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 --- drivers/tty/tty_mutex.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 drivers/tty/tty_mutex.c (limited to 'drivers/tty/tty_mutex.c') diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c new file mode 100644 index 000000000..784e46a0a --- /dev/null +++ b/drivers/tty/tty_mutex.c @@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include "tty.h" + +/* Legacy tty mutex glue */ + +/* + * Getting the big tty mutex. + */ + +void tty_lock(struct tty_struct *tty) +{ + tty_kref_get(tty); + mutex_lock(&tty->legacy_mutex); +} +EXPORT_SYMBOL(tty_lock); + +int tty_lock_interruptible(struct tty_struct *tty) +{ + int ret; + + tty_kref_get(tty); + ret = mutex_lock_interruptible(&tty->legacy_mutex); + if (ret) + tty_kref_put(tty); + return ret; +} + +void tty_unlock(struct tty_struct *tty) +{ + mutex_unlock(&tty->legacy_mutex); + tty_kref_put(tty); +} +EXPORT_SYMBOL(tty_unlock); + +void tty_lock_slave(struct tty_struct *tty) +{ + if (tty && tty != tty->link) + tty_lock(tty); +} + +void tty_unlock_slave(struct tty_struct *tty) +{ + if (tty && tty != tty->link) + tty_unlock(tty); +} + +void tty_set_lock_subclass(struct tty_struct *tty) +{ + lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE); +} -- cgit v1.3.1