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Subject[PATCH 08/17] x86-64: Move oldrsp from PDA to per-cpu.
Date
Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/include/asm/pda.h | 2 +-
arch/x86/kernel/asm-offsets_64.c | 2 --
arch/x86/kernel/entry_64.S | 8 ++++----
arch/x86/kernel/process_64.c | 8 +++++---
arch/x86/xen/xen-asm_64.S | 8 ++++----
5 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 4d28ffb..ae23deb 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -14,7 +14,7 @@ struct x8664_pda {
unsigned long unused1;
unsigned long unused2;
unsigned long unused3;
- unsigned long oldrsp; /* 24 user rsp for system call */
+ unsigned long unused4;
int irqcount; /* 32 Irq nesting counter. Starts -1 */
unsigned int unused6; /* 36 was cpunumber */
#ifdef CONFIG_CC_STACKPROTECTOR
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index cafff5f..6a13983 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -11,7 +11,6 @@
#include <linux/hardirq.h>
#include <linux/suspend.h>
#include <linux/kbuild.h>
-#include <asm/pda.h>
#include <asm/processor.h>
#include <asm/segment.h>
#include <asm/thread_info.h>
@@ -49,7 +48,6 @@ int main(void)
BLANK();
#undef ENTRY
#define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
- ENTRY(oldrsp);
ENTRY(irqcount);
DEFINE(pda_size, sizeof(struct x8664_pda));
BLANK();
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 8f35796..1331fd2 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -210,7 +210,7 @@ ENTRY(native_usergs_sysret64)

/* %rsp:at FRAMEEND */
.macro FIXUP_TOP_OF_STACK tmp offset=0
- movq %gs:pda_oldrsp,\tmp
+ movq PER_CPU_VAR(oldrsp),\tmp
movq \tmp,RSP+\offset(%rsp)
movq $__USER_DS,SS+\offset(%rsp)
movq $__USER_CS,CS+\offset(%rsp)
@@ -221,7 +221,7 @@ ENTRY(native_usergs_sysret64)

.macro RESTORE_TOP_OF_STACK tmp offset=0
movq RSP+\offset(%rsp),\tmp
- movq \tmp,%gs:pda_oldrsp
+ movq \tmp,PER_CPU_VAR(oldrsp)
movq EFLAGS+\offset(%rsp),\tmp
movq \tmp,R11+\offset(%rsp)
.endm
@@ -479,7 +479,7 @@ ENTRY(system_call)
*/
ENTRY(system_call_after_swapgs)

- movq %rsp,%gs:pda_oldrsp
+ movq %rsp,PER_CPU_VAR(oldrsp)
movq PER_CPU_VAR(kernelstack),%rsp
/*
* No need to follow this irqs off/on section - it's straight
@@ -523,7 +523,7 @@ sysret_check:
CFI_REGISTER rip,rcx
RESTORE_ARGS 0,-ARG_SKIP,1
/*CFI_REGISTER rflags,r11*/
- movq %gs:pda_oldrsp, %rsp
+ movq PER_CPU_VAR(oldrsp), %rsp
USERGS_SYSRET64

CFI_RESTORE_STATE
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 2f5bb4d..d4a7391 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -60,6 +60,8 @@ asmlinkage extern void ret_from_fork(void);
DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
EXPORT_PER_CPU_SYMBOL(current_task);

+DEFINE_PER_CPU(unsigned long, oldrsp);
+
unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;

static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -395,7 +397,7 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
load_gs_index(0);
regs->ip = new_ip;
regs->sp = new_sp;
- write_pda(oldrsp, new_sp);
+ percpu_write(oldrsp, new_sp);
regs->cs = __USER_CS;
regs->ss = __USER_DS;
regs->flags = 0x200;
@@ -616,8 +618,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Switch the PDA and FPU contexts.
*/
- prev->usersp = read_pda(oldrsp);
- write_pda(oldrsp, next->usersp);
+ prev->usersp = percpu_read(oldrsp);
+ percpu_write(oldrsp, next->usersp);
percpu_write(current_task, next_p);

percpu_write(kernelstack,
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index eac2794..16d3bfb 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -195,11 +195,11 @@ RELOC(xen_sysexit, 1b+1)
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 %rsp, PER_CPU_VAR(oldrsp)
movq PER_CPU_VAR(kernelstack),%rsp

pushq $__USER_DS
- pushq %gs:pda_oldrsp
+ pushq PER_CPU_VAR(oldrsp)
pushq %r11
pushq $__USER_CS
pushq %rcx
@@ -212,11 +212,11 @@ RELOC(xen_sysret64, 1b+1)
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 %rsp, PER_CPU_VAR(oldrsp)
movq PER_CPU_VAR(kernelstack), %rsp

pushq $__USER32_DS
- pushq %gs:pda_oldrsp
+ pushq PER_CPU_VAR(oldrsp)
pushq %r11
pushq $__USER32_CS
pushq %rcx
--
1.6.1.rc1


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