From: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: Re: [PATCH v2 1/3] riscv: Add Linux hwprobe syscall support
Date: Wed, 29 Mar 2023 15:38:19 -0300 [thread overview]
Message-ID: <9804d26f-449d-9997-be7d-52ec4b616758@linaro.org> (raw)
In-Reply-To: <20230221191537.3159966-2-evan@rivosinc.com>
On 21/02/23 16:15, Evan Green wrote:
> Add awareness and a thin wrapper function around a new Linux system call
> that allows callers to get architecture and microarchitecture
> information about the CPUs from the kernel. This can be used to
> do things like dynamically choose a memcpy implementation.
>
> Signed-off-by: Evan Green <evan@rivosinc.com>
> ---
>
> Changes in v2:
> - hwprobe.h: Use __has_include and duplicate Linux content to make
> compilation work when Linux headers are absent (Adhemerval)
> - hwprobe.h: Put declaration under __USE_GNU (Adhemerval)
> - Use INLINE_SYSCALL_CALL (Adhemerval)
> - Update versions
> - Update UNALIGNED_MASK to match kernel v3 series.
>
> sysdeps/unix/sysv/linux/riscv/Makefile | 4 +-
> sysdeps/unix/sysv/linux/riscv/Versions | 3 +
> sysdeps/unix/sysv/linux/riscv/hwprobe.c | 30 +++++++++
> .../unix/sysv/linux/riscv/rv32/arch-syscall.h | 1 +
> .../unix/sysv/linux/riscv/rv32/libc.abilist | 1 +
> .../unix/sysv/linux/riscv/rv64/arch-syscall.h | 1 +
> .../unix/sysv/linux/riscv/rv64/libc.abilist | 1 +
> sysdeps/unix/sysv/linux/riscv/sys/hwprobe.h | 67 +++++++++++++++++++
> sysdeps/unix/sysv/linux/syscall-names.list | 1 +
> 9 files changed, 107 insertions(+), 2 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/riscv/hwprobe.c
> create mode 100644 sysdeps/unix/sysv/linux/riscv/sys/hwprobe.h
>
> diff --git a/sysdeps/unix/sysv/linux/riscv/Makefile b/sysdeps/unix/sysv/linux/riscv/Makefile
> index 4b6eacb32f..45cc29e40d 100644
> --- a/sysdeps/unix/sysv/linux/riscv/Makefile
> +++ b/sysdeps/unix/sysv/linux/riscv/Makefile
> @@ -1,6 +1,6 @@
> ifeq ($(subdir),misc)
> -sysdep_headers += sys/cachectl.h
> -sysdep_routines += flush-icache
> +sysdep_headers += sys/cachectl.h sys/hwprobe.h
> +sysdep_routines += flush-icache hwprobe
> endif
>
> ifeq ($(subdir),stdlib)
> diff --git a/sysdeps/unix/sysv/linux/riscv/Versions b/sysdeps/unix/sysv/linux/riscv/Versions
> index 5625d2a0b8..8717b62a4a 100644
> --- a/sysdeps/unix/sysv/linux/riscv/Versions
> +++ b/sysdeps/unix/sysv/linux/riscv/Versions
> @@ -8,4 +8,7 @@ libc {
> GLIBC_2.27 {
> __riscv_flush_icache;
> }
> + GLIBC_2.39 {
> + __riscv_hwprobe;
> + }
> }
> diff --git a/sysdeps/unix/sysv/linux/riscv/hwprobe.c b/sysdeps/unix/sysv/linux/riscv/hwprobe.c
> new file mode 100644
> index 0000000000..74f68889ca
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/hwprobe.c
> @@ -0,0 +1,30 @@
> +/* RISC-V hardware feature probing support on Linux
> + Copyright (C) 2023 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 <sys/syscall.h>
> +#include <sys/hwprobe.h>
> +#include <sysdep.h>
> +
> +int
> +__riscv_hwprobe (struct riscv_hwprobe *pairs, long pair_count,
> + long cpu_count, unsigned long *cpus, unsigned long flags)
> +{
> + return INLINE_SYSCALL_CALL (riscv_hwprobe, pairs, pair_count,
> + cpu_count, cpus, flags);
> +}
> diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/arch-syscall.h b/sysdeps/unix/sysv/linux/riscv/rv32/arch-syscall.h
> index 202520ee25..2416e041c8 100644
> --- a/sysdeps/unix/sysv/linux/riscv/rv32/arch-syscall.h
> +++ b/sysdeps/unix/sysv/linux/riscv/rv32/arch-syscall.h
> @@ -198,6 +198,7 @@
> #define __NR_request_key 218
> #define __NR_restart_syscall 128
> #define __NR_riscv_flush_icache 259
> +#define __NR_riscv_hwprobe 258
> #define __NR_rseq 293
> #define __NR_rt_sigaction 134
> #define __NR_rt_sigpending 136
> diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
> index 29be561b60..83b7932db7 100644
> --- a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
> @@ -2416,3 +2416,4 @@ GLIBC_2.38 __isoc23_wcstoul_l F
> GLIBC_2.38 __isoc23_wcstoull F
> GLIBC_2.38 __isoc23_wcstoull_l F
> GLIBC_2.38 __isoc23_wcstoumax F
> +GLIBC_2.39 __riscv_hwprobe F
> diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/arch-syscall.h b/sysdeps/unix/sysv/linux/riscv/rv64/arch-syscall.h
> index 4e65f337d4..a32bc82f60 100644
> --- a/sysdeps/unix/sysv/linux/riscv/rv64/arch-syscall.h
> +++ b/sysdeps/unix/sysv/linux/riscv/rv64/arch-syscall.h
> @@ -205,6 +205,7 @@
> #define __NR_request_key 218
> #define __NR_restart_syscall 128
> #define __NR_riscv_flush_icache 259
> +#define __NR_riscv_hwprobe 258
> #define __NR_rseq 293
> #define __NR_rt_sigaction 134
> #define __NR_rt_sigpending 136
> diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
> index 506a4e6a65..6ddbcfb131 100644
> --- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
> @@ -2616,3 +2616,4 @@ GLIBC_2.38 __isoc23_wcstoul_l F
> GLIBC_2.38 __isoc23_wcstoull F
> GLIBC_2.38 __isoc23_wcstoull_l F
> GLIBC_2.38 __isoc23_wcstoumax F
> +GLIBC_2.39 __riscv_hwprobe F
> diff --git a/sysdeps/unix/sysv/linux/riscv/sys/hwprobe.h b/sysdeps/unix/sysv/linux/riscv/sys/hwprobe.h
> new file mode 100644
> index 0000000000..e619ea43b8
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/sys/hwprobe.h
> @@ -0,0 +1,67 @@
> +/* RISC-V architecture probe interface
> + Copyright (C) 2023 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/>. */
> +
> +#ifndef _SYS_HWPROBE_H
> +#define _SYS_HWPROBE_H 1
> +
> +#include <features.h>
> +#ifdef __has_include
> +# if __has_include (<asm/hwprobe.h>)
> +# include <asm/hwprobe.h>
> +# endif
> +#endif
> +
> +/*
> + * Define a (probably stale) version of the interface if the Linux headers
> + * aren't present.
> + */
> +#ifndef RISCV_HWPROBE_KEY_MVENDORID
> +struct riscv_hwprobe {
> + signed long long key;
> + unsigned long long value;
> +};
Indentation seems ok here, I think curly brackets should be in the next line.
> +
> +#define RISCV_HWPROBE_KEY_MVENDORID 0
> +#define RISCV_HWPROBE_KEY_MARCHID 1
> +#define RISCV_HWPROBE_KEY_MIMPID 2
> +#define RISCV_HWPROBE_KEY_BASE_BEHAVIOR 3
> +#define RISCV_HWPROBE_BASE_BEHAVIOR_IMA (1 << 0)
> +#define RISCV_HWPROBE_KEY_IMA_EXT_0 4
> +#define RISCV_HWPROBE_IMA_FD (1 << 0)
> +#define RISCV_HWPROBE_IMA_C (1 << 1)
> +#define RISCV_HWPROBE_KEY_CPUPERF_0 5
> +#define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0)
> +#define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0)
> +#define RISCV_HWPROBE_MISALIGNED_SLOW (2 << 0)
> +#define RISCV_HWPROBE_MISALIGNED_FAST (3 << 0)
> +#define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
Indentation seems off here.
> +
> +#endif // RISCV_HWPROBE_KEY_MVENDORID
No C99/C++ style comments in public headers.
> +
> +__BEGIN_DECLS
> +
Could you add some minimal comment on the how to use this interface, the
exects parameters, etc?
> +#ifdef __USE_GNU
> +int
> +__riscv_hwprobe (struct riscv_hwprobe *pairs, long pair_count,
> + long cpu_count, unsigned long *cpus, unsigned long flags);
Add 'extern' (for old -std= modes) and put the function on same line as
return type.
> +#endif
> +
> +__END_DECLS
> +
> +#endif /* sys/hwprobe.h */
> diff --git a/sysdeps/unix/sysv/linux/syscall-names.list b/sysdeps/unix/sysv/linux/syscall-names.list
> index 822498d3e3..4f4a62e91c 100644
> --- a/sysdeps/unix/sysv/linux/syscall-names.list
> +++ b/sysdeps/unix/sysv/linux/syscall-names.list
> @@ -477,6 +477,7 @@ renameat2
> request_key
> restart_syscall
> riscv_flush_icache
> +riscv_hwprobe
> rmdir
> rseq
> rt_sigaction
next prev parent reply other threads:[~2023-03-29 18:38 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-21 19:15 [PATCH v2 0/3] RISC-V: ifunced memcpy using new kernel hwprobe interface Evan Green
2023-02-21 19:15 ` [PATCH v2 1/3] riscv: Add Linux hwprobe syscall support Evan Green
2023-03-29 18:38 ` Adhemerval Zanella Netto [this message]
2023-02-21 19:15 ` [PATCH v2 2/3] riscv: Add hwprobe vdso call support Evan Green
2023-03-29 18:39 ` Adhemerval Zanella Netto
2023-02-21 19:15 ` [PATCH v2 3/3] riscv: Add and use alignment-ignorant memcpy Evan Green
2023-03-28 22:54 ` [PATCH v2 0/3] RISC-V: ifunced memcpy using new kernel hwprobe interface Palmer Dabbelt
2023-03-28 23:41 ` Adhemerval Zanella Netto
2023-03-29 0:01 ` Palmer Dabbelt
2023-03-29 19:16 ` Adhemerval Zanella Netto
2023-03-29 19:45 ` Palmer Dabbelt
2023-03-29 20:13 ` Adhemerval Zanella Netto
2023-03-30 18:31 ` Evan Green
2023-03-30 19:43 ` Adhemerval Zanella Netto
2023-03-30 6:20 ` Jeff Law
2023-03-30 18:43 ` Evan Green
2023-03-31 5:09 ` Jeff Law
2023-03-30 19:38 ` Adhemerval Zanella Netto
2023-03-31 18:07 ` Jeff Law
2023-03-31 18:34 ` Palmer Dabbelt
2023-03-31 19:32 ` Adhemerval Zanella Netto
2023-03-31 20:19 ` Jeff Law
2023-03-31 21:03 ` Palmer Dabbelt
2023-03-31 21:35 ` Jeff Law
2023-03-31 21:38 ` Palmer Dabbelt
2023-03-31 22:10 ` Jeff Law
2023-04-07 15:36 ` Palmer Dabbelt
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