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Subject[PATCH] tile: support ftrace on tilegx
This commit adds support for static ftrace, graph function support,
and dynamic tracer support.

Signed-off-by: Tony Lu <zlu@tilera.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
---
I assume it makes sense for this to be pushed via the tile tree;
it's currently queued in tile-next.

arch/tile/Kconfig | 7 +-
arch/tile/include/asm/ftrace.h | 22 +++-
arch/tile/kernel/Makefile | 6 +
arch/tile/kernel/ftrace.c | 246 +++++++++++++++++++++++++++++++++++++++++
arch/tile/kernel/mcount_64.S | 224 +++++++++++++++++++++++++++++++++++++
arch/tile/kernel/vmlinux.lds.S | 1 +
arch/tile/lib/exports.c | 6 +
scripts/recordmcount.pl | 4 +
8 files changed, 514 insertions(+), 2 deletions(-)
create mode 100644 arch/tile/kernel/ftrace.c
create mode 100644 arch/tile/kernel/mcount_64.S

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index e76180e..e1600be 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -119,7 +119,12 @@ config HVC_TILE
def_bool y

config TILEGX
- bool "Building with TILE-Gx (64-bit) compiler and toolchain"
+ bool "Building for TILE-Gx (64-bit) processor"
+ select HAVE_FUNCTION_TRACER
+ select HAVE_FUNCTION_TRACE_MCOUNT_TEST
+ select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_DYNAMIC_FTRACE
+ select HAVE_FTRACE_MCOUNT_RECORD

config TILEPRO
def_bool !TILEGX
diff --git a/arch/tile/include/asm/ftrace.h b/arch/tile/include/asm/ftrace.h
index 461459b..13a9bb81 100644
--- a/arch/tile/include/asm/ftrace.h
+++ b/arch/tile/include/asm/ftrace.h
@@ -15,6 +15,26 @@
#ifndef _ASM_TILE_FTRACE_H
#define _ASM_TILE_FTRACE_H

-/* empty */
+#ifdef CONFIG_FUNCTION_TRACER
+
+#define MCOUNT_ADDR ((unsigned long)(__mcount))
+#define MCOUNT_INSN_SIZE 8 /* sizeof mcount call */
+
+#ifndef __ASSEMBLY__
+extern void __mcount(void);
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ return addr;
+}
+
+struct dyn_arch_ftrace {
+};
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* CONFIG_FUNCTION_TRACER */

#endif /* _ASM_TILE_FTRACE_H */
diff --git a/arch/tile/kernel/Makefile b/arch/tile/kernel/Makefile
index c4a957a..2e6eaa1 100644
--- a/arch/tile/kernel/Makefile
+++ b/arch/tile/kernel/Makefile
@@ -9,6 +9,11 @@ obj-y := backtrace.o entry.o hvglue.o irq.o messaging.o \
sysfs.o time.o traps.o unaligned.o vdso.o \
intvec_$(BITS).o regs_$(BITS).o tile-desc_$(BITS).o

+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_ftrace.o = -pg
+CFLAGS_REMOVE_early_printk.o = -pg
+endif
+
obj-$(CONFIG_HARDWALL) += hardwall.o
obj-$(CONFIG_COMPAT) += compat.o compat_signal.o
obj-$(CONFIG_SMP) += smpboot.o smp.o tlb.o
@@ -22,5 +27,6 @@ obj-$(CONFIG_PCI) += pci.o
endif
obj-$(CONFIG_TILE_USB) += usb.o
obj-$(CONFIG_TILE_HVGLUE_TRACE) += hvglue_trace.o
+obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o mcount_64.o

obj-y += vdso/
diff --git a/arch/tile/kernel/ftrace.c b/arch/tile/kernel/ftrace.c
new file mode 100644
index 0000000..f1c4520
--- /dev/null
+++ b/arch/tile/kernel/ftrace.c
@@ -0,0 +1,246 @@
+/*
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ *
+ * TILE-Gx specific ftrace support
+ */
+
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+
+#include <asm/cacheflush.h>
+#include <asm/ftrace.h>
+#include <asm/sections.h>
+
+#include <arch/opcode.h>
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static inline tilegx_bundle_bits NOP(void)
+{
+ return create_UnaryOpcodeExtension_X0(FNOP_UNARY_OPCODE_X0) |
+ create_RRROpcodeExtension_X0(UNARY_RRR_0_OPCODE_X0) |
+ create_Opcode_X0(RRR_0_OPCODE_X0) |
+ create_UnaryOpcodeExtension_X1(NOP_UNARY_OPCODE_X1) |
+ create_RRROpcodeExtension_X1(UNARY_RRR_0_OPCODE_X1) |
+ create_Opcode_X1(RRR_0_OPCODE_X1);
+}
+
+static int machine_stopped __read_mostly;
+
+int ftrace_arch_code_modify_prepare(void)
+{
+ machine_stopped = 1;
+ return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+ flush_icache_range(0, CHIP_L1I_CACHE_SIZE());
+ machine_stopped = 0;
+ return 0;
+}
+
+/*
+ * Put { move r10, lr; jal ftrace_caller } in a bundle, this lets dynamic
+ * tracer just add one cycle overhead to every kernel function when disabled.
+ */
+static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,
+ bool link)
+{
+ tilegx_bundle_bits opcode_x0, opcode_x1;
+ long pcrel_by_instr = (addr - pc) >> TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES;
+
+ if (link) {
+ /* opcode: jal addr */
+ opcode_x1 =
+ create_Opcode_X1(JUMP_OPCODE_X1) |
+ create_JumpOpcodeExtension_X1(JAL_JUMP_OPCODE_X1) |
+ create_JumpOff_X1(pcrel_by_instr);
+ } else {
+ /* opcode: j addr */
+ opcode_x1 =
+ create_Opcode_X1(JUMP_OPCODE_X1) |
+ create_JumpOpcodeExtension_X1(J_JUMP_OPCODE_X1) |
+ create_JumpOff_X1(pcrel_by_instr);
+ }
+
+ if (addr == FTRACE_ADDR) {
+ /* opcode: or r10, lr, zero */
+ opcode_x0 =
+ create_Dest_X0(10) |
+ create_SrcA_X0(TREG_LR) |
+ create_SrcB_X0(TREG_ZERO) |
+ create_RRROpcodeExtension_X0(OR_RRR_0_OPCODE_X0) |
+ create_Opcode_X0(RRR_0_OPCODE_X0);
+ } else {
+ /* opcode: fnop */
+ opcode_x0 =
+ create_UnaryOpcodeExtension_X0(FNOP_UNARY_OPCODE_X0) |
+ create_RRROpcodeExtension_X0(UNARY_RRR_0_OPCODE_X0) |
+ create_Opcode_X0(RRR_0_OPCODE_X0);
+ }
+
+ return opcode_x1 | opcode_x0;
+}
+
+static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
+{
+ return NOP();
+}
+
+static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
+{
+ return ftrace_gen_branch(pc, addr, true);
+}
+
+static int ftrace_modify_code(unsigned long pc, unsigned long old,
+ unsigned long new)
+{
+ unsigned long pc_wr;
+
+ /* Check if the address is in kernel text space and module space. */
+ if (!kernel_text_address(pc))
+ return -EINVAL;
+
+ /* Operate on writable kernel text mapping. */
+ pc_wr = pc - MEM_SV_START + PAGE_OFFSET;
+
+ if (probe_kernel_write((void *)pc_wr, &new, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ smp_wmb();
+
+ if (!machine_stopped && num_online_cpus() > 1)
+ flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
+
+ return 0;
+}
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ unsigned long pc, old;
+ unsigned long new;
+ int ret;
+
+ pc = (unsigned long)&ftrace_call;
+ memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE);
+ new = ftrace_call_replace(pc, (unsigned long)func);
+
+ ret = ftrace_modify_code(pc, old, new);
+
+ return ret;
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned long new, old;
+ unsigned long ip = rec->ip;
+
+ old = ftrace_nop_replace(rec);
+ new = ftrace_call_replace(ip, addr);
+
+ return ftrace_modify_code(rec->ip, old, new);
+}
+
+int ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned long ip = rec->ip;
+ unsigned long old;
+ unsigned long new;
+ int ret;
+
+ old = ftrace_call_replace(ip, addr);
+ new = ftrace_nop_replace(rec);
+ ret = ftrace_modify_code(ip, old, new);
+
+ return ret;
+}
+
+int __init ftrace_dyn_arch_init(void *data)
+{
+ *(unsigned long *)data = 0;
+
+ return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
+ unsigned long frame_pointer)
+{
+ unsigned long return_hooker = (unsigned long) &return_to_handler;
+ struct ftrace_graph_ent trace;
+ unsigned long old;
+ int err;
+
+ if (unlikely(atomic_read(&current->tracing_graph_pause)))
+ return;
+
+ old = *parent;
+ *parent = return_hooker;
+
+ err = ftrace_push_return_trace(old, self_addr, &trace.depth,
+ frame_pointer);
+ if (err == -EBUSY) {
+ *parent = old;
+ return;
+ }
+
+ trace.func = self_addr;
+
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace)) {
+ current->curr_ret_stack--;
+ *parent = old;
+ }
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern unsigned long ftrace_graph_call;
+
+static int __ftrace_modify_caller(unsigned long *callsite,
+ void (*func) (void), bool enable)
+{
+ unsigned long caller_fn = (unsigned long) func;
+ unsigned long pc = (unsigned long) callsite;
+ unsigned long branch = ftrace_gen_branch(pc, caller_fn, false);
+ unsigned long nop = NOP();
+ unsigned long old = enable ? nop : branch;
+ unsigned long new = enable ? branch : nop;
+
+ return ftrace_modify_code(pc, old, new);
+}
+
+static int ftrace_modify_graph_caller(bool enable)
+{
+ int ret;
+
+ ret = __ftrace_modify_caller(&ftrace_graph_call,
+ ftrace_graph_caller,
+ enable);
+
+ return ret;
+}
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_graph_caller(true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_graph_caller(false);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/tile/kernel/mcount_64.S b/arch/tile/kernel/mcount_64.S
new file mode 100644
index 0000000..70d7bb0
--- /dev/null
+++ b/arch/tile/kernel/mcount_64.S
@@ -0,0 +1,224 @@
+/*
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ *
+ * TILE-Gx specific __mcount support
+ */
+
+#include <linux/linkage.h>
+#include <asm/ftrace.h>
+
+#define REGSIZE 8
+
+ .text
+ .global __mcount
+
+ .macro MCOUNT_SAVE_REGS
+ addli sp, sp, -REGSIZE
+ {
+ st sp, lr
+ addli r29, sp, - (12 * REGSIZE)
+ }
+ {
+ addli sp, sp, - (13 * REGSIZE)
+ st r29, sp
+ }
+ addli r29, r29, REGSIZE
+ { st r29, r0; addli r29, r29, REGSIZE }
+ { st r29, r1; addli r29, r29, REGSIZE }
+ { st r29, r2; addli r29, r29, REGSIZE }
+ { st r29, r3; addli r29, r29, REGSIZE }
+ { st r29, r4; addli r29, r29, REGSIZE }
+ { st r29, r5; addli r29, r29, REGSIZE }
+ { st r29, r6; addli r29, r29, REGSIZE }
+ { st r29, r7; addli r29, r29, REGSIZE }
+ { st r29, r8; addli r29, r29, REGSIZE }
+ { st r29, r9; addli r29, r29, REGSIZE }
+ { st r29, r10; addli r29, r29, REGSIZE }
+ .endm
+
+ .macro MCOUNT_RESTORE_REGS
+ addli r29, sp, (2 * REGSIZE)
+ { ld r0, r29; addli r29, r29, REGSIZE }
+ { ld r1, r29; addli r29, r29, REGSIZE }
+ { ld r2, r29; addli r29, r29, REGSIZE }
+ { ld r3, r29; addli r29, r29, REGSIZE }
+ { ld r4, r29; addli r29, r29, REGSIZE }
+ { ld r5, r29; addli r29, r29, REGSIZE }
+ { ld r6, r29; addli r29, r29, REGSIZE }
+ { ld r7, r29; addli r29, r29, REGSIZE }
+ { ld r8, r29; addli r29, r29, REGSIZE }
+ { ld r9, r29; addli r29, r29, REGSIZE }
+ { ld r10, r29; addli lr, sp, (13 * REGSIZE) }
+ { ld lr, lr; addli sp, sp, (14 * REGSIZE) }
+ .endm
+
+ .macro RETURN_BACK
+ { move r12, lr; move lr, r10 }
+ jrp r12
+ .endm
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+ .align 64
+STD_ENTRY(__mcount)
+__mcount:
+ j ftrace_stub
+STD_ENDPROC(__mcount)
+
+ .align 64
+STD_ENTRY(ftrace_caller)
+ moveli r11, hw2_last(function_trace_stop)
+ { shl16insli r11, r11, hw1(function_trace_stop); move r12, lr }
+ { shl16insli r11, r11, hw0(function_trace_stop); move lr, r10 }
+ ld r11, r11
+ beqz r11, 1f
+ jrp r12
+
+1:
+ { move r10, lr; move lr, r12 }
+ MCOUNT_SAVE_REGS
+
+ /* arg1: self return address */
+ /* arg2: parent's return address */
+ { move r0, lr; move r1, r10 }
+
+ .global ftrace_call
+ftrace_call:
+ /*
+ * a placeholder for the call to a real tracing function, i.e.
+ * ftrace_trace_function()
+ */
+ nop
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ .global ftrace_graph_call
+ftrace_graph_call:
+ /*
+ * a placeholder for the call to a real tracing function, i.e.
+ * ftrace_graph_caller()
+ */
+ nop
+#endif
+ MCOUNT_RESTORE_REGS
+ .global ftrace_stub
+ftrace_stub:
+ RETURN_BACK
+STD_ENDPROC(ftrace_caller)
+
+#else /* ! CONFIG_DYNAMIC_FTRACE */
+
+ .align 64
+STD_ENTRY(__mcount)
+ moveli r11, hw2_last(function_trace_stop)
+ { shl16insli r11, r11, hw1(function_trace_stop); move r12, lr }
+ { shl16insli r11, r11, hw0(function_trace_stop); move lr, r10 }
+ ld r11, r11
+ beqz r11, 1f
+ jrp r12
+
+1:
+ { move r10, lr; move lr, r12 }
+ {
+ moveli r11, hw2_last(ftrace_trace_function)
+ moveli r13, hw2_last(ftrace_stub)
+ }
+ {
+ shl16insli r11, r11, hw1(ftrace_trace_function)
+ shl16insli r13, r13, hw1(ftrace_stub)
+ }
+ {
+ shl16insli r11, r11, hw0(ftrace_trace_function)
+ shl16insli r13, r13, hw0(ftrace_stub)
+ }
+
+ ld r11, r11
+ sub r14, r13, r11
+ bnez r14, static_trace
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ moveli r15, hw2_last(ftrace_graph_return)
+ shl16insli r15, r15, hw1(ftrace_graph_return)
+ shl16insli r15, r15, hw0(ftrace_graph_return)
+ ld r15, r15
+ sub r15, r15, r13
+ bnez r15, ftrace_graph_caller
+
+ {
+ moveli r16, hw2_last(ftrace_graph_entry)
+ moveli r17, hw2_last(ftrace_graph_entry_stub)
+ }
+ {
+ shl16insli r16, r16, hw1(ftrace_graph_entry)
+ shl16insli r17, r17, hw1(ftrace_graph_entry_stub)
+ }
+ {
+ shl16insli r16, r16, hw0(ftrace_graph_entry)
+ shl16insli r17, r17, hw0(ftrace_graph_entry_stub)
+ }
+ ld r16, r16
+ sub r17, r16, r17
+ bnez r17, ftrace_graph_caller
+
+#endif
+ RETURN_BACK
+
+static_trace:
+ MCOUNT_SAVE_REGS
+
+ /* arg1: self return address */
+ /* arg2: parent's return address */
+ { move r0, lr; move r1, r10 }
+
+ /* call ftrace_trace_function() */
+ jalr r11
+
+ MCOUNT_RESTORE_REGS
+
+ .global ftrace_stub
+ftrace_stub:
+ RETURN_BACK
+STD_ENDPROC(__mcount)
+
+#endif /* ! CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+STD_ENTRY(ftrace_graph_caller)
+ftrace_graph_caller:
+#ifndef CONFIG_DYNAMIC_FTRACE
+ MCOUNT_SAVE_REGS
+#endif
+
+ /* arg1: Get the location of the parent's return address */
+ addi r0, sp, 12 * REGSIZE
+ /* arg2: Get self return address */
+ move r1, lr
+
+ jal prepare_ftrace_return
+
+ MCOUNT_RESTORE_REGS
+ RETURN_BACK
+STD_ENDPROC(ftrace_graph_caller)
+
+ .global return_to_handler
+return_to_handler:
+ MCOUNT_SAVE_REGS
+
+ jal ftrace_return_to_handler
+ /* restore the real parent address */
+ move r11, r0
+
+ MCOUNT_RESTORE_REGS
+ jr r11
+
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/tile/kernel/vmlinux.lds.S b/arch/tile/kernel/vmlinux.lds.S
index 0f0edaf..673d00a 100644
--- a/arch/tile/kernel/vmlinux.lds.S
+++ b/arch/tile/kernel/vmlinux.lds.S
@@ -43,6 +43,7 @@ SECTIONS
HEAD_TEXT
SCHED_TEXT
LOCK_TEXT
+ IRQENTRY_TEXT
__fix_text_end = .; /* tile-cpack won't rearrange before this */
TEXT_TEXT
*(.text.*)
diff --git a/arch/tile/lib/exports.c b/arch/tile/lib/exports.c
index 359b1bc..82733c8 100644
--- a/arch/tile/lib/exports.c
+++ b/arch/tile/lib/exports.c
@@ -33,6 +33,12 @@ EXPORT_SYMBOL(dump_stack);
/* arch/tile/kernel/head.S */
EXPORT_SYMBOL(empty_zero_page);

+#ifdef CONFIG_FUNCTION_TRACER
+/* arch/tile/kernel/mcount_64.S */
+#include <asm/ftrace.h>
+EXPORT_SYMBOL(__mcount);
+#endif /* CONFIG_FUNCTION_TRACER */
+
/* arch/tile/lib/, various memcpy files */
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(__copy_to_user_inatomic);
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 858966a..a674fd5 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -364,6 +364,10 @@ if ($arch eq "x86_64") {
} elsif ($arch eq "blackfin") {
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s__mcount\$";
$mcount_adjust = -4;
+} elsif ($arch eq "tilegx") {
+ $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s__mcount\$";
+ $type = ".quad";
+ $alignment = 8;
} else {
die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
}
--
1.8.3.1


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