From 2bc6b218717b9d08f466f88209251d54bc09b207 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 22 Sep 2026 19:14:30 +0100 Subject: arm64/boot: Disable trapping of PMZR_EL0 writes to EL2 __init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2. PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a write from EL0 reaches the trap and takes the host down without a panic message. Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9 bits. Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba Reviewed-by: Anshuman Khandual Reviewed-by: Oliver Upton Signed-off-by: Will Deacon --- include/asm-generic/bitops/instrumented-lock.h | 82 ++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 include/asm-generic/bitops/instrumented-lock.h (limited to 'include/asm-generic/bitops/instrumented-lock.h') diff --git a/include/asm-generic/bitops/instrumented-lock.h b/include/asm-generic/bitops/instrumented-lock.h new file mode 100644 index 000000000..542d3727e --- /dev/null +++ b/include/asm-generic/bitops/instrumented-lock.h @@ -0,0 +1,82 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * This file provides wrappers with sanitizer instrumentation for bit + * locking operations. + * + * To use this functionality, an arch's bitops.h file needs to define each of + * the below bit operations with an arch_ prefix (e.g. arch_set_bit(), + * arch___set_bit(), etc.). + */ +#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H +#define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H + +#include + +/** + * clear_bit_unlock - Clear a bit in memory, for unlock + * @nr: the bit to set + * @addr: the address to start counting from + * + * This operation is atomic and provides release barrier semantics. + */ +static inline void clear_bit_unlock(long nr, volatile unsigned long *addr) +{ + kcsan_release(); + instrument_atomic_write(addr + BIT_WORD(nr), sizeof(long)); + arch_clear_bit_unlock(nr, addr); +} + +/** + * __clear_bit_unlock - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + * + * This is a non-atomic operation but implies a release barrier before the + * memory operation. It can be used for an unlock if no other CPUs can + * concurrently modify other bits in the word. + */ +static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) +{ + kcsan_release(); + instrument_write(addr + BIT_WORD(nr), sizeof(long)); + arch___clear_bit_unlock(nr, addr); +} + +/** + * test_and_set_bit_lock - Set a bit and return its old value, for lock + * @nr: Bit to set + * @addr: Address to count from + * + * This operation is atomic and provides acquire barrier semantics if + * the returned value is 0. + * It can be used to implement bit locks. + */ +static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr) +{ + instrument_atomic_read_write(addr + BIT_WORD(nr), sizeof(long)); + return arch_test_and_set_bit_lock(nr, addr); +} + +/** + * xor_unlock_is_negative_byte - XOR a single byte in memory and test if + * it is negative, for unlock. + * @mask: Change the bits which are set in this mask. + * @addr: The address of the word containing the byte to change. + * + * Changes some of bits 0-6 in the word pointed to by @addr. + * This operation is atomic and provides release barrier semantics. + * Used to optimise some folio operations which are commonly paired + * with an unlock or end of writeback. Bit 7 is used as PG_waiters to + * indicate whether anybody is waiting for the unlock. + * + * Return: Whether the top bit of the byte is set. + */ +static inline bool xor_unlock_is_negative_byte(unsigned long mask, + volatile unsigned long *addr) +{ + kcsan_release(); + instrument_atomic_write(addr, sizeof(long)); + return arch_xor_unlock_is_negative_byte(mask, addr); +} +#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */ -- cgit v1.3.1