From: daichengrong@iscas.ac.cn To: ffmpeg-devel@ffmpeg.org Subject: [FFmpeg-devel] [PATCH] RISC-V:update ff_get_cpu_flags_riscv for RVV Date: Fri, 14 Mar 2025 18:32:57 +0800 Message-ID: <20250314103257.3584723-1-daichengrong@iscas.ac.cn> (raw) From: daichengrong <daichengrong@iscas.ac.cn> Availability of RVV and ZVBB should be determined with dl_hwcap. As those extensions rely on vector registers, kernel vector support is required to save the state of context switching. FFmpeg requires hwprobe for hardware capability detection, and cooperates with dl_hwcap to detect whether the kernel supports vector. --- libavutil/riscv/cpu.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/libavutil/riscv/cpu.c b/libavutil/riscv/cpu.c index 163e4fc14a..fad63eccea 100644 --- a/libavutil/riscv/cpu.c +++ b/libavutil/riscv/cpu.c @@ -55,6 +55,10 @@ int ff_get_cpu_flags_riscv(void) { RISCV_HWPROBE_KEY_CPUPERF_0, 0 }, }; +#if HAVE_GETAUXVAL || HAVE_ELF_AUX_INFO + const unsigned long hwcap = ff_getauxval(AT_HWCAP); +#endif + if (__riscv_hwprobe(pairs, FF_ARRAY_ELEMS(pairs), 0, NULL, 0) == 0) { if (pairs[0].value & RISCV_HWPROBE_BASE_BEHAVIOR_IMA) ret |= AV_CPU_FLAG_RVI; @@ -62,6 +66,12 @@ int ff_get_cpu_flags_riscv(void) if (pairs[1].value & RISCV_HWPROBE_IMA_V) ret |= AV_CPU_FLAG_RVV_I32 | AV_CPU_FLAG_RVV_I64 | AV_CPU_FLAG_RVV_F32 | AV_CPU_FLAG_RVV_F64; +#if HAVE_GETAUXVAL || HAVE_ELF_AUX_INFO + /* The V extension implies all Zve* functional subsets */ + if (!(hwcap & HWCAP_RV('V'))) + ret &= ~(AV_CPU_FLAG_RVV_I32 | AV_CPU_FLAG_RVV_I64 + | AV_CPU_FLAG_RVV_F32 | AV_CPU_FLAG_RVV_F64); +#endif #endif #ifdef RISCV_HWPROBE_EXT_ZBB if (pairs[1].value & RISCV_HWPROBE_EXT_ZBB) @@ -76,6 +86,10 @@ int ff_get_cpu_flags_riscv(void) #ifdef RISCV_HWPROBE_EXT_ZVBB if (pairs[1].value & RISCV_HWPROBE_EXT_ZVBB) ret |= AV_CPU_FLAG_RV_ZVBB; +#if HAVE_GETAUXVAL || HAVE_ELF_AUX_INFO + if (!(hwcap & HWCAP_RV('V'))) + ret &= ~AV_CPU_FLAG_RV_ZVBB; +#endif #endif switch (pairs[2].value & RISCV_HWPROBE_MISALIGNED_MASK) { case RISCV_HWPROBE_MISALIGNED_FAST: -- 2.25.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
next reply other threads:[~2025-03-14 10:33 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2025-03-14 10:32 daichengrong [this message] 2025-03-15 4:03 ` RĂ©mi Denis-Courmont
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20250314103257.3584723-1-daichengrong@iscas.ac.cn \ --to=daichengrong@iscas.ac.cn \ --cc=ffmpeg-devel@ffmpeg.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel This inbox may be cloned and mirrored by anyone: git clone --mirror https://master.gitmailbox.com/ffmpegdev/0 ffmpegdev/git/0.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 ffmpegdev ffmpegdev/ https://master.gitmailbox.com/ffmpegdev \ ffmpegdev@gitmailbox.com public-inbox-index ffmpegdev Example config snippet for mirrors. AGPL code for this site: git clone https://public-inbox.org/public-inbox.git