Messages in this thread | | | Date | Mon, 03 Oct 2022 21:35:25 -0700 (PDT) | Subject | Re: [PATCH v2] RISC-V: Add mvendorid, marchid, and mimpid to /proc/cpuinfo output | From | Palmer Dabbelt <> |
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On Mon, 03 Oct 2022 20:44:54 PDT (-0700), anup@brainfault.org wrote: > On Tue, Oct 4, 2022 at 8:24 AM Palmer Dabbelt <palmer@dabbelt.com> wrote: >> >> On Tue, 26 Jul 2022 21:38:29 PDT (-0700), apatel@ventanamicro.com 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> >> > Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> >> > Tested-by: Nikita Shubin <n.shubin@yadro.com> >> > --- >> > Changes since v1: >> > - Use IS_ENABLED() to check CONFIG defines >> > - Added RB and TB tags in commit description >> > --- >> > arch/riscv/kernel/cpu.c | 51 +++++++++++++++++++++++++++++++++++++++++ >> > 1 file changed, 51 insertions(+) >> >> Sorry for being slow on this one. I'd been worried about sticking more >> stuff into /proc/cpuinfo, as having the only user interface for these >> involve parsing /proc/cpuinfo is really just a recipe for disaster. I >> didn't get around do doing something better, though, and waiting for >> another release seems kind of silly. > > In addition to being useful for perf tool, printing vendor and > implementation details in /proc/cpuinfo is a very useful info. > > Users can easily know the underlying CPU implementer using > "cat /proc/cpuinfo". > >> >> I was going to go put this on for-next, but it looks like it's causing >> kasan boot failures. I'm not actually quite sure how this is triggering >> these, at least based on the backtrace, but there's a bunch of them and >> boot hangs. >> >> Here's the first of them: >> >> [ 3.830416] Hardware name: riscv-virtio,qemu (DT) >> [ 3.830828] epc : kasan_check_range+0x116/0x14c >> [ 3.832377] ra : memset+0x1e/0x4c >> [ 3.832699] epc : ffffffff8026468e ra : ffffffff80264d6e sp : ff600000832afa60 >> [ 3.833051] gp : ffffffff81d800a0 tp : ff600000831d2400 t0 : ff60000083224360 >> [ 3.833397] t1 : ffebfffefffef000 t2 : 0000000000000000 s0 : ff600000832afa90 >> [ 3.833811] s1 : 0000000000000004 a0 : 0000000000000010 a1 : 0000000000000004 >> [ 3.834210] a2 : 0000000000000001 a3 : ffffffff801fa22c a4 : ff5ffffffff78000 >> [ 3.834558] a5 : ffebfffefffef000 a6 : ffebfffefffef001 a7 : ff5ffffffff78003 >> [ 3.834931] s2 : ff5ffffffff78000 s3 : 0000000000000000 s4 : ffffffff815b59b0 >> [ 3.835292] s5 : ffffffff81d815e0 s6 : 0000000000000000 s7 : 0000000000000008 >> [ 3.836400] s8 : ffffffff81d8b0e0 s9 : 0000000000000000 s10: 0000000000000008 >> [ 3.836817] s11: ff5ffffffff78000 t3 : 0000000000000000 t4 : ffebfffefffef000 >> [ 3.837154] t5 : ffebfffefffef001 t6 : 0000000000000002 >> [ 3.837471] status: 0000000000000120 badaddr: ffebfffefffef000 cause: 000000000000000d >> [ 3.837933] [<ffffffff801fa22c>] pcpu_alloc+0x494/0x838 >> [ 3.838324] [<ffffffff801fa5fc>] __alloc_percpu+0x14/0x1c >> [ 3.838623] [<ffffffff800930fa>] __percpu_init_rwsem+0x1a/0x98 >> [ 3.838995] [<ffffffff80286c5a>] alloc_super+0x148/0x3da >> [ 3.839631] [<ffffffff80287af2>] sget_fc+0x90/0x2c4 >> [ 3.840240] [<ffffffff80288498>] get_tree_nodev+0x24/0xa4 >> [ 3.840598] [<ffffffff801e919a>] shmem_get_tree+0x14/0x1c >> [ 3.840891] [<ffffffff80286436>] vfs_get_tree+0x3a/0x11a >> [ 3.841172] [<ffffffff802ba746>] path_mount+0x2ea/0xb44 >> [ 3.841468] [<ffffffff802bb69a>] sys_mount+0x1b2/0x270 >> [ 3.841790] [<ffffffff80003d1c>] ret_from_syscall+0x0/0x2 >> [ 3.842480] ---[ end trace 0000000000000000 ]--- > > Sure, I will try to fix this ASAP. > > Are you willing to take this if the above issue is fixed ?
I still think the other interface is better, but it's taking too long and some stuff is blocked on getting these to userspace so I'm fine with it.
> > Regards, > Anup > >> >> > >> > diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c >> > index fba9e9f46a8c..04bcc91c91ea 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 IS_ENABLED(CONFIG_RISCV_SBI) >> > + 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 IS_ENABLED(CONFIG_RISCV_M_MODE) >> > + 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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