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tracing: Use _text and the kernel offset in last_boot_info

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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: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2025-03-26 22:03:04 -04:00 committed by Steven Rostedt (Google)
parent 35a380ddbc
commit 028a58ec15
1 changed files with 6 additions and 12 deletions
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18
kernel/trace/trace.c
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@ -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;