Revision b90d72a6bfdb5e5c62cd223a8cdf4045bfbcb94d authored by Will Deacon on 12 January 2021, 22:18:55 UTC, committed by Catalin Marinas on 13 January 2021, 15:08:41 UTC
This reverts commit 367c820ef08082e68df8a3bc12e62393af21e4b5. lockup_detector_init() makes heavy use of per-cpu variables and must be called with preemption disabled. Usually, it's handled early during boot in kernel_init_freeable(), before SMP has been initialised. Since we do not know whether or not our PMU interrupt can be signalled as an NMI until considerably later in the boot process, the Arm PMU driver attempts to re-initialise the lockup detector off the back of a device_initcall(). Unfortunately, this is called from preemptible context and results in the following splat: | BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1 | caller is debug_smp_processor_id+0x20/0x2c | CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.10.0+ #276 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace+0x0/0x3c0 | show_stack+0x20/0x6c | dump_stack+0x2f0/0x42c | check_preemption_disabled+0x1cc/0x1dc | debug_smp_processor_id+0x20/0x2c | hardlockup_detector_event_create+0x34/0x18c | hardlockup_detector_perf_init+0x2c/0x134 | watchdog_nmi_probe+0x18/0x24 | lockup_detector_init+0x44/0xa8 | armv8_pmu_driver_init+0x54/0x78 | do_one_initcall+0x184/0x43c | kernel_init_freeable+0x368/0x380 | kernel_init+0x1c/0x1cc | ret_from_fork+0x10/0x30 Rather than bodge this with raw_smp_processor_id() or randomly disabling preemption, simply revert the culprit for now until we figure out how to do this properly. Reported-by: Lecopzer Chen <lecopzer.chen@mediatek.com> Signed-off-by: Will Deacon <will@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Sumit Garg <sumit.garg@linaro.org> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Link: https://lore.kernel.org/r/20201221162249.3119-1-lecopzer.chen@mediatek.com Link: https://lore.kernel.org/r/20210112221855.10666-1-will@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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pmag-ba-fb.h
/*
* linux/include/video/pmag-ba-fb.h
*
* TURBOchannel PMAG-BA Color Frame Buffer (CFB) card support,
* Copyright (C) 1999, 2000, 2001 by
* Michael Engel <engel@unix-ag.org>,
* Karsten Merker <merker@linuxtag.org>
* Copyright (c) 2005 Maciej W. Rozycki
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file COPYING in the main directory of this
* archive for more details.
*/
/* IOmem resource offsets. */
#define PMAG_BA_FBMEM 0x000000 /* frame buffer */
#define PMAG_BA_BT459 0x200000 /* Bt459 RAMDAC */
#define PMAG_BA_IRQ 0x300000 /* IRQ acknowledge */
#define PMAG_BA_ROM 0x380000 /* REX option ROM */
#define PMAG_BA_BT438 0x380000 /* Bt438 clock chip reset */
#define PMAG_BA_SIZE 0x400000 /* address space size */
/* Bt459 register offsets, byte-wide registers. */
#define BT459_ADDR_LO 0x0 /* address low */
#define BT459_ADDR_HI 0x4 /* address high */
#define BT459_DATA 0x8 /* data window register */
#define BT459_CMAP 0xc /* color map window register */
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