Commit 028a58ec authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
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tracing: Use _text and the kernel offset in last_boot_info 

Instead of using kaslr_offset() just record the location of "_text". This
makes it possible for user space to use either the System.map or
/proc/kallsyms as what to map all addresses to functions with.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250326220304.38dbedcd@gandalf.local.home


Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 35a380dd

kernel/trace/trace.c

+6 −12
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ 
#include <linux/workqueue.h>

#include <linux/sort.h>



#include <asm/setup.h> /* COMMAND_LINE_SIZE and kaslr_offset() */

#include <asm/setup.h> /* COMMAND_LINE_SIZE */



#include "trace.h"

#include "trace_output.h"
@@ -5995,7 +5995,7 @@ struct trace_mod_entry { 
};



struct trace_scratch {

	unsigned long		kaslr_addr;

	unsigned long		text_addr;

	unsigned long		nr_entries;

	struct trace_mod_entry	entries[];

};
@@ -6133,11 +6133,7 @@ static void update_last_data(struct trace_array *tr) 
	kfree_rcu(module_delta, rcu);



	/* Set the persistent ring buffer meta data to this address */

#ifdef CONFIG_RANDOMIZE_BASE

	tscratch->kaslr_addr = kaslr_offset();

#else

	tscratch->kaslr_addr = 0;

#endif

	tscratch->text_addr = (unsigned long)_text;

}



/**
@@ -6996,7 +6992,7 @@ static void show_last_boot_header(struct seq_file *m, struct trace_array *tr) 
	 * should not be the same as the current boot.

	 */

	if (tscratch && (tr->flags & TRACE_ARRAY_FL_LAST_BOOT))

		seq_printf(m, "%lx\t[kernel]\n", tscratch->kaslr_addr);

		seq_printf(m, "%lx\t[kernel]\n", tscratch->text_addr);

	else

		seq_puts(m, "# Current\n");

}
@@ -9465,10 +9461,8 @@ static void setup_trace_scratch(struct trace_array *tr, 
	tr->scratch = tscratch;

	tr->scratch_size = size;



#ifdef CONFIG_RANDOMIZE_BASE

	if (tscratch->kaslr_addr)

		tr->text_delta = kaslr_offset() - tscratch->kaslr_addr;

#endif

	if (tscratch->text_addr)

		tr->text_delta = (unsigned long)_text - tscratch->text_addr;



	if (struct_size(tscratch, entries, tscratch->nr_entries) > size)

		goto reset;