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Subject[PATCH 07/17] x86-64: Move kernelstack from PDA to per-cpu.
Date
Also clean up PER_CPU_VAR usage in xen-asm_64.S

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/ia32/ia32entry.S | 8 ++++----
arch/x86/include/asm/pda.h | 4 +---
arch/x86/include/asm/thread_info.h | 11 +++++++----
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 | 2 ++
arch/x86/xen/xen-asm_64.S | 18 +++++++++---------
9 files changed, 31 insertions(+), 27 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 256b00b..16e1524 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(kernelstack), %rsp
+ addq $(KERNELSTACK_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,KERNELSTACK_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(kernelstack),%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..8f33a3d 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -194,17 +194,20 @@ static inline struct thread_info *current_thread_info(void)

#else /* X86_32 */

-#include <asm/pda.h>
+#include <asm/percpu.h>
+#define KERNELSTACK_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__
+DECLARE_PER_CPU(unsigned long, kernelstack);
+
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
- ti = (void *)(read_pda(kernelstack) + PDA_STACKOFFSET - THREAD_SIZE);
+ ti = (void *)(percpu_read(kernelstack) + KERNELSTACK_OFFSET - THREAD_SIZE);
return ti;
}

@@ -220,8 +223,8 @@ 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(kernelstack),reg ; \
+ subq $(THREAD_SIZE-KERNELSTACK_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 fbc8468..f653860 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -884,6 +884,10 @@ struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
DEFINE_PER_CPU_PAGE_ALIGNED(char, irqstack[IRQSTACKSIZE]) __aligned(PAGE_SIZE);
DEFINE_PER_CPU(char *, irqstackptr) = per_cpu_var(irqstack) + IRQSTACKSIZE - 64;

+DEFINE_PER_CPU(unsigned long, kernelstack) = (unsigned long)&init_thread_union -
+ KERNELSTACK_OFFSET + THREAD_SIZE;
+EXPORT_PER_CPU_SYMBOL(kernelstack);
+
void __cpuinit pda_init(int cpu)
{
struct x8664_pda *pda = cpu_pda(cpu);
@@ -895,8 +899,6 @@ 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 5cd892f..8f35796 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,KERNELSTACK_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(kernelstack),%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..2f5bb4d 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(kernelstack,
(unsigned long)task_stack_page(next_p) +
- THREAD_SIZE - PDA_STACKOFFSET);
+ THREAD_SIZE - KERNELSTACK_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 ecc2fc5..8bf1a43 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -800,6 +800,8 @@ do_rest:
#else
clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
+ per_cpu(kernelstack, cpu) = (unsigned long)task_stack_page(c_idle.idle) -
+ KERNELSTACK_OFFSET + THREAD_SIZE;
#endif
is_boot_cpu = 0;
early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 05794c5..eac2794 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>

@@ -33,7 +34,6 @@
never gets used
*/
#define BUG ud2a
-#define PER_CPU_VAR(var, off) 0xdeadbeef
#endif

/*
@@ -45,14 +45,14 @@ 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 +69,7 @@ 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 +87,7 @@ 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 +107,13 @@ 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 +196,7 @@ 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(kernelstack),%rsp

pushq $__USER_DS
pushq %gs:pda_oldrsp
@@ -213,7 +213,7 @@ 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(kernelstack), %rsp

pushq $__USER32_DS
pushq %gs:pda_oldrsp
--
1.6.1.rc1


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