[PATCH 13/22] arm: Add [U]EFI runtime services support
Leif Lindholm
leif.lindholm at linaro.org
Wed Feb 5 12:04:04 EST 2014
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 uses the generic configuration table scanning to populate ACPI and
SMBIOS pointers.
Changes since v2:
- Updated FDT bindings.
- Preserve regions marked RESERVED (but don't map them).
- Rename 'efi' -> 'uefi' within this new port (leaving core code as is).
Signed-off-by: Leif Lindholm <leif.lindholm at linaro.org>
Reviewed-by: Grant Likely <grant.likely at linaro.org>
---
arch/arm/Kconfig | 16 ++
arch/arm/include/asm/uefi.h | 28 +++
arch/arm/kernel/Makefile | 2 +
arch/arm/kernel/setup.c | 7 +-
arch/arm/kernel/uefi.c | 413 +++++++++++++++++++++++++++++++++++++++++++
arch/arm/kernel/uefi_phys.S | 69 ++++++++
6 files changed, 533 insertions(+), 2 deletions(-)
create mode 100644 arch/arm/include/asm/uefi.h
create mode 100644 arch/arm/kernel/uefi.c
create mode 100644 arch/arm/kernel/uefi_phys.S
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a693921..1e1273d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1885,6 +1885,20 @@ config EARLY_IOREMAP
the same virtual memory range as kmap so all early mappings must
be unapped before paging_init() is called.
+config EFI
+ bool "UEFI runtime service support"
+ depends on OF && !CPU_BIG_ENDIAN
+ select UCS2_STRING
+ select EARLY_IOREMAP
+ select UEFI_PARAMS_FROM_FDT
+ ---help---
+ This enables the kernel to use UEFI runtime services that are
+ available (such as the UEFI variable services).
+
+ This option is only useful on systems that have UEFI firmware.
+ However, even with this option, the resultant kernel will
+ continue to boot on non-UEFI platforms.
+
config EFI_STUB
bool "EFI stub support"
depends on EFI && !CPU_BIG_ENDIAN
@@ -2304,6 +2318,8 @@ 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/uefi.h b/arch/arm/include/asm/uefi.h
new file mode 100644
index 0000000..3bc4c60
--- /dev/null
+++ b/arch/arm/include/asm/uefi.h
@@ -0,0 +1,28 @@
+#ifndef _ASM_ARM_EFI_H
+#define _ASM_ARM_EFI_H
+
+#ifdef CONFIG_EFI
+#include <asm/mach/map.h>
+
+extern void uefi_init(void);
+
+typedef efi_status_t uefi_phys_call_t(efi_set_virtual_address_map_t *f,
+ u32 virt_phys_offset,
+ u32 memory_map_size,
+ u32 descriptor_size,
+ u32 descriptor_version,
+ efi_memory_desc_t *dsc);
+
+extern efi_status_t uefi_phys_call(u32, u32, u32, efi_memory_desc_t *,
+ efi_set_virtual_address_map_t *);
+
+#define uefi_remap(cookie, size) __arm_ioremap((cookie), (size), MT_MEMORY_RWX)
+#define uefi_ioremap(cookie, size) __arm_ioremap((cookie), (size), MT_DEVICE)
+#define uefi_unmap(cookie) __arm_iounmap((cookie))
+#define uefi_iounmap(cookie) __arm_iounmap((cookie))
+
+#else
+#define uefi_init()
+#endif /* CONFIG_EFI */
+
+#endif /* _ASM_ARM_EFI_H */
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index a30fc9b..736cce4 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -98,4 +98,6 @@ obj-y += psci.o
obj-$(CONFIG_SMP) += psci_smp.o
endif
+obj-$(CONFIG_EFI) += uefi.o uefi_phys.o
+
extra-y := $(head-y) vmlinux.lds
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index b074ef5..71b8839 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>
@@ -57,6 +58,7 @@
#include <asm/unwind.h>
#include <asm/memblock.h>
#include <asm/virt.h>
+#include <asm/uefi.h>
#include "atags.h"
@@ -878,6 +880,9 @@ void __init setup_arch(char **cmdline_p)
if (mdesc->reboot_mode != REBOOT_HARD)
reboot_mode = mdesc->reboot_mode;
+ early_ioremap_init();
+ uefi_init();
+
init_mm.start_code = (unsigned long) _text;
init_mm.end_code = (unsigned long) _etext;
init_mm.end_data = (unsigned long) _edata;
@@ -889,8 +894,6 @@ void __init setup_arch(char **cmdline_p)
parse_early_param();
- early_ioremap_init();
-
early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));
setup_dma_zone(mdesc);
sanity_check_meminfo();
diff --git a/arch/arm/kernel/uefi.c b/arch/arm/kernel/uefi.c
new file mode 100644
index 0000000..77c18b6
--- /dev/null
+++ b/arch/arm/kernel/uefi.c
@@ -0,0 +1,413 @@
+/*
+ * Based on Unified Extensible Firmware Interface Specification version 2.3.1
+ *
+ * Copyright (C) 2013-2014 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/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/idmap.h>
+#include <asm/setup.h>
+#include <asm/tlbflush.h>
+#include <asm/uefi.h>
+
+struct efi_memory_map memmap;
+
+static efi_runtime_services_t *runtime;
+
+static phys_addr_t uefi_system_table;
+static phys_addr_t uefi_boot_mmap;
+static u32 uefi_boot_mmap_size;
+static u32 uefi_mmap_desc_size;
+static u32 uefi_mmap_desc_ver;
+
+/*
+ * If you want to wire up a debugger and debug the UEFI side, set to 0.
+ */
+#define DISCARD_UNUSED_REGIONS 1
+
+/*
+ * If you need to (temporarily) support buggy firmware, set to 0.
+ */
+#define DISCARD_BOOT_SERVICES_REGIONS 1
+
+static int uefi_debug __initdata;
+static int __init uefi_debug_setup(char *str)
+{
+ uefi_debug = 1;
+
+ return 0;
+}
+early_param("uefi_debug", uefi_debug_setup);
+
+static int __init uefi_systab_init(void)
+{
+ efi_char16_t *c16;
+ char vendor[100] = "unknown";
+ int i, retval;
+
+ efi.systab = early_memremap(uefi_system_table,
+ sizeof(efi_system_table_t));
+
+ /*
+ * Verify the UEFI System Table
+ */
+ if (efi.systab == NULL)
+ panic("Whoa! Can't find UEFI system table.\n");
+ if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
+ panic("Whoa! UEFI system table signature incorrect\n");
+ if ((efi.systab->hdr.revision >> 16) == 0)
+ pr_warn("Warning: UEFI system table version %d.%02d, expected 2.30 or greater\n",
+ efi.systab->hdr.revision >> 16,
+ efi.systab->hdr.revision & 0xffff);
+
+ /* Show what we know for posterity */
+ c16 = early_memremap(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("UEFI v%u.%.02u by %s\n",
+ efi.systab->hdr.revision >> 16,
+ efi.systab->hdr.revision & 0xffff, vendor);
+
+ retval = efi_config_init(NULL);
+ if (retval == 0)
+ set_bit(EFI_CONFIG_TABLES, &efi.flags);
+
+ early_memunmap(c16, sizeof(vendor));
+ early_memunmap(efi.systab, sizeof(efi_system_table_t));
+
+ return retval;
+}
+
+static __init int is_discardable_region(efi_memory_desc_t *md)
+{
+ if (md->attribute & EFI_MEMORY_RUNTIME)
+ return 0;
+
+ switch (md->type) {
+ case EFI_CONVENTIONAL_MEMORY:
+ return 1;
+ case EFI_BOOT_SERVICES_CODE:
+ case EFI_BOOT_SERVICES_DATA:
+ return DISCARD_BOOT_SERVICES_REGIONS;
+ /* Keep tables around for any future kexec operations */
+ case EFI_ACPI_MEMORY_NVS:
+ case EFI_ACPI_RECLAIM_MEMORY:
+ return 0;
+ /* Preserve */
+ case EFI_RESERVED_TYPE:
+ return 0;
+ }
+
+ return DISCARD_UNUSED_REGIONS;
+}
+
+static __initdata struct {
+ u32 type;
+ const char *name;
+} memory_type_name_map[] = {
+ {EFI_RESERVED_TYPE, "reserved"},
+ {EFI_LOADER_CODE, "loader code"},
+ {EFI_LOADER_DATA, "loader data"},
+ {EFI_BOOT_SERVICES_CODE, "boot services code"},
+ {EFI_BOOT_SERVICES_DATA, "boot services data"},
+ {EFI_RUNTIME_SERVICES_CODE, "runtime services code"},
+ {EFI_RUNTIME_SERVICES_DATA, "runtime services data"},
+ {EFI_CONVENTIONAL_MEMORY, "conventional memory"},
+ {EFI_UNUSABLE_MEMORY, "unusable memory"},
+ {EFI_ACPI_RECLAIM_MEMORY, "ACPI reclaim memory"},
+ {EFI_ACPI_MEMORY_NVS, "ACPI memory nvs"},
+ {EFI_MEMORY_MAPPED_IO, "memory mapped I/O"},
+ {EFI_MEMORY_MAPPED_IO_PORT_SPACE, "memory mapped I/O port space"},
+ {EFI_PAL_CODE, "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 void memmap_init(void)
+{
+ efi_memory_desc_t *md;
+ int i = 0;
+
+ if (uefi_debug)
+ pr_info("Processing UEFI memory map:\n");
+
+ memmap.map = early_memremap(uefi_boot_mmap, uefi_boot_mmap_size);
+ if (!memmap.map)
+ return;
+
+ memmap.map_end = memmap.map + uefi_boot_mmap_size;
+ memmap.nr_map = 0;
+
+ for_each_efi_memory_desc(&memmap, md) {
+ pr_info(" %8llu pages @ %016llx (%s)\n",
+ md->num_pages, md->phys_addr,
+ memory_type_name_map[md->type].name);
+ if (md->attribute & EFI_MEMORY_WB) {
+ if (is_discardable_region(md)) {
+ arm_add_memory(md->phys_addr,
+ md->num_pages * EFI_PAGE_SIZE);
+ i++;
+ }
+ }
+ memmap.nr_map++;
+ }
+
+ if (uefi_debug)
+ pr_info("%d memory regions added.\n", i);
+
+ remove_sections(uefi_boot_mmap, uefi_boot_mmap_size);
+
+ early_memunmap(memmap.map, uefi_boot_mmap_size);
+
+ set_bit(EFI_MEMMAP, &efi.flags);
+}
+
+void __init uefi_init(void)
+{
+ struct efi_fdt_params params;
+
+ uefi_debug = 1;
+
+ /* Grab UEFI information placed in FDT by stub */
+ if (!efi_get_fdt_params(¶ms, uefi_debug))
+ return;
+
+ uefi_system_table = params.system_table;
+
+ uefi_boot_mmap = params.mmap;
+ uefi_boot_mmap_size = params.mmap_size;
+ uefi_mmap_desc_size = params.desc_size;
+ uefi_mmap_desc_ver = params.desc_ver;
+ memmap.desc_size = uefi_mmap_desc_size;
+ memmap.map_end = memmap.map + params.mmap_size;
+ if (uefi_boot_mmap > UINT_MAX) {
+ pr_err("UEFI memory map located above 4GB - unusable!");
+ return;
+ }
+
+ if (uefi_systab_init() < 0)
+ return;
+
+ memmap_init();
+
+ set_bit(EFI_BOOT, &efi.flags);
+}
+
+/*
+ * Disable instrrupts, enable idmap and disable caches.
+ */
+static void __init phys_call_prologue(void)
+{
+ local_irq_disable();
+
+ outer_disable();
+
+ idmap_prepare();
+}
+
+/*
+ * 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);
+
+ local_flush_bp_all();
+ local_flush_tlb_all();
+
+ outer_resume();
+
+ local_irq_enable();
+}
+
+static int __init remap_region(efi_memory_desc_t *md, int entry)
+{
+ efi_memory_desc_t *region;
+ u32 va;
+ u64 paddr;
+ u64 size;
+
+ region = memmap.map + entry * memmap.desc_size;
+ *region = *md;
+ paddr = region->phys_addr;
+ size = region->num_pages << EFI_PAGE_SHIFT;
+
+ /*
+ * Map everything writeback-capable as coherent memory,
+ * anything else as device.
+ */
+ if (md->attribute & EFI_MEMORY_WB)
+ va = (u32)uefi_remap(paddr, size);
+ else
+ va = (u32)uefi_ioremap(paddr, size);
+ if (!va)
+ return 0;
+ region->virt_addr = va;
+
+ if (uefi_debug)
+ pr_info(" %016llx-%016llx => 0x%08x : (%s)\n",
+ paddr, paddr + size - 1, va,
+ md->attribute & EFI_MEMORY_WB ? "WB" : "I/O");
+
+ return 1;
+}
+
+static int __init remap_regions(void)
+{
+ void *p;
+ efi_memory_desc_t *md;
+ int mapped_regions;
+
+ memmap.phys_map = uefi_remap(uefi_boot_mmap, uefi_boot_mmap_size);
+ if (!memmap.phys_map)
+ return 0;
+
+ memmap.map_end = memmap.phys_map + uefi_boot_mmap_size;
+ memmap.desc_size = uefi_mmap_desc_size;
+ memmap.desc_version = uefi_mmap_desc_ver;
+
+ /* Allocate space for the physical region map */
+ memmap.map = kzalloc(memmap.nr_map * memmap.desc_size, GFP_ATOMIC);
+ if (!memmap.map)
+ return 0;
+
+ mapped_regions = 0;
+ 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, mapped_regions++))
+ return 0;
+ }
+
+ memmap.map_end = memmap.map + mapped_regions * memmap.desc_size;
+ efi.memmap = &memmap;
+
+ uefi_unmap(memmap.phys_map);
+ memmap.phys_map = efi_lookup_mapped_addr(uefi_boot_mmap);
+ efi.systab = efi_lookup_mapped_addr(uefi_system_table);
+ if (efi.systab)
+ set_bit(EFI_SYSTEM_TABLES, &efi.flags);
+ /*
+ * 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);
+
+ return 1;
+}
+
+
+/*
+ * This function switches the UEFI 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)
+{
+ uefi_phys_call_t *phys_set_map;
+ efi_status_t status;
+
+ phys_call_prologue();
+
+ phys_set_map = (void *)(unsigned long)virt_to_phys(uefi_phys_call);
+
+ /* Called with caches disabled, returns with caches enabled */
+ status = phys_set_map(efi.set_virtual_address_map,
+ PAGE_OFFSET - PHYS_OFFSET,
+ memory_map_size, descriptor_size,
+ descriptor_version, dsc);
+
+ phys_call_epilogue();
+
+ return status;
+}
+
+/*
+ * Called explicitly from init/mm.c
+ */
+void __init efi_enter_virtual_mode(void)
+{
+ efi_status_t status;
+ u32 mmap_phys_addr;
+
+ if (!efi_enabled(EFI_BOOT)) {
+ pr_info("UEFI services will not be available.\n");
+ return;
+ }
+
+ pr_info("Remapping and enabling UEFI services.\n");
+
+ /* Map the regions we memblock_remove:d earlier into kernel
+ address space */
+ if (!remap_regions()) {
+ pr_info("Failed to remap UEFI regions - runtime services will not be available.\n");
+ return;
+ }
+
+ /* Call SetVirtualAddressMap with the physical address of the map */
+ efi.set_virtual_address_map = runtime->set_virtual_address_map;
+
+ /*
+ * __virt_to_phys() takes an unsigned long and returns a phys_addr_t
+ * memmap.phys_map is a void *
+ * The gymnastics below makes this compile validly with/without LPAE.
+ */
+ mmap_phys_addr = __virt_to_phys((u32)memmap.map);
+ memmap.phys_map = (void *)mmap_phys_addr;
+
+ status = phys_set_virtual_address_map(memmap.nr_map * memmap.desc_size,
+ memmap.desc_size,
+ memmap.desc_version,
+ memmap.phys_map);
+ if (status != EFI_SUCCESS) {
+ pr_info("Failed to set UEFI virtual address map!\n");
+ return;
+ }
+
+ /* Set up function pointers for efivars */
+ efi.get_variable = runtime->get_variable;
+ efi.get_next_variable = runtime->get_next_variable;
+ efi.set_variable = runtime->set_variable;
+ efi.set_virtual_address_map = NULL;
+
+ set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+}
diff --git a/arch/arm/kernel/uefi_phys.S b/arch/arm/kernel/uefi_phys.S
new file mode 100644
index 0000000..a999626
--- /dev/null
+++ b/arch/arm/kernel/uefi_phys.S
@@ -0,0 +1,69 @@
+/*
+ * arch/arm/kernel/uefi_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 <asm/assembler.h>
+#include <asm/cp15.h>
+#include <linux/linkage.h>
+#define PAR_MASK 0xfff
+
+ .text
+@ uefi_phys_call(*f, virt_phys_offset, a, b, c, d, ...)
+ .align 5
+ .pushsection .idmap.text, "ax"
+ENTRY(uefi_phys_call)
+ @ Save physical context
+ mov r12, sp
+ ldr sp, =tmpstack
+ stmfd sp, {r4-r5, r12, lr} @ push is redefined by asm/assembler.h
+
+ mov r4, r1
+
+ @ Extract function pointer (don't write lr again before call)
+ mov lr, r0
+
+ @ Shift arguments down
+ mov r0, r2
+ mov r1, r3
+ ldr r2, [r12], #4
+ ldr r3, [r12], #4
+
+ @ Convert sp to physical
+ sub r12, r12, r4
+ mov sp, r12
+
+ @ Disable MMU
+ ldr r5, =(CR_M)
+ update_sctlr r12, , r5
+ isb
+
+ @ Make call
+ blx lr
+
+ @ Enable MMU + Caches
+ ldr r4, =(CR_I | CR_C | CR_M)
+ update_sctlr r12, r4
+ isb
+
+ ldr sp, =tmpstack_top
+ ldmfd sp, {r4-r5, r12, lr}
+
+ @ Restore virtual sp and return
+ mov sp, r12
+ bx lr
+
+ .align 3
+tmpstack_top:
+ .long 0 @ r4
+ .long 0 @ r5
+ .long 0 @ r12
+ .long 0 @ lr
+tmpstack:
+ENDPROC(uefi_phys_call)
+ .popsection
--
1.7.10.4
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