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Date: Mon, 19 Jan 2009 01:39:14 +0900
From: Tejun Heo <tj@...nel.org>
To: mingo@...e.hu, linux-kernel@...r.kernel.org, brgerst@...il.com
Cc: Tejun Heo <tj@...nel.org>
Subject: [PATCH 07/12] x86-64: Move kernelstack from PDA to per-cpu.
From: Brian Gerst <brgerst@...il.com>
Also clean up PER_CPU_VAR usage in xen-asm_64.S
tj: * remove now unused stack_thread_info()
* s/kernelstack/kernel_stack/
* added FIXME comment in xen-asm_64.S
Signed-off-by: Brian Gerst <brgerst@...il.com>
Signed-off-by: Tejun Heo <tj@...nel.org>
---
arch/x86/ia32/ia32entry.S | 8 ++++----
arch/x86/include/asm/pda.h | 4 +---
arch/x86/include/asm/thread_info.h | 20 ++++++++------------
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/cpu/common.c | 6 ++++--
arch/x86/kernel/entry_64.S | 4 ++--
arch/x86/kernel/process_64.c | 4 ++--
arch/x86/kernel/smpboot.c | 3 +++
arch/x86/xen/xen-asm_64.S | 23 +++++++++++------------
9 files changed, 35 insertions(+), 38 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 256b00b..9c79b24 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -112,8 +112,8 @@ ENTRY(ia32_sysenter_target)
CFI_DEF_CFA rsp,0
CFI_REGISTER rsp,rbp
SWAPGS_UNSAFE_STACK
- movq %gs:pda_kernelstack, %rsp
- addq $(PDA_STACKOFFSET),%rsp
+ movq PER_CPU_VAR(kernel_stack), %rsp
+ addq $(KERNEL_STACK_OFFSET),%rsp
/*
* No need to follow this irqs on/off section: the syscall
* disabled irqs, here we enable it straight after entry:
@@ -273,13 +273,13 @@ ENDPROC(ia32_sysenter_target)
ENTRY(ia32_cstar_target)
CFI_STARTPROC32 simple
CFI_SIGNAL_FRAME
- CFI_DEF_CFA rsp,PDA_STACKOFFSET
+ CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq %gs:pda_kernelstack,%rsp
+ movq PER_CPU_VAR(kernel_stack),%rsp
/*
* No need to follow this irqs on/off section: the syscall
* disabled irqs and here we enable it straight after entry:
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 7209302..4d28ffb 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -13,7 +13,7 @@
struct x8664_pda {
unsigned long unused1;
unsigned long unused2;
- unsigned long kernelstack; /* 16 top of kernel stack for current */
+ unsigned long unused3;
unsigned long oldrsp; /* 24 user rsp for system call */
int irqcount; /* 32 Irq nesting counter. Starts -1 */
unsigned int unused6; /* 36 was cpunumber */
@@ -44,6 +44,4 @@ extern void pda_init(int);
#endif
-#define PDA_STACKOFFSET (5*8)
-
#endif /* _ASM_X86_PDA_H */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 9878964..b46f8ca 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -194,25 +194,21 @@ static inline struct thread_info *current_thread_info(void)
#else /* X86_32 */
-#include <asm/pda.h>
+#include <asm/percpu.h>
+#define KERNEL_STACK_OFFSET (5*8)
/*
* macros/functions for gaining access to the thread information structure
* preempt_count needs to be 1 initially, until the scheduler is functional.
*/
#ifndef __ASSEMBLY__
-static inline struct thread_info *current_thread_info(void)
-{
- struct thread_info *ti;
- ti = (void *)(read_pda(kernelstack) + PDA_STACKOFFSET - THREAD_SIZE);
- return ti;
-}
+DECLARE_PER_CPU(unsigned long, kernel_stack);
-/* do not use in interrupt context */
-static inline struct thread_info *stack_thread_info(void)
+static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
- asm("andq %%rsp,%0; " : "=r" (ti) : "0" (~(THREAD_SIZE - 1)));
+ ti = (void *)(percpu_read(kernel_stack) +
+ KERNEL_STACK_OFFSET - THREAD_SIZE);
return ti;
}
@@ -220,8 +216,8 @@ static inline struct thread_info *stack_thread_info(void)
/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
- movq %gs:pda_kernelstack,reg ; \
- subq $(THREAD_SIZE-PDA_STACKOFFSET),reg
+ movq PER_CPU_VAR(kernel_stack),reg ; \
+ subq $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg
#endif
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 4f7a210..cafff5f 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -49,7 +49,6 @@ int main(void)
BLANK();
#undef ENTRY
#define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
- ENTRY(kernelstack);
ENTRY(oldrsp);
ENTRY(irqcount);
DEFINE(pda_size, sizeof(struct x8664_pda));
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index b50e38d..06b6290 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -889,6 +889,10 @@ DEFINE_PER_CPU(char *, irq_stack_ptr) =
per_cpu_var(irq_stack) + IRQ_STACK_SIZE - 64;
#endif
+DEFINE_PER_CPU(unsigned long, kernel_stack) =
+ (unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
+EXPORT_PER_CPU_SYMBOL(kernel_stack);
+
void __cpuinit pda_init(int cpu)
{
struct x8664_pda *pda = cpu_pda(cpu);
@@ -900,8 +904,6 @@ void __cpuinit pda_init(int cpu)
load_pda_offset(cpu);
pda->irqcount = -1;
- pda->kernelstack = (unsigned long)stack_thread_info() -
- PDA_STACKOFFSET + THREAD_SIZE;
if (cpu != 0) {
if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index d22677a..0dd4585 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -468,7 +468,7 @@ END(ret_from_fork)
ENTRY(system_call)
CFI_STARTPROC simple
CFI_SIGNAL_FRAME
- CFI_DEF_CFA rsp,PDA_STACKOFFSET
+ CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
SWAPGS_UNSAFE_STACK
@@ -480,7 +480,7 @@ ENTRY(system_call)
ENTRY(system_call_after_swapgs)
movq %rsp,%gs:pda_oldrsp
- movq %gs:pda_kernelstack,%rsp
+ movq PER_CPU_VAR(kernel_stack),%rsp
/*
* No need to follow this irqs off/on section - it's straight
* and short:
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e00c31a..6c5f576 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -620,9 +620,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
write_pda(oldrsp, next->usersp);
percpu_write(current_task, next_p);
- write_pda(kernelstack,
+ percpu_write(kernel_stack,
(unsigned long)task_stack_page(next_p) +
- THREAD_SIZE - PDA_STACKOFFSET);
+ THREAD_SIZE - KERNEL_STACK_OFFSET);
#ifdef CONFIG_CC_STACKPROTECTOR
write_pda(stack_canary, next_p->stack_canary);
/*
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 5854be0..869b988 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -798,6 +798,9 @@ do_rest:
#else
clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
+ per_cpu(kernel_stack, cpu) =
+ (unsigned long)task_stack_page(c_idle.idle) -
+ KERNEL_STACK_OFFSET + THREAD_SIZE;
#endif
early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
initial_code = (unsigned long)start_secondary;
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 05794c5..5a23e89 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -17,6 +17,7 @@
#include <asm/processor-flags.h>
#include <asm/errno.h>
#include <asm/segment.h>
+#include <asm/percpu.h>
#include <xen/interface/xen.h>
@@ -28,12 +29,10 @@
#if 1
/*
- x86-64 does not yet support direct access to percpu variables
- via a segment override, so we just need to make sure this code
- never gets used
+ FIXME: x86_64 now can support direct access to percpu variables
+ via a segment override. Update xen accordingly.
*/
#define BUG ud2a
-#define PER_CPU_VAR(var, off) 0xdeadbeef
#endif
/*
@@ -45,14 +44,14 @@ ENTRY(xen_irq_enable_direct)
BUG
/* Unmask events */
- movb $0, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
+ movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
/* Preempt here doesn't matter because that will deal with
any pending interrupts. The pending check may end up being
run on the wrong CPU, but that doesn't hurt. */
/* Test for pending */
- testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
+ testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
jz 1f
2: call check_events
@@ -69,7 +68,7 @@ ENDPATCH(xen_irq_enable_direct)
ENTRY(xen_irq_disable_direct)
BUG
- movb $1, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
+ movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
ENDPATCH(xen_irq_disable_direct)
ret
ENDPROC(xen_irq_disable_direct)
@@ -87,7 +86,7 @@ ENDPATCH(xen_irq_disable_direct)
ENTRY(xen_save_fl_direct)
BUG
- testb $0xff, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
+ testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
setz %ah
addb %ah,%ah
ENDPATCH(xen_save_fl_direct)
@@ -107,13 +106,13 @@ ENTRY(xen_restore_fl_direct)
BUG
testb $X86_EFLAGS_IF>>8, %ah
- setz PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_mask)
+ setz PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
/* Preempt here doesn't matter because that will deal with
any pending interrupts. The pending check may end up being
run on the wrong CPU, but that doesn't hurt. */
/* check for unmasked and pending */
- cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info, XEN_vcpu_info_pending)
+ cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
jz 1f
2: call check_events
1:
@@ -196,7 +195,7 @@ ENTRY(xen_sysret64)
/* We're already on the usermode stack at this point, but still
with the kernel gs, so we can easily switch back */
movq %rsp, %gs:pda_oldrsp
- movq %gs:pda_kernelstack,%rsp
+ movq PER_CPU_VAR(kernel_stack),%rsp
pushq $__USER_DS
pushq %gs:pda_oldrsp
@@ -213,7 +212,7 @@ ENTRY(xen_sysret32)
/* We're already on the usermode stack at this point, but still
with the kernel gs, so we can easily switch back */
movq %rsp, %gs:pda_oldrsp
- movq %gs:pda_kernelstack, %rsp
+ movq PER_CPU_VAR(kernel_stack), %rsp
pushq $__USER32_DS
pushq %gs:pda_oldrsp
--
1.6.0.2
--
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