Commit 8ce355cf2e38 ("MIPS: Setup boot_command_line before plat_mem_setup") fixed a problem for systems which have CONFIG_CMDLINE_BOOL=y & use a DT with a chosen node that has either no bootargs property or an empty one. In this configuration early_init_dt_scan_chosen() copies CONFIG_CMDLINE into boot_command_line, but the MIPS code doesn't know this so it appends CONFIG_CMDLINE (via builtin_cmdline) to boot_command_line again. The result is that boot_command_line contains the arguments from CONFIG_CMDLINE twice.
That commit took the approach of simply setting up boot_command_line from the MIPS code before early_init_dt_scan_chosen() runs, causing it not to copy CONFIG_CMDLINE to boot_command_line if a chosen node with no bootargs property is found.
Unfortunately this is problematic for systems which do have a non-empty bootargs property & CONFIG_CMDLINE_BOOL=y. There early_init_dt_scan_chosen() will overwrite boot_command_line with the arguments from DT, which means we lose those from CONFIG_CMDLINE entirely. This breaks CONFIG_MIPS_CMDLINE_DTB_EXTEND. If we have CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER or CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND selected and the DT has a bootargs property which we should ignore, it will instead be honoured breaking those configurations too.
Fix this by reverting commit 8ce355cf2e38 ("MIPS: Setup boot_command_line before plat_mem_setup") to restore the former behaviour, and fixing the CONFIG_CMDLINE duplication issue by initializing boot_command_line to a non-empty string that early_init_dt_scan_chosen() will not overwrite with CONFIG_CMDLINE.
This is a little ugly, but cleanup in this area is on its way. In the meantime this is at least easy to backport & contains the ugliness within arch/mips/.
Signed-off-by: Paul Burton paul.burton@mips.com Fixes: 8ce355cf2e38 ("MIPS: Setup boot_command_line before plat_mem_setup") References: https://patchwork.linux-mips.org/patch/18804/ Cc: Frank Rowand frowand.list@gmail.com Cc: Jaedon Shin jaedon.shin@gmail.com Cc: Mathieu Malaterre malat@debian.org Cc: Rob Herring robh+dt@kernel.org Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # v4.16+ --- This isn't pretty, but further cleanup is underway [1] and this fixes the regression in an easily backportable manner without adding another per-architecture function like v1.
[1] https://www.spinics.net/lists/kernel/msg2918275.html
Changes in v2: - Drop the arch-specific function & just initialize boot_command_line such that early_init_dt_scan_chosen() won't overwrite it with CONFIG_CMDLINE.
v1: https://marc.info/?l=linux-mips&m=153634652318477&w=2 https://marc.info/?l=linux-mips&m=153634653718485&w=2 --- arch/mips/kernel/setup.c | 48 +++++++++++++++++++++++----------------- 1 file changed, 28 insertions(+), 20 deletions(-)
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index c71d1eb7da59..8aaaa42f91ed 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -846,6 +846,34 @@ static void __init arch_mem_init(char **cmdline_p) struct memblock_region *reg; extern void plat_mem_setup(void);
+ /* + * Initialize boot_command_line to an innocuous but non-empty string in + * order to prevent early_init_dt_scan_chosen() from copying + * CONFIG_CMDLINE into it without our knowledge. We handle + * CONFIG_CMDLINE ourselves below & don't want to duplicate its + * content because repeating arguments can be problematic. + */ + strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE); + + /* call board setup routine */ + plat_mem_setup(); + + /* + * Make sure all kernel memory is in the maps. The "UP" and + * "DOWN" are opposite for initdata since if it crosses over + * into another memory section you don't want that to be + * freed when the initdata is freed. + */ + arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT, + PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT, + BOOT_MEM_RAM); + arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT, + PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT, + BOOT_MEM_INIT_RAM); + + pr_info("Determined physical RAM map:\n"); + print_memory_map(); + #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE) strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); #else @@ -873,26 +901,6 @@ static void __init arch_mem_init(char **cmdline_p) } #endif #endif - - /* call board setup routine */ - plat_mem_setup(); - - /* - * Make sure all kernel memory is in the maps. The "UP" and - * "DOWN" are opposite for initdata since if it crosses over - * into another memory section you don't want that to be - * freed when the initdata is freed. - */ - arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT, - PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT, - BOOT_MEM_RAM); - arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT, - PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT, - BOOT_MEM_INIT_RAM); - - pr_info("Determined physical RAM map:\n"); - print_memory_map(); - strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;