Re: [PATCH v4 18/20] x86: Convert to GENERIC_CMDLINE

[Christophe Leroy]

Le 08/04/2021 à 21:41, Rob Herring a écrit :
On Fri, Apr 02, 2021 at 03:18:20PM +0000, Christophe Leroy wrote:
This converts the architecture to GENERIC_CMDLINE.

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
  arch/x86/Kconfig        | 45 ++---------------------------------------
  arch/x86/kernel/setup.c | 17 ++--------------
  2 files changed, 4 insertions(+), 58 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a20684d56b4b..66b384228ca3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -104,6 +104,7 @@ config X86
        select ARCH_USE_QUEUED_SPINLOCKS
        select ARCH_USE_SYM_ANNOTATIONS
        select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
+       select ARCH_WANT_CMDLINE_PREPEND_BY_DEFAULT

Seems to be non-existent kconfig option.

Oops. Added in v5.

@@ -883,18 +881,7 @@ void __init setup_arch(char **cmdline_p)
        bss_resource.start = __pa_symbol(__bss_start);
        bss_resource.end = __pa_symbol(__bss_stop)-1;
  
-#ifdef CONFIG_CMDLINE_BOOL
-#ifdef CONFIG_CMDLINE_FORCE
-       strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
-#else
-       if (builtin_cmdline[0]) {
-               /* append boot loader cmdline to builtin */
-               strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
-               strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
-               strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
-       }
-#endif
-#endif
+       cmdline_build(boot_command_line, boot_command_line);
  
  	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
        *cmdline_p = command_line;

Once this is all done, I wonder if we can get rid of the strlcpy and
perhaps also cmdline_p.


It seems rather complicated, in init/main.c you have heavy manipulations of command lines which 
seems to be done in setup_command_line() which seems to add stuff in front of command lines, at the 
end we end up with several command lines:

/* Untouched saved command line (eg. for /proc) */
char *saved_command_line;
/* Command line for parameter parsing */
static char *static_command_line;
/* Untouched extra command line */
static char *extra_command_line;

Some of them come from the cmdline_p which others are from boot_command_line.

I think a cleanup on all that stuff would be worth it as a further step.