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-rw-r--r--arch/x86/kernel/asm-offsets_32.c9
-rw-r--r--arch/x86/kernel/process_32.c2
2 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index 15b3f45b69cd..82826f2275cc 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -46,9 +46,14 @@ void foo(void)
OFFSET(saved_context_gdt_desc, saved_context, gdt_desc);
BLANK();
- /* Offset from the entry stack to task stack stored in TSS */
+ /*
+ * Offset from the entry stack to task stack stored in TSS. Kernel entry
+ * happens on the per-cpu entry-stack, and the asm code switches to the
+ * task-stack pointer stored in x86_tss.sp1, which is a copy of
+ * task->thread.sp0 where entry code can find it.
+ */
DEFINE(TSS_entry2task_stack,
- offsetof(struct cpu_entry_area, tss.x86_tss.sp0) -
+ offsetof(struct cpu_entry_area, tss.x86_tss.sp1) -
offsetofend(struct cpu_entry_area, entry_stack_page.stack));
#ifdef CONFIG_STACKPROTECTOR
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 0ae659de21eb..ec62cc77388d 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -290,6 +290,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +
THREAD_SIZE);
+ /* SYSENTER reads the task-stack from tss.sp1 */
+ this_cpu_write(cpu_tss_rw.x86_tss.sp1, next_p->thread.sp0);
/*
* Restore %gs if needed (which is common)