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From:   Andrea Righi <andrea.righi@canonical.com>
To:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>
Cc:     Emil Renner Berthing <emil.renner.berthing@canonical.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: increase boot command line size to 1K
Date:   Fri, 25 Nov 2022 14:37:13 +0100
Message-Id: <20221125133713.314796-1-andrea.righi@canonical.com>
MIME-Version: 1.0
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Kernel parameters string is limited to 512 characters on riscv (using
the default from include/uapi/asm-generic/setup.h).

In some testing environments (e.g., qemu with long kernel parameters
string) we may exceed this limit, triggering errors like the following:

[    3.331893] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000
[    3.332625] CPU: 2 PID: 1 Comm: sh Not tainted 6.1.0-rc6-kc #1
[    3.333233] Hardware name: riscv-virtio,qemu (DT)
[    3.333550] Call Trace:
[    3.333736] [<ffffffff800062b6>] dump_backtrace+0x1c/0x24
[    3.334053] [<ffffffff806e8f54>] show_stack+0x2c/0x38
[    3.334260] [<ffffffff806f2d06>] dump_stack_lvl+0x5a/0x7c
[    3.334483] [<ffffffff806f2d3c>] dump_stack+0x14/0x1c
[    3.334687] [<ffffffff806e92fa>] panic+0x116/0x2d0
[    3.334878] [<ffffffff8001b0aa>] do_exit+0x80a/0x810
[    3.335079] [<ffffffff8001b1d0>] do_group_exit+0x24/0x70
[    3.335287] [<ffffffff8001b234>] __wake_up_parent+0x0/0x20
[    3.335502] [<ffffffff80003cee>] ret_from_syscall+0x0/0x2
[    3.335857] SMP: stopping secondary CPUs
[    3.337561] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000 ]---

It seems reasonable enough to increase the default command line size to
1024, like arm, to prevent issues like the one reported above.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
---
 arch/riscv/include/asm/setup.h      | 7 +++++++
 arch/riscv/include/uapi/asm/setup.h | 7 +++++++
 2 files changed, 14 insertions(+)
 create mode 100644 arch/riscv/include/asm/setup.h
 create mode 100644 arch/riscv/include/uapi/asm/setup.h

diff --git a/arch/riscv/include/asm/setup.h b/arch/riscv/include/asm/setup.h
new file mode 100644
index 000000000000..f4fe549aab40
--- /dev/null
+++ b/arch/riscv/include/asm/setup.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASMRISCV_SETUP_H
+#define __ASMRISCV_SETUP_H
+
+#include <uapi/asm/setup.h>
+
+#endif /* __ASMRISCV_SETUP_H */
diff --git a/arch/riscv/include/uapi/asm/setup.h b/arch/riscv/include/uapi/asm/setup.h
new file mode 100644
index 000000000000..5738f93ae437
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/setup.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _UAPI__ASMRISCV_SETUP_H
+#define _UAPI__ASMRISCV_SETUP_H
+
+#define COMMAND_LINE_SIZE 1024
+
+#endif /* _UAPI__ASMRISCV_SETUP_H */
-- 
2.37.2