Messages in this thread | | | From | <> | Subject | Re: [PATCH] RISC-V: Add mvendorid, marchid, and mimpid to /proc/cpuinfo output | Date | Mon, 20 Jun 2022 15:42:44 +0000 |
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Hey Anup, Tested it & got back the (sadly boring) 0s that are set in my hardware.
Two comments below.
Thanks, Conor.
On 20/06/2022 12:55, Anup Patel wrote: > Identifying the underlying RISC-V implementation can be important > for some of the user space applications. For example, the perf tool > uses arch specific CPU implementation id (i.e. CPUID) to select a > JSON file describing custom perf events on a CPU. > > Currently, there is no way to identify RISC-V implementation so we > add mvendorid, marchid, and mimpid to /proc/cpuinfo output. > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > --- > arch/riscv/kernel/cpu.c | 51 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 51 insertions(+) > > diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c > index fba9e9f46a8c..c037b8691bbb 100644 > --- a/arch/riscv/kernel/cpu.c > +++ b/arch/riscv/kernel/cpu.c > @@ -3,10 +3,13 @@ > * Copyright (C) 2012 Regents of the University of California > */ > > +#include <linux/cpu.h> > #include <linux/init.h> > #include <linux/seq_file.h> > #include <linux/of.h> > +#include <asm/csr.h> > #include <asm/hwcap.h> > +#include <asm/sbi.h> > #include <asm/smp.h> > #include <asm/pgtable.h> > > @@ -64,6 +67,50 @@ int riscv_of_parent_hartid(struct device_node *node) > } > > #ifdef CONFIG_PROC_FS > + > +struct riscv_cpuinfo { > + unsigned long mvendorid; > + unsigned long marchid; > + unsigned long mimpid; > +}; > +static DEFINE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo); > + > +static int riscv_cpuinfo_starting(unsigned int cpu) > +{ > + struct riscv_cpuinfo *ci = this_cpu_ptr(&riscv_cpuinfo); > + > +#if defined(CONFIG_RISCV_SBI)
This should be #if IS_ENABLED(CONFIG_RISCV_SBI) to match the other users
> + ci->mvendorid = sbi_spec_is_0_1() ? 0 : sbi_get_mvendorid(); > + ci->marchid = sbi_spec_is_0_1() ? 0 : sbi_get_marchid(); > + ci->mimpid = sbi_spec_is_0_1() ? 0 : sbi_get_mimpid(); > +#elif defined(CONFIG_RISCV_M_MODE)
Ditto
> + ci->mvendorid = csr_read(CSR_MVENDORID); > + ci->marchid = csr_read(CSR_MARCHID); > + ci->mimpid = csr_read(CSR_MIMPID); > +#else > + ci->mvendorid = 0; > + ci->marchid = 0; > + ci->mimpid = 0; > +#endif > + > + return 0; > +} > + > +static int __init riscv_cpuinfo_init(void) > +{ > + int ret; > + > + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "riscv/cpuinfo:starting", > + riscv_cpuinfo_starting, NULL); > + if (ret < 0) { > + pr_err("cpuinfo: failed to register hotplug callbacks.\n"); > + return ret; > + } > + > + return 0; > +} > +device_initcall(riscv_cpuinfo_init); > + > #define __RISCV_ISA_EXT_DATA(UPROP, EXTID) \ > { \ > .uprop = #UPROP, \ > @@ -178,6 +225,7 @@ static int c_show(struct seq_file *m, void *v) > { > unsigned long cpu_id = (unsigned long)v - 1; > struct device_node *node = of_get_cpu_node(cpu_id, NULL); > + struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id); > const char *compat, *isa; > > seq_printf(m, "processor\t: %lu\n", cpu_id); > @@ -188,6 +236,9 @@ static int c_show(struct seq_file *m, void *v) > if (!of_property_read_string(node, "compatible", &compat) > && strcmp(compat, "riscv")) > seq_printf(m, "uarch\t\t: %s\n", compat); > + seq_printf(m, "mvendorid\t: 0x%lx\n", ci->mvendorid); > + seq_printf(m, "marchid\t\t: 0x%lx\n", ci->marchid); > + seq_printf(m, "mimpid\t\t: 0x%lx\n", ci->mimpid); > seq_puts(m, "\n"); > of_node_put(node); >
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