This patch provides documentation of the [U]EFI runtime services and configuration features.

Signed-off-by: Leif Lindholm leif.lindholm@linaro.org --- Documentation/arm/00-INDEX | 3 +++ Documentation/arm/uefi.txt | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) create mode 100644 Documentation/arm/uefi.txt

diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX index 4978456..87e01d1 100644 --- a/Documentation/arm/00-INDEX +++ b/Documentation/arm/00-INDEX @@ -36,3 +36,6 @@ nwfpe/ - NWFPE floating point emulator documentation swp_emulation - SWP/SWPB emulation handler/logging description + +uefi.txt + - [U]EFI configuration and runtime services documentation diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt new file mode 100644 index 0000000..5c48271 --- /dev/null +++ b/Documentation/arm/uefi.txt @@ -0,0 +1,39 @@ +The nomenclature EFI and UEFI are used interchangeably in this document. + +The implementation depends on receiving pointers to the UEFI memory map +and System Table in a Flattened Device Tree - so is only available with +CONFIG_OF. + +It (early) parses the FDT for the following parameters: +- 'efi-system-table': + Physical address of the system table. (required) +- 'efi-runtime-mmap': + Physical address of an EFI memory map, containing at least + the regions to be preserved. (required) +- 'efi-runtime-mmap-size': + Size in bytes of the provided memory map. (required) +- 'efi-mmap-desc-size': + Size of each descriptor in the memory map. (override default) +- 'efi-mmap-desc-ver': + Memory descriptor format version. (override default) + +Since UEFI firmware on ARM systems are required to use a 1:1 memory map +even on LPAE-capable systems, the above fields are 32-bit regardless. + +It also depends on early_ioremap to parse the memory map and preserve +the regions required for runtime services. + +For actually enabling [U]EFI support, enable: +- CONFIG_EFI=y +- CONFIG_EFI_VARS=y or m + +After the kernel has mapped the required regions into its address space, +a SetVirtualAddressMap() call is made into UEFI in order to update +relocations. This call must be performed with all the code in a 1:1 +mapping. This implementation achieves this by temporarily disabling the +MMU for the duration of this call. This can only be done safely: +- before secondary CPUs are brought online. +- after early_initcalls have completed, sinze it uses setup_mm_for_reboot(). + +For verbose debug messages, specify 'uefi_debug' on the kernel command +line.

This patch implements basic support for UEFI runtime services in the ARM architecture - a requirement for using efibootmgr to read and update the system boot configuration.

It also locates any presented SMBIOS configuration table and stores it for potential later use by DMI.

Signed-off-by: Leif Lindholm leif.lindholm@linaro.org --- arch/arm/Kconfig | 2 + arch/arm/include/asm/efi.h | 22 +++ arch/arm/kernel/Makefile | 2 + arch/arm/kernel/efi.c | 456 ++++++++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/efi_phys.S | 59 ++++++ arch/arm/kernel/setup.c | 5 + 6 files changed, 546 insertions(+) create mode 100644 arch/arm/include/asm/efi.h create mode 100644 arch/arm/kernel/efi.c create mode 100644 arch/arm/kernel/efi_phys.S

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index d9fe195..022d2eb 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -2230,6 +2230,8 @@ source "net/Kconfig"

source "drivers/Kconfig"

+source "drivers/firmware/Kconfig" + source "fs/Kconfig"

source "arch/arm/Kconfig.debug" diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h new file mode 100644 index 0000000..aead94c --- /dev/null +++ b/arch/arm/include/asm/efi.h @@ -0,0 +1,22 @@ +#ifndef _ASM_ARM_EFI_H +#define _ASM_ARM_EFI_H + +#include <asm/mach/map.h> + +extern int efi_memblock_arm_reserve_range(void); + +typedef efi_status_t efi_phys_call_t(u32 memory_map_size, + u32 descriptor_size, + u32 descriptor_version, + efi_memory_desc_t *dsc, + efi_set_virtual_address_map_t *f); + +extern efi_status_t efi_phys_call(u32, u32, u32, efi_memory_desc_t *, + efi_set_virtual_address_map_t *); + +#define efi_remap(cookie, size) __arm_ioremap((cookie), (size), MT_MEMORY) +#define efi_ioremap(cookie, size) __arm_ioremap((cookie), (size), MT_DEVICE) +#define efi_unmap(cookie) __arm_iounmap((cookie)) +#define efi_iounmap(cookie) __arm_iounmap((cookie)) + +#endif /* _ASM_ARM_EFI_H */ diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 5f3338e..12b9c30 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -84,4 +84,6 @@ obj-$(CONFIG_EARLY_PRINTK) += early_printk.o obj-$(CONFIG_ARM_VIRT_EXT) += hyp-stub.o obj-$(CONFIG_ARM_PSCI) += psci.o

+obj-$(CONFIG_EFI) += efi.o efi_phys.o + extra-y := $(head-y) vmlinux.lds diff --git a/arch/arm/kernel/efi.c b/arch/arm/kernel/efi.c new file mode 100644 index 0000000..43ecf0b --- /dev/null +++ b/arch/arm/kernel/efi.c @@ -0,0 +1,456 @@ +/* + * Extensible Firmware Interface + * + * Based on Extensible Firmware Interface Specification version 2.3.1 + * + * Copyright (C) 2013 Linaro Ltd. + * + */ + +#include <linux/efi.h> +#include <linux/export.h> +#include <linux/memblock.h> +#include <linux/of.h> +#include <linux/of_fdt.h> +#include <linux/sched.h> +#include <linux/slab.h> + +#include <asm/cacheflush.h> +#include <asm/efi.h> +#include <asm/idmap.h> +#include <asm/tlbflush.h> + +struct efi efi; +EXPORT_SYMBOL(efi); +struct efi_memory_map memmap; + +static efi_runtime_services_t *runtime; + +static phys_addr_t efi_system_table; +static phys_addr_t efi_boot_mmap; +static u32 efi_boot_mmap_size; +static u32 efi_mmap_desc_size; +static u32 efi_mmap_desc_ver; + +/* Default memory map descriptor information */ +#define DESC_SIZE 48 +#define DESC_VER 1 + +/* If you're planning to wire up a debugger and debug the UEFI side ... */ +#undef KEEP_ALL_REGIONS +#define KEEP_BOOT_SERVICES_REGIONS + +static int __initdata uefi_debug; +static int __init uefi_debug_setup(char *str) +{ + uefi_debug = 1; + + return 0; +} +early_param("uefi_debug", uefi_debug_setup); + +static int __init fdt_find_efi_params(unsigned long node, const char *uname, + int depth, void *data) +{ + unsigned long len; + __be32 *prop; + + if (depth != 1 || + (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0)) + return 0; + + pr_info("Getting EFI parameters from FDT.\n"); + + prop = of_get_flat_dt_prop(node, "efi-system-table", &len); + if (!prop) + return 0; + efi_system_table = of_read_ulong(prop, len/4); + + prop = of_get_flat_dt_prop(node, "efi-runtime-mmap", &len); + if (!prop) + return 0; + efi_boot_mmap = of_read_ulong(prop, len/4); + + prop = of_get_flat_dt_prop(node, "efi-runtime-mmap-size", &len); + if (!prop) + return 0; + efi_boot_mmap_size = of_read_ulong(prop, len/4); + + prop = of_get_flat_dt_prop(node, "efi-mmap-desc-size", &len); + if (prop) + efi_mmap_desc_size = of_read_ulong(prop, len/4); + else + efi_mmap_desc_size = DESC_SIZE; + + prop = of_get_flat_dt_prop(node, "efi-mmap-desc-ver", &len); + if (prop) + efi_mmap_desc_ver = of_read_ulong(prop, len/4); + else + efi_mmap_desc_ver = DESC_VER; + + if (uefi_debug) { + pr_info(" EFI system table @ 0x%08x\n", + (unsigned int) efi_system_table); + pr_info(" EFI mmap @ 0x%08x\n", + (unsigned int) efi_boot_mmap); + pr_info(" EFI mmap size = 0x%08x\n", + (unsigned int) efi_boot_mmap_size); + pr_info(" EFI mmap descriptor size = 0x%08x\n", + (unsigned int) efi_mmap_desc_size); + pr_info(" EFI mmap descriptor version = 0x%08x\n", + (unsigned int) efi_mmap_desc_ver); + } + + return 1; +} + +static int __init uefi_config_init(void) +{ + efi_char16_t *c16; + char vendor[100] = "unknown"; + efi_config_table_t *config_tables; + u32 nr_tables; + int i; + + efi.systab = early_ioremap(efi_system_table, + sizeof(efi_system_table_t)); + + /* + * Verify the EFI Table + */ + if (efi.systab == NULL) + panic("Whoa! Can't find EFI system table.\n"); + if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) + panic("Whoa! EFI system table signature incorrect\n"); + if ((efi.systab->hdr.revision >> 16) == 0) + pr_warn("Warning: EFI system table version %d.%02d, expected 1.00 or greater\n", + efi.systab->hdr.revision >> 16, + efi.systab->hdr.revision & 0xffff); + + /* Show what we know for posterity */ + c16 = (efi_char16_t *)early_ioremap(efi.systab->fw_vendor, + sizeof(vendor)); + if (c16) { + for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i) + vendor[i] = c16[i]; + vendor[i] = '\0'; + } + + pr_info("EFI v%u.%.02u by %s\n", + efi.systab->hdr.revision >> 16, + efi.systab->hdr.revision & 0xffff, vendor); + + + nr_tables = efi.systab->nr_tables; + + config_tables = early_ioremap(efi.systab->tables, + sizeof(efi_config_table_t) * nr_tables); + + for (i = 0; i < nr_tables; i++) { + efi_guid_t guid; + unsigned long table; + u8 str[38]; + + guid = config_tables[i].guid; + table = config_tables[i].table; + + efi_guid_unparse(&guid, str); + if (uefi_debug) + pr_info(" Config Table: UUID=%s @ 0x%08x\n", + str, (u32)table); + if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID)) + efi.smbios = table; + } + + early_iounmap(config_tables, sizeof(efi_config_table_t) * nr_tables); + early_iounmap(c16, sizeof(vendor)); + early_iounmap(efi.systab, sizeof(efi_system_table_t)); + + return 0; +} + +static __init int is_discardable_region(efi_memory_desc_t *md) +{ +#ifdef KEEP_ALL_REGIONS + return 0; +#endif + + if (md->attribute & EFI_MEMORY_RUNTIME) + return 0; + + switch (md->type) { +#ifdef KEEP_BOOT_SERVICES_REGIONS + case EFI_BOOT_SERVICES_CODE: + case EFI_BOOT_SERVICES_DATA: +#endif + /* Keep tables around for any future kexec operations */ + case EFI_ACPI_RECLAIM_MEMORY: + return 0; + } + + return 1; +} + +static __initdata struct { + u32 type; + const char *name; +} memory_type_name_map[] = { + {EFI_RESERVED_TYPE, "EFI reserved"}, + {EFI_LOADER_CODE, "EFI loader code"}, + {EFI_LOADER_DATA, "EFI loader data"}, + {EFI_BOOT_SERVICES_CODE, "EFI boot services code"}, + {EFI_BOOT_SERVICES_DATA, "EFI boot services data"}, + {EFI_RUNTIME_SERVICES_CODE, "EFI runtime services code"}, + {EFI_RUNTIME_SERVICES_DATA, "EFI runtime services data"}, + {EFI_CONVENTIONAL_MEMORY, "EFI conventional memory"}, + {EFI_UNUSABLE_MEMORY, "EFI unusable memory"}, + {EFI_ACPI_RECLAIM_MEMORY, "EFI ACPI reclaim memory"}, + {EFI_ACPI_MEMORY_NVS, "EFI ACPI memory nvs"}, + {EFI_MEMORY_MAPPED_IO, "EFI memory mapped I/O"}, + {EFI_MEMORY_MAPPED_IO_PORT_SPACE, "EFI memory mapped I/O port space"}, + {EFI_PAL_CODE, "EFI pal code"}, + {EFI_MAX_MEMORY_TYPE, NULL}, +}; + +static __init void remove_sections(phys_addr_t addr, unsigned long size) +{ + unsigned long section_offset; + unsigned long num_sections; + + section_offset = addr - (addr & SECTION_MASK); + num_sections = size / SECTION_SIZE; + if (size % SECTION_SIZE) + num_sections++; + + memblock_remove(addr - section_offset, num_sections * SECTION_SIZE); +} + +static __init int remove_regions(void) +{ + efi_memory_desc_t *md; + int count = 0; + + void *p; + + memmap.phys_map = early_ioremap(efi_boot_mmap, efi_boot_mmap_size); + + memmap.desc_size = efi_mmap_desc_size; + memmap.desc_version = efi_mmap_desc_ver; + memmap.map_end = (void *) memmap.phys_map + efi_boot_mmap_size; + memmap.nr_map = 0; + + if (uefi_debug) + pr_info("Processing EFI memory map:\n"); + + for (p = memmap.phys_map; p < memmap.map_end; p += memmap.desc_size) { + md = p; + if (is_discardable_region(md)) + continue; + + if (uefi_debug) + pr_info(" %8llu pages @ %016llx (%s)\n", + md->num_pages, md->phys_addr, + memory_type_name_map[md->type].name); + + if (md->type != EFI_MEMORY_MAPPED_IO) { + remove_sections(md->phys_addr, + md->num_pages * PAGE_SIZE); + count++; + } + memmap.nr_map++; + } + + if (uefi_debug) + pr_info("%d regions preserved.\n", memmap.nr_map); + + early_iounmap(memmap.phys_map, efi_boot_mmap_size); + + return 0; +} + +int __init efi_memblock_arm_reserve_range(void) +{ + /* Grab system table location out of FDT (or ACPI) */ + of_scan_flat_dt(fdt_find_efi_params, NULL); + + if (!efi_system_table || !efi_boot_mmap || !efi_boot_mmap_size) + return 0; + + remove_regions(); + + uefi_config_init(); + + return 0; +} + +/* + * Disable instrrupts, enable idmap and disable caches. + */ +static void __init phys_call_prologue(void) +{ + local_irq_disable(); + + /* Take out a flat memory mapping. */ + setup_mm_for_reboot(); + + /* Clean and invalidate caches */ + flush_cache_all(); + + /* Turn off caching */ + cpu_proc_fin(); + + /* Push out any further dirty data, and ensure cache is empty */ + flush_cache_all(); +} + +/* + * Restore original memory map and re-enable interrupts. + */ +static void __init phys_call_epilogue(void) +{ + static struct mm_struct *mm = &init_mm; + + /* Restore original memory mapping */ + cpu_switch_mm(mm->pgd, mm); + + /* Flush branch predictor and TLBs */ + local_flush_bp_all(); +#ifdef CONFIG_CPU_HAS_ASID + local_flush_tlb_all(); +#endif + + local_irq_enable(); +} + +/* + * This function switches the EFI runtime services to virtual mode. + * This operation must be performed only once in the system's lifetime, + * including any kecec calls. + * + * This must be done with a 1:1 mapping. The current implementation + * resolves this by disabling the MMU. + */ +efi_status_t __init phys_set_virtual_address_map(u32 memory_map_size, + u32 descriptor_size, + u32 descriptor_version, + efi_memory_desc_t *dsc) +{ + efi_phys_call_t *phys_set_map; + efi_status_t status; + + phys_call_prologue(); + + phys_set_map = (void *)(unsigned long)virt_to_phys(efi_phys_call); + + /* Called with caches disabled, returns with caches enabled */ + status = phys_set_map(memory_map_size, descriptor_size, + descriptor_version, dsc, + efi.set_virtual_address_map); + + phys_call_epilogue(); + + return status; +} + +static int __init remap_region(efi_memory_desc_t *md, efi_memory_desc_t *entry) +{ + u64 va; + u64 paddr; + u64 size; + + *entry = *md; + paddr = entry->phys_addr; + size = entry->num_pages << EFI_PAGE_SHIFT; + + /* + * Map everything writeback-capable as coherent memory, + * anything else as device. + */ + if (md->attribute & EFI_MEMORY_WB) + va = (u64)((u32)efi_remap(paddr, size) & 0xffffffffUL); + else + va = (u64)((u32)efi_ioremap(paddr, size) & 0xffffffffUL); + if (!va) + return 0; + entry->virt_addr = va; + + if (uefi_debug) + pr_info(" %016llx-%016llx => 0x%08x : (%s)\n", + paddr, paddr + size - 1, (u32)va, + md->attribute & EFI_MEMORY_WB ? "WB" : "I/O"); + + return 1; +} + +static void __init remap_regions(void) +{ + void *p, *next; + efi_memory_desc_t *md; + + memmap.phys_map = efi_remap(efi_boot_mmap, efi_boot_mmap_size); + memmap.map_end = (void *)memmap.phys_map + efi_boot_mmap_size; + + /* Allocate space for the physical region map */ + memmap.map = kzalloc(memmap.nr_map * memmap.desc_size, GFP_KERNEL); + if (!memmap.map) + return; + + next = memmap.map; + for (p = memmap.phys_map; p < memmap.map_end; p += memmap.desc_size) { + md = p; + if (is_discardable_region(md)) + continue; + + if (remap_region(p, next)) + next += memmap.desc_size; + } + + memmap.map_end = next; + + efi_unmap(memmap.phys_map); + + efi.systab = efi_lookup_mapped_addr(efi_system_table); + /* + * efi.systab->runtime is a 32-bit pointer to something guaranteed by + * the UEFI specification to be 1:1 mapped in a 4GB address space. + */ + runtime = efi_lookup_mapped_addr((u32)efi.systab->runtime); +} + + +/* + * Called explicitly from init/mm.c + */ +void __init efi_enter_virtual_mode(void) +{ + efi_status_t status; + + if (efi.systab == NULL) { + pr_info("No EFI system table - EFI services will not be available.\n"); + return; + } else { + pr_info("Remapping and enabling EFI services.\n"); + } + + /* Map the regions we memblock_remove:d earlier into kernel + address space */ + remap_regions(); + + /* Call SetVirtualAddressMap with the physical address of the map */ + efi.set_virtual_address_map = + (efi_set_virtual_address_map_t *) + runtime->set_virtual_address_map; + memmap.phys_map = + (efi_memory_desc_t *)(u32) __virt_to_phys((u32)memmap.map); + + status = phys_set_virtual_address_map(memmap.nr_map * memmap.desc_size, + memmap.desc_size, + memmap.desc_version, + memmap.phys_map); + + /* Set up function pointers for efivars */ + efi.get_variable = (efi_get_variable_t *)runtime->get_variable; + efi.get_next_variable = + (efi_get_next_variable_t *)runtime->get_next_variable; + efi.set_variable = (efi_set_variable_t *)runtime->set_variable; +} diff --git a/arch/arm/kernel/efi_phys.S b/arch/arm/kernel/efi_phys.S new file mode 100644 index 0000000..e36cc17 --- /dev/null +++ b/arch/arm/kernel/efi_phys.S @@ -0,0 +1,59 @@ +/* + * arch/arm/kernel/efi_phys.S + * + * Copyright (C) 2013 Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/linkage.h> +#define PAR_MASK 0xfff + + .text +@ efi_phys_call(a, b, c, d, *f) + .align 5 + .pushsection .idmap.text, "ax" +ENTRY(efi_phys_call) + @ Save physical context + mov r12, sp + push {r4-r5, r12, lr} + + @ Extract function pointer (don't write r12 beyond this) + ldr r12, [sp, #16] + + @ Convert sp to 32-bit physical + mov lr, sp + ldr r4, =PAR_MASK + and r5, lr, r4 @ Extract lower 12 bits of sp + mcr p15, 0, lr, c7, c8, 1 @ Write VA -> ATS1CPW + mrc p15, 0, lr, c7, c4, 0 @ Physical Address Register + mvn r4, r4 + and lr, lr, r4 @ Clear lower 12 bits of PA + add lr, lr, r5 @ Calculate phys sp + mov sp, lr @ Update + + @ Disable MMU + mrc p15, 0, lr, c1, c0, 0 @ ctrl register + bic lr, lr, #0x1 @ ...............m + mcr p15, 0, lr, c1, c0, 0 @ disable MMU + isb + + @ Make call + blx r12 + + pop {r4-r5, r12, lr} + + @ Enable MMU + Caches + mrc p15, 0, r1, c1, c0, 0 @ ctrl register + orr r1, r1, #0x1000 @ ...i............ + orr r1, r1, #0x0005 @ .............c.m + mcr p15, 0, r1, c1, c0, 0 @ enable MMU + isb + + @ Restore virtual sp and return + mov sp, r12 + bx lr +ENDPROC(efi_phys_call) + .popsection diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 290c561..e36c2a6 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -30,6 +30,7 @@ #include <linux/bug.h> #include <linux/compiler.h> #include <linux/sort.h> +#include <linux/efi.h>

#include <asm/unified.h> #include <asm/cp15.h> @@ -56,6 +57,7 @@ #include <asm/unwind.h> #include <asm/memblock.h> #include <asm/virt.h> +#include <asm/efi.h>

#include "atags.h"

@@ -790,6 +792,9 @@ void __init setup_arch(char **cmdline_p) sanity_check_meminfo(); arm_memblock_init(&meminfo, mdesc);

+ if (efi_enabled(EFI_BOOT)) + efi_memblock_arm_reserve_range(); + paging_init(mdesc); request_standard_resources(mdesc);