On 29/08/2019 14.14, Janosch Frank wrote:
> Testing SIGP emulation for the following order codes:
> * start
> * stop
> * restart
> * set prefix
> * store status
> * stop and store status
> * reset
> * initial reset
> * external call
> * emegergency call
>
> restart and set prefix are part of the library and needed to start
> other cpus.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> s390x/Makefile | 1 +
> s390x/smp.c | 242 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 243 insertions(+)
> create mode 100644 s390x/smp.c
>
> diff --git a/s390x/Makefile b/s390x/Makefile
> index d83dd0b..3744372 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -15,6 +15,7 @@ tests += $(TEST_DIR)/cpumodel.elf
> tests += $(TEST_DIR)/diag288.elf
> tests += $(TEST_DIR)/stsi.elf
> tests += $(TEST_DIR)/skrf.elf
> +tests += $(TEST_DIR)/smp.elf
> tests_binary = $(patsubst %.elf,%.bin,$(tests))
>
> all: directories test_cases test_cases_binary
> diff --git a/s390x/smp.c b/s390x/smp.c
> new file mode 100644
> index 0000000..9363cd2
> --- /dev/null
> +++ b/s390x/smp.c
> @@ -0,0 +1,242 @@
> +/*
> + * Tests sigp emulation
> + *
> + * Copyright 2019 IBM Corp.
> + *
> + * Authors:
> + * Janosch Frank <frankja@xxxxxxxxxxxxx>
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2.
> + */
> +#include <libcflat.h>
> +#include <asm/asm-offsets.h>
> +#include <asm/interrupt.h>
> +#include <asm/page.h>
> +#include <asm/facility.h>
> +#include <asm-generic/barrier.h>
> +#include <asm/sigp.h>
> +
> +#include <smp.h>
> +#include <alloc_page.h>
> +
> +static int t = 0;
Single letter variables that are used accross functions are a little bit
ugly. I'd maybe give this a better name, like "testflag" or something
similar?
> +static void cpu_loop(void)
> +{
> + for (;;) {}
> +}
> +
> +static void test_func(void)
> +{
> + t = 1;
I think I'd rather place a mb() here, just to be sure...?
> + cpu_loop();
> +}
> +
> +static void test_start(void)
> +{
> + struct psw psw;
> + psw.mask = extract_psw_mask();
> + psw.addr = (unsigned long)test_func;
> +
> + smp_cpu_setup(1, psw);
> + while (!t) {
> + mb();
> + }
> + report("start", 1);
> +}
> +
> +static void test_stop(void)
> +{
> + int i = 0;
> +
> + smp_cpu_stop(1);
> + /*
> + * The smp library waits for the CPU to shut down, but let's
> + * also do it here, so we don't rely on the library
> + * implementation
> + */
> + while (!smp_cpu_stopped(1)) {}
> + t = 0;
> + /* Let's leave some time for cpu #2 to change t */
CPU #2 ? Where? Why?
> + for (; i < 0x100000; i++) {}
I'm pretty sure the compiler optimizes empty loops away.
> + report("stop", !t);
> +}
> +
> +static void test_stop_store_status(void)
> +{
> + struct cpu *cpu = smp_cpu_from_addr(1);
> + struct lowcore *lc = (void *)0x0;
Do you want to erase the values in the save area before calling the
"store_status"? ... just to be sure that we don't see old values there?
> + smp_cpu_stop_store_status(1);
> + mb();
> + report("stop store status",
> + lc->prefix_sa == (uint32_t)(uintptr_t)cpu->lowcore);
That confused me. Why does the prefix_sa of the lowcore of CPU 0 match
the prefix of CPU 1 ? I'd rather expect cpu->lowcore->prefix_sa to
contain this value?
Maybe you could also check that at least the stack pointer GPR is != 0
in the save area?
> +}
> +
> +static void test_store_status(void)
> +{
> + struct cpu_status *status = alloc_pages(0);
> + uint32_t r;
> +
> + report_prefix_push("status");
> + memset(status, 0, PAGE_SIZE);
> +
> + smp_cpu_restart(1);
> + sigp(1, SIGP_STORE_STATUS_AT_ADDRESS, (uintptr_t)status, &r);
> + report("not stopped", r == SIGP_STATUS_INCORRECT_STATE);
Maybe also check that the save are is still 0?
> + memset(status, 0, PAGE_SIZE);
> + smp_cpu_stop(1);
> + sigp(1, SIGP_STORE_STATUS_AT_ADDRESS, (uintptr_t)status, NULL);
> + while (!status->prefix) {}
status->prefix is not marked as volatile, so please put a "mb()" into
the curly braces here.
> + report("store status", 1);
> + free_pages(status, PAGE_SIZE);
> + report_prefix_pop();
> +}
> +
> +static void ecall(void)
> +{
> + unsigned long mask;
> + struct lowcore *lc = (void *)0x0;
> +
> + ctl_set_bit(0, 13);
> + mask = extract_psw_mask();
> + mask |= PSW_MASK_EXT;
> + load_psw_mask(mask);
> + expect_ext_int();
I think you should move the expect_ext_int() before the enablement of
the interrupt, to avoid races?
> + t = 1;
> + while (lc->ext_int_code != 0x1202) {mb();}
Spaces around the "mb();", please.
> + report("ecall", 1);
> + t = 1;
> +}
> +
> +static void test_ecall(void)
> +{
> + struct psw psw;
> + psw.mask = extract_psw_mask();
> + psw.addr = (unsigned long)ecall;
> +
> + report_prefix_push("ecall");
> + t = 0;
> + smp_cpu_destroy(1);
> +
> + mb();
Why this mb() here?
> + smp_cpu_setup(1, psw);
> + while (!t) {
> + mb();
> + }
> + t = 0;
> + sigp(1, SIGP_EXTERNAL_CALL, 0, NULL);
> + while(!t) {mb();}
Spaces, please.
> + smp_cpu_stop(1);
> + report_prefix_pop();
> +}
> +
> +static void emcall(void)
> +{
> + unsigned long mask;
> + struct lowcore *lc = (void *)0x0;
> +
> + ctl_set_bit(0, 14);
> + mask = extract_psw_mask();
> + mask |= PSW_MASK_EXT;
> + load_psw_mask(mask);
> + expect_ext_int();
I think you should move the expect_ext_int() before the enablement of
the interrupt, to avoid races?
> + t = 1;
> + while (lc->ext_int_code != 0x1201) {mb();}
Spaces.
> + report("ecall", 1);
> + t = 1;
> +}
> +
> +static void test_emcall(void)
> +{
> + struct psw psw;
> + psw.mask = extract_psw_mask();
> + psw.addr = (unsigned long)emcall;
> +
> + report_prefix_push("emcall");
> + t = 0;
> + smp_cpu_destroy(1);
> +
> + mb();
> + smp_cpu_setup(1, psw);
> + while (!t) {
> + mb();
> + }
> + t = 0;
> + sigp(1, SIGP_EMERGENCY_SIGNAL, 0, NULL);
> + while(!t) {mb();}
Spaces.
> + smp_cpu_stop(1);
> + report_prefix_pop();
> +}
> +
> +static void test_reset_initial(void)
> +{
> + struct cpu_status *status = alloc_pages(0);
> + struct psw psw;
> +
> + psw.mask = extract_psw_mask();
> + psw.addr = (unsigned long)test_func;
> +
> + report_prefix_push("reset initial");
> + smp_cpu_setup(1, psw);
> +
> + sigp_retry(1, SIGP_INITIAL_CPU_RESET, 0, NULL);
> + sigp(1, SIGP_STORE_STATUS_AT_ADDRESS, (uintptr_t)status, NULL);
> +
> + report_prefix_push("clear");
> + report("psw", !status->psw.mask && !status->psw.addr);
> + report("prefix", !status->prefix);
> + report("fpc", !status->fpc);
> + report("cpu timer", !status->cputm);
> + report("todpr", !status->todpr);
> + report_prefix_pop();
> +
> + report_prefix_push("initialized");
> + report("cr0 == 0xE0", status->crs[0] == 0xE0UL);
> + report("cr14 == 0xC2000000", status->crs[14] == 0xC2000000UL);
> + report_prefix_pop();
> +
> + report("cpu stopped", smp_cpu_stopped(1));
> + free_pages(status, PAGE_SIZE);
> + report_prefix_pop();
> +}
> +
> +static void test_reset(void)
> +{
> + struct psw psw;
> +
> + psw.mask = extract_psw_mask();
> + psw.addr = (unsigned long)test_func;
> +
> + report_prefix_push("cpu reset");
> + smp_cpu_setup(1, psw);
> +
> + sigp_retry(1, SIGP_CPU_RESET, 0, NULL);
> + report("cpu stopped", smp_cpu_stopped(1));
> + report_prefix_pop();
> +}
> +
> +int main(void)
> +{
> + report_prefix_push("smp");
> +
> + if (smp_query_num_cpus() == 1) {
> + report_abort("need at least 2 cpus for this test");
> + goto done;
> + }
> +
> + test_start();
> + test_stop();
> + test_stop_store_status();
> + test_store_status();
> + test_ecall();
> + test_emcall();
> + test_reset();
> + test_reset_initial();
> +
> +done:
> + report_prefix_pop();
> + return report_summary();
> +}
>
Thomas
