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, 221 insertions, 0 deletions

diff --git a/include/net/rstreason.h b/include/net/rstreason.h
new file mode 100644
index 000000000..979ac87b5
--- /dev/null
+++ b/include/net/rstreason.h
@@ -0,0 +1,221 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _LINUX_RSTREASON_H
+#define _LINUX_RSTREASON_H
+#include <net/dropreason-core.h>
+#include <uapi/linux/mptcp.h>
+
+#define DEFINE_RST_REASON(FN, FNe)	\
+	FN(NOT_SPECIFIED)		\
+	FN(NO_SOCKET)			\
+	FN(TCP_INVALID_ACK_SEQUENCE)	\
+	FN(TCP_RFC7323_PAWS)		\
+	FN(TCP_TOO_OLD_ACK)		\
+	FN(TCP_ACK_UNSENT_DATA)		\
+	FN(TCP_FLAGS)			\
+	FN(TCP_OLD_ACK)			\
+	FN(TCP_ABORT_ON_DATA)		\
+	FN(TCP_TIMEWAIT_SOCKET)		\
+	FN(INVALID_SYN)			\
+	FN(TCP_ABORT_ON_CLOSE)		\
+	FN(TCP_ABORT_ON_LINGER)		\
+	FN(TCP_ABORT_ON_MEMORY)		\
+	FN(TCP_STATE)			\
+	FN(TCP_KEEPALIVE_TIMEOUT)	\
+	FN(TCP_DISCONNECT_WITH_DATA)	\
+	FN(MPTCP_RST_EUNSPEC)		\
+	FN(MPTCP_RST_EMPTCP)		\
+	FN(MPTCP_RST_ERESOURCE)		\
+	FN(MPTCP_RST_EPROHIBIT)		\
+	FN(MPTCP_RST_EWQ2BIG)		\
+	FN(MPTCP_RST_EBADPERF)		\
+	FN(MPTCP_RST_EMIDDLEBOX)	\
+	FN(ERROR)			\
+	FNe(MAX)
+
+/**
+ * enum sk_rst_reason - the reasons of socket reset
+ *
+ * The reasons of sk reset, which are used in TCP/MPTCP protocols.
+ *
+ * There are three parts in order:
+ * 1) skb drop reasons: relying on drop reasons for such as passive reset
+ * 2) independent reset reasons: such as active reset reasons
+ * 3) reset reasons in MPTCP: only for MPTCP use
+ */
+enum sk_rst_reason {
+	/* Refer to include/net/dropreason-core.h
+	 * Rely on skb drop reasons because it indicates exactly why RST
+	 * could happen.
+	 */
+	/** @SK_RST_REASON_NOT_SPECIFIED: reset reason is not specified */
+	SK_RST_REASON_NOT_SPECIFIED,
+	/** @SK_RST_REASON_NO_SOCKET: no valid socket that can be used */
+	SK_RST_REASON_NO_SOCKET,
+	/**
+	 * @SK_RST_REASON_TCP_INVALID_ACK_SEQUENCE: Not acceptable ACK SEQ
+	 * field because ack sequence is not in the window between snd_una
+	 * and snd_nxt
+	 */
+	SK_RST_REASON_TCP_INVALID_ACK_SEQUENCE,
+	/**
+	 * @SK_RST_REASON_TCP_RFC7323_PAWS: PAWS check, corresponding to
+	 * LINUX_MIB_PAWSESTABREJECTED, LINUX_MIB_PAWSACTIVEREJECTED
+	 */
+	SK_RST_REASON_TCP_RFC7323_PAWS,
+	/** @SK_RST_REASON_TCP_TOO_OLD_ACK: TCP ACK is too old */
+	SK_RST_REASON_TCP_TOO_OLD_ACK,
+	/**
+	 * @SK_RST_REASON_TCP_ACK_UNSENT_DATA: TCP ACK for data we haven't
+	 * sent yet
+	 */
+	SK_RST_REASON_TCP_ACK_UNSENT_DATA,
+	/** @SK_RST_REASON_TCP_FLAGS: TCP flags invalid */
+	SK_RST_REASON_TCP_FLAGS,
+	/** @SK_RST_REASON_TCP_OLD_ACK: TCP ACK is old, but in window */
+	SK_RST_REASON_TCP_OLD_ACK,
+	/**
+	 * @SK_RST_REASON_TCP_ABORT_ON_DATA: abort on data
+	 * corresponding to LINUX_MIB_TCPABORTONDATA
+	 */
+	SK_RST_REASON_TCP_ABORT_ON_DATA,
+
+	/* Here start with the independent reasons */
+	/** @SK_RST_REASON_TCP_TIMEWAIT_SOCKET: happen on the timewait socket */
+	SK_RST_REASON_TCP_TIMEWAIT_SOCKET,
+	/**
+	 * @SK_RST_REASON_INVALID_SYN: receive bad syn packet
+	 * RFC 793 says if the state is not CLOSED/LISTEN/SYN-SENT then
+	 * "fourth, check the SYN bit,...If the SYN is in the window it is
+	 * an error, send a reset"
+	 */
+	SK_RST_REASON_INVALID_SYN,
+	/**
+	 * @SK_RST_REASON_TCP_ABORT_ON_CLOSE: abort on close
+	 * corresponding to LINUX_MIB_TCPABORTONCLOSE
+	 */
+	SK_RST_REASON_TCP_ABORT_ON_CLOSE,
+	/**
+	 * @SK_RST_REASON_TCP_ABORT_ON_LINGER: abort on linger
+	 * corresponding to LINUX_MIB_TCPABORTONLINGER
+	 */
+	SK_RST_REASON_TCP_ABORT_ON_LINGER,
+	/**
+	 * @SK_RST_REASON_TCP_ABORT_ON_MEMORY: abort on memory
+	 * corresponding to LINUX_MIB_TCPABORTONMEMORY
+	 */
+	SK_RST_REASON_TCP_ABORT_ON_MEMORY,
+	/**
+	 * @SK_RST_REASON_TCP_STATE: abort on tcp state
+	 * Please see RFC 9293 for all possible reset conditions
+	 */
+	SK_RST_REASON_TCP_STATE,
+	/**
+	 * @SK_RST_REASON_TCP_KEEPALIVE_TIMEOUT: time to timeout
+	 * When we have already run out of all the chances, which means
+	 * keepalive timeout, we have to reset the connection
+	 */
+	SK_RST_REASON_TCP_KEEPALIVE_TIMEOUT,
+	/**
+	 * @SK_RST_REASON_TCP_DISCONNECT_WITH_DATA: disconnect when write
+	 * queue is not empty
+	 * It means user has written data into the write queue when doing
+	 * disconnecting, so we have to send an RST.
+	 */
+	SK_RST_REASON_TCP_DISCONNECT_WITH_DATA,
+
+	/* Copy from include/uapi/linux/mptcp.h.
+	 * These reset fields will not be changed since they adhere to
+	 * RFC 8684. So do not touch them. I'm going to list each definition
+	 * of them respectively.
+	 */
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_EUNSPEC: Unspecified error.
+	 * This is the default error; it implies that the subflow is no
+	 * longer available. The presence of this option shows that the
+	 * RST was generated by an MPTCP-aware device.
+	 */
+	SK_RST_REASON_MPTCP_RST_EUNSPEC,
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_EMPTCP: MPTCP-specific error.
+	 * An error has been detected in the processing of MPTCP options.
+	 * This is the usual reason code to return in the cases where a RST
+	 * is being sent to close a subflow because of an invalid response.
+	 */
+	SK_RST_REASON_MPTCP_RST_EMPTCP,
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_ERESOURCE: Lack of resources.
+	 * This code indicates that the sending host does not have enough
+	 * resources to support the terminated subflow.
+	 */
+	SK_RST_REASON_MPTCP_RST_ERESOURCE,
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_EPROHIBIT: Administratively prohibited.
+	 * This code indicates that the requested subflow is prohibited by
+	 * the policies of the sending host.
+	 */
+	SK_RST_REASON_MPTCP_RST_EPROHIBIT,
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_EWQ2BIG: Too much outstanding data.
+	 * This code indicates that there is an excessive amount of data
+	 * that needs to be transmitted over the terminated subflow while
+	 * having already been acknowledged over one or more other subflows.
+	 * This may occur if a path has been unavailable for a short period
+	 * and it is more efficient to reset and start again than it is to
+	 * retransmit the queued data.
+	 */
+	SK_RST_REASON_MPTCP_RST_EWQ2BIG,
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_EBADPERF: Unacceptable performance.
+	 * This code indicates that the performance of this subflow was
+	 * too low compared to the other subflows of this Multipath TCP
+	 * connection.
+	 */
+	SK_RST_REASON_MPTCP_RST_EBADPERF,
+	/**
+	 * @SK_RST_REASON_MPTCP_RST_EMIDDLEBOX: Middlebox interference.
+	 * Middlebox interference has been detected over this subflow,
+	 * making MPTCP signaling invalid. For example, this may be sent
+	 * if the checksum does not validate.
+	 */
+	SK_RST_REASON_MPTCP_RST_EMIDDLEBOX,
+
+	/** @SK_RST_REASON_ERROR: unexpected error happens */
+	SK_RST_REASON_ERROR,
+
+	/**
+	 * @SK_RST_REASON_MAX: Maximum of socket reset reasons.
+	 * It shouldn't be used as a real 'reason'.
+	 */
+	SK_RST_REASON_MAX,
+};
+
+/* Convert skb drop reasons to enum sk_rst_reason type */
+static inline enum sk_rst_reason
+sk_rst_convert_drop_reason(enum skb_drop_reason reason)
+{
+	switch (reason) {
+	case SKB_DROP_REASON_NOT_SPECIFIED:
+		return SK_RST_REASON_NOT_SPECIFIED;
+	case SKB_DROP_REASON_NO_SOCKET:
+		return SK_RST_REASON_NO_SOCKET;
+	case SKB_DROP_REASON_TCP_INVALID_ACK_SEQUENCE:
+		return SK_RST_REASON_TCP_INVALID_ACK_SEQUENCE;
+	case SKB_DROP_REASON_TCP_RFC7323_PAWS:
+		return SK_RST_REASON_TCP_RFC7323_PAWS;
+	case SKB_DROP_REASON_TCP_TOO_OLD_ACK:
+		return SK_RST_REASON_TCP_TOO_OLD_ACK;
+	case SKB_DROP_REASON_TCP_ACK_UNSENT_DATA:
+		return SK_RST_REASON_TCP_ACK_UNSENT_DATA;
+	case SKB_DROP_REASON_TCP_FLAGS:
+		return SK_RST_REASON_TCP_FLAGS;
+	case SKB_DROP_REASON_TCP_OLD_ACK:
+		return SK_RST_REASON_TCP_OLD_ACK;
+	case SKB_DROP_REASON_TCP_ABORT_ON_DATA:
+		return SK_RST_REASON_TCP_ABORT_ON_DATA;
+	default:
+		/* If we don't have our own corresponding reason */
+		return SK_RST_REASON_NOT_SPECIFIED;
+	}
+}
+#endif