[PATCH 02/39] x86/entry/32: Rename TSS_sysenter_sp0 to TSS_entry2task_stack

From: Joerg Roedel
Date: Wed Jul 18 2018 - 05:41:27 EST


From: Joerg Roedel <jroedel@xxxxxxx>

The stack address doesn't need to be stored in tss.sp0 if
we switch manually like on sysenter. Rename the offset so
that it still makes sense when we change its location.

We will also use this stack for all kernel-entry points, not
just sysenter. Reflect that and the fact that it is the
offset to the task-stack location in the name as well.

Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/entry/entry_32.S | 2 +-
arch/x86/kernel/asm-offsets_32.c | 5 +++--
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index c371bfe..39f711a 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -412,7 +412,7 @@ ENTRY(xen_sysenter_target)
* 0(%ebp) arg6
*/
ENTRY(entry_SYSENTER_32)
- movl TSS_sysenter_sp0(%esp), %esp
+ movl TSS_entry2task_stack(%esp), %esp
.Lsysenter_past_esp:
pushl $__USER_DS /* pt_regs->ss */
pushl %ebp /* pt_regs->sp (stashed in bp) */
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index a4a3be3..15b3f45 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -46,8 +46,9 @@ void foo(void)
OFFSET(saved_context_gdt_desc, saved_context, gdt_desc);
BLANK();

- /* Offset from the sysenter stack to tss.sp0 */
- DEFINE(TSS_sysenter_sp0, offsetof(struct cpu_entry_area, tss.x86_tss.sp0) -
+ /* Offset from the entry stack to task stack stored in TSS */
+ DEFINE(TSS_entry2task_stack,
+ offsetof(struct cpu_entry_area, tss.x86_tss.sp0) -
offsetofend(struct cpu_entry_area, entry_stack_page.stack));

#ifdef CONFIG_STACKPROTECTOR
--
2.7.4