[PATCH 1/8] of: reserve: add xn flag mem entries

Ahmad Fatoum a.fatoum at pengutronix.de
Tue Apr 20 09:45:23 BST 2021


Hello,

On 20.04.21 09:56, Rouven Czerwinski wrote:
> If the OF_RESERVE_ENTRY_FLAG_XN flag is passed while creating the
> entry, a subsequent commit will use this information in the mmu to map
> the area as non-executable.
> 
> Signed-off-by: Rouven Czerwinski <r.czerwinski at pengutronix.de>
> ---
>  arch/arm/cpu/sm.c              | 2 +-
>  arch/arm/cpu/start.c           | 2 +-
>  arch/arm/mach-layerscape/ppa.c | 2 +-
>  common/bootm.c                 | 3 ++-
>  drivers/of/fdt.c               | 6 +++++-
>  drivers/video/fb.c             | 3 ++-
>  drivers/video/simplefb-fixup.c | 2 +-
>  fs/pstore/ram.c                | 3 ++-
>  include/of.h                   | 7 +++++--
>  9 files changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/arm/cpu/sm.c b/arch/arm/cpu/sm.c
> index f5a1edbd4f..ebd5f76e14 100644
> --- a/arch/arm/cpu/sm.c
> +++ b/arch/arm/cpu/sm.c
> @@ -203,7 +203,7 @@ static int of_secure_monitor_fixup(struct device_node *root, void *unused)
>  	res_start = (unsigned long)_stext;
>  	res_end = (unsigned long)__bss_stop;
>  
> -	of_add_reserve_entry(res_start, res_end);
> +	of_add_reserve_entry(res_start, res_end, 0);
>  
>  	pr_debug("Reserved memory range from 0x%08lx to 0x%08lx\n", res_start, res_end);
>  
> diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> index c61db66865..10ac070fe3 100644
> --- a/arch/arm/cpu/start.c
> +++ b/arch/arm/cpu/start.c
> @@ -227,7 +227,7 @@ __noreturn __no_sanitize_address void barebox_non_pbl_start(unsigned long membas
>  	mem_malloc_init((void *)malloc_start, (void *)malloc_end - 1);
>  
>  	if (IS_ENABLED(CONFIG_BOOTM_OPTEE))
> -		of_add_reserve_entry(endmem - OPTEE_SIZE, endmem - 1);
> +		of_add_reserve_entry(endmem - OPTEE_SIZE, endmem - 1, OF_RESERVE_ENTRY_FLAG_XN);
>  
>  	pr_debug("starting barebox...\n");
>  
> diff --git a/arch/arm/mach-layerscape/ppa.c b/arch/arm/mach-layerscape/ppa.c
> index d962fba751..6e61766e54 100644
> --- a/arch/arm/mach-layerscape/ppa.c
> +++ b/arch/arm/mach-layerscape/ppa.c
> @@ -130,7 +130,7 @@ int ls1046a_ppa_init(resource_size_t ppa_start, resource_size_t ppa_size)
>  	if (ret)
>  		return ret;
>  
> -	of_add_reserve_entry(ppa_start, ppa_end);
> +	of_add_reserve_entry(ppa_start, ppa_end, 0);

IMO this should be mapped _XN too. Sascha, Steffen could you check
and send a patch for this?

>  
>  	return 0;
>  }
> diff --git a/common/bootm.c b/common/bootm.c
> index 092116beb9..5c2ad1ad3a 100644
> --- a/common/bootm.c
> +++ b/common/bootm.c
> @@ -410,7 +410,8 @@ void *bootm_get_devicetree(struct image_data *data)
>  	if (data->initrd_res) {
>  		of_add_initrd(data->of_root_node, data->initrd_res->start,
>  				data->initrd_res->end);
> -		of_add_reserve_entry(data->initrd_res->start, data->initrd_res->end);
> +		of_add_reserve_entry(data->initrd_res->start,
> +				     data->initrd_res->end, 0);
>  	}
>  
>  	oftree = of_get_fixed_tree(data->of_root_node);
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index d98913e54a..6aade13fa0 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -537,7 +537,8 @@ out_free:
>  
>  static struct of_reserve_map of_reserve_map;
>  
> -int of_add_reserve_entry(resource_size_t start, resource_size_t end)
> +int of_add_reserve_entry(resource_size_t start, resource_size_t end,
> +			 int flags)
>  {
>  	int e = of_reserve_map.num_entries;
>  
> @@ -548,6 +549,9 @@ int of_add_reserve_entry(resource_size_t start, resource_size_t end)
>  	of_reserve_map.end[e] = end;
>  	of_reserve_map.num_entries++;
>  
> +	if (flags & OF_RESERVE_ENTRY_FLAG_XN)
> +		of_reserve_map.xn |= BIT(e);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/video/fb.c b/drivers/video/fb.c
> index 113c1419a1..8aa4a77ef3 100644
> --- a/drivers/video/fb.c
> +++ b/drivers/video/fb.c
> @@ -202,7 +202,8 @@ static int fb_of_reserve_fixup(struct device_node *root, void *context)
>  		return 0;
>  
>  	of_add_reserve_entry((unsigned long)info->screen_base,
> -			(unsigned long)info->screen_base + info->screen_size);
> +			(unsigned long)info->screen_base + info->screen_size,
> +			0);
>  
>  	return 0;
>  }
> diff --git a/drivers/video/simplefb-fixup.c b/drivers/video/simplefb-fixup.c
> index a2c59de364..af7554d10f 100644
> --- a/drivers/video/simplefb-fixup.c
> +++ b/drivers/video/simplefb-fixup.c
> @@ -131,7 +131,7 @@ static int simplefb_create_node(struct device_node *root,
>  		return ret;
>  
>  	of_add_reserve_entry((u32)fbi->screen_base,
> -			(u32)fbi->screen_base + fbi->screen_size);
> +			(u32)fbi->screen_base + fbi->screen_size, 0);
>  
>  	return of_property_write_string(node, "status", "okay");
>  }
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 958f46b0ea..e404187c83 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -639,7 +639,8 @@ static int ramoops_probe(struct device_d *dev)
>  			  ramoops_ecc);
>  		globalvar_add_simple("linux.bootargs.ramoops", kernelargs);
>  	} else {
> -		of_add_reserve_entry(cxt->phys_addr, cxt->phys_addr + mem_size);
> +		of_add_reserve_entry(cxt->phys_addr, cxt->phys_addr + mem_size,
> +				0);
>  		of_register_fixup(ramoops_of_fixup, pdata);
>  	}
>  
> diff --git a/include/of.h b/include/of.h
> index 645f429bde..7c8640a1d6 100644
> --- a/include/of.h
> +++ b/include/of.h
> @@ -54,10 +54,13 @@ struct of_reserve_map {
>  	uint64_t start[OF_MAX_RESERVE_MAP];
>  	uint64_t end[OF_MAX_RESERVE_MAP];
>  	int num_entries;
> +	u32 xn;

I'd prefer a u16 xn : OF_MAX_RESERVE_MAP. That way the relation
is clearly documented and less likely to be overlooked should
OF_MAX_RESERVE_MAP be increased in future.

>  };
>  
> -int of_add_reserve_entry(resource_size_t start, resource_size_t end);
> -struct of_reserve_map *of_get_reserve_map(void);

Why is of_get_reserve_map being deleted?

> +#define OF_RESERVE_ENTRY_FLAG_XN		BIT(0)
> +
> +int of_add_reserve_entry(resource_size_t start, resource_size_t end,
> +		 int flags);
>  void of_clean_reserve_map(void);
>  void fdt_add_reserve_map(void *fdt);
>  
> 

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