x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack

If the kernel oopses while on the trampoline stack, it will print
"<SYSENTER>" even if SYSENTER is not involved.  That is rather confusing.

The "SYSENTER" stack is used for a lot more than SYSENTER now.  Give it a
better string to display in stack dumps, and rename the kernel code to
match.

Also move the 32-bit code over to the new naming even though it still uses
the entry stack only for SYSENTER.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

11 files changed, 44 insertions, 38 deletions

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index bd8b57a5c874..ace8f321a5a1 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -942,9 +942,9 @@ ENTRY(debug)
 
         /* Are we currently on the SYSENTER stack? */
         movl    PER_CPU_VAR(cpu_entry_area), %ecx
-        addl    $CPU_ENTRY_AREA_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
-        subl    %eax, %ecx      /* ecx = (end of SYSENTER_stack) - esp */
-        cmpl    $SIZEOF_SYSENTER_stack, %ecx
+        addl    $CPU_ENTRY_AREA_entry_stack + SIZEOF_entry_stack, %ecx
+        subl    %eax, %ecx      /* ecx = (end of entry_stack) - esp */
+        cmpl    $SIZEOF_entry_stack, %ecx
         jb      .Ldebug_from_sysenter_stack
 
         TRACE_IRQS_OFF
@@ -986,9 +986,9 @@ ENTRY(nmi)
 
         /* Are we currently on the SYSENTER stack? */
         movl    PER_CPU_VAR(cpu_entry_area), %ecx
-        addl    $CPU_ENTRY_AREA_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx
-        subl    %eax, %ecx      /* ecx = (end of SYSENTER_stack) - esp */
-        cmpl    $SIZEOF_SYSENTER_stack, %ecx
+        addl    $CPU_ENTRY_AREA_entry_stack + SIZEOF_entry_stack, %ecx
+        subl    %eax, %ecx      /* ecx = (end of entry_stack) - esp */
+        cmpl    $SIZEOF_entry_stack, %ecx
         jb      .Lnmi_from_sysenter_stack
 
         /* Not on SYSENTER stack. */
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 2812ce043a7a..87cebe78bbef 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -154,8 +154,8 @@ END(native_usergs_sysret64)
         _entry_trampoline - CPU_ENTRY_AREA_entry_trampoline(%rip)
 
 /* The top word of the SYSENTER stack is hot and is usable as scratch space. */
-#define RSP_SCRATCH     CPU_ENTRY_AREA_SYSENTER_stack + \
-                        SIZEOF_SYSENTER_stack - 8 + CPU_ENTRY_AREA
+#define RSP_SCRATCH     CPU_ENTRY_AREA_entry_stack + \
+                        SIZEOF_entry_stack - 8 + CPU_ENTRY_AREA
 
 ENTRY(entry_SYSCALL_64_trampoline)
         UNWIND_HINT_EMPTY
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 94fc4fa14127..8153b8d86a3c 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -56,10 +56,10 @@ struct cpu_entry_area {
         char gdt[PAGE_SIZE];
 
         /*
-         * The GDT is just below SYSENTER_stack and thus serves (on x86_64) as
+         * The GDT is just below entry_stack and thus serves (on x86_64) as
          * a a read-only guard page.
          */
-        struct SYSENTER_stack_page SYSENTER_stack_page;
+        struct entry_stack_page entry_stack_page;
 
         /*
          * On x86_64, the TSS is mapped RO.  On x86_32, it's mapped RW because
@@ -250,9 +250,9 @@ static inline struct cpu_entry_area *get_cpu_entry_area(int cpu)
         return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));
 }
 
-static inline struct SYSENTER_stack *cpu_SYSENTER_stack(int cpu)
+static inline struct entry_stack *cpu_entry_stack(int cpu)
 {
-        return &get_cpu_entry_area(cpu)->SYSENTER_stack_page.stack;
+        return &get_cpu_entry_area(cpu)->entry_stack_page.stack;
 }
 
 #endif /* !__ASSEMBLY__ */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index da943411d3d8..9e482d8b0b97 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -336,12 +336,12 @@ struct x86_hw_tss {
 #define IO_BITMAP_OFFSET                (offsetof(struct tss_struct, io_bitmap) - offsetof(struct tss_struct, x86_tss))
 #define INVALID_IO_BITMAP_OFFSET        0x8000
 
-struct SYSENTER_stack {
+struct entry_stack {
         unsigned long           words[64];
 };
 
-struct SYSENTER_stack_page {
-        struct SYSENTER_stack stack;
+struct entry_stack_page {
+        struct entry_stack stack;
 } __aligned(PAGE_SIZE);
 
 struct tss_struct {
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index f8062bfd43a0..f73706878772 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -16,7 +16,7 @@ enum stack_type {
         STACK_TYPE_TASK,
         STACK_TYPE_IRQ,
         STACK_TYPE_SOFTIRQ,
-        STACK_TYPE_SYSENTER,
+        STACK_TYPE_ENTRY,
         STACK_TYPE_EXCEPTION,
         STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
 };
@@ -29,7 +29,7 @@ struct stack_info {
 bool in_task_stack(unsigned long *stack, struct task_struct *task,
                    struct stack_info *info);
 
-bool in_sysenter_stack(unsigned long *stack, struct stack_info *info);
+bool in_entry_stack(unsigned long *stack, struct stack_info *info);
 
 int get_stack_info(unsigned long *stack, struct task_struct *task,
                    struct stack_info *info, unsigned long *visit_mask);
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index cd360a5e0dca..676b7cf4b62b 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -97,6 +97,6 @@ void common(void) {
         /* Layout info for cpu_entry_area */
         OFFSET(CPU_ENTRY_AREA_tss, cpu_entry_area, tss);
         OFFSET(CPU_ENTRY_AREA_entry_trampoline, cpu_entry_area, entry_trampoline);
-        OFFSET(CPU_ENTRY_AREA_SYSENTER_stack, cpu_entry_area, SYSENTER_stack_page);
-        DEFINE(SIZEOF_SYSENTER_stack, sizeof(struct SYSENTER_stack));
+        OFFSET(CPU_ENTRY_AREA_entry_stack, cpu_entry_area, entry_stack_page);
+        DEFINE(SIZEOF_entry_stack, sizeof(struct entry_stack));
 }
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index 7d20d9c0b3d6..fa1261eefa16 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -48,7 +48,7 @@ void foo(void)
 
         /* Offset from the sysenter stack to tss.sp0 */
         DEFINE(TSS_sysenter_sp0, offsetof(struct cpu_entry_area, tss.x86_tss.sp0) -
-               offsetofend(struct cpu_entry_area, SYSENTER_stack_page.stack));
+               offsetofend(struct cpu_entry_area, entry_stack_page.stack));
 
 #ifdef CONFIG_CC_STACKPROTECTOR
         BLANK();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 034900623adf..ed4acbce37a8 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -487,8 +487,8 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
         [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
 #endif
 
-static DEFINE_PER_CPU_PAGE_ALIGNED(struct SYSENTER_stack_page,
-                                   SYSENTER_stack_storage);
+static DEFINE_PER_CPU_PAGE_ALIGNED(struct entry_stack_page,
+                                   entry_stack_storage);
 
 static void __init
 set_percpu_fixmap_pages(int idx, void *ptr, int pages, pgprot_t prot)
@@ -523,8 +523,8 @@ static void __init setup_cpu_entry_area(int cpu)
 #endif
 
         __set_fixmap(get_cpu_entry_area_index(cpu, gdt), get_cpu_gdt_paddr(cpu), gdt_prot);
-        set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, SYSENTER_stack_page),
-                                per_cpu_ptr(&SYSENTER_stack_storage, cpu), 1,
+        set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, entry_stack_page),
+                                per_cpu_ptr(&entry_stack_storage, cpu), 1,
                                 PAGE_KERNEL);
 
         /*
@@ -1323,7 +1323,7 @@ void enable_sep_cpu(void)
 
         tss->x86_tss.ss1 = __KERNEL_CS;
         wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0);
-        wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1), 0);
+        wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0);
         wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
 
         put_cpu();
@@ -1440,7 +1440,7 @@ void syscall_init(void)
          * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
          */
         wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
-        wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1));
+        wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1));
         wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
 #else
         wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
@@ -1655,7 +1655,7 @@ void cpu_init(void)
          */
         set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
         load_TR_desc();
-        load_sp0((unsigned long)(cpu_SYSENTER_stack(cpu) + 1));
+        load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1));
 
         load_mm_ldt(&init_mm);
 
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index bbd6d986e2d0..1dd3f533d78c 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -43,9 +43,9 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task,
         return true;
 }
 
-bool in_sysenter_stack(unsigned long *stack, struct stack_info *info)
+bool in_entry_stack(unsigned long *stack, struct stack_info *info)
 {
-        struct SYSENTER_stack *ss = cpu_SYSENTER_stack(smp_processor_id());
+        struct entry_stack *ss = cpu_entry_stack(smp_processor_id());
 
         void *begin = ss;
         void *end = ss + 1;
@@ -53,7 +53,7 @@ bool in_sysenter_stack(unsigned long *stack, struct stack_info *info)
         if ((void *)stack < begin || (void *)stack >= end)
                 return false;
 
-        info->type      = STACK_TYPE_SYSENTER;
+        info->type      = STACK_TYPE_ENTRY;
         info->begin     = begin;
         info->end       = end;
         info->next_sp   = NULL;
@@ -111,13 +111,13 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
          * - task stack
          * - interrupt stack
          * - HW exception stacks (double fault, nmi, debug, mce)
-         * - SYSENTER stack
+         * - entry stack
          *
          * x86-32 can have up to four stacks:
          * - task stack
          * - softirq stack
          * - hardirq stack
-         * - SYSENTER stack
+         * - entry stack
          */
         for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
                 const char *stack_name;
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 5ff13a6b3680..04170f63e3a1 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -26,8 +26,8 @@ const char *stack_type_name(enum stack_type type)
         if (type == STACK_TYPE_SOFTIRQ)
                 return "SOFTIRQ";
 
-        if (type == STACK_TYPE_SYSENTER)
-                return "SYSENTER";
+        if (type == STACK_TYPE_ENTRY)
+                return "ENTRY_TRAMPOLINE";
 
         return NULL;
 }
@@ -96,7 +96,7 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
         if (task != current)
                 goto unknown;
 
-        if (in_sysenter_stack(stack, info))
+        if (in_entry_stack(stack, info))
                 goto recursion_check;
 
         if (in_hardirq_stack(stack, info))
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index abc828f8c297..563e28d14f2c 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -37,8 +37,14 @@ const char *stack_type_name(enum stack_type type)
         if (type == STACK_TYPE_IRQ)
                 return "IRQ";
 
-        if (type == STACK_TYPE_SYSENTER)
-                return "SYSENTER";
+        if (type == STACK_TYPE_ENTRY) {
+                /*
+                 * On 64-bit, we have a generic entry stack that we
+                 * use for all the kernel entry points, including
+                 * SYSENTER.
+                 */
+                return "ENTRY_TRAMPOLINE";
+        }
 
         if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
                 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
@@ -118,7 +124,7 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
         if (in_irq_stack(stack, info))
                 goto recursion_check;
 
-        if (in_sysenter_stack(stack, info))
+        if (in_entry_stack(stack, info))
                 goto recursion_check;
 
         goto unknown;