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    Subject[PATCH 11/18] 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 | 2 +-
    arch/x86/kernel/process_64.c | 2 +-
    arch/x86/kernel/vm86_32.c | 14 ++++++--------
    arch/x86/xen/enlighten_pv.c | 7 +++----
    8 files changed, 20 insertions(+), 25 deletions(-)

    diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
    index 12deec722cf0..43d4f90edebc 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 280d94c36dad..a916788ac478 100644
    --- a/arch/x86/include/asm/paravirt_types.h
    +++ b/arch/x86/include/asm/paravirt_types.h
    @@ -133,7 +133,7 @@ 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 0167e3e35a57..064b84722166 100644
    --- a/arch/x86/include/asm/processor.h
    +++ b/arch/x86/include/asm/processor.h
    @@ -517,9 +517,9 @@ 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)
    @@ -544,10 +544,9 @@ 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 c9176bae7fd8..079648bd85ed 100644
    --- a/arch/x86/kernel/cpu/common.c
    +++ b/arch/x86/kernel/cpu/common.c
    @@ -1572,7 +1572,7 @@ void cpu_init(void)
    initialize_tlbstate_and_flush();
    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);
    @@ -1627,7 +1627,7 @@ void cpu_init(void)
    initialize_tlbstate_and_flush();
    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 84d6c9f554d0..8bdf9aaa92a0 100644
    --- a/arch/x86/kernel/process_32.c
    +++ b/arch/x86/kernel/process_32.c
    @@ -286,7 +286,7 @@ __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);
    + 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) +
    diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
    index a6ff6d1a0110..2124304fb77a 100644
    --- a/arch/x86/kernel/process_64.c
    +++ b/arch/x86/kernel/process_64.c
    @@ -465,7 +465,7 @@ __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 5bc1c3ab6287..0f1d92cd20ad 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;
    @@ -146,13 +145,13 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
    do_exit(SIGSEGV);
    }

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

    memcpy(&regs->pt, &vm86->regs32, sizeof(struct pt_regs));

    @@ -238,7 +237,6 @@ 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;
    @@ -366,8 +364,8 @@ 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 */
    + preempt_disable();
    tsk->thread.sp0 += 16;

    if (static_cpu_has(X86_FEATURE_SEP)) {
    @@ -375,8 +373,8 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
    refresh_sysenter_cs(&tsk->thread);
    }

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

    if (vm86->flags & VM86_SCREEN_BITMAP)
    mark_screen_rdonly(tsk->mm);
    diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
    index 8da4eff19c2a..e7b213047724 100644
    --- a/arch/x86/xen/enlighten_pv.c
    +++ b/arch/x86/xen/enlighten_pv.c
    @@ -810,15 +810,14 @@ 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)
    --
    2.13.6
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