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Re: [PATCH 6/6] aarch64: Add hwcap string routines
On 01/06/2017 17:12, Siddhesh Poyarekar wrote:
> Add support for routines in dl-procinfo.h to show string versions of
> HWCAP entries when a program is invoked with the LD_SHOW_AUXV
> environment variable set and also to aid in path resolution for
> ldconfig.
>
> * sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
> (_dl_aarch64_cap_flags): New array.
> * sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h
> (_dl_hwcap_string, _dl_string_hwcap, _dl_procinfo): Implement
> functions.
LGTM. On the subject, I think current dl-procinfo.h macro quite messy
and error prone, so I think a future cleanup would be worth it.
Since you are there, it would be good to sync with kernel recent updates
for v8.3 [1] [2] [3] which addes HWCAP_JSCVT, HWCAP_FCMA, and HWCAP_LRCPC.
[1] c8c3798d2369e4285da44b244638eafe446a8f8a
[2] cb567e79fa504575cb97fb2f866d2040ed1c92e7
[3] c651aae5a7732287c1c9bc974ece4ed798780544
> ---
> sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c | 15 +++++++
> sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h | 58 +++++++++++++++++++++++----
> 2 files changed, 65 insertions(+), 8 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
> index 438046a..bc37bad 100644
> --- a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
> +++ b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
> @@ -56,5 +56,20 @@ PROCINFO_CLASS struct cpu_features _dl_aarch64_cpu_features
> # endif
> #endif
>
> +#if !defined PROCINFO_DECL && defined SHARED
> + ._dl_aarch64_cap_flags
> +#else
> +PROCINFO_CLASS const char _dl_aarch64_cap_flags[13][10]
> +#endif
> +#ifndef PROCINFO_DECL
> += { "fp", "asimd", "evtstrm", "aes", "pmull", "sha1", "sha2", "crc32",
> + "atomics", "fphp", "asimdhp", "cpuid", "asimdrdm"}
> +#endif
> +#if !defined SHARED || defined PROCINFO_DECL
> +;
> +#else
> +,
> +#endif
> +
> #undef PROCINFO_DECL
> #undef PROCINFO_CLASS
> diff --git a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h
> index 7a60d72..cdb36d3 100644
> --- a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h
> +++ b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h
> @@ -20,25 +20,67 @@
> #define _DL_PROCINFO_H 1
>
> #include <sys/auxv.h>
> +#include <unistd.h>
> +#include <ldsodefs.h>
> +#include <sysdep.h>
>
> /* We cannot provide a general printing function. */
> -#define _dl_procinfo(type, word) -1
> +static inline int
> +__attribute__ ((unused))
> +_dl_procinfo (unsigned int type, unsigned long int word)
> +{
> + /* This table should match the information from arch/arm64/kernel/cpuinfo.c
> + in the kernel sources. */
> + int i;
>
> -/* There are no hardware capabilities defined. */
> -#define _dl_hwcap_string(idx) ""
> + /* Fallback to unknown output mechanism. */
> + if (type == AT_HWCAP2)
> + return -1;
> +
> + _dl_printf ("AT_HWCAP: ");
> +
> + for (i = 0; i < 32; ++i)
> + if (word & (1 << i))
> + _dl_printf (" %s", GLRO(dl_aarch64_cap_flags)[i]);
> +
> + _dl_printf ("\n");
> +
> + return 0;
> +}
> +
> +static inline const char *
> +__attribute__ ((unused))
> +_dl_hwcap_string (int idx)
> +{
> + return GLRO(dl_aarch64_cap_flags)[idx];
> +};
> +
> +
> +/* 13 HWCAP bits set. */
> +#define _DL_HWCAP_COUNT 13
> +
> +/* Low 13 bits are allocated in HWCAP. */
> +#define _DL_HWCAP_LAST 12
>
> /* HWCAP_CPUID should be available by default to influence IFUNC as well as
> library search. */
> #define HWCAP_IMPORTANT HWCAP_CPUID
>
> +static inline int
> +__attribute__ ((unused))
> +_dl_string_hwcap (const char *str)
> +{
> + for (int i = 0; i < _DL_HWCAP_COUNT; i++)
> + {
> + if (strcmp (str, _dl_hwcap_string (i)) == 0)
> + return i;
> + }
> + return -1;
> +};
> +
> /* There're no platforms to filter out. */
> #define _DL_HWCAP_PLATFORM 0
>
> -/* We don't have any hardware capabilities. */
> -#define _DL_HWCAP_COUNT 0
> -
> -#define _dl_string_hwcap(str) (-1)
> -
> #define _dl_string_platform(str) (-1)
>
> #endif /* dl-procinfo.h */
>