Re: [patch part-II V2 04/13] x86/entry/64: Trace irqflags unconditionally as ON when returning to user space

Alexandre Chartre
2020-03-10T10:26:36Z

On 3/8/20 11:24 PM, Thomas Gleixner wrote:
> User space cannot longer disable interrupts so trace return to user space
> unconditionally as IRQS_ON.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> V2: Cover 32bit as well
> ---
> arch/x86/entry/entry_32.S | 2 +-
> arch/x86/entry/entry_64.S | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>

Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>

alex.

> --- a/arch/x86/entry/entry_32.S
> +++ b/arch/x86/entry/entry_32.S
> @@ -1088,7 +1088,7 @@ SYM_FUNC_START(entry_INT80_32)
> STACKLEAK_ERASE
>
> restore_all:
> - TRACE_IRQS_IRET
> + TRACE_IRQS_ON
> SWITCH_TO_ENTRY_STACK
> CHECK_AND_APPLY_ESPFIX
>
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -174,7 +174,7 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_h
> movq %rsp, %rsi
> call do_syscall_64 /* returns with IRQs disabled */
>
> - TRACE_IRQS_IRETQ /* we're about to change IF */
> + TRACE_IRQS_ON /* return enables interrupts */
>
> /*
> * Try to use SYSRET instead of IRET if we're returning to
> @@ -619,7 +619,7 @@ SYM_CODE_START_LOCAL(common_interrupt)
> .Lretint_user:
> mov %rsp,%rdi
> call prepare_exit_to_usermode
> - TRACE_IRQS_IRETQ
> + TRACE_IRQS_ON
>
> SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL)
> #ifdef CONFIG_DEBUG_ENTRY
>