Re: [PATCH v2 3/3] of: request reserved memory regions so other code can't

[Sascha Hauer <sha@pengutronix.de>]

On Thu, Jun 09, 2022 at 01:18:10PM +0200, Ahmad Fatoum wrote:
> Add a new of_reserved_mem_walk that can be used to request
> reserved memory regions. This avoids e.g. bootm trying to
> place the kernel into a reserved region.
> 
> Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v1 -> v2:
>   - don't use of_reserve_entry accounting and instead
>     directly request memory (Sascha)
> ---
>  common/memory.c           | 21 ++++++++++--
>  drivers/of/Makefile       |  1 +
>  drivers/of/reserved-mem.c | 71 +++++++++++++++++++++++++++++++++++++++
>  include/of.h              |  9 +++++
>  4 files changed, 99 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/of/reserved-mem.c
> 
> diff --git a/common/memory.c b/common/memory.c
> index 95995bb6e310..fd782c7f24f6 100644
> --- a/common/memory.c
> +++ b/common/memory.c
> @@ -3,6 +3,8 @@
>   * Copyright (c) 2011 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
>   */
>  
> +#define pr_fmt(fmt) "memory: " fmt
> +
>  #include <common.h>
>  #include <memory.h>
>  #include <of.h>
> @@ -12,6 +14,7 @@
>  #include <asm-generic/memory_layout.h>
>  #include <asm/sections.h>
>  #include <malloc.h>
> +#include <of.h>
>  
>  /*
>   * Begin and End of memory area for malloc(), and current "brk"
> @@ -53,9 +56,20 @@ void mem_malloc_init(void *start, void *end)
>  	mem_malloc_initialized = 1;
>  }
>  
> -#if !defined __SANDBOX__
> +static int request_reservation(const struct resource *res)
> +{
> +	if (!(res->flags & IORESOURCE_EXCLUSIVE))
> +		return 0;
> +
> +	pr_debug("region %s %pa-%pa\n", res->name, &res->start, &res->end);
> +
> +	request_sdram_region(res->name, res->start, resource_size(res));
> +	return 0;
> +}
> +
>  static int mem_malloc_resource(void)
>  {
> +#if !defined __SANDBOX__
>  	/*
>  	 * Normally it's a bug when one of these fails,
>  	 * but we have some setups where some of these
> @@ -77,13 +91,14 @@ static int mem_malloc_resource(void)
>  			(unsigned long)&__bss_start,
>  			(unsigned long)&__bss_stop -
>  			(unsigned long)&__bss_start);
> +#endif
>  #ifdef STACK_BASE
>  	request_sdram_region("stack", STACK_BASE, STACK_SIZE);
>  #endif
> -	return 0;
> +
> +	return of_reserved_mem_walk(request_reservation);
>  }
>  coredevice_initcall(mem_malloc_resource);
> -#endif
>  
>  static void *sbrk_no_zero(ptrdiff_t increment)
>  {
> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
> index ca8da71cb4f0..99b610cba85e 100644
> --- a/drivers/of/Makefile
> +++ b/drivers/of/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_OF_GPIO) += of_gpio.o
>  obj-$(CONFIG_OF_PCI) += of_pci.o
>  obj-y += partition.o
>  obj-y += of_net.o
> +obj-$(CONFIG_OFDEVICE) += reserved-mem.o

Compilation of this file depends on CONFIG_OFDEVICE, but the static
inline wrapper or not decision depends on CONFIG_OFTREE. This breaks a
number of defconfigs.
I took the easiest way out for now and changed to obj-y above to fix
this.

Sascha

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