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| author |   Vasily Gorbik <gor@linux.ibm.com> | 2020-10-13 22:35:27 +0200 |
|---|---|---|
| committer |   Heiko Carstens <hca@linux.ibm.com> | 2020-11-09 11:20:58 +0100 |
| commit | 85cde0192a983b227341be11af2c3625d39bc374 (patch) | |
| tree | 5f2ad53b6f1cc90058350ebe04f7e342b509ca09 | |
| parent | s390/head: set io/ext handlers to disabled wait (diff) | |
| download | linux-dev-85cde0192a983b227341be11af2c3625d39bc374.tar.xz linux-dev-85cde0192a983b227341be11af2c3625d39bc374.zip | |
s390/udelay: make it work for the early code
Currently udelay relies on working EXT interrupts handler, which is not
the case during early startup. In such cases udelay_simple() has to be
used instead.
To avoid mistakes of calling udelay too early, which could happen from
the common code as well - make udelay work for the early code by
introducing static branch and redirecting all udelay calls to
udelay_simple until EXT interrupts handler is fully initialized and
async stack is allocated.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
| -rw-r--r-- | arch/s390/include/asm/delay.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/setup.c | 1 | ||||
| -rw-r--r-- | arch/s390/lib/delay.c | 13 |
3 files changed, 15 insertions, 0 deletions
diff --git a/arch/s390/include/asm/delay.h b/arch/s390/include/asm/delay.h index 898323fd93d2..4a08379cd1eb 100644 --- a/arch/s390/include/asm/delay.h +++ b/arch/s390/include/asm/delay.h @@ -13,6 +13,7 @@ #ifndef _S390_DELAY_H #define _S390_DELAY_H +void udelay_enable(void); void __ndelay(unsigned long long nsecs); void __udelay(unsigned long long usecs); void udelay_simple(unsigned long long usecs); diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 4d843e64496f..2076415aee4b 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -336,6 +336,7 @@ int __init arch_early_irq_init(void) if (!stack) panic("Couldn't allocate async stack"); S390_lowcore.async_stack = stack + STACK_INIT_OFFSET; + udelay_enable(); return 0; } diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index daca7bad66de..1734a5c19834 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -13,11 +13,19 @@ #include <linux/export.h> #include <linux/irqflags.h> #include <linux/interrupt.h> +#include <linux/jump_label.h> #include <linux/irq.h> #include <asm/vtimer.h> #include <asm/div64.h> #include <asm/idle.h> +static DEFINE_STATIC_KEY_FALSE(udelay_ready); + +void __init udelay_enable(void) +{ + static_branch_enable(&udelay_ready); +} + void __delay(unsigned long loops) { /* @@ -77,6 +85,11 @@ void __udelay(unsigned long long usecs) { unsigned long flags; + if (!static_branch_likely(&udelay_ready)) { + udelay_simple(usecs); + return; + } + preempt_disable(); local_irq_save(flags); if (in_irq()) { |