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
blake2s.h 
/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/*
 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */

#ifndef BLAKE2S_H
#define BLAKE2S_H

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>

#include <asm/bug.h>

enum blake2s_lengths {
	BLAKE2S_BLOCK_SIZE = 64,
	BLAKE2S_HASH_SIZE = 32,
	BLAKE2S_KEY_SIZE = 32,

	BLAKE2S_128_HASH_SIZE = 16,
	BLAKE2S_160_HASH_SIZE = 20,
	BLAKE2S_224_HASH_SIZE = 28,
	BLAKE2S_256_HASH_SIZE = 32,
};

struct blake2s_state {
	u32 h[8];
	u32 t[2];
	u32 f[2];
	u8 buf[BLAKE2S_BLOCK_SIZE];
	unsigned int buflen;
	unsigned int outlen;
};

enum blake2s_iv {
	BLAKE2S_IV0 = 0x6A09E667UL,
	BLAKE2S_IV1 = 0xBB67AE85UL,
	BLAKE2S_IV2 = 0x3C6EF372UL,
	BLAKE2S_IV3 = 0xA54FF53AUL,
	BLAKE2S_IV4 = 0x510E527FUL,
	BLAKE2S_IV5 = 0x9B05688CUL,
	BLAKE2S_IV6 = 0x1F83D9ABUL,
	BLAKE2S_IV7 = 0x5BE0CD19UL,
};

void blake2s_update(struct blake2s_state *state, const u8 *in, size_t inlen);
void blake2s_final(struct blake2s_state *state, u8 *out);

static inline void blake2s_init_param(struct blake2s_state *state,
				      const u32 param)
{
	*state = (struct blake2s_state){{
		BLAKE2S_IV0 ^ param,
		BLAKE2S_IV1,
		BLAKE2S_IV2,
		BLAKE2S_IV3,
		BLAKE2S_IV4,
		BLAKE2S_IV5,
		BLAKE2S_IV6,
		BLAKE2S_IV7,
	}};
}

static inline void blake2s_init(struct blake2s_state *state,
				const size_t outlen)
{
	blake2s_init_param(state, 0x01010000 | outlen);
	state->outlen = outlen;
}

static inline void blake2s_init_key(struct blake2s_state *state,
				    const size_t outlen, const void *key,
				    const size_t keylen)
{
	WARN_ON(IS_ENABLED(DEBUG) && (!outlen || outlen > BLAKE2S_HASH_SIZE ||
		!key || !keylen || keylen > BLAKE2S_KEY_SIZE));

	blake2s_init_param(state, 0x01010000 | keylen << 8 | outlen);
	memcpy(state->buf, key, keylen);
	state->buflen = BLAKE2S_BLOCK_SIZE;
	state->outlen = outlen;
}

static inline void blake2s(u8 *out, const u8 *in, const u8 *key,
			   const size_t outlen, const size_t inlen,
			   const size_t keylen)
{
	struct blake2s_state state;

	WARN_ON(IS_ENABLED(DEBUG) && ((!in && inlen > 0) || !out || !outlen ||
		outlen > BLAKE2S_HASH_SIZE || keylen > BLAKE2S_KEY_SIZE ||
		(!key && keylen)));

	if (keylen)
		blake2s_init_key(&state, outlen, key, keylen);
	else
		blake2s_init(&state, outlen);

	blake2s_update(&state, in, inlen);
	blake2s_final(&state, out);
}

void blake2s256_hmac(u8 *out, const u8 *in, const u8 *key, const size_t inlen,
		     const size_t keylen);

#endif /* BLAKE2S_H */
back to top