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To: Rob Herring Cc: Will Deacon , Daniel Walker , Daniel Gimpelevich , "open list:GENERIC INCLUDE/ASM HEADER FILES" , devicetree@vger.kernel.org, linuxppc-dev , "linux-kernel@vger.kernel.org" , linux-arm-kernel , microblaze , "open list:MIPS" , nios2 , Openrisc , linux-hexagon@vger.kernel.org, linux-riscv , X86 ML , linux-xtensa@linux-xtensa.org, SH-Linux , sparclinux References: <878228ad88df38f8914c7aa25dede3ed05c50f48.1616765869.git.christophe.leroy@csgroup.eu> From: Christophe Leroy Message-ID: <58834b01-aad5-fa1e-554e-6417b2357202@csgroup.eu> Date: Fri, 26 Mar 2021 16:55:31 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 26/03/2021 à 16:42, Rob Herring a écrit : > On Fri, Mar 26, 2021 at 7:44 AM Christophe Leroy > wrote: >> >> This code provides architectures with a way to build command line >> based on what is built in the kernel and what is handed over by the >> bootloader, based on selected compile-time options. > > Note that I have this patch pending: > > https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20210316193820.3137-1-alex@ghiti.fr/ > > It's going to need to be adapted for this. I've held off applying to > see if this gets settled. good point. Hope we can't have things like option="beautiful weather" > >> >> Signed-off-by: Christophe Leroy >> --- >> v3: >> - Addressed comments from Will >> - Added capability to have src == dst >> --- >> include/linux/cmdline.h | 57 +++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 57 insertions(+) >> create mode 100644 include/linux/cmdline.h >> >> diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h >> new file mode 100644 >> index 000000000000..dea87edd41be >> --- /dev/null >> +++ b/include/linux/cmdline.h >> @@ -0,0 +1,57 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +#ifndef _LINUX_CMDLINE_H >> +#define _LINUX_CMDLINE_H >> + >> +#include >> + >> +/* Allow architectures to override strlcat, powerpc can't use strings so early */ >> +#ifndef cmdline_strlcat >> +#define cmdline_strlcat strlcat >> +#endif >> + >> +/* >> + * This function will append or prepend a builtin command line to the command >> + * line provided by the bootloader. Kconfig options can be used to alter >> + * the behavior of this builtin command line. >> + * @dst: The destination of the final appended/prepended string. >> + * @src: The starting string or NULL if there isn't one. >> + * @len: the length of dest buffer. >> + */ >> +static __always_inline void __cmdline_build(char *dst, const char *src, size_t len) >> +{ >> + if (!len || src == dst) >> + return; >> + >> + if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !src) { >> + dst[0] = 0; >> + cmdline_strlcat(dst, CONFIG_CMDLINE, len); >> + return; >> + } >> + >> + if (dst != src) >> + dst[0] = 0; >> + >> + if (IS_ENABLED(CONFIG_CMDLINE_PREPEND)) >> + cmdline_strlcat(dst, CONFIG_CMDLINE " ", len); >> + >> + cmdline_strlcat(dst, src, len); >> + >> + if (IS_ENABLED(CONFIG_CMDLINE_EXTEND)) > > Should be APPEND. Not yet. For the time being all architectures use EXTEND only. In patch 3 it is changed to: - if (IS_ENABLED(CONFIG_CMDLINE_EXTEND)) + if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || IS_ENABLED(CONFIG_CMDLINE_APPEND)) Then in last patch, I forgot but I should have done: - if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || IS_ENABLED(CONFIG_CMDLINE_APPEND)) + if (IS_ENABLED(CONFIG_CMDLINE_APPEND)) > >> + cmdline_strlcat(dst, " " CONFIG_CMDLINE, len); >> +} >> + >> +#define cmdline_build(dst, src, len) do { \ > > Perhaps a comment why we need this to be a define. Probably we don't need anymore as I finally decided to use COMMAND_LINE_SIZE instead of 'len' as the size of the temporary buffer. > >> + char *__c_dst = (dst); \ >> + const char *__c_src = (src); \ >> + \ >> + if (__c_src == __c_dst) { \ >> + static char __c_tmp[COMMAND_LINE_SIZE] __initdata = ""; \ >> + \ >> + cmdline_strlcat(__c_tmp, __c_src, COMMAND_LINE_SIZE); \ >> + __cmdline_build(__c_dst, __c_tmp, (len)); \ >> + } else { \ >> + __cmdline_build(__c_dst, __c_src, (len)); \ >> + } \ >> +} while (0) >> + >> +#endif /* _LINUX_CMDLINE_H */ >> -- >> 2.25.0 >> Christophe