linux-kernel - Re: [PATCH v2] of/fdt: Fix #ifdef dependency of early flattree declarations

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Message-ID: <CAL_JsqJH4inAKjq9eH_j-aQhwODfCYOe0Qt2nPP=jS2au99OKQ@mail.gmail.com>
Date:   Fri, 5 Jan 2018 14:26:26 -0600
From:   Rob Herring <robh+dt@...nel.org>
To:     Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Frank Rowand <frowand.list@...il.com>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] of/fdt: Fix #ifdef dependency of early flattree declarations

On Thu, Jan 4, 2018 at 3:08 AM, Geert Uytterhoeven
<geert+renesas@...der.be> wrote:
> If OF_FLATTREE=y, but OF_EARLY_FLATTREE=n:
>
>     drivers/tty/serial/earlycon.o: In function `param_setup_earlycon':
>     earlycon.c:(.init.text+0x3a4): undefined reference to `early_init_dt_scan_chosen_stdout'
>
> Fix this by moving the early flattree forward declarations and dummy
> implementations inside an #ifdef CONFIG_OF_EARLY_FLATTREE block.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> ---
> Seen after forcing OF_FLATTREE=y on sparc64 allmodconfig
> (Hi, out-of-tree OF_CONFIGFS!).
>
> v2:
>   - Move "#ifdef CONFIG_OF_EARLY_FLATTREE" section outside "#ifdef
>     CONFIG_OF_FLATTREE" section to provide dummies if !OF_FLATTREE,
>   - Move architecture-specific early_init_devtree() and
>     early_get_first_memblock_info() inside "#ifdef
>     CONFIG_OF_EARLY_FLATTREE" section.
> ---
>  include/linux/of_fdt.h | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 013c5418aeecfdbd..444e6e283828a27e 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -47,6 +47,12 @@ extern void *initial_boot_params;
>  extern char __dtb_start[];
>  extern char __dtb_end[];
>
> +/* Other Prototypes */
> +extern u64 of_flat_dt_translate_address(unsigned long node);
> +extern void of_fdt_limit_memory(int limit);
> +#endif /* CONFIG_OF_FLATTREE */
> +
> +#ifdef CONFIG_OF_EARLY_FLATTREE
>  /* For scanning the flat device-tree at boot time */
>  extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname,
>                                      int depth, void *data),
> @@ -97,16 +103,14 @@ extern void unflatten_device_tree(void);
>  extern void unflatten_and_copy_device_tree(void);
>  extern void early_init_devtree(void *);
>  extern void early_get_first_memblock_info(void *, phys_addr_t *);
> -extern u64 of_flat_dt_translate_address(unsigned long node);
> -extern void of_fdt_limit_memory(int limit);
> -#else /* CONFIG_OF_FLATTREE */
> +#else /* CONFIG_OF_EARLY_FLATTREE */
>  static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }
>  static inline void early_init_fdt_scan_reserved_mem(void) {}
>  static inline void early_init_fdt_reserve_self(void) {}
>  static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }
>  static inline void unflatten_device_tree(void) {}
>  static inline void unflatten_and_copy_device_tree(void) {}
> -#endif /* CONFIG_OF_FLATTREE */
> +#endif /* CONFIG_OF_EARLY_FLATTREE */

Really, I think most of these shouldn't need dummy versions as they
are called from DT only code, but I guess we had some need to have
them. Ideally, we'd also remove some of these and avoid any arch
specific code, but looks like most do get used. I do see some further
memblock/bootmem clean-up we can do.

Anyway, it better than it was with your change, so I've applied it.

Rob