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microblaze: ftrace: add function graph support
For more information look at Documentation/trace folder. Signed-off-by: Michal Simek <monstr@monstr.eu>
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3 changed files with 100 additions and 0 deletions
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@ -8,6 +8,7 @@ config MICROBLAZE
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select HAVE_LMB
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select HAVE_FUNCTION_TRACER
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select HAVE_FUNCTION_TRACE_MCOUNT_TEST
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select HAVE_FUNCTION_GRAPH_TRACER
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select HAVE_DYNAMIC_FTRACE
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select HAVE_FTRACE_MCOUNT_RECORD
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select USB_ARCH_HAS_EHCI
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@ -14,6 +14,64 @@
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#include <asm/cacheflush.h>
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#include <linux/ftrace.h>
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* Hook the return address and push it in the stack of return addrs
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* in current thread info.
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*/
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void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
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{
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unsigned long old;
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int faulted, err;
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struct ftrace_graph_ent trace;
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unsigned long return_hooker = (unsigned long)
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&return_to_handler;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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/*
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* Protect against fault, even if it shouldn't
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* happen. This tool is too much intrusive to
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* ignore such a protection.
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*/
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asm volatile(" 1: lwi %0, %2, 0; \
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2: swi %3, %2, 0; \
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addik %1, r0, 0; \
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3: \
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.section .fixup, \"ax\"; \
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4: brid 3b; \
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addik %1, r0, 1; \
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.previous; \
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.section __ex_table,\"a\"; \
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.word 1b,4b; \
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.word 2b,4b; \
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.previous;" \
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: "=&r" (old), "=r" (faulted)
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: "r" (parent), "r" (return_hooker)
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);
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if (unlikely(faulted)) {
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ftrace_graph_stop();
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WARN_ON(1);
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return;
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}
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err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0);
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if (err == -EBUSY) {
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*parent = old;
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return;
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}
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trace.func = self_addr;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace)) {
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current->curr_ret_stack--;
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*parent = old;
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}
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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#ifdef CONFIG_DYNAMIC_FTRACE
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/* save value to addr - it is save to do it in asm */
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static int ftrace_modify_code(unsigned long addr, unsigned int value)
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@ -96,6 +96,27 @@ ENTRY(ftrace_caller)
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bneid r5, end;
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nop;
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/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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lwi r5, r0, ftrace_graph_return;
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addik r6, r0, ftrace_stub; /* asm implementation */
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cmpu r5, r5, r6; /* ftrace_graph_return != ftrace_stub */
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beqid r5, end_graph_tracer;
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nop;
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lwi r6, r0, ftrace_graph_entry;
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addik r5, r0, ftrace_graph_entry_stub; /* implemented in C */
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cmpu r5, r5, r6; /* ftrace_graph_entry != ftrace_graph_entry_stub */
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beqid r5, end_graph_tracer;
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nop;
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addik r5, r1, 120; /* MS: load parent addr */
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addik r6, r15, 0; /* MS: load current function addr */
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bralid r15, prepare_ftrace_return;
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nop;
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/* MS: graph was taken that's why - can jump over function trace */
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brid end;
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nop;
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end_graph_tracer:
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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#ifndef CONFIG_DYNAMIC_FTRACE
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/* MS: test function trace if is taken or not */
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lwi r20, r0, ftrace_trace_function;
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@ -121,3 +142,23 @@ end:
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rtsd r15, 8; /* MS: jump back */
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nop;
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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ENTRY(return_to_handler)
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nop; /* MS: just barrier for rtsd r15, 8 */
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nop;
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SAVE_REGS
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swi r15, r1, 0;
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/* MS: find out returning address */
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bralid r15, ftrace_return_to_handler;
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nop;
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/* MS: return value from ftrace_return_to_handler is my returning addr
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* must be before restore regs because I have to restore r3 content */
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addik r15, r3, 0;
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RESTORE_REGS
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rtsd r15, 8; /* MS: jump back */
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nop;
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#endif /* CONFIG_FUNCTION_TRACER */
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