Skip to main content

Browse the archive

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 
Revert "arm64: Enable perf events based hard lockup detector"
 
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>
1 parent df06824
Raw File
sha1.h 
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Common values for SHA-1 algorithms
 */

#ifndef _CRYPTO_SHA1_H
#define _CRYPTO_SHA1_H

#include <linux/types.h>

#define SHA1_DIGEST_SIZE        20
#define SHA1_BLOCK_SIZE         64

#define SHA1_H0		0x67452301UL
#define SHA1_H1		0xefcdab89UL
#define SHA1_H2		0x98badcfeUL
#define SHA1_H3		0x10325476UL
#define SHA1_H4		0xc3d2e1f0UL

extern const u8 sha1_zero_message_hash[SHA1_DIGEST_SIZE];

struct sha1_state {
	u32 state[SHA1_DIGEST_SIZE / 4];
	u64 count;
	u8 buffer[SHA1_BLOCK_SIZE];
};

struct shash_desc;

extern int crypto_sha1_update(struct shash_desc *desc, const u8 *data,
			      unsigned int len);

extern int crypto_sha1_finup(struct shash_desc *desc, const u8 *data,
			     unsigned int len, u8 *hash);

/*
 * An implementation of SHA-1's compression function.  Don't use in new code!
 * You shouldn't be using SHA-1, and even if you *have* to use SHA-1, this isn't
 * the correct way to hash something with SHA-1 (use crypto_shash instead).
 */
#define SHA1_DIGEST_WORDS	(SHA1_DIGEST_SIZE / 4)
#define SHA1_WORKSPACE_WORDS	16
void sha1_init(__u32 *buf);
void sha1_transform(__u32 *digest, const char *data, __u32 *W);

#endif /* _CRYPTO_SHA1_H */
back to top