On 08.04.2025 17:57, Oleksii Kurochko wrote:
> Initialize cpu_{possible, online, present}_map by using smp_clear_cpu_maps().
>
> Drop DEFINE_PER_CPU(unsigned int, cpu_id) from stubs.c as this variable isn't
> expected to be used in RISC-V at all.
>
> Move declaration of cpu_{possible,online,present}_map from stubs.c to
> smpboot.c
> as now smpboot.c is now introduced.
> Other defintions keep in stubs.c as they are not initialized and not needed,
> at
> the moment.
>
> Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
> ---
> xen/arch/riscv/Makefile | 1 +
> xen/arch/riscv/include/asm/smp.h | 2 ++
> xen/arch/riscv/setup.c | 2 ++
> xen/arch/riscv/smpboot.c | 15 +++++++++++++++
> xen/arch/riscv/stubs.c | 6 ------
> 5 files changed, 20 insertions(+), 6 deletions(-)
> create mode 100644 xen/arch/riscv/smpboot.c
>
> diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile
> index 0c6c4a38a3..f551bf32a2 100644
> --- a/xen/arch/riscv/Makefile
> +++ b/xen/arch/riscv/Makefile
> @@ -10,6 +10,7 @@ obj-y += sbi.o
> obj-y += setup.o
> obj-y += shutdown.o
> obj-y += smp.o
> +obj-y += smpboot.o
> obj-y += stubs.o
> obj-y += time.o
> obj-y += traps.o
> diff --git a/xen/arch/riscv/include/asm/smp.h
> b/xen/arch/riscv/include/asm/smp.h
> index 5e170b57b3..188c033718 100644
> --- a/xen/arch/riscv/include/asm/smp.h
> +++ b/xen/arch/riscv/include/asm/smp.h
> @@ -26,6 +26,8 @@ static inline void set_cpuid_to_hartid(unsigned long cpuid,
>
> void setup_tp(unsigned int cpuid);
>
> +void smp_clear_cpu_maps(void);
> +
> #endif
>
> /*
> diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
> index 4e416f6e44..7f68f3f5b7 100644
> --- a/xen/arch/riscv/setup.c
> +++ b/xen/arch/riscv/setup.c
> @@ -72,6 +72,8 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
>
> remove_identity_mapping();
>
> + smp_clear_cpu_maps();
> +
> set_processor_id(0);
>
> set_cpuid_to_hartid(0, bootcpu_id);
> diff --git a/xen/arch/riscv/smpboot.c b/xen/arch/riscv/smpboot.c
> new file mode 100644
> index 0000000000..0f4dcc28e1
> --- /dev/null
> +++ b/xen/arch/riscv/smpboot.c
> @@ -0,0 +1,15 @@
> +#include <xen/cpumask.h>
> +#include <xen/init.h>
> +
> +cpumask_t cpu_online_map;
> +cpumask_t cpu_present_map;
> +cpumask_t cpu_possible_map;
__read_mostly for all of them, perhaps (if CPU hotplug isn't expected to
be supported) even __ro_after_init for the latter two?
As to cpu_possible_map - do you predict that you'll actually use it? Arm
does (and instead has only a fake cpu_present_map), but on x86 we get away
without.
> +void __init smp_clear_cpu_maps(void)
> +{
> + cpumask_clear(&cpu_possible_map);
> + cpumask_clear(&cpu_online_map);
What's the point of these? All three maps start out fully zeroed.
> + cpumask_set_cpu(0, &cpu_possible_map);
> + cpumask_set_cpu(0, &cpu_online_map);
These are contradicting the name of the function. The somewhat equivalent
function we have on x86 is smp_prepare_boot_cpu().
> + cpumask_copy(&cpu_present_map, &cpu_possible_map);
Another cpumask_set_cpu() is probably cheaper here then.
Jan
