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s390/ftrace: Avoid extra serialization for graph caller patching

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The only context where ftrace_enable_ftrace_graph_caller()
or ftrace_disable_ftrace_graph_caller() is called also calls
ftrace_arch_code_modify_post_process(), which already performs
text_poke_sync_lock().

ftrace_run_update_code()
	arch_ftrace_update_code()
		ftrace_modify_all_code()
			ftrace_enable_ftrace_graph_caller()/ftrace_disable_ftrace_graph_caller()
	ftrace_arch_code_modify_post_process()
		text_poke_sync_lock()

Remove the redundant serialization.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Vasily Gorbik 2024-08-28 19:07:00 +02:00
parent 5200614080
commit 36dff49b96
1 changed files with 2 additions and 14 deletions
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16
arch/s390/kernel/ftrace.c
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@ -290,26 +290,14 @@ NOKPROBE_SYMBOL(prepare_ftrace_return);
*/
int ftrace_enable_ftrace_graph_caller(void)
{
int rc;
/* Expect brc 0xf,... */
rc = ftrace_patch_branch_mask(ftrace_graph_caller, 0xa7f4, false);
if (rc)
return rc;
text_poke_sync_lock();
return 0;
return ftrace_patch_branch_mask(ftrace_graph_caller, 0xa7f4, false);
}
int ftrace_disable_ftrace_graph_caller(void)
{
int rc;
/* Expect brc 0x0,... */
rc = ftrace_patch_branch_mask(ftrace_graph_caller, 0xa704, true);
if (rc)
return rc;
text_poke_sync_lock();
return 0;
return ftrace_patch_branch_mask(ftrace_graph_caller, 0xa704, true);
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */