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From:   Evan Green <evan@rivosinc.com>
Date:   Wed, 5 Jul 2023 08:51:24 -0700
Message-ID: <CALs-Hsua+Y9EvZAz0vX=2-2MmuOcnZQ8zYyiZP+2Y873mEgQeQ@mail.gmail.com>
Subject: Re: [PATCH v3 01/11] RISC-V: Provide a more helpful error message on
 invalid ISA strings
To:     Conor Dooley <conor.dooley@microchip.com>
Cc:     palmer@dabbelt.com, conor@kernel.org,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Jonathan Corbet <corbet@lwn.net>,
        Andrew Jones <ajones@ventanamicro.com>,
        Heiko Stuebner <heiko.stuebner@vrull.eu>,
        Sunil V L <sunilvl@ventanamicro.com>,
        linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Palmer Dabbelt <palmer@rivosinc.com>
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On Mon, Jul 3, 2023 at 3:29=E2=80=AFAM Conor Dooley <conor.dooley@microchip=
.com> wrote:
>
> From: Palmer Dabbelt <palmer@rivosinc.com>
>
> Right now we provide a somewhat unhelpful error message on systems with
> invalid error messages, something along the lines of
>
>         CPU with hartid=3D0 is not available
>         ------------[ cut here ]------------
>         kernel BUG at arch/riscv/kernel/smpboot.c:174!
>         Kernel BUG [#1]
>         Modules linked in:
>         CPU: 0 PID: 0 Comm: swapper Not tainted 6.4.0-rc1-00096-ge0097d2c=
62d5-dirty #1
>         Hardware name: Microchip PolarFire-SoC Icicle Kit (DT)
>         epc : of_parse_and_init_cpus+0x16c/0x16e
>          ra : of_parse_and_init_cpus+0x9a/0x16e
>         epc : ffffffff80c04e0a ra : ffffffff80c04d38 sp : ffffffff81603e2=
0
>          gp : ffffffff8182d658 tp : ffffffff81613f80 t0 : 000000000000006=
e
>          t1 : 0000000000000064 t2 : 0000000000000000 s0 : ffffffff81603e8=
0
>          s1 : 0000000000000000 a0 : 0000000000000000 a1 : 000000000000000=
0
>          a2 : 0000000000000000 a3 : 0000000000000000 a4 : 000000000000000=
0
>          a5 : 0000000000001fff a6 : 0000000000001fff a7 : ffffffff816148b=
0
>          s2 : 0000000000000001 s3 : ffffffff81492a4c s4 : ffffffff81a4b09=
0
>          s5 : ffffffff81506030 s6 : 0000000000000040 s7 : 000000000000000=
0
>          s8 : 00000000bfb6f046 s9 : 0000000000000001 s10: 000000000000000=
0
>          s11: 00000000bf389700 t3 : 0000000000000000 t4 : 000000000000000=
0
>          t5 : ffffffff824dd188 t6 : ffffffff824dd187
>         status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000=
000000003
>         [<ffffffff80c04e0a>] of_parse_and_init_cpus+0x16c/0x16e
>         [<ffffffff80c04c96>] setup_smp+0x1e/0x26
>         [<ffffffff80c03ffe>] setup_arch+0x6e/0xb2
>         [<ffffffff80c00384>] start_kernel+0x72/0x400
>         Code: 80e7 4a00 a603 0009 b795 1097 ffe5 80e7 92c0 9002 (9002) 71=
5d
>         ---[ end trace 0000000000000000 ]---
>         Kernel panic - not syncing: Fatal exception in interrupt
>
> Add a warning for the cases where the ISA string isn't valid.  It's still
> above the BUG_ON cut, but hopefully it's at least a bit easier for users.
>
> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Reviewed-by: Evan Green <evan@rivosinc.com>