On 2018-12-18 10:26, 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/io.c | 2 +-
> lib/s390x/sclp-console.c | 3 +++
> lib/s390x/sclp.c | 39 +++++++++++++++++++++++++++++++++++++--
> lib/s390x/sclp.h | 4 ++++
> 7 files changed, 58 insertions(+), 5 deletions(-)
>
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index d2d6e02..27c6b85 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -33,6 +33,7 @@ struct psw {
> uint64_t addr;
> };
>
> +#define PSW_MASK_EXT 0x0100000000000000UL
> #define PSW_MASK_DAT 0x0400000000000000UL
> #define PSW_MASK_PSTATE 0x0001000000000000UL
>
> diff --git a/lib/s390x/asm/interrupt.h b/lib/s390x/asm/interrupt.h
> index 013709f..f485e96 100644
> --- a/lib/s390x/asm/interrupt.h
> +++ b/lib/s390x/asm/interrupt.h
> @@ -11,6 +11,8 @@
> #define _ASMS390X_IRQ_H_
> #include <asm/arch_def.h>
>
> +#define EXT_IRQ_SERVICE_SIG 0x2401
> +
> void handle_pgm_int(void);
> void handle_ext_int(void);
> void handle_mcck_int(void);
> diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
> index cf0a794..7118577 100644
> --- a/lib/s390x/interrupt.c
> +++ b/lib/s390x/interrupt.c
> @@ -12,6 +12,7 @@
> #include <libcflat.h>
> #include <asm/interrupt.h>
> #include <asm/barrier.h>
> +#include <sclp.h>
>
> static bool pgm_int_expected;
> static struct lowcore *lc;
> @@ -107,8 +108,15 @@ void handle_pgm_int(void)
>
> void handle_ext_int(void)
> {
> - report_abort("Unexpected external call interrupt: at %#lx",
> - lc->ext_old_psw.addr);
> + if (lc->ext_int_code != EXT_IRQ_SERVICE_SIG)
> + report_abort("Unexpected external call interrupt: at %#lx",
> + lc->ext_old_psw.addr);
Since we're (mostly) using kernel coding style, could you please add
curly braces around that report_abort() statement, too?
> + else {
> + lc->ext_old_psw.mask &= ~PSW_MASK_EXT;
> + lc->sw_int_cr0 &= ~(1UL << 9);
> + sclp_handle_ext();
> + lc->ext_int_code = 0;
> + }
> }
>
> void handle_mcck_int(void)
> diff --git a/lib/s390x/io.c b/lib/s390x/io.c
> index 05a0765..7294165 100644
> --- a/lib/s390x/io.c
> +++ b/lib/s390x/io.c
> @@ -45,8 +45,8 @@ void setup(void)
> {
> setup_args_progname(ipl_args);
> setup_facilities();
> - sclp_console_setup();
> sclp_memory_setup();
> + sclp_console_setup();
Why this change?
> }
>
> void exit(int code)
> diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
> index bc01f41..2016ea0 100644
> --- a/lib/s390x/sclp-console.c
> +++ b/lib/s390x/sclp-console.c
> @@ -17,6 +17,7 @@ static void sclp_set_write_mask(void)
> {
> WriteEventMask *sccb = (void *)_sccb;
>
> + sclp_mark_busy();
> sccb->h.length = sizeof(WriteEventMask);
> sccb->mask_length = sizeof(unsigned int);
> sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
> @@ -37,6 +38,7 @@ void sclp_print(const char *str)
> int len = strlen(str);
> WriteEventData *sccb = (void *)_sccb;
>
> + sclp_mark_busy();
> sccb->h.length = sizeof(WriteEventData) + len;
> sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
> sccb->ebh.length = sizeof(EventBufferHeader) + len;
> @@ -45,4 +47,5 @@ void sclp_print(const char *str)
> memcpy(sccb->data, str, len);
>
> sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
> + sclp_wait_busy();
> }
I wonder whether it would be easier / less error prone if we'd do the
sclp_mark_busy() at the start of sclp_service_call() and then simply
always sclp_wait_busy() at the end of sclp_service_call() ?
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 7f556e5..eed51ef 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)));
> +volatile bool sclp_busy;
>
> static void mem_init(phys_addr_t mem_end)
> {
> @@ -32,17 +34,49 @@ 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)
> +{
> + mb();
> + while (sclp_busy)
> + /* Wait for SCLP request to complete */;
> +}
I'd maybe rather write this as:
while (sclp_busy)
mb();
... but it should not really matter.
Thomas
