On 03.01.19 11:08, Janosch Frank wrote:
> With smp CPUs have to compete for sclp. Let's add some locking, so
> they execute sclp calls in an orderly fashion.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> lib/s390x/sclp.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 817c692..947a533 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -15,6 +15,7 @@
> #include <asm/arch_def.h>
> #include <asm/interrupt.h>
> #include <asm/barrier.h>
> +#include <asm/spinlock.h>
> #include "sclp.h"
> #include <alloc_phys.h>
>
> @@ -26,6 +27,7 @@ static uint64_t ram_size;
>
> char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> static volatile bool sclp_busy;
> +static struct spinlock sclp_lock;
>
> static void mem_init(phys_addr_t mem_end)
> {
> @@ -48,7 +50,9 @@ static void sclp_setup_int(void)
> void sclp_handle_ext(void)
> {
> ctl_clear_bit(0, 9);
> + spin_lock(&sclp_lock);
> sclp_busy = false;
> + spin_unlock(&sclp_lock);
> }
>
> void sclp_wait_busy(void)
> @@ -59,7 +63,19 @@ void sclp_wait_busy(void)
>
> void sclp_mark_busy(void)
> {
> + /*
> + * With multiple CPUs we might need to wait for another CPU's
> + * request before grabbing the busy indication.
> + */
> +retry_wait:
> + sclp_wait_busy();
> + spin_lock(&sclp_lock);
> + if (sclp_busy) {
> + spin_unlock(&sclp_lock);
> + goto retry_wait;
> + }
> sclp_busy = true;
> + spin_unlock(&sclp_lock);
> }
>
> static void sclp_read_scp_info(ReadInfo *ri, int length)
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
