/* * Watchdog timer driver for the WinSystems EBC-C384 * Copyright (C) 2016 William Breathitt Gray * * 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. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #define MODULE_NAME "ebc-c384_wdt" #define WATCHDOG_TIMEOUT 60 /* * The timeout value in minutes must fit in a single byte when sent to the * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. */ #define WATCHDOG_MAX_TIMEOUT 15300 #define BASE_ADDR 0x564 #define ADDR_EXTENT 5 #define CFG_ADDR (BASE_ADDR + 1) #define PET_ADDR (BASE_ADDR + 2) static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static unsigned timeout; module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); static int ebc_c384_wdt_start(struct watchdog_device *wdev) { unsigned t = wdev->timeout; /* resolution is in minutes for timeouts greater than 255 seconds */ if (t > 255) t = DIV_ROUND_UP(t, 60); outb(t, PET_ADDR); return 0; } static int ebc_c384_wdt_stop(struct watchdog_device *wdev) { outb(0x00, PET_ADDR); return 0; } static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) { /* resolution is in minutes for timeouts greater than 255 seconds */ if (t > 255) { /* round second resolution up to minute granularity */ wdev->timeout = roundup(t, 60); /* set watchdog timer for minutes */ outb(0x00, CFG_ADDR); } else { wdev->timeout = t; /* set watchdog timer for seconds */ outb(0x80, CFG_ADDR); } return 0; } static const struct watchdog_ops ebc_c384_wdt_ops = { .start = ebc_c384_wdt_start, .stop = ebc_c384_wdt_stop, .set_timeout = ebc_c384_wdt_set_timeout }; static const struct watchdog_info ebc_c384_wdt_info = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, .identity = MODULE_NAME }; static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) { struct watchdog_device *wdd; if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", BASE_ADDR, BASE_ADDR + ADDR_EXTENT); return -EBUSY; } wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); if (!wdd) return -ENOMEM; wdd->info = &ebc_c384_wdt_info; wdd->ops = &ebc_c384_wdt_ops; wdd->timeout = WATCHDOG_TIMEOUT; wdd->min_timeout = 1; wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; watchdog_set_nowayout(wdd, nowayout); if (watchdog_init_timeout(wdd, timeout, dev)) dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n", timeout, WATCHDOG_TIMEOUT); dev_set_drvdata(dev, wdd); return watchdog_register_device(wdd); } static int ebc_c384_wdt_remove(struct device *dev, unsigned int id) { struct watchdog_device *wdd = dev_get_drvdata(dev); watchdog_unregister_device(wdd); return 0; } static struct isa_driver ebc_c384_wdt_driver = { .probe = ebc_c384_wdt_probe, .driver = { .name = MODULE_NAME }, .remove = ebc_c384_wdt_remove }; static int __init ebc_c384_wdt_init(void) { if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) return -ENODEV; return isa_register_driver(&ebc_c384_wdt_driver, 1); } static void __exit ebc_c384_wdt_exit(void) { isa_unregister_driver(&ebc_c384_wdt_driver); } module_init(ebc_c384_wdt_init); module_exit(ebc_c384_wdt_exit); MODULE_AUTHOR("William Breathitt Gray "); MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("isa:" MODULE_NAME); ected='selected'>unified
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /security/tomoyo/realpath.c
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") fixed an issue in the memory map handling of the stub FDT code, but inadvertently created an issue with such firmware, by moving some of the FDT manipulation to after the invocation of ExitBootServices(). Given that the stub's libfdt implementation uses the ordinary, accelerated string functions, which rely on hardware handling of unaligned accesses, manipulating the FDT with the MMU off may result in alignment faults. So fix the situation by moving the update_fdt_memmap() call into the callback function invoked by efi_exit_boot_services() right before it calls the ExitBootServices() UEFI service (which is arguably a better place for it anyway) Note that disabling the MMU in ExitBootServices() is not compliant with the UEFI spec, and carries great risk due to the fact that switching from cached to uncached memory accesses halfway through compiler generated code (i.e., involving a stack) can never be done in a way that is architecturally safe. Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Riku Voipio <riku.voipio@linaro.org> Cc: <stable@vger.kernel.org> Cc: mark.rutland@arm.com Cc: linux-efi@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: leif.lindholm@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'security/tomoyo/realpath.c')