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975a6166a8
Replace the variable set function from "efivar_entry_set" to "efivar_entry_set_safe" in efibc panic notifier. In safe function parameter "block" will set to false and will call "efivar_entry_set_nonblocking"to set efi variables. efivar_entry_set_nonblocking is guaranteed to not block and is suitable for calling from crash/panic handlers. In UEFI android platform, when warm reset happens, with this change, efibc will not block the reboot process. Otherwise, set variable will call queue work and send to other offlined cpus then cause another panic, finally will cause reboot failure. Signed-off-by: Tian Baofeng <baofeng.tian@intel.com> Signed-off-by: Luo XinanX <xinanx.luo@intel.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* efibc: control EFI bootloaders which obey LoaderEntryOneShot var
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* Copyright (c) 2013-2016, Intel Corporation.
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*/
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#define pr_fmt(fmt) "efibc: " fmt
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#include <linux/efi.h>
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#include <linux/module.h>
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#include <linux/reboot.h>
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#include <linux/slab.h>
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static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
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{
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size_t i;
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for (i = 0; i < strlen(str); i++)
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str16[i] = str[i];
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str16[i] = '\0';
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}
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static int efibc_set_variable(const char *name, const char *value)
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{
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int ret;
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efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
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struct efivar_entry *entry;
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size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
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if (size > sizeof(entry->var.Data)) {
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pr_err("value is too large (%zu bytes) for '%s' EFI variable\n", size, name);
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return -EINVAL;
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}
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entry = kmalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry) {
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pr_err("failed to allocate efivar entry for '%s' EFI variable\n", name);
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return -ENOMEM;
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}
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efibc_str_to_str16(name, entry->var.VariableName);
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efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
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memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
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ret = efivar_entry_set_safe(entry->var.VariableName,
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entry->var.VendorGuid,
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EFI_VARIABLE_NON_VOLATILE
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| EFI_VARIABLE_BOOTSERVICE_ACCESS
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| EFI_VARIABLE_RUNTIME_ACCESS,
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false, size, entry->var.Data);
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if (ret)
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pr_err("failed to set %s EFI variable: 0x%x\n",
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name, ret);
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kfree(entry);
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return ret;
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}
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static int efibc_reboot_notifier_call(struct notifier_block *notifier,
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unsigned long event, void *data)
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{
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const char *reason = "shutdown";
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int ret;
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if (event == SYS_RESTART)
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reason = "reboot";
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ret = efibc_set_variable("LoaderEntryRebootReason", reason);
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if (ret || !data)
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return NOTIFY_DONE;
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efibc_set_variable("LoaderEntryOneShot", (char *)data);
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return NOTIFY_DONE;
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}
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static struct notifier_block efibc_reboot_notifier = {
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.notifier_call = efibc_reboot_notifier_call,
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};
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static int __init efibc_init(void)
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{
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int ret;
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if (!efi_enabled(EFI_RUNTIME_SERVICES))
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return -ENODEV;
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ret = register_reboot_notifier(&efibc_reboot_notifier);
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if (ret)
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pr_err("unable to register reboot notifier\n");
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return ret;
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}
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module_init(efibc_init);
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static void __exit efibc_exit(void)
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{
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unregister_reboot_notifier(&efibc_reboot_notifier);
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}
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module_exit(efibc_exit);
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MODULE_AUTHOR("Jeremy Compostella <jeremy.compostella@intel.com>");
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MODULE_AUTHOR("Matt Gumbel <matthew.k.gumbel@intel.com");
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MODULE_DESCRIPTION("EFI Bootloader Control");
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MODULE_LICENSE("GPL v2");
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