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Date: Wed, 26 Jun 2013 16:22:39 +0200
From: Leif Lindholm <leif.lindholm@...aro.org>
To: Grant Likely <grant.likely@...retlab.ca>
Cc: "linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>, linux-efi@...r.kernel.org,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"patches@...aro.org" <patches@...aro.org>,
"H. Peter Anvin" <hpa@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>, matt.fleming@...el.com
Subject: Re: [PATCH 3/4] arm: Add [U]EFI runtime services support
On Wed, Jun 26, 2013 at 02:46:09PM +0100, Grant Likely wrote:
> > 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@...aro.org>
> > ---
> > arch/arm/Kconfig | 15 ++
> > 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, 559 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 bf8e55d..022d2eb 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1763,6 +1763,19 @@ config EARLY_IOREMAP
> > Provides a mechanism for kernel initialisation code to temporarily
> > map, in a highmem-agnostic way, memory pages in before paging_init().
> >
> > +config EFI
> > +bool "UEFI runtime service support"
> > + depends on OF
> > + 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 should
>
> Be confident! s/should/will/ :-)
Ok.
> > + continue to boot on existing non-UEFI platforms.
>
> s/existing//
Ok.
> > +
> > config SECCOMP
> > bool
> > prompt "Enable seccomp to safely compute untrusted bytecode"
> > @@ -2217,6 +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.
>
> Was any of the above code extracted from the x86/ia64 efi code base?
> If so then make sure the copyright header and license text gets
> retained.
Well, some of efi_config_init() was, but it looks like I will be movng
it out now.
> > + *
> > + */
> > +
> > +#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;
>
> The above symbols should be pulled out of x86 and ia64 and made part
> of drivers/efi/efi.c. Although in my quick look I don't see memmap
> defined for ia64. You'll need to make sure that it actually exists
> before moving it.
Happy to do that. Can be ifdef'd if need be.
> That will also affect your earlier patch which moves
> the memmap lookup function. I suspect that function won't build on
> ia64.
Argh, indeed. I had that ifdef'd ARM/X86, but it seems to have fallen
out.
> > +
> > +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;
>
> As discussed in the binding patch, if the memmap is being passed in
> from GRUB, then it can be embedded directly into the device tree which
> will change the above code.
Yes.
> > +
> > + 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},
> > +};
>
> The above *definitely* belongs in common code! :-)
>
> > +
> > +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;
> > +}
>
> Eventually we'll need to look at how this interacts with kexec. A
> kexec'd kernel will need to use the mapping already chosen by a
> previous kernel, but that's an issue for another patch series.
Yes please :]
> The patch needs some rework, but otherwise looks good, although I'm
> concerned about duplicate code. However, I've not dug deep into the
> mmu handling code. Others more cluefull that I on the MMU details will
> need to weigh in on that.
Thanks.
/
Leif
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