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| author |   Petr Mladek <pmladek@suse.com> | 2020-02-24 13:13:31 +0100 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2020-05-19 15:51:16 +0200 |
| commit | 8c4e93c362ff114def211d4629b120af86eb1275 (patch) | |
| tree | e2568aa0d2327ceb10846e0273740820f6d6c4ac /kernel | |
| parent | Merge tag 'noinstr-lds-2020-05-19' into core/rcu (diff) | |
| download | wireguard-linux-8c4e93c362ff114def211d4629b120af86eb1275.tar.xz wireguard-linux-8c4e93c362ff114def211d4629b120af86eb1275.zip | |
printk: Prepare for nested printk_nmi_enter()
There is plenty of space in the printk_context variable. Reserve one byte
there for the NMI context to be on the safe side.
It should never overflow. The BUG_ON(in_nmi() == NMI_MASK) in nmi_enter()
will trigger much earlier.
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134100.681374113@linutronix.de
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/printk/internal.h | 8 | ||||
| -rw-r--r-- | kernel/printk/printk_safe.c | 4 |
2 files changed, 7 insertions, 5 deletions
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index b2b0f526f249..660f9a6bf73a 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -6,9 +6,11 @@ #ifdef CONFIG_PRINTK -#define PRINTK_SAFE_CONTEXT_MASK 0x3fffffff -#define PRINTK_NMI_DIRECT_CONTEXT_MASK 0x40000000 -#define PRINTK_NMI_CONTEXT_MASK 0x80000000 +#define PRINTK_SAFE_CONTEXT_MASK 0x007ffffff +#define PRINTK_NMI_DIRECT_CONTEXT_MASK 0x008000000 +#define PRINTK_NMI_CONTEXT_MASK 0xff0000000 + +#define PRINTK_NMI_CONTEXT_OFFSET 0x010000000 extern raw_spinlock_t logbuf_lock; diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index d9a659a686f3..e8791f206417 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -295,12 +295,12 @@ static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) void notrace printk_nmi_enter(void) { - this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK); + this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET); } void notrace printk_nmi_exit(void) { - this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK); + this_cpu_sub(printk_context, PRINTK_NMI_CONTEXT_OFFSET); } /* |