microblaze: ftrace: Pass the first calling instruction for dynamic ftrace

Selftest for dynamic ftrace requres to pass address of the first calling instruction because hash function is calculated from it. ftrace_update_ftrace_func setups pointer to function which is called in _mcount function. trace_selftest is not aware about instruction size (for microblaze 8 - imm and addik) and that's why we have to pass in r5 address of imm not addik which is in r15.12 For more info look at ftrace_ops_list_func/ftrace.c. Signed-off-by: Michal Simek <monstr@monstr.eu>

microblaze: ftrace: Pass the first calling instruction for dynamic ftrace
Selftest for dynamic ftrace requres to pass address of the first calling instruction because hash function is calculated from it. ftrace_update_ftrace_func setups pointer to function which is called in _mcount function. trace_selftest is not aware about instruction size (for microblaze 8 - imm and addik) and that's why we have to pass in r5 address of imm not addik which is in r15.12 For more info look at ftrace_ops_list_func/ftrace.c. Signed-off-by: Michal Simek <monstr@monstr.eu>
Michal Simek
1 parent f397c077e1
Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff
arch/microblaze/kernel/mcount.S
@@ -138,7 +138,7 @@
 #endif /* CONFIG_DYNAMIC_FTRACE */
 /* static normal trace */
 	lwi	r6, r1, 120; /* MS: load parent addr */
-	addik	r5, r15, 0; /* MS: load current function addr */
+	addik	r5, r15, -4; /* MS: load current function addr */
 	/* MS: here is dependency on previous code */
 	brald	r15, r20; /* MS: jump to ftrace handler */
 	nop;
...	...	@@ -138,7 +138,7 @@
138	138	#endif /* CONFIG_DYNAMIC_FTRACE */
139	139	/* static normal trace */
140	140	lwi r6, r1, 120; /* MS: load parent addr */
141		- addik r5, r15, 0; /* MS: load current function addr */
	141	+ addik r5, r15, -4; /* MS: load current function addr */
142	142	/* MS: here is dependency on previous code */
143	143	brald r15, r20; /* MS: jump to ftrace handler */
144	144	nop;