From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/firewire/phy-packet-definitions.h | 302 ++++++++++++++++++++++++++++++ 1 file changed, 302 insertions(+) create mode 100644 drivers/firewire/phy-packet-definitions.h (limited to 'drivers/firewire/phy-packet-definitions.h') diff --git a/drivers/firewire/phy-packet-definitions.h b/drivers/firewire/phy-packet-definitions.h new file mode 100644 index 000000000..03c7c6067 --- /dev/null +++ b/drivers/firewire/phy-packet-definitions.h @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// +// phy-packet-definitions.h - The definitions of phy packet for IEEE 1394. +// +// Copyright (c) 2024 Takashi Sakamoto + +#ifndef _FIREWIRE_PHY_PACKET_DEFINITIONS_H +#define _FIREWIRE_PHY_PACKET_DEFINITIONS_H + +#define PACKET_IDENTIFIER_MASK 0xc0000000 +#define PACKET_IDENTIFIER_SHIFT 30 + +static inline unsigned int phy_packet_get_packet_identifier(u32 quadlet) +{ + return (quadlet & PACKET_IDENTIFIER_MASK) >> PACKET_IDENTIFIER_SHIFT; +} + +static inline void phy_packet_set_packet_identifier(u32 *quadlet, unsigned int packet_identifier) +{ + *quadlet &= ~PACKET_IDENTIFIER_MASK; + *quadlet |= (packet_identifier << PACKET_IDENTIFIER_SHIFT) & PACKET_IDENTIFIER_MASK; +} + +#define PHY_PACKET_PACKET_IDENTIFIER_PHY_CONFIG 0 + +#define PHY_CONFIG_ROOT_ID_MASK 0x3f000000 +#define PHY_CONFIG_ROOT_ID_SHIFT 24 +#define PHY_CONFIG_FORCE_ROOT_NODE_MASK 0x00800000 +#define PHY_CONFIG_FORCE_ROOT_NODE_SHIFT 23 +#define PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK 0x00400000 +#define PHY_CONFIG_GAP_COUNT_OPTIMIZATION_SHIFT 22 +#define PHY_CONFIG_GAP_COUNT_MASK 0x003f0000 +#define PHY_CONFIG_GAP_COUNT_SHIFT 16 + +static inline unsigned int phy_packet_phy_config_get_root_id(u32 quadlet) +{ + return (quadlet & PHY_CONFIG_ROOT_ID_MASK) >> PHY_CONFIG_ROOT_ID_SHIFT; +} + +static inline void phy_packet_phy_config_set_root_id(u32 *quadlet, unsigned int root_id) +{ + *quadlet &= ~PHY_CONFIG_ROOT_ID_MASK; + *quadlet |= (root_id << PHY_CONFIG_ROOT_ID_SHIFT) & PHY_CONFIG_ROOT_ID_MASK; +} + +static inline bool phy_packet_phy_config_get_force_root_node(u32 quadlet) +{ + return (quadlet & PHY_CONFIG_FORCE_ROOT_NODE_MASK) >> PHY_CONFIG_FORCE_ROOT_NODE_SHIFT; +} + +static inline void phy_packet_phy_config_set_force_root_node(u32 *quadlet, bool has_force_root_node) +{ + *quadlet &= ~PHY_CONFIG_FORCE_ROOT_NODE_MASK; + *quadlet |= (has_force_root_node << PHY_CONFIG_FORCE_ROOT_NODE_SHIFT) & PHY_CONFIG_FORCE_ROOT_NODE_MASK; +} + +static inline bool phy_packet_phy_config_get_gap_count_optimization(u32 quadlet) +{ + return (quadlet & PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK) >> PHY_CONFIG_GAP_COUNT_OPTIMIZATION_SHIFT; +} + +static inline void phy_packet_phy_config_set_gap_count_optimization(u32 *quadlet, bool has_gap_count_optimization) +{ + *quadlet &= ~PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK; + *quadlet |= (has_gap_count_optimization << PHY_CONFIG_GAP_COUNT_OPTIMIZATION_SHIFT) & PHY_CONFIG_GAP_COUNT_OPTIMIZATION_MASK; +} + +static inline unsigned int phy_packet_phy_config_get_gap_count(u32 quadlet) +{ + return (quadlet & PHY_CONFIG_GAP_COUNT_MASK) >> PHY_CONFIG_GAP_COUNT_SHIFT; +} + +static inline void phy_packet_phy_config_set_gap_count(u32 *quadlet, unsigned int gap_count) +{ + *quadlet &= ~PHY_CONFIG_GAP_COUNT_MASK; + *quadlet |= (gap_count << PHY_CONFIG_GAP_COUNT_SHIFT) & PHY_CONFIG_GAP_COUNT_MASK; +} + +#define PHY_PACKET_PACKET_IDENTIFIER_SELF_ID 2 + +#define SELF_ID_PHY_ID_MASK 0x3f000000 +#define SELF_ID_PHY_ID_SHIFT 24 +#define SELF_ID_EXTENDED_MASK 0x00800000 +#define SELF_ID_EXTENDED_SHIFT 23 +#define SELF_ID_MORE_PACKETS_MASK 0x00000001 +#define SELF_ID_MORE_PACKETS_SHIFT 0 + +#define SELF_ID_ZERO_LINK_ACTIVE_MASK 0x00400000 +#define SELF_ID_ZERO_LINK_ACTIVE_SHIFT 22 +#define SELF_ID_ZERO_GAP_COUNT_MASK 0x003f0000 +#define SELF_ID_ZERO_GAP_COUNT_SHIFT 16 +#define SELF_ID_ZERO_SCODE_MASK 0x0000c000 +#define SELF_ID_ZERO_SCODE_SHIFT 14 +#define SELF_ID_ZERO_CONTENDER_MASK 0x00000800 +#define SELF_ID_ZERO_CONTENDER_SHIFT 11 +#define SELF_ID_ZERO_POWER_CLASS_MASK 0x00000700 +#define SELF_ID_ZERO_POWER_CLASS_SHIFT 8 +#define SELF_ID_ZERO_INITIATED_RESET_MASK 0x00000002 +#define SELF_ID_ZERO_INITIATED_RESET_SHIFT 1 + +#define SELF_ID_EXTENDED_SEQUENCE_MASK 0x00700000 +#define SELF_ID_EXTENDED_SEQUENCE_SHIFT 20 + +#define SELF_ID_PORT_STATUS_MASK 0x3 + +#define SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT 4 + +static inline unsigned int phy_packet_self_id_get_phy_id(u32 quadlet) +{ + return (quadlet & SELF_ID_PHY_ID_MASK) >> SELF_ID_PHY_ID_SHIFT; +} + +static inline void phy_packet_self_id_set_phy_id(u32 *quadlet, unsigned int phy_id) +{ + *quadlet &= ~SELF_ID_PHY_ID_MASK; + *quadlet |= (phy_id << SELF_ID_PHY_ID_SHIFT) & SELF_ID_PHY_ID_MASK; +} + +static inline bool phy_packet_self_id_get_extended(u32 quadlet) +{ + return (quadlet & SELF_ID_EXTENDED_MASK) >> SELF_ID_EXTENDED_SHIFT; +} + +static inline void phy_packet_self_id_set_extended(u32 *quadlet, bool extended) +{ + *quadlet &= ~SELF_ID_EXTENDED_MASK; + *quadlet |= (extended << SELF_ID_EXTENDED_SHIFT) & SELF_ID_EXTENDED_MASK; +} + +static inline bool phy_packet_self_id_zero_get_link_active(u32 quadlet) +{ + return (quadlet & SELF_ID_ZERO_LINK_ACTIVE_MASK) >> SELF_ID_ZERO_LINK_ACTIVE_SHIFT; +} + +static inline void phy_packet_self_id_zero_set_link_active(u32 *quadlet, bool is_active) +{ + *quadlet &= ~SELF_ID_ZERO_LINK_ACTIVE_MASK; + *quadlet |= (is_active << SELF_ID_ZERO_LINK_ACTIVE_SHIFT) & SELF_ID_ZERO_LINK_ACTIVE_MASK; +} + +static inline unsigned int phy_packet_self_id_zero_get_gap_count(u32 quadlet) +{ + return (quadlet & SELF_ID_ZERO_GAP_COUNT_MASK) >> SELF_ID_ZERO_GAP_COUNT_SHIFT; +} + +static inline void phy_packet_self_id_zero_set_gap_count(u32 *quadlet, unsigned int gap_count) +{ + *quadlet &= ~SELF_ID_ZERO_GAP_COUNT_MASK; + *quadlet |= (gap_count << SELF_ID_ZERO_GAP_COUNT_SHIFT) & SELF_ID_ZERO_GAP_COUNT_MASK; +} + +static inline unsigned int phy_packet_self_id_zero_get_scode(u32 quadlet) +{ + return (quadlet & SELF_ID_ZERO_SCODE_MASK) >> SELF_ID_ZERO_SCODE_SHIFT; +} + +static inline void phy_packet_self_id_zero_set_scode(u32 *quadlet, unsigned int speed) +{ + *quadlet &= ~SELF_ID_ZERO_SCODE_MASK; + *quadlet |= (speed << SELF_ID_ZERO_SCODE_SHIFT) & SELF_ID_ZERO_SCODE_MASK; +} + +static inline bool phy_packet_self_id_zero_get_contender(u32 quadlet) +{ + return (quadlet & SELF_ID_ZERO_CONTENDER_MASK) >> SELF_ID_ZERO_CONTENDER_SHIFT; +} + +static inline void phy_packet_self_id_zero_set_contender(u32 *quadlet, bool is_contender) +{ + *quadlet &= ~SELF_ID_ZERO_CONTENDER_MASK; + *quadlet |= (is_contender << SELF_ID_ZERO_CONTENDER_SHIFT) & SELF_ID_ZERO_CONTENDER_MASK; +} + +static inline unsigned int phy_packet_self_id_zero_get_power_class(u32 quadlet) +{ + return (quadlet & SELF_ID_ZERO_POWER_CLASS_MASK) >> SELF_ID_ZERO_POWER_CLASS_SHIFT; +} + +static inline void phy_packet_self_id_zero_set_power_class(u32 *quadlet, unsigned int power_class) +{ + *quadlet &= ~SELF_ID_ZERO_POWER_CLASS_MASK; + *quadlet |= (power_class << SELF_ID_ZERO_POWER_CLASS_SHIFT) & SELF_ID_ZERO_POWER_CLASS_MASK; +} + +static inline bool phy_packet_self_id_zero_get_initiated_reset(u32 quadlet) +{ + return (quadlet & SELF_ID_ZERO_INITIATED_RESET_MASK) >> SELF_ID_ZERO_INITIATED_RESET_SHIFT; +} + +static inline void phy_packet_self_id_zero_set_initiated_reset(u32 *quadlet, bool is_initiated_reset) +{ + *quadlet &= ~SELF_ID_ZERO_INITIATED_RESET_MASK; + *quadlet |= (is_initiated_reset << SELF_ID_ZERO_INITIATED_RESET_SHIFT) & SELF_ID_ZERO_INITIATED_RESET_MASK; +} + +static inline bool phy_packet_self_id_get_more_packets(u32 quadlet) +{ + return (quadlet & SELF_ID_MORE_PACKETS_MASK) >> SELF_ID_MORE_PACKETS_SHIFT; +} + +static inline void phy_packet_self_id_set_more_packets(u32 *quadlet, bool is_more_packets) +{ + *quadlet &= ~SELF_ID_MORE_PACKETS_MASK; + *quadlet |= (is_more_packets << SELF_ID_MORE_PACKETS_SHIFT) & SELF_ID_MORE_PACKETS_MASK; +} + +static inline unsigned int phy_packet_self_id_extended_get_sequence(u32 quadlet) +{ + return (quadlet & SELF_ID_EXTENDED_SEQUENCE_MASK) >> SELF_ID_EXTENDED_SEQUENCE_SHIFT; +} + +static inline void phy_packet_self_id_extended_set_sequence(u32 *quadlet, unsigned int sequence) +{ + *quadlet &= ~SELF_ID_EXTENDED_SEQUENCE_MASK; + *quadlet |= (sequence << SELF_ID_EXTENDED_SHIFT) & SELF_ID_EXTENDED_SEQUENCE_MASK; +} + +struct self_id_sequence_enumerator { + const u32 *cursor; + unsigned int quadlet_count; +}; + +static inline const u32 *self_id_sequence_enumerator_next( + struct self_id_sequence_enumerator *enumerator, unsigned int *quadlet_count) +{ + const u32 *self_id_sequence, *cursor; + u32 quadlet; + unsigned int count; + unsigned int sequence; + + if (enumerator->cursor == NULL || enumerator->quadlet_count == 0) + return ERR_PTR(-ENODATA); + cursor = enumerator->cursor; + count = 1; + + quadlet = *cursor; + sequence = 0; + while (phy_packet_self_id_get_more_packets(quadlet)) { + if (count >= enumerator->quadlet_count || + count >= SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT) + return ERR_PTR(-EPROTO); + ++cursor; + ++count; + quadlet = *cursor; + + if (!phy_packet_self_id_get_extended(quadlet) || + sequence != phy_packet_self_id_extended_get_sequence(quadlet)) + return ERR_PTR(-EPROTO); + ++sequence; + } + + *quadlet_count = count; + self_id_sequence = enumerator->cursor; + + enumerator->cursor += count; + enumerator->quadlet_count -= count; + + return self_id_sequence; +} + +enum phy_packet_self_id_port_status { + PHY_PACKET_SELF_ID_PORT_STATUS_NONE = 0, + PHY_PACKET_SELF_ID_PORT_STATUS_NCONN = 1, + PHY_PACKET_SELF_ID_PORT_STATUS_PARENT = 2, + PHY_PACKET_SELF_ID_PORT_STATUS_CHILD = 3, +}; + +static inline unsigned int self_id_sequence_get_port_capacity(unsigned int quadlet_count) +{ + return quadlet_count * 8 - 5; +} + +static inline enum phy_packet_self_id_port_status self_id_sequence_get_port_status( + const u32 *self_id_sequence, unsigned int quadlet_count, unsigned int port_index) +{ + unsigned int index, shift; + + index = (port_index + 5) / 8; + shift = 16 - ((port_index + 5) % 8) * 2; + + if (index < quadlet_count && index < SELF_ID_SEQUENCE_MAXIMUM_QUADLET_COUNT) + return (self_id_sequence[index] >> shift) & SELF_ID_PORT_STATUS_MASK; + + return PHY_PACKET_SELF_ID_PORT_STATUS_NONE; +} + +static inline void self_id_sequence_set_port_status(u32 *self_id_sequence, unsigned int quadlet_count, + unsigned int port_index, + enum phy_packet_self_id_port_status status) +{ + unsigned int index, shift; + + index = (port_index + 5) / 8; + shift = 16 - ((port_index + 5) % 8) * 2; + + if (index < quadlet_count) { + self_id_sequence[index] &= ~(SELF_ID_PORT_STATUS_MASK << shift); + self_id_sequence[index] |= status << shift; + } +} + +#endif // _FIREWIRE_PHY_PACKET_DEFINITIONS_H -- cgit v1.3.1