1 files changed, 267 insertions, 0 deletions

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
new file mode 100644
index 000000000000..7e3099c610dd
--- /dev/null
+++ b/arch/x86/platform/efi/quirks.c
@@ -0,0 +1,267 @@
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/time.h>
+#include <linux/types.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/bootmem.h>
+#include <asm/efi.h>
+#include <asm/uv/uv.h>
+
+#define EFI_MIN_RESERVE 5120
+
+#define EFI_DUMMY_GUID \
+        EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
+
+static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
+
+static bool efi_no_storage_paranoia;
+
+/*
+ * Some firmware implementations refuse to boot if there's insufficient
+ * space in the variable store. The implementation of garbage collection
+ * in some FW versions causes stale (deleted) variables to take up space
+ * longer than intended and space is only freed once the store becomes
+ * almost completely full.
+ *
+ * Enabling this option disables the space checks in
+ * efi_query_variable_store() and forces garbage collection.
+ *
+ * Only enable this option if deleting EFI variables does not free up
+ * space in your variable store, e.g. if despite deleting variables
+ * you're unable to create new ones.
+ */
+static int __init setup_storage_paranoia(char *arg)
+{
+        efi_no_storage_paranoia = true;
+        return 0;
+}
+early_param("efi_no_storage_paranoia", setup_storage_paranoia);
+
+/*
+ * Deleting the dummy variable which kicks off garbage collection
+*/
+void efi_delete_dummy_variable(void)
+{
+        efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+                         EFI_VARIABLE_NON_VOLATILE |
+                         EFI_VARIABLE_BOOTSERVICE_ACCESS |
+                         EFI_VARIABLE_RUNTIME_ACCESS,
+                         0, NULL);
+}
+
+/*
+ * Some firmware implementations refuse to boot if there's insufficient space
+ * in the variable store. Ensure that we never use more than a safe limit.
+ *
+ * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
+ * store.
+ */
+efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
+{
+        efi_status_t status;
+        u64 storage_size, remaining_size, max_size;
+
+        if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
+                return 0;
+
+        status = efi.query_variable_info(attributes, &storage_size,
+                                         &remaining_size, &max_size);
+        if (status != EFI_SUCCESS)
+                return status;
+
+        /*
+         * We account for that by refusing the write if permitting it would
+         * reduce the available space to under 5KB. This figure was provided by
+         * Samsung, so should be safe.
+         */
+        if ((remaining_size - size < EFI_MIN_RESERVE) &&
+                !efi_no_storage_paranoia) {
+
+                /*
+                 * Triggering garbage collection may require that the firmware
+                 * generate a real EFI_OUT_OF_RESOURCES error. We can force
+                 * that by attempting to use more space than is available.
+                 */
+                unsigned long dummy_size = remaining_size + 1024;
+                void *dummy = kzalloc(dummy_size, GFP_ATOMIC);
+
+                if (!dummy)
+                        return EFI_OUT_OF_RESOURCES;
+
+                status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+                                          EFI_VARIABLE_NON_VOLATILE |
+                                          EFI_VARIABLE_BOOTSERVICE_ACCESS |
+                                          EFI_VARIABLE_RUNTIME_ACCESS,
+                                          dummy_size, dummy);
+
+                if (status == EFI_SUCCESS) {
+                        /*
+                         * This should have failed, so if it didn't make sure
+                         * that we delete it...
+                         */
+                        efi_delete_dummy_variable();
+                }
+
+                kfree(dummy);
+
+                /*
+                 * The runtime code may now have triggered a garbage collection
+                 * run, so check the variable info again
+                 */
+                status = efi.query_variable_info(attributes, &storage_size,
+                                                 &remaining_size, &max_size);
+
+                if (status != EFI_SUCCESS)
+                        return status;
+
+                /*
+                 * There still isn't enough room, so return an error
+                 */
+                if (remaining_size - size < EFI_MIN_RESERVE)
+                        return EFI_OUT_OF_RESOURCES;
+        }
+
+        return EFI_SUCCESS;
+}
+EXPORT_SYMBOL_GPL(efi_query_variable_store);
+
+/*
+ * The UEFI specification makes it clear that the operating system is free to do
+ * whatever it wants with boot services code after ExitBootServices() has been
+ * called. Ignoring this recommendation a significant bunch of EFI implementations 
+ * continue calling into boot services code (SetVirtualAddressMap). In order to 
+ * work around such buggy implementations we reserve boot services region during 
+ * EFI init and make sure it stays executable. Then, after SetVirtualAddressMap(), it
+* is discarded.
+*/
+void __init efi_reserve_boot_services(void)
+{
+        void *p;
+
+        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+                efi_memory_desc_t *md = p;
+                u64 start = md->phys_addr;
+                u64 size = md->num_pages << EFI_PAGE_SHIFT;
+
+                if (md->type != EFI_BOOT_SERVICES_CODE &&
+                    md->type != EFI_BOOT_SERVICES_DATA)
+                        continue;
+                /* Only reserve where possible:
+                 * - Not within any already allocated areas
+                 * - Not over any memory area (really needed, if above?)
+                 * - Not within any part of the kernel
+                 * - Not the bios reserved area
+                */
+                if ((start + size > __pa_symbol(_text)
+                                && start <= __pa_symbol(_end)) ||
+                        !e820_all_mapped(start, start+size, E820_RAM) ||
+                        memblock_is_region_reserved(start, size)) {
+                        /* Could not reserve, skip it */
+                        md->num_pages = 0;
+                        memblock_dbg("Could not reserve boot range [0x%010llx-0x%010llx]\n",
+                                     start, start+size-1);
+                } else
+                        memblock_reserve(start, size);
+        }
+}
+
+void __init efi_free_boot_services(void)
+{
+        void *p;
+
+        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+                efi_memory_desc_t *md = p;
+                unsigned long long start = md->phys_addr;
+                unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
+
+                if (md->type != EFI_BOOT_SERVICES_CODE &&
+                    md->type != EFI_BOOT_SERVICES_DATA)
+                        continue;
+
+                /* Could not reserve boot area */
+                if (!size)
+                        continue;
+
+                free_bootmem_late(start, size);
+        }
+
+        efi_unmap_memmap();
+}
+
+/*
+ * A number of config table entries get remapped to virtual addresses
+ * after entering EFI virtual mode. However, the kexec kernel requires
+ * their physical addresses therefore we pass them via setup_data and
+ * correct those entries to their respective physical addresses here.
+ *
+ * Currently only handles smbios which is necessary for some firmware
+ * implementation.
+ */
+int __init efi_reuse_config(u64 tables, int nr_tables)
+{
+        int i, sz, ret = 0;
+        void *p, *tablep;
+        struct efi_setup_data *data;
+
+        if (!efi_setup)
+                return 0;
+
+        if (!efi_enabled(EFI_64BIT))
+                return 0;
+
+        data = early_memremap(efi_setup, sizeof(*data));
+        if (!data) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        if (!data->smbios)
+                goto out_memremap;
+
+        sz = sizeof(efi_config_table_64_t);
+
+        p = tablep = early_memremap(tables, nr_tables * sz);
+        if (!p) {
+                pr_err("Could not map Configuration table!\n");
+                ret = -ENOMEM;
+                goto out_memremap;
+        }
+
+        for (i = 0; i < efi.systab->nr_tables; i++) {
+                efi_guid_t guid;
+
+                guid = ((efi_config_table_64_t *)p)->guid;
+
+                if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
+                        ((efi_config_table_64_t *)p)->table = data->smbios;
+                p += sz;
+        }
+        early_iounmap(tablep, nr_tables * sz);
+
+out_memremap:
+        early_iounmap(data, sizeof(*data));
+out:
+        return ret;
+}
+
+void __init efi_apply_memmap_quirks(void)
+{
+        /*
+         * Once setup is done earlier, unmap the EFI memory map on mismatched
+         * firmware/kernel architectures since there is no support for runtime
+         * services.
+         */
+        if (!efi_runtime_supported()) {
+                pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n");
+                efi_unmap_memmap();
+        }
+
+        /*
+         * UV doesn't support the new EFI pagetable mapping yet.
+         */
+        if (is_uv_system())
+                set_bit(EFI_OLD_MEMMAP, &efi.flags);
+}