On Mon, 31 Jan 2022 14:55:09 +0100
David Hildenbrand <david@xxxxxxxxxx> wrote:
> On 28.01.22 19:54, Claudio Imbrenda wrote:
> > Guarantee that the boot CPU has index 0. This simplifies the
> > implementation of tests that require multiple CPUs.
> >
> > Also fix a small bug in the allocation of the cpus array.
> >
> > Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> > Fixes: f77c0515 ("s390x: Add initial smp code")
> > Fixes: 52076a63 ("s390x: Consolidate sclp read info")
> > ---
> > lib/s390x/smp.c | 16 ++++++++--------
> > 1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
> > index 64c647ec..01f513f0 100644
> > --- a/lib/s390x/smp.c
> > +++ b/lib/s390x/smp.c
> > @@ -25,7 +25,6 @@
> > #include "sclp.h"
> >
> > static struct cpu *cpus;
> > -static struct cpu *cpu0;
> > static struct spinlock lock;
> >
> > extern void smp_cpu_setup_state(void);
> > @@ -81,7 +80,7 @@ static int smp_cpu_stop_nolock(uint16_t addr, bool store)
> > uint8_t order = store ? SIGP_STOP_AND_STORE_STATUS : SIGP_STOP;
> >
> > cpu = smp_cpu_from_addr(addr);
> > - if (!cpu || cpu == cpu0)
> > + if (!cpu || addr == cpus[0].addr)
> > return -1;
> >
> > if (sigp_retry(addr, order, 0, NULL))
> > @@ -205,7 +204,7 @@ int smp_cpu_setup(uint16_t addr, struct psw psw)
> > sigp_retry(cpu->addr, SIGP_SET_PREFIX, (unsigned long )lc, NULL);
> >
> > /* Copy all exception psws. */
> > - memcpy(lc, cpu0->lowcore, 512);
> > + memcpy(lc, cpus[0].lowcore, 512);
> >
> > /* Setup stack */
> > cpu->stack = (uint64_t *)alloc_pages(2);
> > @@ -263,15 +262,16 @@ void smp_setup(void)
> > if (num > 1)
> > printf("SMP: Initializing, found %d cpus\n", num);
> >
> > - cpus = calloc(num, sizeof(cpus));
> > + cpus = calloc(num, sizeof(*cpus));
> > for (i = 0; i < num; i++) {
> > cpus[i].addr = entry[i].address;
> > cpus[i].active = false;
> > if (entry[i].address == cpu0_addr) {
> > - cpu0 = &cpus[i];
> > - cpu0->stack = stackptr;
> > - cpu0->lowcore = (void *)0;
> > - cpu0->active = true;
> > + cpus[i].addr = cpus[0].addr;
>
> Might deserve a comment that we'll move the the boot CPU to index 0.
fair enough.
>
> What's the expected behavior if i == 0?
>
in that case, the boot CPU was already the one with index 0. The code
will do a few extra useless steps, but in the end everything should Just
Work™
