8 files changed, 11 insertions, 16 deletions

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 50190e15c1b6..acbff3fb96a1 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -311,7 +311,7 @@ ENDPROC(ia32_sysenter_target)
 ENTRY(ia32_cstar_target)
         CFI_STARTPROC32 simple
         CFI_SIGNAL_FRAME
-        CFI_DEF_CFA     rsp,KERNEL_STACK_OFFSET
+        CFI_DEF_CFA     rsp,0
         CFI_REGISTER    rip,rcx
         /*CFI_REGISTER  rflags,r11*/
         SWAPGS_UNSAFE_STACK
@@ -323,7 +323,7 @@ ENTRY(ia32_cstar_target)
          * disabled irqs and here we enable it straight after entry:
          */
         ENABLE_INTERRUPTS(CLBR_NONE)
-        ALLOC_PT_GPREGS_ON_STACK 8      /* +8: space for orig_ax */
+        ALLOC_PT_GPREGS_ON_STACK 6*8 /* 6*8: space for orig_ax and iret frame */
         SAVE_C_REGS_EXCEPT_RCX_R891011
         movl    %eax,%eax       /* zero extension */
         movq    %rax,ORIG_RAX(%rsp)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index ae9c2f13b476..ad0ee3423da5 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -172,7 +172,6 @@ struct thread_info {
 #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
 
 #define STACK_WARN              (THREAD_SIZE/8)
-#define KERNEL_STACK_OFFSET     (5*(BITS_PER_LONG/8))
 
 /*
  * macros/functions for gaining access to the thread information structure
@@ -201,10 +200,10 @@ static inline unsigned long current_stack_pointer(void)
 
 #else /* !__ASSEMBLY__ */
 
-/* how to get the thread information struct from ASM */
+/* Load thread_info address into "reg" */
 #define GET_THREAD_INFO(reg) \
         _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
-        _ASM_SUB $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg ;
+        _ASM_SUB $(THREAD_SIZE),reg ;
 
 /*
  * ASM operand which evaluates to thread_info address
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 66d62aef7214..002216ab9145 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1116,7 +1116,7 @@ static __init int setup_disablecpuid(char *arg)
 __setup("clearcpuid=", setup_disablecpuid);
 
 DEFINE_PER_CPU(unsigned long, kernel_stack) =
-        (unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
+        (unsigned long)&init_thread_union + THREAD_SIZE;
 EXPORT_PER_CPU_SYMBOL(kernel_stack);
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 8076df982a18..eae69bba3a2c 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -225,7 +225,7 @@ ENDPROC(native_usergs_sysret64)
 ENTRY(system_call)
         CFI_STARTPROC   simple
         CFI_SIGNAL_FRAME
-        CFI_DEF_CFA     rsp,KERNEL_STACK_OFFSET
+        CFI_DEF_CFA     rsp,0
         CFI_REGISTER    rip,rcx
         /*CFI_REGISTER  rflags,r11*/
         SWAPGS_UNSAFE_STACK
@@ -242,9 +242,8 @@ GLOBAL(system_call_after_swapgs)
          * so we can enable interrupts only after we're done with using rsp_scratch:
          */
         movq    %rsp,PER_CPU_VAR(rsp_scratch)
-        /* kernel_stack is set so that 5 slots (iret frame) are preallocated */
         movq    PER_CPU_VAR(kernel_stack),%rsp
-        ALLOC_PT_GPREGS_ON_STACK 8              /* +8: space for orig_ax */
+        ALLOC_PT_GPREGS_ON_STACK 6*8 /* 6*8: space for orig_ax and iret frame */
         movq    %rcx,RIP(%rsp)
         movq    PER_CPU_VAR(rsp_scratch),%rcx
         movq    %r11,EFLAGS(%rsp)
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index c5e987022ca0..8ed2106b06da 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -308,7 +308,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         load_sp0(tss, next);
         this_cpu_write(kernel_stack,
                        (unsigned long)task_stack_page(next_p) +
-                       THREAD_SIZE - KERNEL_STACK_OFFSET);
+                       THREAD_SIZE);
         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 da8b74598d90..4baaa972f52a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -410,8 +410,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         load_sp0(tss, next);
 
         this_cpu_write(kernel_stack,
-                  (unsigned long)task_stack_page(next_p) +
-                  THREAD_SIZE - KERNEL_STACK_OFFSET);
+                (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
 
         /*
          * Now maybe reload the debug registers and handle I/O bitmaps
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 759388c538cf..7b20ffd2fffc 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -813,8 +813,7 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
         initial_gs = per_cpu_offset(cpu);
 #endif
         per_cpu(kernel_stack, cpu) =
-                (unsigned long)task_stack_page(idle) -
-                KERNEL_STACK_OFFSET + THREAD_SIZE;
+                (unsigned long)task_stack_page(idle) + THREAD_SIZE;
         early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
         initial_code = (unsigned long)start_secondary;
         stack_start  = idle->thread.sp;
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 08e8489c47f1..765b7684f858 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -452,8 +452,7 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
         clear_tsk_thread_flag(idle, TIF_FORK);
 #endif
         per_cpu(kernel_stack, cpu) =
-                (unsigned long)task_stack_page(idle) -
-                KERNEL_STACK_OFFSET + THREAD_SIZE;
+                (unsigned long)task_stack_page(idle) + THREAD_SIZE;
 
         xen_setup_runstate_info(cpu);
         xen_setup_timer(cpu);