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Subject[PATCH v2 2/3] arm: Add [U]EFI runtime services support
Date
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.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
---
arch/arm/Kconfig | 15 ++
arch/arm/include/asm/efi.h | 22 ++
arch/arm/kernel/Makefile | 2 +
arch/arm/kernel/efi.c | 485 ++++++++++++++++++++++++++++++++++++++++++++
arch/arm/kernel/efi_phys.S | 59 ++++++
arch/arm/kernel/setup.c | 6 +
include/linux/efi.h | 2 +-
7 files changed, 590 insertions(+), 1 deletion(-)
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 5916a90..317c75d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1855,6 +1855,19 @@ config EARLY_IOREMAP
It generates its map entries in kmap region (0xfff00000) before kmap
is initialized.

+config EFI
+ bool "UEFI runtime service support"
+ depends on OF && !CPU_BIG_ENDIAN
+ select UCS2_STRING
+ select EARLY_IOREMAP
+ ---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 SECCOMP
bool
prompt "Enable seccomp to safely compute untrusted bytecode"
@@ -2267,6 +2280,8 @@ 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 5140df5f..81b8865 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -96,4 +96,6 @@ obj-y += psci.o
obj-$(CONFIG_SMP) += psci_smp.o
endif

+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..a7c2c8d
--- /dev/null
+++ b/arch/arm/kernel/efi.c
@@ -0,0 +1,485 @@
+/*
+ * 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_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;
+
+static unsigned long arm_efi_facility;
+
+/*
+ * 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
+
+/*
+ * If you need to (temporarily) support buggy firmware.
+ */
+#define KEEP_BOOT_SERVICES_REGIONS
+
+/*
+ * Returns 1 if 'facility' is enabled, 0 otherwise.
+ */
+int efi_enabled(int facility)
+{
+ return test_bit(facility, &arm_efi_facility) != 0;
+}
+EXPORT_SYMBOL(efi_enabled);
+
+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 fdt_find_efi_params(unsigned long node, const char *uname,
+ int depth, void *data)
+{
+ unsigned long len;
+ void *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, "linux,efi-system-table", &len);
+ if (!prop)
+ return 0;
+ efi_system_table = of_read_ulong(prop, len/4);
+
+ prop = of_get_flat_dt_prop(node, "linux,efi-mmap", &len);
+ if (!prop)
+ return 0;
+ efi_boot_mmap = (u32) prop;
+ efi_boot_mmap_size = len;
+
+ prop = of_get_flat_dt_prop(node, "linux,efi-mmap-desc-size", NULL);
+ if (prop)
+ efi_mmap_desc_size = of_read_ulong(prop, 1);
+ else
+ efi_mmap_desc_size = DESC_SIZE;
+
+ prop = of_get_flat_dt_prop(node, "linux,efi-mmap-desc-ver", NULL);
+ if (prop)
+ efi_mmap_desc_ver = of_read_ulong(prop, 1);
+ 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_init(void)
+{
+ efi_char16_t *c16;
+ char vendor[100] = "unknown";
+ int i, retval;
+
+ 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);
+
+ retval = efi_config_init(NULL);
+ if (retval == 0)
+ set_bit(EFI_CONFIG_TABLES, &arm_efi_facility);
+
+ early_iounmap(c16, sizeof(vendor));
+ early_iounmap(efi.systab, sizeof(efi_system_table_t));
+
+ return retval;
+}
+
+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 = (void *) (u32) efi_boot_mmap;
+ 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);
+
+ return 0;
+}
+
+int __init efi_memblock_arm_reserve_range(void)
+{
+ if (!of_scan_flat_dt(fdt_find_efi_params, NULL))
+ return 0;
+
+ set_bit(EFI_BOOT, &arm_efi_facility);
+
+ uefi_init();
+
+ remove_regions();
+
+ 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();
+}
+
+/*
+ * Memory map was previously extracted from flattened device tree for
+ * reserving regions. Now we need to grab it from the unflattened tree
+ * in order to access it for remapping purposes.
+ */
+static void __init *get_runtime_mmap(void)
+{
+ struct device_node *node;
+ int len;
+ void *map;
+
+ node = of_find_node_by_path("/chosen");
+ if (node != NULL) {
+ map = (void *) of_get_property(node, "linux,efi-mmap", &len);
+
+ if (len != efi_boot_mmap_size) {
+ pr_info(" EFI mmap size mismatch!\n");
+ map = NULL;
+ }
+ } else {
+ map = NULL;
+ }
+
+ return map;
+}
+
+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 int __init remap_regions(void)
+{
+ void *p, *next;
+ efi_memory_desc_t *md;
+
+ memmap.phys_map = get_runtime_mmap();
+ if (!memmap.phys_map)
+ return 0;
+ 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 0;
+
+ 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))
+ return 0;
+
+ next += memmap.desc_size;
+ }
+
+ memmap.map_end = next;
+ efi.memmap = &memmap;
+
+ efi.systab = efi_lookup_mapped_addr(efi_system_table);
+ if (efi.systab)
+ set_bit(EFI_SYSTEM_TABLES, &arm_efi_facility);
+ /*
+ * 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 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;
+}
+
+/*
+ * Called explicitly from init/mm.c
+ */
+void __init efi_enter_virtual_mode(void)
+{
+ efi_status_t status;
+
+ if (!efi_enabled(EFI_BOOT)) {
+ pr_info("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 */
+ if (!remap_regions()) {
+ pr_info("Failed to remap EFI regions - runtime services will not be available.\n");
+ return;
+ }
+
+ /* 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);
+
+ if (status != EFI_SUCCESS) {
+ pr_info("Failed to set EFI virtual address map!\n");
+ return;
+ }
+
+ /* 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;
+ set_bit(EFI_RUNTIME_SERVICES, &arm_efi_facility);
+}
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 b0b2360..87ff95d 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/efi.h>

#include "atags.h"

@@ -884,6 +886,10 @@ void __init setup_arch(char **cmdline_p)
sanity_check_meminfo();
arm_memblock_init(&meminfo, mdesc);

+#ifdef CONFIG_EFI
+ efi_memblock_arm_reserve_range();
+#endif
+
paging_init(mdesc);
request_standard_resources(mdesc);

diff --git a/include/linux/efi.h b/include/linux/efi.h
index c084b6d..ba4d175 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -644,7 +644,7 @@ extern int __init efi_setup_pcdp_console(char *);
#define EFI_64BIT 5 /* Is the firmware 64-bit? */

#ifdef CONFIG_EFI
-# ifdef CONFIG_X86
+# if defined(CONFIG_X86) || defined(CONFIG_ARM)
extern int efi_enabled(int facility);
# else
static inline int efi_enabled(int facility)
--
1.7.10.4


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