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, 419 insertions, 0 deletions

diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h
new file mode 100644
index 000000000..f5bf17fc4
--- /dev/null
+++ b/include/acpi/acpiosxf.h
@@ -0,0 +1,419 @@
+/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 */
+/******************************************************************************
+ *
+ * Name: acpiosxf.h - All interfaces to the OS Services Layer (OSL). These
+ *                    interfaces must be implemented by OSL to interface the
+ *                    ACPI components to the host operating system.
+ *
+ * Copyright (C) 2000 - 2026, Intel Corp.
+ *
+ *****************************************************************************/
+
+#ifndef __ACPIOSXF_H__
+#define __ACPIOSXF_H__
+
+#include <acpi/platform/acenv.h>
+#include <acpi/actypes.h>
+
+/* Types for acpi_os_execute */
+
+typedef enum {
+	OSL_GLOBAL_LOCK_HANDLER,
+	OSL_NOTIFY_HANDLER,
+	OSL_GPE_HANDLER,
+	OSL_DEBUGGER_MAIN_THREAD,
+	OSL_DEBUGGER_EXEC_THREAD,
+	OSL_EC_POLL_HANDLER,
+	OSL_EC_BURST_HANDLER
+} acpi_execute_type;
+
+#define ACPI_NO_UNIT_LIMIT          ((u32) -1)
+#define ACPI_MUTEX_SEM              1
+
+/* Functions for acpi_os_signal */
+
+#define ACPI_SIGNAL_FATAL           0
+#define ACPI_SIGNAL_BREAKPOINT      1
+
+struct acpi_signal_fatal_info {
+	u32 type;
+	u32 code;
+	u32 argument;
+};
+
+/*
+ * OSL Initialization and shutdown primitives
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_initialize
+acpi_status acpi_os_initialize(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_terminate
+acpi_status acpi_os_terminate(void);
+#endif
+
+/*
+ * ACPI Table interfaces
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_root_pointer
+acpi_physical_address acpi_os_get_root_pointer(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_predefined_override
+acpi_status
+acpi_os_predefined_override(const struct acpi_predefined_names *init_val,
+			    acpi_string *new_val);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_table_override
+acpi_status
+acpi_os_table_override(struct acpi_table_header *existing_table,
+		       struct acpi_table_header **new_table);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_physical_table_override
+acpi_status
+acpi_os_physical_table_override(struct acpi_table_header *existing_table,
+				acpi_physical_address *new_address,
+				u32 *new_table_length);
+#endif
+
+/*
+ * Spinlock primitives
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_lock
+acpi_status acpi_os_create_lock(acpi_spinlock * out_handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_delete_lock
+void acpi_os_delete_lock(acpi_spinlock handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_acquire_lock
+acpi_cpu_flags acpi_os_acquire_lock(acpi_spinlock handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_release_lock
+void acpi_os_release_lock(acpi_spinlock handle, acpi_cpu_flags flags);
+#endif
+
+/*
+ * RAW spinlock primitives. If the OS does not provide them, fallback to
+ * spinlock primitives
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_raw_lock
+# define acpi_os_create_raw_lock(out_handle)	acpi_os_create_lock(out_handle)
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_delete_raw_lock
+# define acpi_os_delete_raw_lock(handle)	acpi_os_delete_lock(handle)
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_acquire_raw_lock
+# define acpi_os_acquire_raw_lock(handle)	acpi_os_acquire_lock(handle)
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_release_raw_lock
+# define acpi_os_release_raw_lock(handle, flags)	\
+	acpi_os_release_lock(handle, flags)
+#endif
+
+/*
+ * Semaphore primitives
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_semaphore
+acpi_status
+acpi_os_create_semaphore(u32 max_units,
+			 u32 initial_units, acpi_semaphore * out_handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_delete_semaphore
+acpi_status acpi_os_delete_semaphore(acpi_semaphore handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_wait_semaphore
+acpi_status
+acpi_os_wait_semaphore(acpi_semaphore handle, u32 units, u16 timeout);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_signal_semaphore
+acpi_status acpi_os_signal_semaphore(acpi_semaphore handle, u32 units);
+#endif
+
+/*
+ * Mutex primitives. May be configured to use semaphores instead via
+ * ACPI_MUTEX_TYPE (see platform/acenv.h)
+ */
+#if (ACPI_MUTEX_TYPE != ACPI_BINARY_SEMAPHORE)
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_mutex
+acpi_status acpi_os_create_mutex(acpi_mutex * out_handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_delete_mutex
+void acpi_os_delete_mutex(acpi_mutex handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_acquire_mutex
+acpi_status acpi_os_acquire_mutex(acpi_mutex handle, u16 timeout);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_release_mutex
+void acpi_os_release_mutex(acpi_mutex handle);
+#endif
+
+#endif
+
+/*
+ * Memory allocation and mapping
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_allocate
+void *acpi_os_allocate(acpi_size size);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_allocate_zeroed
+void *acpi_os_allocate_zeroed(acpi_size size);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_free
+void acpi_os_free(void *memory);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_map_memory
+void *acpi_os_map_memory(acpi_physical_address where, acpi_size length);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_unmap_memory
+void acpi_os_unmap_memory(void *logical_address, acpi_size size);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_physical_address
+acpi_status
+acpi_os_get_physical_address(void *logical_address,
+			     acpi_physical_address *physical_address);
+#endif
+
+/*
+ * Memory/Object Cache
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_cache
+acpi_status
+acpi_os_create_cache(char *cache_name,
+		     u16 object_size,
+		     u16 max_depth, acpi_cache_t ** return_cache);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_delete_cache
+acpi_status acpi_os_delete_cache(acpi_cache_t * cache);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_purge_cache
+acpi_status acpi_os_purge_cache(acpi_cache_t * cache);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_acquire_object
+void *acpi_os_acquire_object(acpi_cache_t * cache);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_release_object
+acpi_status acpi_os_release_object(acpi_cache_t * cache, void *object);
+#endif
+
+/*
+ * Interrupt handlers
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_install_interrupt_handler
+acpi_status
+acpi_os_install_interrupt_handler(u32 interrupt_number,
+				  acpi_osd_handler service_routine,
+				  void *context);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_remove_interrupt_handler
+acpi_status
+acpi_os_remove_interrupt_handler(u32 interrupt_number,
+				 acpi_osd_handler service_routine);
+#endif
+
+/*
+ * Threads and Scheduling
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_thread_id
+acpi_thread_id acpi_os_get_thread_id(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_execute
+acpi_status
+acpi_os_execute(acpi_execute_type type,
+		acpi_osd_exec_callback function, void *context);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_wait_events_complete
+void acpi_os_wait_events_complete(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_sleep
+void acpi_os_sleep(u64 milliseconds);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_stall
+void acpi_os_stall(u32 microseconds);
+#endif
+
+/*
+ * Platform and hardware-independent I/O interfaces
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_read_port
+acpi_status acpi_os_read_port(acpi_io_address address, u32 *value, u32 width);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_write_port
+acpi_status acpi_os_write_port(acpi_io_address address, u32 value, u32 width);
+#endif
+
+/*
+ * Platform and hardware-independent physical memory interfaces
+ */
+int acpi_os_read_iomem(void __iomem *virt_addr, u64 *value, u32 width);
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_read_memory
+acpi_status
+acpi_os_read_memory(acpi_physical_address address, u64 *value, u32 width);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_write_memory
+acpi_status
+acpi_os_write_memory(acpi_physical_address address, u64 value, u32 width);
+#endif
+
+/*
+ * Platform and hardware-independent PCI configuration space access
+ * Note: Can't use "Register" as a parameter, changed to "Reg" --
+ * certain compilers complain.
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_read_pci_configuration
+acpi_status
+acpi_os_read_pci_configuration(struct acpi_pci_id *pci_id,
+			       u32 reg, u64 *value, u32 width);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_write_pci_configuration
+acpi_status
+acpi_os_write_pci_configuration(struct acpi_pci_id *pci_id,
+				u32 reg, u64 value, u32 width);
+#endif
+
+/*
+ * Miscellaneous
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_readable
+u8 acpi_os_readable(void *pointer, acpi_size length);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_writable
+u8 acpi_os_writable(void *pointer, acpi_size length);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_timer
+u64 acpi_os_get_timer(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_signal
+acpi_status acpi_os_signal(u32 function, void *info);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_enter_sleep
+acpi_status acpi_os_enter_sleep(u8 sleep_state, u32 rega_value, u32 regb_value);
+#endif
+
+/*
+ * Debug print routines
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_printf
+ACPI_PRINTF_LIKE(1)
+void ACPI_INTERNAL_VAR_XFACE acpi_os_printf(const char *format, ...);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_vprintf
+void acpi_os_vprintf(const char *format, va_list args);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_redirect_output
+void acpi_os_redirect_output(void *destination);
+#endif
+
+/*
+ * Debug IO
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_line
+acpi_status acpi_os_get_line(char *buffer, u32 buffer_length, u32 *bytes_read);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_initialize_debugger
+acpi_status acpi_os_initialize_debugger(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_terminate_debugger
+void acpi_os_terminate_debugger(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_wait_command_ready
+acpi_status acpi_os_wait_command_ready(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_notify_command_complete
+acpi_status acpi_os_notify_command_complete(void);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_trace_point
+void
+acpi_os_trace_point(acpi_trace_event_type type,
+		    u8 begin, u8 *aml, char *pathname);
+#endif
+
+/*
+ * Obtain ACPI table(s)
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_table_by_name
+acpi_status
+acpi_os_get_table_by_name(char *signature,
+			  u32 instance,
+			  struct acpi_table_header **table,
+			  acpi_physical_address *address);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_table_by_index
+acpi_status
+acpi_os_get_table_by_index(u32 index,
+			   struct acpi_table_header **table,
+			   u32 *instance, acpi_physical_address *address);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_table_by_address
+acpi_status
+acpi_os_get_table_by_address(acpi_physical_address address,
+			     struct acpi_table_header **table);
+#endif
+
+/*
+ * Directory manipulation
+ */
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_open_directory
+void *acpi_os_open_directory(char *pathname,
+			     char *wildcard_spec, char requested_file_type);
+#endif
+
+/* requeste_file_type values */
+
+#define REQUEST_FILE_ONLY                   0
+#define REQUEST_DIR_ONLY                    1
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_next_filename
+char *acpi_os_get_next_filename(void *dir_handle);
+#endif
+
+#ifndef ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_close_directory
+void acpi_os_close_directory(void *dir_handle);
+#endif
+
+#endif				/* __ACPIOSXF_H__ */