[patch 4/8] x86/entry: Move irq tracing on syscall entry to C-code

Thomas Gleixner
2020-02-25T23:30:03Z

Now that the C entry points are safe, move the irq flags tracing code into
the entry helper.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/common.c | 5 +++++
arch/x86/entry/entry_32.S | 12 ------------
arch/x86/entry/entry_64.S | 2 --
arch/x86/entry/entry_64_compat.S | 18 ------------------
4 files changed, 5 insertions(+), 32 deletions(-)

--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -57,6 +57,11 @@ static inline void enter_from_user_mode(
*/
static __always_inline void syscall_entry_fixups(void)
{
+ /*
+ * Usermode is traced as interrupts enabled, but the syscall entry
+ * mechanisms disable interrupts. Tell the tracer.
+ */
+ trace_hardirqs_off();
enter_from_user_mode();
local_irq_enable();
}
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -960,12 +960,6 @@ SYM_FUNC_START(entry_SYSENTER_32)
jnz .Lsysenter_fix_flags
.Lsysenter_flags_fixed:

- /*
- * User mode is traced as though IRQs are on, and SYSENTER
- * turned them off.
- */
- TRACE_IRQS_OFF
-
movl %esp, %eax
call do_fast_syscall_32
/* XEN PV guests always use IRET path */
@@ -1075,12 +1069,6 @@ SYM_FUNC_START(entry_INT80_32)

SAVE_ALL pt_regs_ax=$-ENOSYS switch_stacks=1 /* save rest */

- /*
- * User mode is traced as though IRQs are on, and the interrupt gate
- * turned them off.
- */
- TRACE_IRQS_OFF
-
movl %esp, %eax
call do_int80_syscall_32
.Lsyscall_32_done:
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -167,8 +167,6 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_h

PUSH_AND_CLEAR_REGS rax=$-ENOSYS

- TRACE_IRQS_OFF
-
/* IRQs are off. */
movq %rax, %rdi
movq %rsp, %rsi
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -129,12 +129,6 @@ SYM_FUNC_START(entry_SYSENTER_compat)
jnz .Lsysenter_fix_flags
.Lsysenter_flags_fixed:

- /*
- * User mode is traced as though IRQs are on, and SYSENTER
- * turned them off.
- */
- TRACE_IRQS_OFF
-
movq %rsp, %rdi
call do_fast_syscall_32
/* XEN PV guests always use IRET path */
@@ -247,12 +241,6 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_aft
pushq $0 /* pt_regs->r15 = 0 */
xorl %r15d, %r15d /* nospec r15 */

- /*
- * User mode is traced as though IRQs are on, and SYSENTER
- * turned them off.
- */
- TRACE_IRQS_OFF
-
movq %rsp, %rdi
call do_fast_syscall_32
/* XEN PV guests always use IRET path */
@@ -403,12 +391,6 @@ SYM_CODE_START(entry_INT80_compat)
xorl %r15d, %r15d /* nospec r15 */
cld

- /*
- * User mode is traced as though IRQs are on, and the interrupt
- * gate turned them off.
- */
- TRACE_IRQS_OFF
-
movq %rsp, %rdi
call do_int80_syscall_32
.Lsyscall_32_done: