diff options
author | Andrew Jones <ajones@ventanamicro.com> | 2023-12-20 17:00:14 +0100 |
---|---|---|
committer | Anup Patel <anup@brainfault.org> | 2023-12-30 06:55:03 +0100 |
commit | 323925ed6dbb0ed877047b28fae4152527cc63db (patch) | |
tree | d22cf639397eaedd990f55d65c89fed22174db4d /arch/riscv/kernel | |
parent | RISC-V: KVM: Fix indentation in kvm_riscv_vcpu_set_reg_csr() (diff) | |
download | linux-323925ed6dbb0ed877047b28fae4152527cc63db.tar.xz linux-323925ed6dbb0ed877047b28fae4152527cc63db.zip |
RISC-V: paravirt: Add skeleton for pv-time support
Add the files and functions needed to support paravirt time on
RISC-V. Also include the common code needed for the first
application of pv-time, which is steal-time. In the next
patches we'll complete the functions to fully enable steal-time
support.
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Diffstat (limited to 'arch/riscv/kernel')
-rw-r--r-- | arch/riscv/kernel/Makefile | 1 | ||||
-rw-r--r-- | arch/riscv/kernel/paravirt.c | 79 | ||||
-rw-r--r-- | arch/riscv/kernel/time.c | 3 |
3 files changed, 83 insertions, 0 deletions
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index fee22a3d1b53..807c2bde1f83 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -85,6 +85,7 @@ obj-$(CONFIG_SMP) += sbi-ipi.o obj-$(CONFIG_SMP) += cpu_ops_sbi.o endif obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o +obj-$(CONFIG_PARAVIRT) += paravirt.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_KEXEC_CORE) += kexec_relocate.o crash_save_regs.o machine_kexec.o obj-$(CONFIG_KEXEC_FILE) += elf_kexec.o machine_kexec_file.o diff --git a/arch/riscv/kernel/paravirt.c b/arch/riscv/kernel/paravirt.c new file mode 100644 index 000000000000..48d802df7739 --- /dev/null +++ b/arch/riscv/kernel/paravirt.c @@ -0,0 +1,79 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2023 Ventana Micro Systems Inc. + */ + +#define pr_fmt(fmt) "riscv-pv: " fmt + +#include <linux/cpuhotplug.h> +#include <linux/init.h> +#include <linux/jump_label.h> +#include <linux/printk.h> +#include <linux/static_call.h> +#include <linux/types.h> + +#include <asm/paravirt.h> + +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; + +static u64 native_steal_clock(int cpu) +{ + return 0; +} + +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); + +static bool steal_acc = true; +static int __init parse_no_stealacc(char *arg) +{ + steal_acc = false; + return 0; +} + +early_param("no-steal-acc", parse_no_stealacc); + +static bool __init has_pv_steal_clock(void) +{ + return false; +} + +static int pv_time_cpu_online(unsigned int cpu) +{ + return 0; +} + +static int pv_time_cpu_down_prepare(unsigned int cpu) +{ + return 0; +} + +static u64 pv_time_steal_clock(int cpu) +{ + return 0; +} + +int __init pv_time_init(void) +{ + int ret; + + if (!has_pv_steal_clock()) + return 0; + + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, + "riscv/pv_time:online", + pv_time_cpu_online, + pv_time_cpu_down_prepare); + if (ret < 0) + return ret; + + static_call_update(pv_steal_clock, pv_time_steal_clock); + + static_key_slow_inc(¶virt_steal_enabled); + if (steal_acc) + static_key_slow_inc(¶virt_steal_rq_enabled); + + pr_info("Computing paravirt steal-time\n"); + + return 0; +} diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c index 23641e82a9df..ba3477197789 100644 --- a/arch/riscv/kernel/time.c +++ b/arch/riscv/kernel/time.c @@ -12,6 +12,7 @@ #include <asm/sbi.h> #include <asm/processor.h> #include <asm/timex.h> +#include <asm/paravirt.h> unsigned long riscv_timebase __ro_after_init; EXPORT_SYMBOL_GPL(riscv_timebase); @@ -45,4 +46,6 @@ void __init time_init(void) timer_probe(); tick_setup_hrtimer_broadcast(); + + pv_time_init(); } |