On Fri, 11 Dec 2020 05:00:33 -0500
Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
> Let's only read the information once and pass a pointer to it instead
> of calling sclp multiple times.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
> ---
> lib/s390x/io.c | 1 +
> lib/s390x/sclp.c | 31 +++++++++++++++++++++++++------
> lib/s390x/sclp.h | 3 +++
> lib/s390x/smp.c | 27 +++++++++++----------------
> 4 files changed, 40 insertions(+), 22 deletions(-)
>
> diff --git a/lib/s390x/io.c b/lib/s390x/io.c
> index 1ff0589..6a1da63 100644
> --- a/lib/s390x/io.c
> +++ b/lib/s390x/io.c
> @@ -34,6 +34,7 @@ void setup(void)
> {
> setup_args_progname(ipl_args);
> setup_facilities();
> + sclp_read_info();
> sclp_console_setup();
> sclp_memory_setup();
> smp_setup();
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 08a4813..bf1d9c0 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -23,6 +23,8 @@ extern unsigned long stacktop;
> static uint64_t storage_increment_size;
> static uint64_t max_ram_size;
> static uint64_t ram_size;
> +char _read_info[PAGE_SIZE] __attribute__((__aligned__(4096)));
why not __aligned__((PAGE_SIZE)) ?
> +static ReadInfo *read_info;
I wonder if a union would be cleaner? although later on you check if
the pointer is NULL to see if the information is there, so I guess it
can stay
>
> char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
> static volatile bool sclp_busy;
> @@ -108,6 +110,24 @@ static void sclp_read_scp_info(ReadInfo *ri, int
> length) report_abort("READ_SCP_INFO failed");
> }
>
> +void sclp_read_info(void)
> +{
> + sclp_read_scp_info((void *)_read_info, SCCB_SIZE);
> + read_info = (ReadInfo *)_read_info;
> +}
> +
> +int sclp_get_cpu_num(void)
> +{
> + assert(read_info);
> + return read_info->entries_cpu;
> +}
> +
> +CPUEntry *sclp_get_cpu_entries(void)
> +{
> + assert(read_info);
> + return (void *)read_info + read_info->offset_cpu;
are you doing arithmetic on a void pointer? please don't, it's ugly and
against the specs. moreover you do have a char pointer...
why not:
return (CPUEntry *)(_read_info + read_info->offset_cpu);
> +}
> +
> /* Perform service call. Return 0 on success, non-zero otherwise. */
> int sclp_service_call(unsigned int command, void *sccb)
> {
> @@ -125,23 +145,22 @@ int sclp_service_call(unsigned int command,
> void *sccb)
> void sclp_memory_setup(void)
> {
> - ReadInfo *ri = (void *)_sccb;
> uint64_t rnmax, rnsize;
> int cc;
>
> - sclp_read_scp_info(ri, SCCB_SIZE);
> + assert(read_info);
>
> /* calculate the storage increment size */
> - rnsize = ri->rnsize;
> + rnsize = read_info->rnsize;
> if (!rnsize) {
> - rnsize = ri->rnsize2;
> + rnsize = read_info->rnsize2;
> }
> storage_increment_size = rnsize << 20;
>
> /* calculate the maximum memory size */
> - rnmax = ri->rnmax;
> + rnmax = read_info->rnmax;
> if (!rnmax) {
> - rnmax = ri->rnmax2;
> + rnmax = read_info->rnmax2;
> }
> max_ram_size = rnmax * storage_increment_size;
>
> diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
> index 9a6aad0..acd86d5 100644
> --- a/lib/s390x/sclp.h
> +++ b/lib/s390x/sclp.h
> @@ -268,6 +268,9 @@ void sclp_wait_busy(void);
> void sclp_mark_busy(void);
> void sclp_console_setup(void);
> void sclp_print(const char *str);
> +void sclp_read_info(void);
> +int sclp_get_cpu_num(void);
> +CPUEntry *sclp_get_cpu_entries(void);
> int sclp_service_call(unsigned int command, void *sccb);
> void sclp_memory_setup(void);
> uint64_t get_ram_size(void);
> diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
> index c4f02dc..dfcfd28 100644
> --- a/lib/s390x/smp.c
> +++ b/lib/s390x/smp.c
> @@ -23,7 +23,6 @@
> #include "smp.h"
> #include "sclp.h"
>
> -static char cpu_info_buffer[PAGE_SIZE]
> __attribute__((__aligned__(4096))); static struct cpu *cpus;
> static struct cpu *cpu0;
> static struct spinlock lock;
> @@ -32,8 +31,7 @@ extern void smp_cpu_setup_state(void);
>
> int smp_query_num_cpus(void)
> {
> - struct ReadCpuInfo *info = (void *)cpu_info_buffer;
> - return info->nr_configured;
> + return sclp_get_cpu_num();
> }
>
> struct cpu *smp_cpu_from_addr(uint16_t addr)
> @@ -226,10 +224,10 @@ void smp_teardown(void)
> {
> int i = 0;
> uint16_t this_cpu = stap();
> - struct ReadCpuInfo *info = (void *)cpu_info_buffer;
> + int num = smp_query_num_cpus();
>
> spin_lock(&lock);
> - for (; i < info->nr_configured; i++) {
> + for (; i < num; i++) {
> if (cpus[i].active &&
> cpus[i].addr != this_cpu) {
> sigp_retry(cpus[i].addr, SIGP_STOP, 0, NULL);
> @@ -243,22 +241,19 @@ extern uint64_t *stackptr;
> void smp_setup(void)
> {
> int i = 0;
> + int num = smp_query_num_cpus();
> unsigned short cpu0_addr = stap();
> - struct ReadCpuInfo *info = (void *)cpu_info_buffer;
> + struct CPUEntry *entry = sclp_get_cpu_entries();
>
> spin_lock(&lock);
> - sclp_mark_busy();
> - info->h.length = PAGE_SIZE;
> - sclp_service_call(SCLP_READ_CPU_INFO, cpu_info_buffer);
> + if (num > 1)
> + printf("SMP: Initializing, found %d cpus\n", num);
>
> - if (smp_query_num_cpus() > 1)
> - printf("SMP: Initializing, found %d cpus\n",
> info->nr_configured); -
> - cpus = calloc(info->nr_configured, sizeof(cpus));
> - for (i = 0; i < info->nr_configured; i++) {
> - cpus[i].addr = info->entries[i].address;
> + cpus = calloc(num, sizeof(cpus));
> + for (i = 0; i < num; i++) {
> + cpus[i].addr = entry[i].address;
> cpus[i].active = false;
> - if (info->entries[i].address == cpu0_addr) {
> + if (entry[i].address == cpu0_addr) {
> cpu0 = &cpus[i];
> cpu0->stack = stackptr;
> cpu0->lowcore = (void *)0;
