From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers 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 Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- tools/perf/util/debug.h | 92 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 tools/perf/util/debug.h (limited to 'tools/perf/util/debug.h') diff --git a/tools/perf/util/debug.h b/tools/perf/util/debug.h new file mode 100644 index 000000000..6b737e195 --- /dev/null +++ b/tools/perf/util/debug.h @@ -0,0 +1,92 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* For debugging general purposes */ +#ifndef __PERF_DEBUG_H +#define __PERF_DEBUG_H + +#include +#include +#include +#include + +extern int verbose; +extern int debug_kmaps; +extern int debug_peo_args; +extern bool quiet, dump_trace; +extern int debug_ordered_events; +extern int debug_data_convert; +extern int debug_type_profile; + +#ifndef pr_fmt +#define pr_fmt(fmt) fmt +#endif + +#define pr_err(fmt, ...) \ + eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_warning(fmt, ...) \ + eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_warning_once(fmt, ...) ({ \ + static int __warned; \ + if (unlikely(!__warned)) { \ + pr_warning(fmt, ##__VA_ARGS__); \ + __warned = 1; \ + } \ +}) +#define pr_info(fmt, ...) \ + eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_debug(fmt, ...) \ + eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_debugN(n, fmt, ...) \ + eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_debug3(fmt, ...) pr_debugN(3, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_debug4(fmt, ...) pr_debugN(4, pr_fmt(fmt), ##__VA_ARGS__) + +/* Special macro to print perf_event_open arguments/return value. */ +#define pr_debug2_peo(fmt, ...) { \ + if (debug_peo_args) \ + pr_debugN(0, pr_fmt(fmt), ##__VA_ARGS__); \ + else \ + pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__); \ +} + +#define pr_time_N(n, var, t, fmt, ...) \ + eprintf_time(n, var, t, fmt, ##__VA_ARGS__) + +#define pr_oe_time(t, fmt, ...) pr_time_N(1, debug_ordered_events, t, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_oe_time2(t, fmt, ...) pr_time_N(2, debug_ordered_events, t, pr_fmt(fmt), ##__VA_ARGS__) + +#define STRERR_BUFSIZE 128 /* For the buffer size of str_error_r */ + +union perf_event; + +int dump_printf(const char *fmt, ...) __printf(1, 2); +void trace_event(union perf_event *event); + +int ui__error(const char *format, ...) __printf(1, 2); +int ui__warning(const char *format, ...) __printf(1, 2); +#define ui__warning_once(format, ...) ({ \ + static int __warned; \ + if (unlikely(!__warned)) { \ + ui__warning(format, ##__VA_ARGS__); \ + __warned = 1; \ + } \ +}) + +void pr_stat(const char *fmt, ...); + +int eprintf(int level, int var, const char *fmt, ...) __printf(3, 4); +int eprintf_time(int level, int var, u64 t, const char *fmt, ...) __printf(4, 5); +int veprintf(int level, int var, const char *fmt, va_list args); + +int perf_debug_option(const char *str); +FILE *debug_file(void); +void debug_set_file(FILE *file); +void debug_set_display_time(bool set); +void perf_debug_setup(void); +int perf_quiet_option(void); + +void __dump_stack(FILE *file, void **stackdump, size_t stackdump_size); +void dump_stack(void); +void sighandler_dump_stack(int sig); + +#endif /* __PERF_DEBUG_H */ -- cgit v1.3.1