Re: [PATCH 31/42] x86, efi: Copy SETUP_EFI data and access directly

[Matt Fleming <matt@codeblueprint.co.uk>]

(Pulling in Dave since he wrote the code)

On Tue, 07 Jul, at 01:20:17PM, Yinghai Lu wrote:
> The copy will be in __initdata, and it is small.
> 
> We can use pointer to access the setup_data instead of using early_memmap
> everywhere.
 
Is that the only advantage to copying the data, that we save ourselves
the overhead of calling early_memremap()? That seems fair enough, I just
want to be clear.

> Cc: Matt Fleming <matt.fleming@intel.com>
> Cc: linux-efi@vger.kernel.org
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> ---
>  arch/x86/include/asm/efi.h     |  2 +-
>  arch/x86/platform/efi/efi.c    | 13 ++-----------
>  arch/x86/platform/efi/efi_64.c | 10 +++++++++-
>  arch/x86/platform/efi/quirks.c | 23 ++++++-----------------
>  4 files changed, 18 insertions(+), 30 deletions(-)
> 
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index 155162e..a3e3aee 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -116,7 +116,7 @@ struct efi_setup_data {
>  	u64 reserved[8];
>  };
>  
> -extern u64 efi_setup;
> +extern struct efi_setup_data *efi_setup;
>  
>  #ifdef CONFIG_EFI
>  
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index cfba30f..33036ce 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -68,7 +68,7 @@ static efi_config_table_type_t arch_tables[] __initdata = {
>  	{NULL_GUID, NULL, NULL},
>  };
>  
> -u64 efi_setup;		/* efi setup_data physical address */
> +struct efi_setup_data *efi_setup __initdata; /* cached efi setup_data pointer */
>  
>  static int add_efi_memmap __initdata;
>  static int __init setup_add_efi_memmap(char *arg)
> @@ -257,20 +257,13 @@ static int __init efi_systab_init(void *phys)
>  {
>  	if (efi_enabled(EFI_64BIT)) {
>  		efi_system_table_64_t *systab64;
> -		struct efi_setup_data *data = NULL;
> +		struct efi_setup_data *data = efi_setup;
>  		u64 tmp = 0;
>  
> -		if (efi_setup) {
> -			data = early_memremap(efi_setup, sizeof(*data));
> -			if (!data)
> -				return -ENOMEM;
> -		}
>  		systab64 = early_memremap((unsigned long)phys,
>  					 sizeof(*systab64));
>  		if (systab64 == NULL) {
>  			pr_err("Couldn't map the system table!\n");
> -			if (data)
> -				early_memunmap(data, sizeof(*data));
>  			return -ENOMEM;
>  		}
>  
> @@ -303,8 +296,6 @@ static int __init efi_systab_init(void *phys)
>  		tmp |= data ? data->tables : systab64->tables;
>  
>  		early_memunmap(systab64, sizeof(*systab64));
> -		if (data)
> -			early_memunmap(data, sizeof(*data));
>  #ifdef CONFIG_X86_32
>  		if (tmp >> 32) {
>  			pr_err("EFI data located above 4GB, disabling EFI.\n");
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index a0ac0f9..a255491 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -295,9 +295,17 @@ void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
>  	return (void __iomem *)__va(phys_addr);
>  }
>  
> +static struct efi_setup_data efi_setup_data __initdata;
> +
>  void __init parse_efi_setup(u64 phys_addr, u32 data_len)
>  {
> -	efi_setup = phys_addr + sizeof(struct setup_data);
> +	struct efi_setup_data *data;
> +
> +	data = early_memremap(phys_addr + sizeof(struct setup_data),
> +			      sizeof(*data));
> +	efi_setup_data = *data;
> +	early_memunmap(data, sizeof(*data));
> +	efi_setup = &efi_setup_data;
>  }
>  
>  void __init efi_runtime_mkexec(void)
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index 1c7380d..45fec7d 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -203,9 +203,8 @@ void __init efi_free_boot_services(void)
>   */
>  int __init efi_reuse_config(u64 tables, int nr_tables)
>  {
> -	int i, sz, ret = 0;
> +	int i, sz;
>  	void *p, *tablep;
> -	struct efi_setup_data *data;
>  
>  	if (!efi_setup)
>  		return 0;
> @@ -213,22 +212,15 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
>  	if (!efi_enabled(EFI_64BIT))
>  		return 0;
>  
> -	data = early_memremap(efi_setup, sizeof(*data));
> -	if (!data) {
> -		ret = -ENOMEM;
> -		goto out;
> -	}
> -
> -	if (!data->smbios)
> -		goto out_memremap;
> +	if (!efi_setup->smbios)
> +		return 0;
>  
>  	sz = sizeof(efi_config_table_64_t);
>  
>  	p = tablep = early_memremap(tables, nr_tables * sz);
>  	if (!p) {
>  		pr_err("Could not map Configuration table!\n");
> -		ret = -ENOMEM;
> -		goto out_memremap;
> +		return -ENOMEM;
>  	}
>  
>  	for (i = 0; i < efi.systab->nr_tables; i++) {
> @@ -237,15 +229,12 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
>  		guid = ((efi_config_table_64_t *)p)->guid;
>  
>  		if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
> -			((efi_config_table_64_t *)p)->table = data->smbios;
> +			((efi_config_table_64_t *)p)->table = efi_setup->smbios;
>  		p += sz;
>  	}
>  	early_memunmap(tablep, nr_tables * sz);
>  
> -out_memremap:
> -	early_memunmap(data, sizeof(*data));
> -out:
> -	return ret;
> +	return 0;
>  }
>  
>  void __init efi_apply_memmap_quirks(void)
> -- 
> 1.8.4.5
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

-- 
Matt Fleming, Intel Open Source Technology Center