kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 360 insertions, 0 deletions

diff --git a/include/trace/events/scsi.h b/include/trace/events/scsi.h
new file mode 100644
index 000000000..c36c72ab7
--- /dev/null
+++ b/include/trace/events/scsi.h
@@ -0,0 +1,360 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM scsi
+
+#if !defined(_TRACE_SCSI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SCSI_H
+
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+#include <linux/tracepoint.h>
+#include <linux/trace_seq.h>
+
+#define scsi_opcode_name(opcode)	{ opcode, #opcode }
+#define show_opcode_name(val)					\
+	__print_symbolic(val,					\
+		scsi_opcode_name(TEST_UNIT_READY),		\
+		scsi_opcode_name(REZERO_UNIT),			\
+		scsi_opcode_name(REQUEST_SENSE),		\
+		scsi_opcode_name(FORMAT_UNIT),			\
+		scsi_opcode_name(READ_BLOCK_LIMITS),		\
+		scsi_opcode_name(REASSIGN_BLOCKS),		\
+		scsi_opcode_name(INITIALIZE_ELEMENT_STATUS),	\
+		scsi_opcode_name(READ_6),			\
+		scsi_opcode_name(WRITE_6),			\
+		scsi_opcode_name(SEEK_6),			\
+		scsi_opcode_name(READ_REVERSE),			\
+		scsi_opcode_name(WRITE_FILEMARKS),		\
+		scsi_opcode_name(SPACE),			\
+		scsi_opcode_name(INQUIRY),			\
+		scsi_opcode_name(RECOVER_BUFFERED_DATA),	\
+		scsi_opcode_name(MODE_SELECT),			\
+		scsi_opcode_name(RESERVE_6),			\
+		scsi_opcode_name(RELEASE_6),			\
+		scsi_opcode_name(COPY),				\
+		scsi_opcode_name(ERASE),			\
+		scsi_opcode_name(MODE_SENSE),			\
+		scsi_opcode_name(START_STOP),			\
+		scsi_opcode_name(RECEIVE_DIAGNOSTIC),		\
+		scsi_opcode_name(SEND_DIAGNOSTIC),		\
+		scsi_opcode_name(ALLOW_MEDIUM_REMOVAL),		\
+		scsi_opcode_name(SET_WINDOW),			\
+		scsi_opcode_name(READ_CAPACITY),		\
+		scsi_opcode_name(READ_10),			\
+		scsi_opcode_name(WRITE_10),			\
+		scsi_opcode_name(SEEK_10),			\
+		scsi_opcode_name(POSITION_TO_ELEMENT),		\
+		scsi_opcode_name(WRITE_VERIFY),			\
+		scsi_opcode_name(VERIFY),			\
+		scsi_opcode_name(SEARCH_HIGH),			\
+		scsi_opcode_name(SEARCH_EQUAL),			\
+		scsi_opcode_name(SEARCH_LOW),			\
+		scsi_opcode_name(SET_LIMITS),			\
+		scsi_opcode_name(PRE_FETCH),			\
+		scsi_opcode_name(READ_POSITION),		\
+		scsi_opcode_name(SYNCHRONIZE_CACHE),		\
+		scsi_opcode_name(LOCK_UNLOCK_CACHE),		\
+		scsi_opcode_name(READ_DEFECT_DATA),		\
+		scsi_opcode_name(MEDIUM_SCAN),			\
+		scsi_opcode_name(COMPARE),			\
+		scsi_opcode_name(COPY_VERIFY),			\
+		scsi_opcode_name(WRITE_BUFFER),			\
+		scsi_opcode_name(READ_BUFFER),			\
+		scsi_opcode_name(UPDATE_BLOCK),			\
+		scsi_opcode_name(READ_LONG),			\
+		scsi_opcode_name(WRITE_LONG),			\
+		scsi_opcode_name(CHANGE_DEFINITION),		\
+		scsi_opcode_name(WRITE_SAME),			\
+		scsi_opcode_name(UNMAP),			\
+		scsi_opcode_name(READ_TOC),			\
+		scsi_opcode_name(LOG_SELECT),			\
+		scsi_opcode_name(LOG_SENSE),			\
+		scsi_opcode_name(XDWRITEREAD_10),		\
+		scsi_opcode_name(MODE_SELECT_10),		\
+		scsi_opcode_name(RESERVE_10),			\
+		scsi_opcode_name(RELEASE_10),			\
+		scsi_opcode_name(MODE_SENSE_10),		\
+		scsi_opcode_name(PERSISTENT_RESERVE_IN),	\
+		scsi_opcode_name(PERSISTENT_RESERVE_OUT),	\
+		scsi_opcode_name(VARIABLE_LENGTH_CMD),		\
+		scsi_opcode_name(REPORT_LUNS),			\
+		scsi_opcode_name(MAINTENANCE_IN),		\
+		scsi_opcode_name(MAINTENANCE_OUT),		\
+		scsi_opcode_name(MOVE_MEDIUM),			\
+		scsi_opcode_name(EXCHANGE_MEDIUM),		\
+		scsi_opcode_name(READ_12),			\
+		scsi_opcode_name(WRITE_12),			\
+		scsi_opcode_name(WRITE_VERIFY_12),		\
+		scsi_opcode_name(SEARCH_HIGH_12),		\
+		scsi_opcode_name(SEARCH_EQUAL_12),		\
+		scsi_opcode_name(SEARCH_LOW_12),		\
+		scsi_opcode_name(READ_ELEMENT_STATUS),		\
+		scsi_opcode_name(SEND_VOLUME_TAG),		\
+		scsi_opcode_name(WRITE_LONG_2),			\
+		scsi_opcode_name(READ_16),			\
+		scsi_opcode_name(WRITE_16),			\
+		scsi_opcode_name(VERIFY_16),			\
+		scsi_opcode_name(WRITE_SAME_16),		\
+		scsi_opcode_name(ZBC_OUT),			\
+		scsi_opcode_name(ZBC_IN),			\
+		scsi_opcode_name(SERVICE_ACTION_IN_16),		\
+		scsi_opcode_name(READ_32),			\
+		scsi_opcode_name(WRITE_32),			\
+		scsi_opcode_name(WRITE_SAME_32),		\
+		scsi_opcode_name(ATA_16),			\
+		scsi_opcode_name(WRITE_ATOMIC_16),		\
+		scsi_opcode_name(ATA_12))
+
+#define scsi_hostbyte_name(result)	{ result, #result }
+#define show_hostbyte_name(val)					\
+	__print_symbolic(val,					\
+		scsi_hostbyte_name(DID_OK),			\
+		scsi_hostbyte_name(DID_NO_CONNECT),		\
+		scsi_hostbyte_name(DID_BUS_BUSY),		\
+		scsi_hostbyte_name(DID_TIME_OUT),		\
+		scsi_hostbyte_name(DID_BAD_TARGET),		\
+		scsi_hostbyte_name(DID_ABORT),			\
+		scsi_hostbyte_name(DID_PARITY),			\
+		scsi_hostbyte_name(DID_ERROR),			\
+		scsi_hostbyte_name(DID_RESET),			\
+		scsi_hostbyte_name(DID_BAD_INTR),		\
+		scsi_hostbyte_name(DID_PASSTHROUGH),		\
+		scsi_hostbyte_name(DID_SOFT_ERROR),		\
+		scsi_hostbyte_name(DID_IMM_RETRY),		\
+		scsi_hostbyte_name(DID_REQUEUE),		\
+		scsi_hostbyte_name(DID_TRANSPORT_DISRUPTED),	\
+		scsi_hostbyte_name(DID_TRANSPORT_FAILFAST))
+
+#define scsi_statusbyte_name(result)	{ result, #result }
+#define show_statusbyte_name(val)				\
+	__print_symbolic(val,					\
+		scsi_statusbyte_name(SAM_STAT_GOOD),		\
+		scsi_statusbyte_name(SAM_STAT_CHECK_CONDITION),	\
+		scsi_statusbyte_name(SAM_STAT_CONDITION_MET),	\
+		scsi_statusbyte_name(SAM_STAT_BUSY),		\
+		scsi_statusbyte_name(SAM_STAT_INTERMEDIATE),	\
+		scsi_statusbyte_name(SAM_STAT_INTERMEDIATE_CONDITION_MET), \
+		scsi_statusbyte_name(SAM_STAT_RESERVATION_CONFLICT),	\
+		scsi_statusbyte_name(SAM_STAT_COMMAND_TERMINATED),	\
+		scsi_statusbyte_name(SAM_STAT_TASK_SET_FULL),	\
+		scsi_statusbyte_name(SAM_STAT_ACA_ACTIVE),	\
+		scsi_statusbyte_name(SAM_STAT_TASK_ABORTED))
+
+#define scsi_prot_op_name(result)	{ result, #result }
+#define show_prot_op_name(val)					\
+	__print_symbolic(val,					\
+		scsi_prot_op_name(SCSI_PROT_NORMAL),		\
+		scsi_prot_op_name(SCSI_PROT_READ_INSERT),	\
+		scsi_prot_op_name(SCSI_PROT_WRITE_STRIP),	\
+		scsi_prot_op_name(SCSI_PROT_READ_STRIP),	\
+		scsi_prot_op_name(SCSI_PROT_WRITE_INSERT),	\
+		scsi_prot_op_name(SCSI_PROT_READ_PASS),		\
+		scsi_prot_op_name(SCSI_PROT_WRITE_PASS))
+
+const char *scsi_trace_parse_cdb(struct trace_seq*, unsigned char*, int);
+#define __parse_cdb(cdb, len) scsi_trace_parse_cdb(p, cdb, len)
+
+TRACE_EVENT(scsi_dispatch_cmd_start,
+
+	TP_PROTO(struct scsi_cmnd *cmd),
+
+	TP_ARGS(cmd),
+
+	TP_STRUCT__entry(
+		__field( unsigned int,	host_no	)
+		__field( unsigned int,	channel	)
+		__field( unsigned int,	id	)
+		__field( unsigned int,	lun	)
+		__field( unsigned int,	opcode	)
+		__field( unsigned int,	cmd_len )
+		__field( int,	driver_tag)
+		__field( int,	scheduler_tag)
+		__field( unsigned int,	data_sglen )
+		__field( unsigned int,	prot_sglen )
+		__field( unsigned char,	prot_op )
+		__dynamic_array(unsigned char,	cmnd, cmd->cmd_len)
+	),
+
+	TP_fast_assign(
+		__entry->host_no	= cmd->device->host->host_no;
+		__entry->channel	= cmd->device->channel;
+		__entry->id		= cmd->device->id;
+		__entry->lun		= cmd->device->lun;
+		__entry->opcode		= cmd->cmnd[0];
+		__entry->cmd_len	= cmd->cmd_len;
+		__entry->driver_tag	= scsi_cmd_to_rq(cmd)->tag;
+		__entry->scheduler_tag	= scsi_cmd_to_rq(cmd)->internal_tag;
+		__entry->data_sglen	= scsi_sg_count(cmd);
+		__entry->prot_sglen	= scsi_prot_sg_count(cmd);
+		__entry->prot_op	= scsi_get_prot_op(cmd);
+		memcpy(__get_dynamic_array(cmnd), cmd->cmnd, cmd->cmd_len);
+	),
+
+	TP_printk("host_no=%u channel=%u id=%u lun=%u data_sgl=%u prot_sgl=%u" \
+		  " prot_op=%s driver_tag=%d scheduler_tag=%d cmnd=(%s %s raw=%s)",
+		  __entry->host_no, __entry->channel, __entry->id,
+		  __entry->lun, __entry->data_sglen, __entry->prot_sglen,
+		  show_prot_op_name(__entry->prot_op), __entry->driver_tag,
+		  __entry->scheduler_tag, show_opcode_name(__entry->opcode),
+		  __parse_cdb(__get_dynamic_array(cmnd), __entry->cmd_len),
+		  __print_hex(__get_dynamic_array(cmnd), __entry->cmd_len))
+);
+
+#define scsi_rtn_name(result)	{ result, #result }
+#define show_rtn_name(val)					\
+	__print_symbolic(val,					\
+		scsi_rtn_name(SCSI_MLQUEUE_HOST_BUSY),		\
+		scsi_rtn_name(SCSI_MLQUEUE_DEVICE_BUSY),	\
+		scsi_rtn_name(SCSI_MLQUEUE_EH_RETRY),		\
+		scsi_rtn_name(SCSI_MLQUEUE_TARGET_BUSY))
+
+TRACE_EVENT(scsi_dispatch_cmd_error,
+
+	TP_PROTO(struct scsi_cmnd *cmd, int rtn),
+
+	TP_ARGS(cmd, rtn),
+
+	TP_STRUCT__entry(
+		__field( unsigned int,	host_no	)
+		__field( unsigned int,	channel	)
+		__field( unsigned int,	id	)
+		__field( unsigned int,	lun	)
+		__field( int,		rtn	)
+		__field( unsigned int,	opcode	)
+		__field( unsigned int,	cmd_len )
+		__field( int,	driver_tag)
+		__field( int,	scheduler_tag)
+		__field( unsigned int,	data_sglen )
+		__field( unsigned int,	prot_sglen )
+		__field( unsigned char,	prot_op )
+		__dynamic_array(unsigned char,	cmnd, cmd->cmd_len)
+	),
+
+	TP_fast_assign(
+		__entry->host_no	= cmd->device->host->host_no;
+		__entry->channel	= cmd->device->channel;
+		__entry->id		= cmd->device->id;
+		__entry->lun		= cmd->device->lun;
+		__entry->rtn		= rtn;
+		__entry->opcode		= cmd->cmnd[0];
+		__entry->cmd_len	= cmd->cmd_len;
+		__entry->driver_tag	= scsi_cmd_to_rq(cmd)->tag;
+		__entry->scheduler_tag	= scsi_cmd_to_rq(cmd)->internal_tag;
+		__entry->data_sglen	= scsi_sg_count(cmd);
+		__entry->prot_sglen	= scsi_prot_sg_count(cmd);
+		__entry->prot_op	= scsi_get_prot_op(cmd);
+		memcpy(__get_dynamic_array(cmnd), cmd->cmnd, cmd->cmd_len);
+	),
+
+	TP_printk("host_no=%u channel=%u id=%u lun=%u data_sgl=%u prot_sgl=%u" \
+		  " prot_op=%s driver_tag=%d scheduler_tag=%d cmnd=(%s %s raw=%s)" \
+		  " rtn=%s",
+		  __entry->host_no, __entry->channel, __entry->id,
+		  __entry->lun, __entry->data_sglen, __entry->prot_sglen,
+		  show_prot_op_name(__entry->prot_op), __entry->driver_tag,
+		  __entry->scheduler_tag, show_opcode_name(__entry->opcode),
+		  __parse_cdb(__get_dynamic_array(cmnd), __entry->cmd_len),
+		  __print_hex(__get_dynamic_array(cmnd), __entry->cmd_len),
+		  show_rtn_name(__entry->rtn)
+	  )
+);
+
+DECLARE_EVENT_CLASS(scsi_cmd_done_timeout_template,
+
+	TP_PROTO(struct scsi_cmnd *cmd),
+
+	TP_ARGS(cmd),
+
+	TP_STRUCT__entry(
+		__field( unsigned int,	host_no	)
+		__field( unsigned int,	channel	)
+		__field( unsigned int,	id	)
+		__field( unsigned int,	lun	)
+		__field( int,		result	)
+		__field( unsigned int,	opcode	)
+		__field( unsigned int,	cmd_len )
+		__field( int,	driver_tag)
+		__field( int,	scheduler_tag)
+		__field( unsigned int,	data_sglen )
+		__field( unsigned int,	prot_sglen )
+		__field( unsigned char,	prot_op )
+		__dynamic_array(unsigned char,	cmnd, cmd->cmd_len)
+		__field( u8, sense_key )
+		__field( u8, asc )
+		__field( u8, ascq )
+	),
+
+	TP_fast_assign(
+		struct scsi_sense_hdr sshdr;
+
+		__entry->host_no	= cmd->device->host->host_no;
+		__entry->channel	= cmd->device->channel;
+		__entry->id		= cmd->device->id;
+		__entry->lun		= cmd->device->lun;
+		__entry->result		= cmd->result;
+		__entry->opcode		= cmd->cmnd[0];
+		__entry->cmd_len	= cmd->cmd_len;
+		__entry->driver_tag	= scsi_cmd_to_rq(cmd)->tag;
+		__entry->scheduler_tag	= scsi_cmd_to_rq(cmd)->internal_tag;
+		__entry->data_sglen	= scsi_sg_count(cmd);
+		__entry->prot_sglen	= scsi_prot_sg_count(cmd);
+		__entry->prot_op	= scsi_get_prot_op(cmd);
+		memcpy(__get_dynamic_array(cmnd), cmd->cmnd, cmd->cmd_len);
+		if (cmd->sense_buffer && SCSI_SENSE_VALID(cmd) &&
+		    scsi_command_normalize_sense(cmd, &sshdr)) {
+			__entry->sense_key = sshdr.sense_key;
+			__entry->asc = sshdr.asc;
+			__entry->ascq = sshdr.ascq;
+		} else {
+			__entry->sense_key = 0;
+			__entry->asc = 0;
+			__entry->ascq = 0;
+		}
+	),
+
+	TP_printk("host_no=%u channel=%u id=%u lun=%u data_sgl=%u prot_sgl=%u " \
+		  "prot_op=%s driver_tag=%d scheduler_tag=%d cmnd=(%s %s raw=%s) " \
+		  "result=(driver=%s host=%s message=%s status=%s) "
+		  "sense=(key=%#x asc=%#x ascq=%#x)",
+		  __entry->host_no, __entry->channel, __entry->id,
+		  __entry->lun, __entry->data_sglen, __entry->prot_sglen,
+		  show_prot_op_name(__entry->prot_op), __entry->driver_tag,
+		  __entry->scheduler_tag, show_opcode_name(__entry->opcode),
+		  __parse_cdb(__get_dynamic_array(cmnd), __entry->cmd_len),
+		  __print_hex(__get_dynamic_array(cmnd), __entry->cmd_len),
+		  "DRIVER_OK",
+		  show_hostbyte_name(((__entry->result) >> 16) & 0xff),
+		  "COMMAND_COMPLETE",
+		  show_statusbyte_name(__entry->result & 0xff),
+		  __entry->sense_key, __entry->asc, __entry->ascq)
+);
+
+DEFINE_EVENT(scsi_cmd_done_timeout_template, scsi_dispatch_cmd_done,
+	     TP_PROTO(struct scsi_cmnd *cmd),
+	     TP_ARGS(cmd));
+
+DEFINE_EVENT(scsi_cmd_done_timeout_template, scsi_dispatch_cmd_timeout,
+	     TP_PROTO(struct scsi_cmnd *cmd),
+	     TP_ARGS(cmd));
+
+TRACE_EVENT(scsi_eh_wakeup,
+
+	TP_PROTO(struct Scsi_Host *shost),
+
+	TP_ARGS(shost),
+
+	TP_STRUCT__entry(
+		__field( unsigned int,	host_no	)
+	),
+
+	TP_fast_assign(
+		__entry->host_no	= shost->host_no;
+	),
+
+	TP_printk("host_no=%u", __entry->host_no)
+);
+
+#endif /*  _TRACE_SCSI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>