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Subject[RFC 10/17] x86/asm/64: Pass sp0 directly to load_sp0()
Date
load_sp0() had an odd signature:

void load_sp0(struct tss_struct *tss, struct thread_struct *thread);

Simplify it to:

void load_sp0(unsigned long sp0);

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/include/asm/paravirt.h | 5 ++---
arch/x86/include/asm/paravirt_types.h | 2 +-
arch/x86/include/asm/processor.h | 9 ++++-----
arch/x86/kernel/cpu/common.c | 4 ++--
arch/x86/kernel/process_32.c | 4 ++--
arch/x86/kernel/process_64.c | 2 +-
arch/x86/kernel/vm86_32.c | 12 ++++--------
arch/x86/lguest/boot.c | 7 +++----
arch/x86/xen/enlighten_pv.c | 7 +++----
9 files changed, 22 insertions(+), 30 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 9ccac1926587..209dada6207e 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -15,10 +15,9 @@
#include <linux/cpumask.h>
#include <asm/frame.h>

-static inline void load_sp0(struct tss_struct *tss,
- struct thread_struct *thread)
+static inline void load_sp0(unsigned long sp0)
{
- PVOP_VCALL2(pv_cpu_ops.load_sp0, tss, thread);
+ PVOP_VCALL1(pv_cpu_ops.load_sp0, sp0);
}

/* The paravirtualized CPUID instruction. */
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 9ffc36bfe4cd..04a091615c08 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -136,7 +136,7 @@ struct pv_cpu_ops {
void (*alloc_ldt)(struct desc_struct *ldt, unsigned entries);
void (*free_ldt)(struct desc_struct *ldt, unsigned entries);

- void (*load_sp0)(struct tss_struct *tss, struct thread_struct *t);
+ void (*load_sp0)(unsigned long sp0);

void (*set_iopl_mask)(unsigned mask);

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ee37fb86900a..85ddfc1a9bb5 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -510,9 +510,9 @@ static inline void native_set_iopl_mask(unsigned mask)
}

static inline void
-native_load_sp0(struct tss_struct *tss, struct thread_struct *thread)
+native_load_sp0(unsigned long sp0)
{
- tss->x86_tss.sp0 = thread->sp0;
+ this_cpu_write(cpu_tss.x86_tss.sp0, sp0);
}

static inline void native_swapgs(void)
@@ -537,10 +537,9 @@ static inline unsigned long current_top_of_stack(void)
#else
#define __cpuid native_cpuid

-static inline void load_sp0(struct tss_struct *tss,
- struct thread_struct *thread)
+static inline void load_sp0(unsigned long sp0)
{
- native_load_sp0(tss, thread);
+ native_load_sp0(sp0);
}

#define set_iopl_mask native_set_iopl_mask
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c8b39870f33e..40312b3ef9de 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1554,7 +1554,7 @@ void cpu_init(void)
BUG_ON(me->mm);
enter_lazy_tlb(&init_mm, me);

- load_sp0(t, &current->thread);
+ load_sp0(current->thread.sp0);
set_tss_desc(cpu, t);
load_TR_desc();
load_mm_ldt(&init_mm);
@@ -1608,7 +1608,7 @@ void cpu_init(void)
BUG_ON(curr->mm);
enter_lazy_tlb(&init_mm, curr);

- load_sp0(t, thread);
+ load_sp0(thread->sp0);
set_tss_desc(cpu, t);
load_TR_desc();
load_mm_ldt(&init_mm);
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 9f217b5ef438..e06a98e3a772 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -286,8 +286,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* Reload esp0 and cpu_current_top_of_stack. This changes
* current_thread_info().
*/
- load_sp0(tss, next);
- refresh_sysenter_cs(); /* in case prev or next is vm86 */
+ load_sp0(next->sp0);
+ refresh_sysenter_cs(next); /* in case prev or next is vm86 */
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 985e7569ab57..06c4393b19b3 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -437,7 +437,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
this_cpu_write(current_task, next_p);

/* Reload sp0. */
- load_sp0(tss, next);
+ load_sp0(next->sp0);

/*
* Now maybe reload the debug registers and handle I/O bitmaps
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 9edda73dcc90..3b98b7771f15 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -94,7 +94,6 @@

void save_v86_state(struct kernel_vm86_regs *regs, int retval)
{
- struct tss_struct *tss;
struct task_struct *tsk = current;
struct vm86plus_struct __user *user;
struct vm86 *vm86 = current->thread.vm86;
@@ -146,11 +145,10 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
do_exit(SIGSEGV);
}

- tss = &per_cpu(cpu_tss, get_cpu());
tsk->thread.sp0 = vm86->saved_sp0;
tsk->thread.sysenter_cs = __KERNEL_CS;
- load_sp0(tss, &tsk->thread);
- refresh_sysenter_cs();
+ load_sp0(tsk->thread.sp0);
+ refresh_sysenter_cs(&tsk->thread);
vm86->saved_sp0 = 0;
put_cpu();

@@ -238,7 +236,6 @@ SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg)

static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
{
- struct tss_struct *tss;
struct task_struct *tsk = current;
struct vm86 *vm86 = tsk->thread.vm86;
struct kernel_vm86_regs vm86regs;
@@ -366,16 +363,15 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
vm86->saved_sp0 = tsk->thread.sp0;
lazy_save_gs(vm86->regs32.gs);

- tss = &per_cpu(cpu_tss, get_cpu());
/* make room for real-mode segments */
tsk->thread.sp0 += 16;

if (static_cpu_has(X86_FEATURE_SEP)) {
tsk->thread.sysenter_cs = 0;
- refresh_sysenter_cs();
+ refresh_sysenter_cs(&tsk->thread);
}

- load_sp0(tss, &tsk->thread);
+ load_sp0(tsk->thread.sp0);
put_cpu();

if (vm86->flags & VM86_SCREEN_BITMAP)
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 99472698c931..07bb8e9a69ac 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -1054,12 +1054,11 @@ static void lguest_time_init(void)
* will not tolerate us trying to use that), the stack pointer, and the number
* of pages in the stack.
*/
-static void lguest_load_sp0(struct tss_struct *tss,
- struct thread_struct *thread)
+static void lguest_load_sp0(unsigned long sp0)
{
- lazy_hcall3(LHCALL_SET_STACK, __KERNEL_DS | 0x1, thread->sp0,
+ lazy_hcall3(LHCALL_SET_STACK, __KERNEL_DS | 0x1, sp0,
THREAD_SIZE / PAGE_SIZE);
- tss->x86_tss.sp0 = thread->sp0;
+ this_cpu_write(cpu_tss.x86_tss.sp0, sp0);
}

/* Let's just say, I wouldn't do debugging under a Guest. */
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 811e4ddb3f37..6c803c3ee831 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -771,15 +771,14 @@ static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
}
}

-static void xen_load_sp0(struct tss_struct *tss,
- struct thread_struct *thread)
+static void xen_load_sp0(unsigned long sp0)
{
struct multicall_space mcs;

mcs = xen_mc_entry(0);
- MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
+ MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
xen_mc_issue(PARAVIRT_LAZY_CPU);
- tss->x86_tss.sp0 = thread->sp0;
+ this_cpu_write(cpu_tss.x86_tss.sp0, sp0);
}

void xen_set_iopl_mask(unsigned mask)
--
2.13.5
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