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/char/tpm/tpm-dev.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 drivers/char/tpm/tpm-dev.c (limited to 'drivers/char/tpm/tpm-dev.c') diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c new file mode 100644 index 000000000..74488f0a7 --- /dev/null +++ b/drivers/char/tpm/tpm-dev.c @@ -0,0 +1,67 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2004 IBM Corporation + * Authors: + * Leendert van Doorn + * Dave Safford + * Reiner Sailer + * Kylene Hall + * + * Copyright (C) 2013 Obsidian Research Corp + * Jason Gunthorpe + * + * Device file system interface to the TPM + */ +#include +#include "tpm-dev.h" + +static int tpm_open(struct inode *inode, struct file *file) +{ + struct tpm_chip *chip; + struct file_priv *priv; + + chip = container_of(inode->i_cdev, struct tpm_chip, cdev); + + /* It's assured that the chip will be opened just once, + * by the check of is_open variable, which is protected + * by driver_lock. */ + if (test_and_set_bit(0, &chip->is_open)) { + dev_dbg(&chip->dev, "Another process owns this TPM\n"); + return -EBUSY; + } + + priv = kzalloc_obj(*priv); + if (priv == NULL) + goto out; + + tpm_common_open(file, chip, priv, NULL); + + return nonseekable_open(inode, file); + + out: + clear_bit(0, &chip->is_open); + return -ENOMEM; +} + +/* + * Called on file close + */ +static int tpm_release(struct inode *inode, struct file *file) +{ + struct file_priv *priv = file->private_data; + + tpm_common_release(file, priv); + clear_bit(0, &priv->chip->is_open); + kfree(priv); + + return 0; +} + +const struct file_operations tpm_fops = { + .owner = THIS_MODULE, + .open = tpm_open, + .read = tpm_common_read, + .write = tpm_common_write, + .poll = tpm_common_poll, + .release = tpm_release, +}; -- cgit v1.3.1