Messages in this thread Patch in this message | | | Date | Wed, 27 May 2020 17:45:28 +0200 | From | Peter Zijlstra <> | Subject | [PATCH 1/6] x86/entry: Clarify irq_{enter,exit}_rcu() |
| |
Because:
irq_enter_rcu() includes lockdep_hardirq_enter() irq_exit_rcu() does *NOT* include lockdep_hardirq_exit()
Which resulted two 'stray' lockdep_hardirq_exit() calls in idtentry.h, and me spending a long time trying to find the matching enters.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/include/asm/idtentry.h | 2 -- kernel/softirq.c | 19 +++++++++++++------ 2 files changed, 13 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -206,7 +206,6 @@ __visible noinstr void func(struct pt_re kvm_set_cpu_l1tf_flush_l1d(); \ __##func (regs, (u8)error_code); \ irq_exit_rcu(); \ - lockdep_hardirq_exit(); \ instrumentation_end(); \ idtentry_exit_cond_rcu(regs, rcu_exit); \ } \ @@ -249,7 +248,6 @@ __visible noinstr void func(struct pt_re kvm_set_cpu_l1tf_flush_l1d(); \ run_on_irqstack_cond(__##func, regs, regs); \ irq_exit_rcu(); \ - lockdep_hardirq_exit(); \ instrumentation_end(); \ idtentry_exit_cond_rcu(regs, rcu_exit); \ } \ --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -404,12 +404,7 @@ static inline void tick_irq_exit(void) #endif } -/** - * irq_exit_rcu() - Exit an interrupt context without updating RCU - * - * Also processes softirqs if needed and possible. - */ -void irq_exit_rcu(void) +static inline void __irq_exit_rcu(void) { #ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED local_irq_disable(); @@ -425,6 +420,18 @@ void irq_exit_rcu(void) } /** + * irq_exit_rcu() - Exit an interrupt context without updating RCU + * + * Also processes softirqs if needed and possible. + */ +void irq_exit_rcu(void) +{ + __irq_exit_rcu(); + /* must be last! */ + lockdep_hardirq_exit(); +} + +/** * irq_exit - Exit an interrupt context, update RCU and lockdep * * Also processes softirqs if needed and possible.
| |