/* * debugfs file to track time spent in suspend * * Copyright (c) 2011, Google, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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 "timekeeping_internal.h" #define NUM_BINS 32 static unsigned int sleep_time_bin[NUM_BINS] = {0}; static int tk_debug_show_sleep_time(struct seq_file *s, void *data) { unsigned int bin; seq_puts(s, " time (secs) count\n"); seq_puts(s, "------------------------------\n"); for (bin = 0; bin < 32; bin++) { if (sleep_time_bin[bin] == 0) continue; seq_printf(s, "%10u - %-10u %4u\n", bin ? 1 << (bin - 1) : 0, 1 << bin, sleep_time_bin[bin]); } return 0; } static int tk_debug_sleep_time_open(struct inode *inode, struct file *file) { return single_open(file, tk_debug_show_sleep_time, NULL); } static const struct file_operations tk_debug_sleep_time_fops = { .open = tk_debug_sleep_time_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; static int __init tk_debug_sleep_time_init(void) { struct dentry *d; d = debugfs_create_file("sleep_time", 0444, NULL, NULL, &tk_debug_sleep_time_fops); if (!d) { pr_err("Failed to create sleep_time debug file\n"); return -ENOMEM; } return 0; } late_initcall(tk_debug_sleep_time_init); void tk_debug_account_sleep_time(struct timespec64 *t) { /* Cap bin index so we don't overflow the array */ int bin = min(fls(t->tv_sec), NUM_BINS-1); sleep_time_bin[bin]++; pr_info("Suspended for %lld.%03lu seconds\n", (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC); } ude'>
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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 /include
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>
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