On 2019-01-03 11:08, Janosch Frank wrote:
> We need to properly implement interrupt handling for SCLP, because on
> z/VM and LPAR SCLP calls are not synchronous!
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> lib/s390x/asm/arch_def.h | 1 +
> lib/s390x/asm/interrupt.h | 2 ++
> lib/s390x/interrupt.c | 12 ++++++++++--
> lib/s390x/sclp-console.c | 2 ++
> lib/s390x/sclp.c | 39 +++++++++++++++++++++++++++++++++++++--
> lib/s390x/sclp.h | 3 +++
> 6 files changed, 55 insertions(+), 4 deletions(-)
[...]
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 7f556e5..817c692 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -14,6 +14,7 @@
> #include <asm/page.h>
> #include <asm/arch_def.h>
> #include <asm/interrupt.h>
> +#include <asm/barrier.h>
> #include "sclp.h"
> #include <alloc_phys.h>
>
> @@ -24,6 +25,7 @@ static uint64_t max_ram_size;
> static uint64_t ram_size;
>
> char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> +static volatile bool sclp_busy;
>
> static void mem_init(phys_addr_t mem_end)
> {
> @@ -32,17 +34,48 @@ static void mem_init(phys_addr_t mem_end)
> phys_alloc_init(freemem_start, mem_end - freemem_start);
> }
>
> +static void sclp_setup_int(void)
> +{
> + uint64_t mask;
> +
> + ctl_set_bit(0, 9);
> +
> + mask = extract_psw_mask();
> + mask |= PSW_MASK_EXT;
> + load_psw_mask(mask);
> +}
> +
> +void sclp_handle_ext(void)
> +{
> + ctl_clear_bit(0, 9);
> + sclp_busy = false;
> +}
> +
> +void sclp_wait_busy(void)
> +{
> + while (sclp_busy)
> + mb();
> +}
> +
> +void sclp_mark_busy(void)
> +{
> + sclp_busy = true;
> +}
> +
> static void sclp_read_scp_info(ReadInfo *ri, int length)
> {
> unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED,
> SCLP_CMDW_READ_SCP_INFO };
> - int i;
> + int i, cc;
>
> for (i = 0; i < ARRAY_SIZE(commands); i++) {
> memset(&ri->h, 0, sizeof(ri->h));
> ri->h.length = length;
>
> - if (sclp_service_call(commands[i], ri))
> + sclp_mark_busy();
> + cc = sclp_service_call(commands[i], ri);
> + sclp_wait_busy();
You already do the sclp_wait_busy() in sclp_service_call now, so I think
you don't need the sclp_wait_busy() here anymore?
Also, what about moving the sclp_mark_busy() calls to the beginning of
sclp_service_call() instead?
> + if (cc)
> break;
> if (ri->h.response_code == SCLP_RC_NORMAL_READ_COMPLETION)
> return;
> @@ -57,12 +90,14 @@ int sclp_service_call(unsigned int command, void *sccb)
> {
> int cc;
>
> + sclp_setup_int();
> asm volatile(
> " .insn rre,0xb2200000,%1,%2\n" /* servc %1,%2 */
> " ipm %0\n"
> " srl %0,28"
> : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
> : "cc", "memory");
> + sclp_wait_busy();
> if (cc == 3)
> return -1;
> if (cc == 2)
Thomas
