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/sched.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 include/asm-generic/bitops/sched.h (limited to 'include/asm-generic/bitops/sched.h') diff --git a/include/asm-generic/bitops/sched.h b/include/asm-generic/bitops/sched.h new file mode 100644 index 000000000..86470cfce --- /dev/null +++ b/include/asm-generic/bitops/sched.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_SCHED_H_ +#define _ASM_GENERIC_BITOPS_SCHED_H_ + +#include /* unlikely() */ +#include + +/* + * Every architecture must define this function. It's the fastest + * way of searching a 100-bit bitmap. It's guaranteed that at least + * one of the 100 bits is cleared. + */ +static inline int sched_find_first_bit(const unsigned long *b) +{ +#if BITS_PER_LONG == 64 + if (b[0]) + return __ffs(b[0]); + return __ffs(b[1]) + 64; +#elif BITS_PER_LONG == 32 + if (b[0]) + return __ffs(b[0]); + if (b[1]) + return __ffs(b[1]) + 32; + if (b[2]) + return __ffs(b[2]) + 64; + return __ffs(b[3]) + 96; +#else +#error BITS_PER_LONG not defined +#endif +} + +#endif /* _ASM_GENERIC_BITOPS_SCHED_H_ */ -- cgit v1.3.1