x86/entry/64: Make cpu_entry_area.tss read-only

[thirdparty/kernel/stable.git] / arch / x86 / include / asm / switch_to.h

diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index 010cd6e4eafc6e0b7b4846018498b5fddb2fe824..9b6df68d8fd1eba26f3651faa5c8b8f4dcf223f1 100644 (file)
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_X86_SWITCH_TO_H
 #define _ASM_X86_SWITCH_TO_H
 
@@ -78,10 +79,10 @@ do {                                                                        \
 static inline void refresh_sysenter_cs(struct thread_struct *thread)
 {
        /* Only happens when SEP is enabled, no need to test "SEP"arately: */
-       if (unlikely(this_cpu_read(cpu_tss.x86_tss.ss1) == thread->sysenter_cs))
+       if (unlikely(this_cpu_read(cpu_tss_rw.x86_tss.ss1) == thread->sysenter_cs))
                return;
 
-       this_cpu_write(cpu_tss.x86_tss.ss1, thread->sysenter_cs);
+       this_cpu_write(cpu_tss_rw.x86_tss.ss1, thread->sysenter_cs);
        wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
 }
 #endif
@@ -89,10 +90,12 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread)
 /* This is used when switching tasks or entering/exiting vm86 mode. */
 static inline void update_sp0(struct task_struct *task)
 {
+       /* On x86_64, sp0 always points to the entry trampoline stack, which is constant: */
 #ifdef CONFIG_X86_32
        load_sp0(task->thread.sp0);
 #else
-       load_sp0(task_top_of_stack(task));
+       if (static_cpu_has(X86_FEATURE_XENPV))
+               load_sp0(task_top_of_stack(task));
 #endif
 }