On Fri, Mar 26, 2021 at 7:44 AM Christophe Leroy <christophe.leroy@xxxxxxxxxx> 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@xxxxxxxx/ It's going to need to be adapted for this. I've held off applying to see if this gets settled. > > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> > --- > 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 <linux/string.h> > + > +/* 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. > + cmdline_strlcat(dst, " " CONFIG_CMDLINE, len); > +} > + > +#define cmdline_build(dst, src, len) do { \ Perhaps a comment why we need this to be a define. > + 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 >
