| Message ID | ddf8aad3798c861d5b8916c309135a90bf655ff3.1712312063.git.fweimer@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Enhanced CPU diagnostics for ld.so | expand |
On 05/04/24 07:16, Florian Weimer wrote: > This prints some information from struct cpu_features, and the midr_el1 > and dczid_el0 system register contents on every CPU. > --- > 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..6f4acf321d 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 > +that is used by @theglibc{} to select alternative function > +implementations. Maybe also add some options are security related and not really tied to ifunc support (mte, bti). > + > +@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. Maybe just 2024 here. > + 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); > + } > + } > +} The rest looks ok.
The 04/05/2024 12:16, Florian Weimer wrote: > This prints some information from struct cpu_features, and the midr_el1 > and dczid_el0 system register contents on every CPU. thanks. i think we already rely on zva size to be the same across all cores (in memset) and i don't think linux allows different dczid_el0 per core (even if somebody built such a system). so i don't think that is needed. ... > +++ 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); i would use something like const struct cpu_features *p = &GLRO (dl_aarch64_cpu_features); ... p->bti ... or even #define P(x) print_cpu_features_value (#x, GLRO (dl_aarch64_cpu_features).x) to make this list more compact. i wonder if we should place a comment in init-arch.h to update _dl_diagnostics_cpu in case ifunc rules change as this seems easy to forget > + > + 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 >
* Szabolcs Nagy: > The 04/05/2024 12:16, Florian Weimer wrote: >> This prints some information from struct cpu_features, and the midr_el1 >> and dczid_el0 system register contents on every CPU. > > thanks. > > i think we already rely on zva size to be the same across all cores > (in memset) and i don't think linux allows different dczid_el0 per > core (even if somebody built such a system). > > so i don't think that is needed. Well … we've seen per-core feature sets change on some cores after suspend/resume (although not on aarch64). That's why we have t he per-CPU iterator in the first place. > i wonder if we should place a comment in init-arch.h to update > _dl_diagnostics_cpu in case ifunc rules change as this seems > easy to forget I'll add a comment. Thanks, Florian
The 04/05/2024 16:54, Florian Weimer wrote: > * Szabolcs Nagy: > > > The 04/05/2024 12:16, Florian Weimer wrote: > >> This prints some information from struct cpu_features, and the midr_el1 > >> and dczid_el0 system register contents on every CPU. > > > > thanks. > > > > i think we already rely on zva size to be the same across all cores > > (in memset) and i don't think linux allows different dczid_el0 per > > core (even if somebody built such a system). > > > > so i don't think that is needed. > > Well … we've seen per-core feature sets change on some cores after > suspend/resume (although not on aarch64). That's why we have t he > per-CPU iterator in the first place. linux does not support mismatch across cores and they check for it, so unless you resume after reboot with a different set of cpus online there should not be a mismatch. but if you think it is still useful just to be sure i'm not against printing it n times.
* Adhemerval Zanella Netto: > On 05/04/24 07:16, Florian Weimer wrote: >> This prints some information from struct cpu_features, and the midr_el1 >> and dczid_el0 system register contents on every CPU. >> --- >> 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..6f4acf321d 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 >> +that is used by @theglibc{} to select alternative function >> +implementations. > > Maybe also add some options are security related and not really tied > to ifunc support (mte, bti). I think MTE is also about selecting an implementation variant. I will add something regarding BTI. >> 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. > > Maybe just 2024 here. I started with a copy of the x86 file. Thanks, Florian
diff --git a/manual/dynlink.texi b/manual/dynlink.texi index f2f2341818..6f4acf321d 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 +that is used by @theglibc{} 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); + } + } +}