Re: [ 105/128] efi: Make efi_enabled a function to query EFI facilities

[Ben Hutchings <ben@decadent.org.uk>]

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On Sun, 2013-02-03 at 15:48 +0100, Ben Hutchings wrote:
> 3.2-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Matt Fleming <matt.fleming@intel.com>
> 
> commit 83e68189745ad931c2afd45d8ee3303929233e7f upstream.
[...]
> [bwh: Backported to 3.2:
>  - Adjust context (a lot)
>  - Add efi_is_native() function from commit 5189c2a7c776
>    ('x86: efi: Turn off efi_enabled after setup on mixed fw/kernel')
>  - Make efi_init() bail out when booted non-native, as it would previously
>    not be called in this case
>  - Drop inapplicable changes to start_kernel()]
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

As you can see this needed quite a lot of work to backport, and I
haven't been able to test it yet.  So I would particularly appreciate
careful review of this.

Ben.

> ---
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -90,6 +90,7 @@ extern void __iomem *efi_ioremap(unsigne
>  #endif /* CONFIG_X86_32 */
>  
>  extern int add_efi_memmap;
> +extern unsigned long x86_efi_facility;
>  extern void efi_set_executable(efi_memory_desc_t *md, bool executable);
>  extern void efi_memblock_x86_reserve_range(void);
>  extern void efi_call_phys_prelog(void);
> --- a/arch/x86/kernel/reboot.c
> +++ b/arch/x86/kernel/reboot.c
> @@ -603,7 +603,7 @@ static void native_machine_emergency_res
>  			break;
>  
>  		case BOOT_EFI:
> -			if (efi_enabled)
> +			if (efi_enabled(EFI_RUNTIME_SERVICES))
>  				efi.reset_system(reboot_mode ?
>  						 EFI_RESET_WARM :
>  						 EFI_RESET_COLD,
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -750,15 +750,16 @@ void __init setup_arch(char **cmdline_p)
>  #endif
>  #ifdef CONFIG_EFI
>  	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
> -#ifdef CONFIG_X86_32
> -		     "EL32",
> -#else
> -		     "EL64",
> -#endif
> -	 4)) {
> -		efi_enabled = 1;
> -		efi_memblock_x86_reserve_range();
> +		     "EL32", 4)) {
> +		set_bit(EFI_BOOT, &x86_efi_facility);
> +	} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
> +		     "EL64", 4)) {
> +		set_bit(EFI_BOOT, &x86_efi_facility);
> +		set_bit(EFI_64BIT, &x86_efi_facility);
>  	}
> +
> +	if (efi_enabled(EFI_BOOT))
> +		efi_memblock_x86_reserve_range();
>  #endif
>  
>  	x86_init.oem.arch_setup();
> @@ -831,7 +832,7 @@ void __init setup_arch(char **cmdline_p)
>  
>  	finish_e820_parsing();
>  
> -	if (efi_enabled)
> +	if (efi_enabled(EFI_BOOT))
>  		efi_init();
>  
>  	dmi_scan_machine();
> @@ -914,7 +915,7 @@ void __init setup_arch(char **cmdline_p)
>  	 * The EFI specification says that boot service code won't be called
>  	 * after ExitBootServices(). This is, in fact, a lie.
>  	 */
> -	if (efi_enabled)
> +	if (efi_enabled(EFI_MEMMAP))
>  		efi_reserve_boot_services();
>  
>  	/* preallocate 4k for mptable mpc */
> @@ -1048,7 +1049,7 @@ void __init setup_arch(char **cmdline_p)
>  
>  #ifdef CONFIG_VT
>  #if defined(CONFIG_VGA_CONSOLE)
> -	if (!efi_enabled || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
> +	if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
>  		conswitchp = &vga_con;
>  #elif defined(CONFIG_DUMMY_CONSOLE)
>  	conswitchp = &dummy_con;
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -49,9 +49,6 @@
>  #define EFI_DEBUG	1
>  #define PFX 		"EFI: "
>  
> -int efi_enabled;
> -EXPORT_SYMBOL(efi_enabled);
> -
>  struct efi __read_mostly efi = {
>  	.mps        = EFI_INVALID_TABLE_ADDR,
>  	.acpi       = EFI_INVALID_TABLE_ADDR,
> @@ -70,9 +67,25 @@ struct efi_memory_map memmap;
>  static struct efi efi_phys __initdata;
>  static efi_system_table_t efi_systab __initdata;
>  
> +static inline bool efi_is_native(void)
> +{
> +	return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT);
> +}
> +
> +unsigned long x86_efi_facility;
> +
> +/*
> + * Returns 1 if 'facility' is enabled, 0 otherwise.
> + */
> +int efi_enabled(int facility)
> +{
> +	return test_bit(facility, &x86_efi_facility) != 0;
> +}
> +EXPORT_SYMBOL(efi_enabled);
> +
>  static int __init setup_noefi(char *arg)
>  {
> -	efi_enabled = 0;
> +	clear_bit(EFI_BOOT, &x86_efi_facility);
>  	return 0;
>  }
>  early_param("noefi", setup_noefi);
> @@ -440,6 +453,9 @@ void __init efi_init(void)
>  	int i = 0;
>  	void *tmp;
>  
> +	if (!efi_is_native())
> +		return;
> +
>  #ifdef CONFIG_X86_32
>  	efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
>  #else
> @@ -467,6 +483,8 @@ void __init efi_init(void)
>  		       efi.systab->hdr.revision >> 16,
>  		       efi.systab->hdr.revision & 0xffff);
>  
> +	set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
> +
>  	/*
>  	 * Show what we know for posterity
>  	 */
> @@ -529,6 +547,8 @@ void __init efi_init(void)
>  	early_iounmap(config_tables,
>  			  efi.systab->nr_tables * sizeof(efi_config_table_t));
>  
> +	set_bit(EFI_CONFIG_TABLES, &x86_efi_facility);
> +
>  	/*
>  	 * Check out the runtime services table. We need to map
>  	 * the runtime services table so that we can grab the physical
> @@ -552,6 +572,8 @@ void __init efi_init(void)
>  		 * virtual mode.
>  		 */
>  		efi.get_time = phys_efi_get_time;
> +
> +		set_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility);
>  	} else
>  		printk(KERN_ERR "Could not map the EFI runtime service "
>  		       "table!\n");
> @@ -571,6 +593,8 @@ void __init efi_init(void)
>  	if (add_efi_memmap)
>  		do_add_efi_memmap();
>  
> +	set_bit(EFI_MEMMAP, &x86_efi_facility);
> +
>  #ifdef CONFIG_X86_32
>  	x86_platform.get_wallclock = efi_get_time;
>  	x86_platform.set_wallclock = efi_set_rtc_mmss;
> @@ -747,6 +771,7 @@ void __init efi_enter_virtual_mode(void)
>  	efi.query_capsule_caps = virt_efi_query_capsule_caps;
>  	if (__supported_pte_mask & _PAGE_NX)
>  		runtime_code_page_mkexec();
> +	clear_bit(EFI_MEMMAP, &x86_efi_facility);
>  	early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
>  	memmap.map = NULL;
>  	kfree(new_memmap);
> @@ -760,6 +785,9 @@ u32 efi_mem_type(unsigned long phys_addr
>  	efi_memory_desc_t *md;
>  	void *p;
>  
> +	if (!efi_enabled(EFI_MEMMAP))
> +		return 0;
> +
>  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
>  		md = p;
>  		if ((md->phys_addr <= phys_addr) &&
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -255,7 +255,7 @@ acpi_physical_address __init acpi_os_get
>  		return acpi_rsdp;
>  #endif
>  
> -	if (efi_enabled) {
> +	if (efi_enabled(EFI_CONFIG_TABLES)) {
>  		if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
>  			return efi.acpi20;
>  		else if (efi.acpi != EFI_INVALID_TABLE_ADDR)
> --- a/drivers/firmware/dmi_scan.c
> +++ b/drivers/firmware/dmi_scan.c
> @@ -432,7 +432,7 @@ void __init dmi_scan_machine(void)
>  	char __iomem *p, *q;
>  	int rc;
>  
> -	if (efi_enabled) {
> +	if (efi_enabled(EFI_CONFIG_TABLES)) {
>  		if (efi.smbios == EFI_INVALID_TABLE_ADDR)
>  			goto error;
>  
> --- a/drivers/firmware/efivars.c
> +++ b/drivers/firmware/efivars.c
> @@ -1222,7 +1222,7 @@ efivars_init(void)
>  	printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
>  	       EFIVARS_DATE);
>  
> -	if (!efi_enabled)
> +	if (!efi_enabled(EFI_RUNTIME_SERVICES))
>  		return 0;
>  
>  	/* For now we'll register the efi directory at /sys/firmware/efi */
> @@ -1260,7 +1260,7 @@ err_put:
>  static void __exit
>  efivars_exit(void)
>  {
> -	if (efi_enabled) {
> +	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
>  		unregister_efivars(&__efivars);
>  		kobject_put(efi_kobj);
>  	}
> --- a/drivers/firmware/iscsi_ibft_find.c
> +++ b/drivers/firmware/iscsi_ibft_find.c
> @@ -99,7 +99,7 @@ unsigned long __init find_ibft_region(un
>  	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
>  	 * only use ACPI for this */
>  
> -	if (!efi_enabled)
> +	if (!efi_enabled(EFI_BOOT))
>  		find_ibft_in_mem();
>  
>  	if (ibft_addr) {
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -354,7 +354,8 @@ bool radeon_card_posted(struct radeon_de
>  {
>  	uint32_t reg;
>  
> -	if (efi_enabled && rdev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE)
> +	if (efi_enabled(EFI_BOOT) &&
> +	    rdev->pdev->subsystem_vendor == PCI_VENDOR_ID_APPLE)
>  		return false;
>  
>  	/* first check CRTCs */
> --- a/drivers/platform/x86/ibm_rtl.c
> +++ b/drivers/platform/x86/ibm_rtl.c
> @@ -255,7 +255,7 @@ static int __init ibm_rtl_init(void) {
>  	if (force)
>  		pr_warn("module loaded by force\n");
>  	/* first ensure that we are running on IBM HW */
> -	else if (efi_enabled || !dmi_check_system(ibm_rtl_dmi_table))
> +	else if (efi_enabled(EFI_BOOT) || !dmi_check_system(ibm_rtl_dmi_table))
>  		return -ENODEV;
>  
>  	/* Get the address for the Extended BIOS Data Area */
> --- a/drivers/scsi/isci/init.c
> +++ b/drivers/scsi/isci/init.c
> @@ -459,7 +459,7 @@ static int __devinit isci_pci_probe(stru
>  		return -ENOMEM;
>  	pci_set_drvdata(pdev, pci_info);
>  
> -	if (efi_enabled)
> +	if (efi_enabled(EFI_RUNTIME_SERVICES))
>  		orom = isci_get_efi_var(pdev);
>  
>  	if (!orom)
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -364,17 +364,30 @@ extern int __init efi_setup_pcdp_console
>  #endif
>  
>  /*
> - * We play games with efi_enabled so that the compiler will, if possible, remove
> - * EFI-related code altogether.
> + * We play games with efi_enabled so that the compiler will, if
> + * possible, remove EFI-related code altogether.
>   */
> +#define EFI_BOOT		0	/* Were we booted from EFI? */
> +#define EFI_SYSTEM_TABLES	1	/* Can we use EFI system tables? */
> +#define EFI_CONFIG_TABLES	2	/* Can we use EFI config tables? */
> +#define EFI_RUNTIME_SERVICES	3	/* Can we use runtime services? */
> +#define EFI_MEMMAP		4	/* Can we use EFI memory map? */
> +#define EFI_64BIT		5	/* Is the firmware 64-bit? */
> +
>  #ifdef CONFIG_EFI
>  # ifdef CONFIG_X86
> -   extern int efi_enabled;
> +extern int efi_enabled(int facility);
>  # else
> -#  define efi_enabled 1
> +static inline int efi_enabled(int facility)
> +{
> +	return 1;
> +}
>  # endif
>  #else
> -# define efi_enabled 0
> +static inline int efi_enabled(int facility)
> +{
> +	return 0;
> +}
>  #endif
>  
>  /*
> --- a/init/main.c
> +++ b/init/main.c
> @@ -606,7 +606,7 @@ asmlinkage void __init start_kernel(void
>  	pidmap_init();
>  	anon_vma_init();
>  #ifdef CONFIG_X86
> -	if (efi_enabled)
> +	if (efi_enabled(EFI_RUNTIME_SERVICES))
>  		efi_enter_virtual_mode();
>  #endif
>  	thread_info_cache_init();
> 
> 
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> 

-- 
Ben Hutchings
Everything should be made as simple as possible, but not simpler.
                                                           - Albert Einstein

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