x86/entry: Stop using PER_CPU_VAR(kernel_stack)

PER_CPU_VAR(kernel_stack) is redundant:

  - On the 64-bit build, we can use PER_CPU_VAR(cpu_tss + TSS_sp0).
  - On the 32-bit build, we can use PER_CPU_VAR(cpu_current_top_of_stack).

PER_CPU_VAR(kernel_stack) will be deleted by a separate change.

Signed-off-by: Denys Vlasenko <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Drewry <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 2ab0f7182df34b4c65489f225aaa2782b04ecfd1..1b1330c07971b6503c7f538a1eb6e6814ec1ba46 100644 (file)
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -346,7 +346,7 @@ ENTRY(ia32_cstar_target)
        SWAPGS_UNSAFE_STACK
        movl    %esp,%r8d
        CFI_REGISTER    rsp,r8
-       movq    PER_CPU_VAR(kernel_stack),%rsp
+       movq    PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
        ENABLE_INTERRUPTS(CLBR_NONE)
 
        /* Zero-extending 32-bit regs, do not remove */

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index b4bdec3e9523e03b7ece3154302c8d95ce2a9ac8..d656a363e1eb86b209ee1df102bb801ac6608dbe 100644 (file)
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -198,9 +198,15 @@ static inline unsigned long current_stack_pointer(void)
 #else /* !__ASSEMBLY__ */
 
 /* Load thread_info address into "reg" */
+#ifdef CONFIG_X86_32
 #define GET_THREAD_INFO(reg) \
-       _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
+       _ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
        _ASM_SUB $(THREAD_SIZE),reg ;
+#else
+#define GET_THREAD_INFO(reg) \
+       _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
+       _ASM_SUB $(THREAD_SIZE),reg ;
+#endif
 
 /*
  * ASM operand which evaluates to a 'thread_info' address of

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7423e3e2f5c54cc23178afaf8cca70081f1d3a5c..c13b86b40176e664bee0d69c3118e7985a0698b2 100644 (file)
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
 GLOBAL(system_call_after_swapgs)
 
        movq    %rsp,PER_CPU_VAR(rsp_scratch)
-       movq    PER_CPU_VAR(kernel_stack),%rsp
+       movq    PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
 
        /* Construct struct pt_regs on stack */
        pushq_cfi $__USER_DS                    /* pt_regs->ss */

diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index a2cabb8bd6bf6bb769961afc193b1b160b72970c..5aa7ec607b9e3d3b7bb48dfdcd3341a55ac00dda 100644 (file)
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -15,6 +15,7 @@
 #include <asm/percpu.h>
 #include <asm/processor-flags.h>
 #include <asm/segment.h>
+#include <asm/asm-offsets.h>
 
 #include <xen/interface/xen.h>
 
@@ -53,7 +54,7 @@ ENTRY(xen_sysret64)
         * still with the kernel gs, so we can easily switch back
         */
        movq %rsp, PER_CPU_VAR(rsp_scratch)
-       movq PER_CPU_VAR(kernel_stack), %rsp
+       movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
 
        pushq $__USER_DS
        pushq PER_CPU_VAR(rsp_scratch)
@@ -72,7 +73,7 @@ ENTRY(xen_sysret32)
         * still with the kernel gs, so we can easily switch back
         */
        movq %rsp, PER_CPU_VAR(rsp_scratch)
-       movq PER_CPU_VAR(kernel_stack), %rsp
+       movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
 
        pushq $__USER32_DS
        pushq PER_CPU_VAR(rsp_scratch)