On Fri, Sep 7, 2018 at 8:55 PM Paul Burton <paul.burton@xxxxxxxx> wrote:
>
> 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 instead
> providing a no-op implementation of early_init_dt_fixup_cmdline_arch()
> to prevent early_init_dt_scan_chosen() from using CONFIG_CMDLINE.
Sorry I cannot test this patch ATM. I've simply CCed Paul C. just in case.
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
> Fixes: 8ce355cf2e38 ("MIPS: Setup boot_command_line before plat_mem_setup")
> References: https://patchwork.linux-mips.org/patch/18804/
> Cc: Frank Rowand <frowand.list@xxxxxxxxx>
> Cc: Jaedon Shin <jaedon.shin@xxxxxxxxx>
> Cc: Mathieu Malaterre <malat@xxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-mips@xxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx # v4.16+
> ---
> arch/mips/kernel/setup.c | 47 +++++++++++++++++++++++-----------------
> 1 file changed, 27 insertions(+), 20 deletions(-)
>
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index c71d1eb7da59..7f755bc8a91c 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -841,11 +841,38 @@ static void __init request_crashkernel(struct resource *res)
> #define BUILTIN_EXTEND_WITH_PROM \
> IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)
>
> +void __init early_init_dt_fixup_cmdline_arch(char *data)
> +{
> + /*
> + * Do nothing - arch_mem_init() will assemble our command line below,
> + * for both the DT & non-DT cases.
> + */
> +}
> +
> static void __init arch_mem_init(char **cmdline_p)
> {
> struct memblock_region *reg;
> extern void plat_mem_setup(void);
>
> + /* 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 +900,6 @@ 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;
> --
> 2.18.0
>
