arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__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 <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/accessibility/speakup/serialio.h b/drivers/accessibility/speakup/serialio.h
new file mode 100644
index 000000000..b4f9a1925
--- /dev/null
+++ b/drivers/accessibility/speakup/serialio.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SPEAKUP_SERIAL_H
+#define _SPEAKUP_SERIAL_H
+
+#include <linux/serial.h>	/* for rs_table, serial constants */
+#include <linux/serial_reg.h>	/* for more serial constants */
+#include <linux/serial_core.h>
+
+#include "spk_priv.h"
+
+/*
+ * this is cut&paste from 8250.h. Get rid of the structure, the definitions
+ * and this whole broken driver.
+ */
+struct old_serial_port {
+	unsigned int uart; /* unused */
+	unsigned int baud_base;
+	unsigned int port;
+	unsigned int irq;
+	upf_t flags; /* unused */
+};
+
+/* countdown values for serial timeouts in us */
+#define SPK_SERIAL_TIMEOUT SPK_SYNTH_TIMEOUT
+/* countdown values transmitter/dsr timeouts in us */
+#define SPK_XMITR_TIMEOUT 100000
+/* countdown values cts timeouts in us */
+#define SPK_CTS_TIMEOUT 100000
+/* check ttyS0 ... ttyS3 */
+#define SPK_LO_TTY 0
+#define SPK_HI_TTY 3
+/* # of timeouts permitted before disable */
+#define NUM_DISABLE_TIMEOUTS 3
+/* buffer timeout in ms */
+#define SPK_TIMEOUT 100
+
+#define spk_serial_tx_busy() \
+	(!uart_lsr_tx_empty(inb(speakup_info.port_tts + UART_LSR)))
+
+#endif