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 --- drivers/gpu/host1x/debug.c | 218 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 218 insertions(+) create mode 100644 drivers/gpu/host1x/debug.c (limited to 'drivers/gpu/host1x/debug.c') diff --git a/drivers/gpu/host1x/debug.c b/drivers/gpu/host1x/debug.c new file mode 100644 index 000000000..6433c00d5 --- /dev/null +++ b/drivers/gpu/host1x/debug.c @@ -0,0 +1,218 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2010 Google, Inc. + * Author: Erik Gilling + * + * Copyright (C) 2011-2013 NVIDIA Corporation + */ + +#include +#include +#include +#include + +#include + +#include "dev.h" +#include "debug.h" +#include "channel.h" + +static DEFINE_MUTEX(debug_lock); + +unsigned int host1x_debug_trace_cmdbuf; + +static pid_t host1x_debug_force_timeout_pid; +static u32 host1x_debug_force_timeout_val; +static u32 host1x_debug_force_timeout_channel; + +void host1x_debug_output(struct output *o, const char *fmt, ...) +{ + va_list args; + int len; + + va_start(args, fmt); + len = vsnprintf(o->buf, sizeof(o->buf), fmt, args); + va_end(args); + + o->fn(o->ctx, o->buf, len, false); +} + +void host1x_debug_cont(struct output *o, const char *fmt, ...) +{ + va_list args; + int len; + + va_start(args, fmt); + len = vsnprintf(o->buf, sizeof(o->buf), fmt, args); + va_end(args); + + o->fn(o->ctx, o->buf, len, true); +} + +static int show_channel(struct host1x_channel *ch, void *data, bool show_fifo) +{ + struct host1x *m = dev_get_drvdata(ch->dev->parent); + struct output *o = data; + int err; + + err = pm_runtime_resume_and_get(m->dev); + if (err < 0) + return err; + + mutex_lock(&ch->cdma.lock); + mutex_lock(&debug_lock); + + if (show_fifo) + host1x_hw_show_channel_fifo(m, ch, o); + + host1x_hw_show_channel_cdma(m, ch, o); + + mutex_unlock(&debug_lock); + mutex_unlock(&ch->cdma.lock); + + pm_runtime_put(m->dev); + + return 0; +} + +static void show_syncpts(struct host1x *m, struct output *o, bool show_all) +{ + unsigned long irqflags; + struct list_head *pos; + unsigned int i; + int err; + + host1x_debug_output(o, "---- syncpts ----\n"); + + err = pm_runtime_resume_and_get(m->dev); + if (err < 0) + return; + + for (i = 0; i < host1x_syncpt_nb_pts(m); i++) { + u32 max = host1x_syncpt_read_max(m->syncpt + i); + u32 min = host1x_syncpt_load(m->syncpt + i); + unsigned int waiters = 0; + + spin_lock_irqsave(&m->syncpt[i].fences.lock, irqflags); + list_for_each(pos, &m->syncpt[i].fences.list) + waiters++; + spin_unlock_irqrestore(&m->syncpt[i].fences.lock, irqflags); + + if (!kref_read(&m->syncpt[i].ref)) + continue; + + if (!show_all && !min && !max && !waiters) + continue; + + host1x_debug_output(o, + "id %u (%s) min %d max %d (%d waiters)\n", + i, m->syncpt[i].name, min, max, waiters); + } + + for (i = 0; i < host1x_syncpt_nb_bases(m); i++) { + u32 base_val; + + base_val = host1x_syncpt_load_wait_base(m->syncpt + i); + if (base_val) + host1x_debug_output(o, "waitbase id %u val %d\n", i, + base_val); + } + + pm_runtime_put(m->dev); + + host1x_debug_output(o, "\n"); +} + +static void show_all(struct host1x *m, struct output *o, bool show_fifo) +{ + unsigned int i; + + host1x_hw_show_mlocks(m, o); + show_syncpts(m, o, true); + host1x_debug_output(o, "---- channels ----\n"); + + for (i = 0; i < m->info->nb_channels; ++i) { + struct host1x_channel *ch = host1x_channel_get_index(m, i); + + if (ch) { + show_channel(ch, o, show_fifo); + host1x_channel_put(ch); + } + } +} + +static int host1x_debug_all_show(struct seq_file *s, void *unused) +{ + struct output o = { + .fn = write_to_seqfile, + .ctx = s + }; + + show_all(s->private, &o, true); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(host1x_debug_all); + +static int host1x_debug_show(struct seq_file *s, void *unused) +{ + struct output o = { + .fn = write_to_seqfile, + .ctx = s + }; + + show_all(s->private, &o, false); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(host1x_debug); + +static void host1x_debugfs_init(struct host1x *host1x) +{ + struct dentry *de = debugfs_create_dir("tegra-host1x", NULL); + + /* Store the created entry */ + host1x->debugfs = de; + + debugfs_create_file("status", S_IRUGO, de, host1x, &host1x_debug_fops); + debugfs_create_file("status_all", S_IRUGO, de, host1x, + &host1x_debug_all_fops); + + debugfs_create_u32("trace_cmdbuf", S_IRUGO|S_IWUSR, de, + &host1x_debug_trace_cmdbuf); + + host1x_hw_debug_init(host1x, de); + + debugfs_create_u32("force_timeout_pid", S_IRUGO|S_IWUSR, de, + &host1x_debug_force_timeout_pid); + debugfs_create_u32("force_timeout_val", S_IRUGO|S_IWUSR, de, + &host1x_debug_force_timeout_val); + debugfs_create_u32("force_timeout_channel", S_IRUGO|S_IWUSR, de, + &host1x_debug_force_timeout_channel); +} + +static void host1x_debugfs_exit(struct host1x *host1x) +{ + debugfs_remove_recursive(host1x->debugfs); +} + +void host1x_debug_init(struct host1x *host1x) +{ + if (IS_ENABLED(CONFIG_DEBUG_FS)) + host1x_debugfs_init(host1x); +} + +void host1x_debug_deinit(struct host1x *host1x) +{ + if (IS_ENABLED(CONFIG_DEBUG_FS)) + host1x_debugfs_exit(host1x); +} + +void host1x_debug_dump(struct host1x *host1x) +{ + struct output o = { + .fn = write_to_printk + }; + + show_all(host1x, &o, true); +} -- cgit v1.3.1