5bf9cbef99
The mcount support that was finally added to the Blackfin gcc port isn't exactly the same as what ftrace was developed against. Now that the final gcc version is in place, update the ftrace code to match. While updating this, fix the swapped arguments to the tracer (signature is (ip, parent_ip) while we were passing (parent_ip, ip)). Signed-off-by: Yi Li <yi.li@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
142 lines
3.6 KiB
ArmAsm
142 lines
3.6 KiB
ArmAsm
/*
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* mcount and friends -- ftrace stuff
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*
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* Copyright (C) 2009 Analog Devices Inc.
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/linkage.h>
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#include <asm/ftrace.h>
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.text
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/* GCC will have called us before setting up the function prologue, so we
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* can clobber the normal scratch registers, but we need to make sure to
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* save/restore the registers used for argument passing (R0-R2) in case
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* the profiled function is using them. With data registers, R3 is the
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* only one we can blow away. With pointer registers, we have P0-P2.
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*
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* Upon entry, the RETS will point to the top of the current profiled
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* function. And since GCC pushed the previous RETS for us, the previous
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* function will be waiting there. mmmm pie.
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*/
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ENTRY(__mcount)
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/* save third function arg early so we can do testing below */
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[--sp] = r2;
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/* load the function pointer to the tracer */
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p0.l = _ftrace_trace_function;
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p0.h = _ftrace_trace_function;
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r3 = [p0];
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/* optional micro optimization: don't call the stub tracer */
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r2.l = _ftrace_stub;
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r2.h = _ftrace_stub;
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cc = r2 == r3;
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if ! cc jump .Ldo_trace;
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* if the ftrace_graph_return function pointer is not set to
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* the ftrace_stub entry, call prepare_ftrace_return().
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*/
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p0.l = _ftrace_graph_return;
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p0.h = _ftrace_graph_return;
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r3 = [p0];
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cc = r2 == r3;
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if ! cc jump _ftrace_graph_caller;
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/* similarly, if the ftrace_graph_entry function pointer is not
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* set to the ftrace_graph_entry_stub entry, ...
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*/
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p0.l = _ftrace_graph_entry;
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p0.h = _ftrace_graph_entry;
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r2.l = _ftrace_graph_entry_stub;
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r2.h = _ftrace_graph_entry_stub;
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r3 = [p0];
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cc = r2 == r3;
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if ! cc jump _ftrace_graph_caller;
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#endif
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r2 = [sp++];
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rts;
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.Ldo_trace:
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/* save first/second function arg and the return register */
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[--sp] = r0;
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[--sp] = r1;
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[--sp] = rets;
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/* setup the tracer function */
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p0 = r3;
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/* function_trace_call(unsigned long ip, unsigned long parent_ip):
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* ip: this point was called by ...
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* parent_ip: ... this function
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* the ip itself will need adjusting for the mcount call
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*/
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r0 = rets;
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r1 = [sp + 16]; /* skip the 4 local regs on stack */
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r0 += -MCOUNT_INSN_SIZE;
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/* call the tracer */
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call (p0);
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/* restore state and get out of dodge */
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.Lfinish_trace:
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rets = [sp++];
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r1 = [sp++];
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r0 = [sp++];
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r2 = [sp++];
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.globl _ftrace_stub
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_ftrace_stub:
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rts;
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ENDPROC(__mcount)
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* The prepare_ftrace_return() function is similar to the trace function
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* except it takes a pointer to the location of the frompc. This is so
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* the prepare_ftrace_return() can hijack it temporarily for probing
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* purposes.
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*/
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ENTRY(_ftrace_graph_caller)
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/* save first/second function arg and the return register */
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[--sp] = r0;
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[--sp] = r1;
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[--sp] = rets;
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/* prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) */
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r0 = sp;
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r1 = rets;
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r0 += 16; /* skip the 4 local regs on stack */
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r1 += -MCOUNT_INSN_SIZE;
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call _prepare_ftrace_return;
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jump .Lfinish_trace;
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ENDPROC(_ftrace_graph_caller)
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/* Undo the rewrite caused by ftrace_graph_caller(). The common function
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* ftrace_return_to_handler() will return the original rets so we can
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* restore it and be on our way.
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*/
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ENTRY(_return_to_handler)
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/* make sure original return values are saved */
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[--sp] = p0;
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[--sp] = r0;
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[--sp] = r1;
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/* get original return address */
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call _ftrace_return_to_handler;
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rets = r0;
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/* anomaly 05000371 - make sure we have at least three instructions
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* between rets setting and the return
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*/
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r1 = [sp++];
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r0 = [sp++];
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p0 = [sp++];
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rts;
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ENDPROC(_return_to_handler)
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#endif
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