From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Florian Weimer <fweimer@redhat.com>, libc-alpha@sourceware.org
Subject: Re: [PATCH v4 3/3] aarch64: Enhanced CPU diagnostics for ld.so
Date: Mon, 8 Apr 2024 14:16:07 +0100 [thread overview]
Message-ID: <ZhPuF6V8sfaP3Puy@arm.com> (raw)
In-Reply-To: <85f152292c8de61442f7ebc2ba0e50f949404b4d.1712574353.git.fweimer@redhat.com>
The 04/08/2024 13:08, Florian Weimer wrote:
> This prints some information from struct cpu_features, and the midr_el1
> and dczid_el0 system register contents on every CPU.
OK.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
> ---
> v4: Manual update.
>
> manual/dynlink.texi | 34 +++++++++++
> sysdeps/aarch64/dl-diagnostics-cpu.c | 84 ++++++++++++++++++++++++++++
> 2 files changed, 118 insertions(+)
> create mode 100644 sysdeps/aarch64/dl-diagnostics-cpu.c
>
> diff --git a/manual/dynlink.texi b/manual/dynlink.texi
> index f2f2341818..d71f7a30d6 100644
> --- a/manual/dynlink.texi
> +++ b/manual/dynlink.texi
> @@ -224,6 +224,40 @@ reflect adjustment by @theglibc{}.
> These Linux-specific items show the values of @code{struct utsname}, as
> reported by the @code{uname} function. @xref{Platform Type}.
>
> +@item aarch64.cpu_features.@dots{}
> +These items are specific to the AArch64 architectures. They report data
> +@theglibc{} uses to activate conditionally supported features such as
> +BTI and MTE, and to select alternative function implementations.
> +
> +@item aarch64.processor[@var{index}].@dots{}
> +These are additional items for the AArch64 architecture and are
> +described below.
> +
> +@item aarch64.processor[@var{index}].requested=@var{kernel-cpu}
> +The kernel is told to run the subsequent probing on the CPU numbered
> +@var{kernel-cpu}. The values @var{kernel-cpu} and @var{index} can be
> +distinct if there are gaps in the process CPU affinity mask. This line
> +is not included if CPU affinity mask information is not available.
> +
> +@item aarch64.processor[@var{index}].observed=@var{kernel-cpu}
> +This line reports the kernel CPU number @var{kernel-cpu} on which the
> +probing code initially ran. If the CPU number cannot be obtained,
> +this line is not printed.
> +
> +@item aarch64.processor[@var{index}].observed_node=@var{node}
> +This reports the observed NUMA node number, as reported by the
> +@code{getcpu} system call. If this information cannot be obtained, this
> +line is not printed.
> +
> +@item aarch64.processor[@var{index}].midr_el1=@var{value}
> +The value of the @code{midr_el1} system register on the processor
> +@var{index}. This line is only printed if the kernel indicates that
> +this system register is supported.
> +
> +@item aarch64.processor[@var{index}].dczid_el0=@var{value}
> +The value of the @code{dczid_el0} system register on the processor
> +@var{index}.
> +
> @cindex CPUID (diagnostics)
> @item x86.cpu_features.@dots{}
> These items are specific to the i386 and x86-64 architectures. They
> diff --git a/sysdeps/aarch64/dl-diagnostics-cpu.c b/sysdeps/aarch64/dl-diagnostics-cpu.c
> new file mode 100644
> index 0000000000..e037e6ea8c
> --- /dev/null
> +++ b/sysdeps/aarch64/dl-diagnostics-cpu.c
> @@ -0,0 +1,84 @@
> +/* Print CPU diagnostics data in ld.so. AArch64 version.
> + Copyright (C) 2021-2024 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <dl-diagnostics.h>
> +
> +#include <cpu-features.h>
> +#include <dl-iterate_cpu.h>
> +#include <ldsodefs.h>
> +#include <sys/auxv.h>
> +
> +static void
> +print_cpu_features_value (const char *label, uint64_t value)
> +{
> + _dl_printf ("aarch64.cpu_features.");
> + _dl_diagnostics_print_labeled_value (label, value);
> +}
> +
> +static void
> +print_per_cpu_value (const struct dl_iterate_cpu *dic,
> + const char *label, uint64_t value)
> +{
> + _dl_printf ("aarch64.processor[0x%x].", dic->processor_index);
> + _dl_diagnostics_print_labeled_value (label, value);
> +}
> +
> +void
> +_dl_diagnostics_cpu (void)
> +{
> + print_cpu_features_value ("bti", GLRO (dl_aarch64_cpu_features).bti);
> + print_cpu_features_value ("midr_el1",
> + GLRO (dl_aarch64_cpu_features).midr_el1);
> + print_cpu_features_value ("mops", GLRO (dl_aarch64_cpu_features).mops);
> + print_cpu_features_value ("mte_state",
> + GLRO (dl_aarch64_cpu_features).mte_state);
> + print_cpu_features_value ("prefer_sve_ifuncs",
> + GLRO (dl_aarch64_cpu_features).prefer_sve_ifuncs);
> + print_cpu_features_value ("sve", GLRO (dl_aarch64_cpu_features).sve);
> + print_cpu_features_value ("zva_size",
> + GLRO (dl_aarch64_cpu_features).zva_size);
> +
> + struct dl_iterate_cpu dic;
> + _dl_iterate_cpu_init (&dic);
> +
> + while (_dl_iterate_cpu_next (&dic))
> + {
> + if (dic.requested_cpu >= 0)
> + _dl_printf ("aarch64.processor[0x%x].requested=0x%x\n",
> + dic.processor_index, dic.requested_cpu);
> + if (dic.actual_cpu >= 0)
> + _dl_printf ("aarch64.processor[0x%x].observed=0x%x\n",
> + dic.processor_index, dic.actual_cpu);
> + if (dic.actual_node >= 0)
> + _dl_printf ("aarch64.processor[0x%x].observed_node=0x%x\n",
> + dic.processor_index, dic.actual_node);
> +
> + if (GLRO (dl_hwcap) & HWCAP_CPUID)
> + {
> + uint64_t midr_el1;
> + asm ("mrs %0, midr_el1" : "=r" (midr_el1));
> + print_per_cpu_value (&dic, "midr_el1", midr_el1);
> + }
> +
> + {
> + uint64_t dczid_el0;
> + asm ("mrs %0, dczid_el0" : "=r" (dczid_el0));
> + print_per_cpu_value (&dic, "dczid_el0", dczid_el0);
> + }
> + }
> +}
> --
> 2.44.0
>
prev parent reply other threads:[~2024-04-08 13:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-08 11:07 [PATCH v4 0/3] " Florian Weimer
2024-04-08 11:07 ` [PATCH v4 1/3] elf: Add CPU iteration support for future use in ld.so diagnostics Florian Weimer
2024-04-08 13:32 ` Szabolcs Nagy
2024-04-08 11:08 ` [PATCH v4 2/3] x86: Add generic CPUID data dumper to ld.so --list-diagnostics Florian Weimer
2024-04-08 11:08 ` [PATCH v4 3/3] aarch64: Enhanced CPU diagnostics for ld.so Florian Weimer
2024-04-08 13:16 ` Szabolcs Nagy [this message]
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