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Sun, 4 Apr 2021 19:20:48 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id b-KtXSnASDF0; Sun, 4 Apr 2021 19:20:48 +0200 (CEST) Received: from po16121vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4454D8B76A; Sun, 4 Apr 2021 19:20:48 +0200 (CEST) Received: by po16121vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 06D3A67685; Sun, 4 Apr 2021 17:20:48 +0000 (UTC) Message-Id: <34d20d1dbb88f26d418b33985557b0475374a1a5.1617556785.git.christophe.leroy@csgroup.eu> From: Christophe Leroy Subject: [RFC PATCH v6 1/1] cmdline: Add capability to both append and prepend at the same time To: will@kernel.org, danielwa@cisco.com, robh@kernel.org, daniel@gimpelevich.san-francisco.ca.us, arnd@kernel.org, akpm@linux-foundation.org Cc: linux-arch@vger.kernel.org, devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, microblaze , linux-mips@vger.kernel.org, nios2 , openrisc@lists.librecores.org, linux-hexagon@vger.kernel.org, linux-riscv@lists.infradead.org, x86@kernel.org, linux-xtensa@linux-xtensa.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org Date: Sun, 4 Apr 2021 17:20:48 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210404_182103_167769_9C9F2BDB X-CRM114-Status: GOOD ( 16.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org One user has expressed the need to both append and prepend some built-in parameters to the command line provided by the bootloader. Allthough it is a corner case, it is easy to implement so let's do it. When the user chooses to prepend the bootloader provided command line with the built-in command line, he is offered the possibility to enter an additionnal built-in command line to be appended after the bootloader provided command line. It is a complementary feature which has no impact on the already existing ones and/or the existing defconfig. Suggested-by: Daniel Walker Signed-off-by: Christophe Leroy --- Sending this out as an RFC, applies on top of the series ("Implement GENERIC_CMDLINE"). I will add it to the series next spin unless someone is against it. --- include/linux/cmdline.h | 3 +++ init/Kconfig | 12 +++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h index 020028e2bdf0..fb274a4d5519 100644 --- a/include/linux/cmdline.h +++ b/include/linux/cmdline.h @@ -36,6 +36,9 @@ static __always_inline bool __cmdline_build(char *dst, const char *src) len = cmdline_strlcat(dst, src, COMMAND_LINE_SIZE); + if (IS_ENABLED(CONFIG_CMDLINE_PREPEND)) + len = cmdline_strlcat(dst, " " CONFIG_CMDLINE_MORE, COMMAND_LINE_SIZE); + if (IS_ENABLED(CONFIG_CMDLINE_APPEND)) len = cmdline_strlcat(dst, " " CONFIG_CMDLINE, COMMAND_LINE_SIZE); diff --git a/init/Kconfig b/init/Kconfig index fa002e3765ab..cd3087ff4f28 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -128,6 +128,14 @@ config CMDLINE If this string is not empty, additional choices are proposed below to determine how it will be used by the kernel. +config CMDLINE_MORE + string "Additional default kernel command string" if GENERIC_CMDLINE && CMDLINE_PREPEND + default "" + help + Defines an additional default kernel command string. + If this string is not empty, it is appended to the + command-line arguments provided by the bootloader + choice prompt "Kernel command line type" if CMDLINE != "" default CMDLINE_PREPEND if ARCH_WANT_CMDLINE_PREPEND_BY_DEFAULT @@ -154,7 +162,9 @@ config CMDLINE_PREPEND bool "Prepend to the bootloader kernel arguments" help The default kernel command string will be prepended to the - command-line arguments provided by the bootloader. + command-line arguments provided by the bootloader. When this + option is selected, another string can be added which will + be appended. config CMDLINE_FORCE bool "Always use the default kernel command string"