c | 4 ----
arch/x86/kernel/process_32.c | 5 +----
arch/x86/kernel/process_64.c | 3 ---
arch/x86/kernel/smpboot.c | 2 --
5 files changed, 1 insertion(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index d656a36..4722889 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -177,8 +177,6 @@ struct thread_info {
*/
#ifndef __ASSEMBLY__
-DECLARE_PER_CPU(unsigned long, kernel_stack);
-
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a62cf04..6bec0b5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1155,10 +1155,6 @@ static __init int setup_disablecpuid(char *arg)
}
__setup("clearcpuid=", setup_disablecpuid);
-DEFINE_PER_CPU(unsigned long, kernel_stack) =
- (unsigned long)&init_thread_union + THREAD_SIZE;
-EXPORT_PER_CPU_SYMBOL(kernel_stack);
-
#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8ed2106..a99900c 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -302,13 +302,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
arch_end_context_switch(next_p);
/*
- * Reload esp0, kernel_stack, and current_top_of_stack. This changes
+ * Reload esp0 and cpu_current_top_of_stack. This changes
* current_thread_info().
*/
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) +
- THREAD_SIZE);
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +
THREAD_SIZE);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ddfdbf7..8213450 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -409,9 +409,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/* Reload esp0 and ss1. This changes current_thread_info(). */
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
-
/*
* Now maybe reload the debug registers and handle I/O bitmaps
*/
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 50e547e..023cccf 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -792,8 +792,6 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
clear_tsk_thread_flag(idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
#endif
- per_cpu(kernel_stack, cpu) =
- (unsigned long)task_stack_page(idle) + THREAD_SIZE;
}
/*
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 3/3] x86: Define cpu_current_top_of_stack for 64-bit code
2015-04-24 15:31 [PATCH 1/3] x86: Stop using PER_CPU_VAR(kernel_stack) Denys Vlasenko
2015-04-24 15:31 ` [PATCH 2/3] x86: Remove unused kernel_stack per-cpu variable Denys Vlasenko
@ 2015-04-24 15:31 ` Denys Vlasenko
2015-04-24 19:35 ` Denys Vlasenko
2015-05-08 13:30 ` [tip:x86/asm] x86/entry: Define 'cpu_current_top_of_stack' " tip-bot for Denys Vlasenko
2015-05-08 13:30 ` [tip:x86/asm] x86/entry: Stop using PER_CPU_VAR(kernel_stack) tip-bot for Denys Vlasenko
2 siblings, 2 replies; 8+ messages in thread
From: Denys Vlasenko @ 2015-04-24 15:31 UTC (permalink / raw)
To: Ingo Molnar
Cc: Denys Vlasenko, Linus Torvalds, Steven Rostedt, Borislav Petkov,
H. Peter Anvin, Andy Lutomirski, Oleg Nesterov,
Frederic Weisbecker, Alexei Starovoitov, Will Drewry, Kees Cook,
x86, linux-kernel
32-bit code has PER_CPU_VAR(cpu_current_top_of_stack).
64-bit code uses somewhat more obscure PER_CPU_VAR(cpu_tss + TSS_sp0).
Define cpu_current_top_of_stack macro on CONFIG_X86_64 so that
PER_CPU_VAR(cpu_current_top_of_stack) expression can be used in both
32-bit and 64-bit code.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Alexei Starovoitov <ast@plumgrid.com>
CC: Will Drewry <wad@chromium.org>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
The idea of this patch was suggested by Steven Rostedt.
I'm okay if only patches 1 and 2 will be applied.
arch/x86/ia32/ia32entry.S | 4 ++--
arch/x86/include/asm/processor.h | 2 ++
arch/x86/include/asm/thread_info.h | 10 ++++------
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
5 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 3f28678..c06a9c6 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -119,7 +119,7 @@ ENTRY(ia32_sysenter_target)
* it is too small to ever cause noticeable irq latency.
*/
SWAPGS_UNSAFE_STACK
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
@@ -352,7 +352,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 23ba676..3754dac 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -304,6 +304,8 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
#ifdef CONFIG_X86_32
DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
+#else
+#define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
#endif
/*
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 4722889..5b1e833 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -195,16 +195,14 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
+#ifdef CONFIG_X86_64
+#define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
+#endif
+
/* Load thread_info address into "reg" */
-#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
-#else
-#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
- _ASM_SUB $(THREAD_SIZE),reg ;
-#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 508fe4e..5db3488 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index acc49e0..5e15e92 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -16,6 +16,7 @@
#include <asm/processor-flags.h>
#include <asm/segment.h>
#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
#include <xen/interface/xen.h>
@@ -70,7 +71,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -89,7 +90,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)
--
1.8.1.4
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 3/3] x86: Define cpu_current_top_of_stack for 64-bit code
2015-04-24 15:31 ` [PATCH 3/3] x86: Define cpu_current_top_of_stack for 64-bit code Denys Vlasenko
@ 2015-04-24 19:35 ` Denys Vlasenko
2015-05-08 13:30 ` [tip:x86/asm] x86/entry: Define 'cpu_current_top_of_stack' " tip-bot for Denys Vlasenko
1 sibling, 0 replies; 8+ messages in thread
From: Denys Vlasenko @ 2015-04-24 19:35 UTC (permalink / raw)
To: Denys Vlasenko
Cc: Ingo Molnar, Linus Torvalds, Steven Rostedt, Borislav Petkov,
H. Peter Anvin, Andy Lutomirski, Oleg Nesterov,
Frederic Weisbecker, Alexei Starovoitov, Will Drewry, Kees Cook,
X86 ML, Linux Kernel Mailing List
On Fri, Apr 24, 2015 at 5:31 PM, Denys Vlasenko <dvlasenk@redhat.com>
> diff --git a/arch/x86/include/asm/processor.h
b/arch/x86/include/asm/processor.h
> index 23ba676..3754dac 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -304,6 +304,8 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
>
> #ifdef CONFIG_X86_32
> DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
> +#else
> +#define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
> #endif
>
> /*
> diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
Oops... this hunk (one touching processor.h) shouldn't be there.
It is bogus. It works simply because this define isn't used
by 64-bit builds. Just drop this hunk. The rest is correct.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:x86/asm] x86/entry: Define 'cpu_current_top_of_stack' for 64-bit code
2015-04-24 15:31 ` [PATCH 3/3] x86: Define cpu_current_top_of_stack for 64-bit code Denys Vlasenko
2015-04-24 19:35 ` Denys Vlasenko
@ 2015-05-08 13:30 ` tip-bot for Denys Vlasenko
1 sibling, 0 replies; 8+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-05-08 13:30 UTC (permalink / raw)
To: linux-tip-commits
Cc: dvlasenk, torvalds, bp, akpm, oleg, ast, linux-kernel, peterz,
hpa, fweisbec, wad, tglx, luto, keescook, rostedt, mingo
Commit-ID: 3a23208e69679597e767cf3547b1a30dd845d9b5
Gitweb: http://git.kernel.org/tip/3a23208e69679597e767cf3547b1a30dd845d9b5
Author: Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Fri, 24 Apr 2015 17:31:35 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 May 2015 13:50:02 +0200
x86/entry: Define 'cpu_current_top_of_stack' for 64-bit code
32-bit code has PER_CPU_VAR(cpu_current_top_of_stack).
64-bit code uses somewhat more obscure: PER_CPU_VAR(cpu_tss + TSS_sp0).
Define the 'cpu_current_top_of_stack' macro on CONFIG_X86_64
as well so that the PER_CPU_VAR(cpu_current_top_of_stack)
expression can be used in both 32-bit and 64-bit code.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/ia32/ia32entry.S | 4 ++--
arch/x86/include/asm/thread_info.h | 10 ++++------
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
4 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 1b1330c..63450a5 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -113,7 +113,7 @@ ENTRY(ia32_sysenter_target)
* it is too small to ever cause noticeable irq latency.
*/
SWAPGS_UNSAFE_STACK
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
@@ -346,7 +346,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 4722889..225ee54 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -195,16 +195,14 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
+#ifdef CONFIG_X86_64
+# define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
+#endif
+
/* Load thread_info address into "reg" */
-#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
-#else
-#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
- _ASM_SUB $(THREAD_SIZE),reg ;
-#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index c13b86b..09c3f9e 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 5aa7ec6..04529e6 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -16,6 +16,7 @@
#include <asm/processor-flags.h>
#include <asm/segment.h>
#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
#include <xen/interface/xen.h>
@@ -54,7 +55,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -73,7 +74,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)
^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:x86/asm] x86/entry: Stop using PER_CPU_VAR(kernel_stack)
2015-04-24 15:31 [PATCH 1/3] x86: Stop using PER_CPU_VAR(kernel_stack) Denys Vlasenko
2015-04-24 15:31 ` [PATCH 2/3] x86: Remove unused kernel_stack per-cpu variable Denys Vlasenko
2015-04-24 15:31 ` [PATCH 3/3] x86: Define cpu_current_top_of_stack for 64-bit code Denys Vlasenko
@ 2015-05-08 13:30 ` tip-bot for Denys Vlasenko
2 siblings, 0 replies; 8+ messages in thread
From: tip-bot for Denys Vlasenko @ 2015-05-08 13:30 UTC (permalink / raw)
To: linux-tip-commits
Cc: keescook, fweisbec, oleg, akpm, torvalds, rostedt, mingo, bp,
luto, peterz, hpa, linux-kernel, tglx, wad, ast, dvlasenk
Commit-ID: 63332a8455d8310b77d38779c6c21a660a8d9feb
Gitweb: http://git.kernel.org/tip/63332a8455d8310b77d38779c6c21a660a8d9feb
Author: Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Fri, 24 Apr 2015 17:31:33 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 May 2015 13:43:52 +0200
x86/entry: Stop using PER_CPU_VAR(kernel_stack)
PER_CPU_VAR(kernel_stack) is redundant:
- On the 64-bit build, we can use PER_CPU_VAR(cpu_tss + TSS_sp0).
- On the 32-bit build, we can use PER_CPU_VAR(cpu_current_top_of_stack).
PER_CPU_VAR(kernel_stack) will be deleted by a separate change.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/ia32/ia32entry.S | 2 +-
arch/x86/include/asm/thread_info.h | 8 +++++++-
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
4 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 2ab0f71..1b1330c 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -346,7 +346,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(kernel_stack),%rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index b4bdec3..d656a36 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -198,9 +198,15 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
/* Load thread_info address into "reg" */
+#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
+ _ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
+#else
+#define GET_THREAD_INFO(reg) \
+ _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
+ _ASM_SUB $(THREAD_SIZE),reg ;
+#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7423e3e..c13b86b 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack),%rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index a2cabb8..5aa7ec6 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -15,6 +15,7 @@
#include <asm/percpu.h>
#include <asm/processor-flags.h>
#include <asm/segment.h>
+#include <asm/asm-offsets.h>
#include <xen/interface/xen.h>
@@ -53,7 +54,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack), %rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -72,7 +73,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack), %rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)
^ permalink raw reply [flat|nested] 8+ messages in thread