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Subject: Re: [PATCH] MIPS/bpf: Enable bpf_probe_read{, str}() on MIPS again
To:     Tiezhu Yang <yangtiezhu@loongson.cn>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     linux-mips@vger.kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, Xuefeng Li <lixuefeng@loongson.cn>
References: <1615965307-6926-1-git-send-email-yangtiezhu@loongson.cn>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Organization: Brain-dead Software
Message-ID: <af0fec67-d858-f555-7728-7a083127b57b@gmail.com>
Date:   Wed, 17 Mar 2021 12:59:38 +0300
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On 17.03.2021 10:15, Tiezhu Yang wrote:

> After commit 0ebeea8ca8a4 ("bpf: Restrict bpf_probe_read{, str}() only to
> archs where they work"), bpf_probe_read{, str}() functions were not longer

    No longer.

> available on MIPS, so there exists some errors when running bpf program:

     Exist.

> root@linux:/home/loongson/bcc# python examples/tracing/task_switch.py
> bpf: Failed to load program: Invalid argument
> [...]
> 11: (85) call bpf_probe_read#4
> unknown func bpf_probe_read#4
> [...]
> Exception: Failed to load BPF program count_sched: Invalid argument
> 
> So select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE in arch/mips/Kconfig,
> otherwise the bpf old helper bpf_probe_read() will not be available.
> 
> This is similar with the commit d195b1d1d1196 ("powerpc/bpf: Enable
> bpf_probe_read{, str}() on powerpc again").
> 
> Fixes: 0ebeea8ca8a4 ("bpf: Restrict bpf_probe_read{, str}() only to archs where they work")
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
[...]

MBR, Sergei