On 05.12.18 16:39, 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 | 29 +++++++++--------------------
> lib/s390x/sclp.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> lib/s390x/sclp.h | 4 +++-
> 7 files changed, 68 insertions(+), 24 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..de15d9e 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);
> + 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();
> }
>
> void exit(int code)
> diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
> index deacbde..13ab03d 100644
> --- a/lib/s390x/sclp-console.c
> +++ b/lib/s390x/sclp-console.c
> @@ -13,30 +13,13 @@
> #include <asm/page.h>
> #include "sclp.h"
>
> -char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> -
> -/* Perform service call. Return 0 on success, non-zero otherwise. */
> -int sclp_service_call(unsigned int command, void *sccb)
> -{
> - int cc;
> -
> - 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");
> - if (cc == 3)
> - return -1;
> - if (cc == 2)
> - return -1;
> - return 0;
> -}
> -
> static void sclp_set_write_mask(void)
> {
> WriteEventMask *sccb = (void *)_sccb;
>
> + while (sclp_busy)
> + /* Wait for SCLP request to complete */;
should we use barrier(); here to make this clearer?
> + sclp_busy = true;
> sccb->h.length = sizeof(WriteEventMask);
> sccb->mask_length = sizeof(unsigned int);
> sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
> @@ -57,6 +40,9 @@ void sclp_print(const char *str)
> int len = strlen(str);
> WriteEventData *sccb = (void *)_sccb;
>
> + while (sclp_busy)
> + /* Wait for SCLP request to complete */;
dito
(I guess do not we need barriers between setting sclp_busy and testing
it, because we're using volatile and we don't have multi-threading
messing with the value)
> + sclp_busy = true;
> sccb->h.length = sizeof(WriteEventData) + len;
> sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
> sccb->ebh.length = sizeof(EventBufferHeader) + len;
> @@ -65,4 +51,7 @@ void sclp_print(const char *str)
> memcpy(sccb->data, str, len);
>
> sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
> + while (sclp_busy)
> + /* Wait for SCLP request to complete */;
dito
> +
> }
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 1d4a010..cd0e5e5 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -23,6 +23,9 @@ static uint64_t storage_increment_size;
> static uint64_t max_ram_size;
> static uint64_t ram_size;
>
> +char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> +volatile bool sclp_busy = false;
false should be the default value already.
> +
> static void mem_init(phys_addr_t mem_end)
> {
> phys_addr_t freemem_start = (phys_addr_t)&stacktop;
> @@ -30,6 +33,42 @@ 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)
> +{
Error out if !sclp_busy but we get an interrupt?
> + ctl_clear_bit(0, 9);
> + sclp_busy = false;
> +}
> +
> +/* Perform service call. Return 0 on success, non-zero otherwise. */
> +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");
> + if (cc == 3)
> + return -1;
> + if (cc == 2)
> + return -1;
> + return 0;
> +}
Guess moving that (including _sccb) could also be a separate patch ;)
> +
> void sclp_memory_setup(void)
> {
> ReadInfo *ri = (void *)_sccb;
> @@ -37,7 +76,10 @@ void sclp_memory_setup(void)
> int cc;
>
> ri->h.length = SCCB_SIZE;
> + sclp_busy = true;
> sclp_service_call(SCLP_CMDW_READ_SCP_INFO_FORCED, ri);
> + while (sclp_busy)
> + /* Wait for SCLP request to complete */;
Should we factor that out into something like
sclp_start_request()
{
sclp_busy = true;
}
sclp_wait_response()
{
while (sclp_busy)
barrier();
}
>
> /* calculate the storage increment size */
> rnsize = ri->rnsize;
> diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
> index e008932..a91aad1 100644
> --- a/lib/s390x/sclp.h
> +++ b/lib/s390x/sclp.h
> @@ -207,9 +207,11 @@ typedef struct ReadEventData {
> uint32_t mask;
> } __attribute__((packed)) ReadEventData;
>
> +extern char _sccb[];
> +volatile bool sclp_busy;
> +void sclp_handle_ext(void);
> void sclp_console_setup(void);
> void sclp_print(const char *str);
> -extern char _sccb[];
> int sclp_service_call(unsigned int command, void *sccb);
> void sclp_memory_setup(void);
>
>
--
Thanks,
David / dhildenb
