On Wed, Aug 06, 2014 at 04:38:25PM +0800, Dave Young wrote: > > Adding a noefi boot param like in X86 to disable efi runtime services support. > > This will be useful for debugging uefi problems. Also it will be useful > for later kexec/kdump work. Kexec on uefi support in X86 depends on a fixed vm > area specific for uefi runtime 1:1 mapping, kernel will switch to a different > page table for any uefi runtime callback in virtual mode. In arm64 similar > work probably is necessary. But kexec boot will just works with 'noefi' with > the limitaion of lacking runtime services. The runtime services is not critical > for kdump kernel for now. So as for kexec/kdump just leave the 1:1 mapping a > future work. Since this is really turning an x86-specific feature into a generic one, could it be moved to core code? Maybe an efi.mask, reusing the efi_enabled defines, with an efi_disabled macro? Also, since this patch (and its x86 predecessor) is not really "noefi", could this be integrated with the "efi=" patch (http://permalink.gmane.org/gmane.linux.kernel.efi/4405), as an efi=noruntime option? On x86, due to CSM, "noefi" was a useful fallback for completely broken (U)EFI implementations - but on an arm* UEFI system, there will be no fallback. Could it be wrapped in a kernel hacking config option? Partial code description, not even compile tested: --- diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index 14db1f6..a295a5c 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -386,7 +386,7 @@ static int __init arm64_enter_virtual_mode(void) int count = 0; unsigned long flags; - if (!efi_enabled(EFI_BOOT)) { + if (!efi_enabled(EFI_BOOT) || efi_disabled(EFI_RUNTIME_SERVICES)) { pr_info("EFI services will not be available.\n"); return -1; } diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 87fc96b..b59a7c6 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -77,14 +77,6 @@ static efi_config_table_type_t arch_tables[] __initdata = { u64 efi_setup; /* efi setup_data physical address */ -static bool disable_runtime __initdata = false; -static int __init setup_noefi(char *arg) -{ - disable_runtime = true; - return 0; -} -early_param("noefi", setup_noefi); - int add_efi_memmap; EXPORT_SYMBOL(add_efi_memmap); @@ -764,7 +756,7 @@ void __init efi_init(void) if (!efi_runtime_supported()) pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n"); else { - if (disable_runtime || efi_runtime_init()) + if (efi_disabled(EFI_RUNTIME_SERVICES) || efi_runtime_init()) return; } if (efi_memmap_init()) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index dc79346..ffc4a45 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -43,6 +43,15 @@ EXPORT_SYMBOL(efi); static struct kobject *efi_kobj; static struct kobject *efivars_kobj; +static int __init setup_noefi(char *arg) +{ +#if defined(CONFIG_X86) || defined(CONFIG_EFI_DEBUG) + set_bit(EFI_RUNTIME_SERVICES, &efi.mask); +#endif + return 0; +} +early_param("noefi", setup_noefi); + /* * Let's not leave out systab information that snuck into * the efivars driver diff --git a/include/linux/efi.h b/include/linux/efi.h index 41bbf8b..9533d0e 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -826,6 +826,7 @@ extern struct efi { efi_set_virtual_address_map_t *set_virtual_address_map; struct efi_memory_map *memmap; unsigned long flags; + unsigned long mask; } efi; static inline int @@ -926,6 +927,10 @@ static inline bool efi_enabled(int feature) { return test_bit(feature, &efi.flags) != 0; } +static inline bool efi_disabled(int feature) +{ + return test_bit(feature, &efi.mask) == 0; +} #else static inline bool efi_enabled(int feature) { --- / Leif > Signed-off-by: Dave Young <dyoung@xxxxxxxxxx> > --- > arch/arm64/kernel/efi.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > Index: linux-2.6/arch/arm64/kernel/efi.c > =================================================================== > --- linux-2.6.orig/arch/arm64/kernel/efi.c > +++ linux-2.6/arch/arm64/kernel/efi.c > @@ -31,6 +31,14 @@ static efi_runtime_services_t *runtime; > > static u64 efi_system_table; > > +static bool disable_runtime __initdata = false; > +static int __init setup_noefi(char *arg) > +{ > + disable_runtime = true; > + return 0; > +} > +early_param("noefi", setup_noefi); > + > static int uefi_debug __initdata; > static int __init uefi_debug_setup(char *str) > { > @@ -391,11 +399,14 @@ static int __init arm64_enter_virtual_mo > return -1; > } > > - pr_info("Remapping and enabling EFI services.\n"); > - > - /* replace early memmap mapping with permanent mapping */ > mapsize = memmap.map_end - memmap.map; > early_memunmap(memmap.map, mapsize); > + > + if (disable_runtime) > + return -ENODEV; > + > + pr_info("Remapping and enabling EFI services.\n"); > + /* replace early memmap mapping with permanent mapping */ > memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map, > mapsize); > memmap.map_end = memmap.map + mapsize; -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
