This enables the UEFI Runtime Services needed to manipulate the non-volatile variable store when running under a BE kernel.
Signed-off-by: Ard Biesheuvel <[email protected]> --- arch/arm64/include/asm/efi.h | 2 + arch/arm64/kernel/efi-be-call.S | 55 ++++++++++++++++++++ arch/arm64/kernel/efi-be-runtime.c | 104 +++++++++++++++++++++++++++++++++++++ arch/arm64/kernel/efi.c | 15 ++++++ 4 files changed, 176 insertions(+) create mode 100644 arch/arm64/kernel/efi-be-call.S create mode 100644 arch/arm64/kernel/efi-be-runtime.c diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index a34fd3b12e2b..44e642b6ab61 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -44,4 +44,6 @@ extern void efi_idmap_init(void); #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) +extern void efi_be_runtime_setup(void); + #endif /* _ASM_EFI_H */ diff --git a/arch/arm64/kernel/efi-be-call.S b/arch/arm64/kernel/efi-be-call.S new file mode 100644 index 000000000000..24c92a4c352b --- /dev/null +++ b/arch/arm64/kernel/efi-be-call.S @@ -0,0 +1,55 @@ + +#include <linux/linkage.h> + + .text + .align 3 +ENTRY(efi_be_phys_call) + /* + * Entered at physical address with 1:1 mapping enabled. + */ + stp x29, x30, [sp, #-96]! + mov x29, sp + str x27, [sp, #16] + + ldr x8, =efi_be_phys_call // virt address of this function + adr x9, efi_be_phys_call // phys address of this function + sub x9, x8, x9 // calculate virt to phys offset in x9 + + /* preserve all inputs */ + stp x0, x1, [sp, #32] + stp x2, x3, [sp, #48] + stp x4, x5, [sp, #64] + stp x6, x7, [sp, #80] + + /* get phys address of stack */ + sub sp, sp, x9 + + /* switch to LE, disable MMU and D-cache but leave I-cache enabled */ + mrs x27, sctlr_el1 + bic x8, x27, #1 << 2 // clear SCTLR.C + msr sctlr_el1, x8 + + bl flush_cache_all + + /* restore inputs but rotated by 1 register */ + ldp x7, x0, [sp, #32] + ldp x1, x2, [sp, #48] + ldp x3, x4, [sp, #64] + ldp x5, x6, [sp, #80] + + bic x8, x27, #1 << 2 // clear SCTLR.C + bic x8, x8, #1 << 0 // clear SCTLR.M + bic x8, x8, #1 << 25 // clear SCTLR.EE + msr sctlr_el1, x8 + isb + + blr x7 + + /* switch back to BE and reenable MMU and D-cache */ + msr sctlr_el1, x27 + + mov sp, x29 + ldr x27, [sp, #16] + ldp x29, x30, [sp], #96 + ret +ENDPROC(efi_be_phys_call) diff --git a/arch/arm64/kernel/efi-be-runtime.c b/arch/arm64/kernel/efi-be-runtime.c new file mode 100644 index 000000000000..62e6c441b77b --- /dev/null +++ b/arch/arm64/kernel/efi-be-runtime.c @@ -0,0 +1,104 @@ + +#include <linux/efi.h> +#include <linux/spinlock.h> +#include <asm/efi.h> +#include <asm/neon.h> +#include <asm/tlbflush.h> + +static efi_runtime_services_t *runtime; +static efi_status_t (*efi_be_call)(phys_addr_t func, ...); + +static DEFINE_SPINLOCK(efi_be_rt_lock); + +static unsigned long efi_be_call_pre(void) +{ + unsigned long flags; + + kernel_neon_begin(); + spin_lock_irqsave(&efi_be_rt_lock, flags); + cpu_switch_mm(idmap_pg_dir, &init_mm); + flush_tlb_all(); + return flags; +} + +static void efi_be_call_post(unsigned long flags) +{ + cpu_switch_mm(current, current->active_mm); + flush_tlb_all(); + spin_unlock_irqrestore(&efi_be_rt_lock, flags); + kernel_neon_end(); +} + +static efi_status_t efi_be_get_variable(efi_char16_t *name, + efi_guid_t *vendor, + u32 *attr, + unsigned long *data_size, + void *data) +{ + unsigned long flags; + efi_status_t status; + + *data_size = cpu_to_le64(*data_size); + flags = efi_be_call_pre(); + status = efi_be_call(le64_to_cpu(runtime->get_variable), + virt_to_phys(name), virt_to_phys(vendor), + virt_to_phys(attr), virt_to_phys(data_size), + virt_to_phys(data)); + efi_be_call_post(flags); + *attr = le32_to_cpu(*attr); + *data_size = le64_to_cpu(*data_size); + return status; +} + +static efi_status_t efi_be_get_next_variable(unsigned long *name_size, + efi_char16_t *name, + efi_guid_t *vendor) +{ + unsigned long flags; + efi_status_t status; + + *name_size = cpu_to_le64(*name_size); + flags = efi_be_call_pre(); + status = efi_be_call(le64_to_cpu(runtime->get_next_variable), + virt_to_phys(name_size), virt_to_phys(name), + virt_to_phys(vendor)); + efi_be_call_post(flags); + *name_size = le64_to_cpu(*name_size); + return status; +} + +static efi_status_t efi_be_set_variable(efi_char16_t *name, + efi_guid_t *vendor, + u32 attr, + unsigned long data_size, + void *data) +{ + unsigned long flags; + efi_status_t status; + + flags = efi_be_call_pre(); + status = efi_be_call(le64_to_cpu(runtime->set_variable), + virt_to_phys(name), virt_to_phys(vendor), + cpu_to_le32(attr), cpu_to_le64(data_size), + virt_to_phys(data)); + efi_be_call_post(flags); + return status; +} + +void efi_be_runtime_setup(void) +{ + extern u8 efi_be_phys_call[]; + + runtime = ioremap_cache(le64_to_cpu(efi.systab->runtime), + sizeof(efi_runtime_services_t)); + if (!runtime) { + pr_err("Failed to set up BE wrappers for UEFI Runtime Services!\n"); + return; + } + + efi_be_call = (void *)virt_to_phys(efi_be_phys_call); + + efi.get_variable = efi_be_get_variable; + efi.get_next_variable = efi_be_get_next_variable; + efi.set_variable = efi_be_set_variable; +} diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index 96df58824189..21e98810c5dd 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -406,6 +406,21 @@ static int __init arm64_enter_virtual_mode(void) efi.memmap = &memmap; + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) { + efi.systab = ioremap_cache(efi_system_table, + sizeof(efi_system_table_t)); + if (!efi.systab) { + pr_err("Failed to remap EFI system table!\n"); + return -1; + } + free_boot_services(); + efi_be_runtime_setup(); + + set_bit(EFI_SYSTEM_TABLES, &efi.flags); + set_bit(EFI_RUNTIME_SERVICES, &efi.flags); + return 0; + } + /* Map the runtime regions */ virtmap = kmalloc(mapsize, GFP_KERNEL); if (!virtmap) { -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
