[PATCH 03/21] x86/irq: Remove an old outdated comment about context tracking races

From: Ingo Molnar
Date: Mon Nov 27 2017 - 06:03:15 EST


From: Andy Lutomirski <luto@xxxxxxxxxx>

That race has been fixed and code cleaned up for a while now.

Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/12e75976dbbb7ece2b0a64238f1d3892dfed1e16.1511497875.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/irq.c | 12 ------------
1 file changed, 12 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 49cfd9fe7589..68e1867cca80 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -219,18 +219,6 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;

- /*
- * NB: Unlike exception entries, IRQ entries do not reliably
- * handle context tracking in the low-level entry code. This is
- * because syscall entries execute briefly with IRQs on before
- * updating context tracking state, so we can take an IRQ from
- * kernel mode with CONTEXT_USER. The low-level entry code only
- * updates the context if we came from user mode, so we won't
- * switch to CONTEXT_KERNEL. We'll fix that once the syscall
- * code is cleaned up enough that we can cleanly defer enabling
- * IRQs.
- */
-
entering_irq();

/* entering_irq() tells RCU that we're not quiescent. Check it. */
--
2.14.1