ftrace, ia64: IA64 dynamic ftrace support (a14a07b8) · Commits · 戴 / test

arch/ia64/Kconfig

+2 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,8 @@ config IA64
		select HAVE_OPROFILE
		select HAVE_KPROBES
		select HAVE_KRETPROBES
		select HAVE_FTRACE_MCOUNT_RECORD
		select HAVE_DYNAMIC_FTRACE if (!ITANIUM)
		select HAVE_FUNCTION_TRACER
		select HAVE_DMA_ATTRS
		select HAVE_KVM

arch/ia64/include/asm/ftrace.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -8,6 +8,19 @@
		extern void _mcount(unsigned long pfs, unsigned long r1, unsigned long b0, unsigned long r0);
		#define mcount _mcount

		#include <asm/kprobes.h>
		/* In IA64, MCOUNT_ADDR is set in link time, so it's not a constant at compile time */
		#define MCOUNT_ADDR (((struct fnptr *)mcount)->ip)
		#define FTRACE_ADDR (((struct fnptr *)ftrace_caller)->ip)

		static inline unsigned long ftrace_call_adjust(unsigned long addr)
		{
		/* second bundle, insn 2 */
		return addr - 0x12;
		}

		struct dyn_arch_ftrace {
		};
		#endif

		#endif /* CONFIG_FUNCTION_TRACER */

arch/ia64/kernel/Makefile

+5 −0

Original line number	Diff line number	Diff line
		@@ -2,6 +2,10 @@
		# Makefile for the linux kernel.
		#

		ifdef CONFIG_DYNAMIC_FTRACE
		CFLAGS_REMOVE_ftrace.o = -pg
		endif

		extra-y := head.o init_task.o vmlinux.lds

		obj-y := acpi.o entry.o efi.o efi_stub.o gate-data.o fsys.o ia64_ksyms.o irq.o irq_ia64.o \
		@@ -28,6 +32,7 @@ obj-$(CONFIG_IA64_CYCLONE) += cyclone.o
		obj-$(CONFIG_CPU_FREQ) += cpufreq/
		obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o
		obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o
		obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
		obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
		obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
		obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR) += uncached.o

arch/ia64/kernel/entry.S

+51 −0

Original line number	Diff line number	Diff line
		@@ -1406,6 +1406,56 @@ GLOBAL_ENTRY(unw_init_running)
		END(unw_init_running)

		#ifdef CONFIG_FUNCTION_TRACER
		#ifdef CONFIG_DYNAMIC_FTRACE
		GLOBAL_ENTRY(_mcount)
		br ftrace_stub
		END(_mcount)

		.here:
		br.ret.sptk.many b0

		GLOBAL_ENTRY(ftrace_caller)
		alloc out0 = ar.pfs, 8, 0, 4, 0
		mov out3 = r0
		;;
		mov out2 = b0
		add r3 = 0x20, r3
		mov out1 = r1;
		br.call.sptk.many b0 = ftrace_patch_gp
		//this might be called from module, so we must patch gp
		ftrace_patch_gp:
		movl gp=__gp
		mov b0 = r3
		;;
		.global ftrace_call;
		ftrace_call:
		{
		.mlx
		nop.m 0x0
		movl r3 = .here;;
		}
		alloc loc0 = ar.pfs, 4, 4, 2, 0
		;;
		mov loc1 = b0
		mov out0 = b0
		mov loc2 = r8
		mov loc3 = r15
		;;
		adds out0 = -MCOUNT_INSN_SIZE, out0
		mov out1 = in2
		mov b6 = r3

		br.call.sptk.many b0 = b6
		;;
		mov ar.pfs = loc0
		mov b0 = loc1
		mov r8 = loc2
		mov r15 = loc3
		br ftrace_stub
		;;
		END(ftrace_caller)

		#else
		GLOBAL_ENTRY(_mcount)
		movl r2 = ftrace_stub
		movl r3 = ftrace_trace_function;;
		@@ -1435,6 +1485,7 @@ GLOBAL_ENTRY(_mcount)
		br ftrace_stub
		;;
		END(_mcount)
		#endif

		GLOBAL_ENTRY(ftrace_stub)
		mov r3 = b0

arch/ia64/kernel/ftrace.c

0 → 100644

+206 −0

Original line number	Diff line number	Diff line
		/*
		* Dynamic function tracing support.
		*
		* Copyright (C) 2008 Shaohua Li <shaohua.li@intel.com>
		*
		* For licencing details, see COPYING.
		*
		* Defines low-level handling of mcount calls when the kernel
		* is compiled with the -pg flag. When using dynamic ftrace, the
		* mcount call-sites get patched lazily with NOP till they are
		* enabled. All code mutation routines here take effect atomically.
		*/

		#include <linux/uaccess.h>
		#include <linux/ftrace.h>

		#include <asm/cacheflush.h>
		#include <asm/patch.h>

		/* In IA64, each function will be added below two bundles with -pg option */
		static unsigned char __attribute__((aligned(8)))
		ftrace_orig_code[MCOUNT_INSN_SIZE] = {
		0x02, 0x40, 0x31, 0x10, 0x80, 0x05, /* alloc r40=ar.pfs,12,8,0 */
		0xb0, 0x02, 0x00, 0x00, 0x42, 0x40, /* mov r43=r0;; */
		0x05, 0x00, 0xc4, 0x00, /* mov r42=b0 */
		0x11, 0x48, 0x01, 0x02, 0x00, 0x21, /* mov r41=r1 */
		0x00, 0x00, 0x00, 0x02, 0x00, 0x00, /* nop.i 0x0 */
		0x08, 0x00, 0x00, 0x50 /* br.call.sptk.many b0 = _mcount;; */
		};

		struct ftrace_orig_insn {
		u64 dummy1, dummy2, dummy3;
		u64 dummy4:64-41+13;
		u64 imm20:20;
		u64 dummy5:3;
		u64 sign:1;
		u64 dummy6:4;
		};

		/* mcount stub will be converted below for nop */
		static unsigned char ftrace_nop_code[MCOUNT_INSN_SIZE] = {
		0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MII] nop.m 0x0 */
		0x30, 0x00, 0x00, 0x60, 0x00, 0x00, /* mov r3=ip */
		0x00, 0x00, 0x04, 0x00, /* nop.i 0x0 */
		0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0x0 */
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* nop.x 0x0;; */
		0x00, 0x00, 0x04, 0x00
		};

		static unsigned char *ftrace_nop_replace(void)
		{
		return ftrace_nop_code;
		}

		/*
		* mcount stub will be converted below for call
		* Note: Just the last instruction is changed against nop
		* */
		static unsigned char __attribute__((aligned(8)))
		ftrace_call_code[MCOUNT_INSN_SIZE] = {
		0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MII] nop.m 0x0 */
		0x30, 0x00, 0x00, 0x60, 0x00, 0x00, /* mov r3=ip */
		0x00, 0x00, 0x04, 0x00, /* nop.i 0x0 */
		0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0x0 */
		0xff, 0xff, 0xff, 0xff, 0x7f, 0x00, /* brl.many .;;*/
		0xf8, 0xff, 0xff, 0xc8
		};

		struct ftrace_call_insn {
		u64 dummy1, dummy2;
		u64 dummy3:48;
		u64 imm39_l:16;
		u64 imm39_h:23;
		u64 dummy4:13;
		u64 imm20:20;
		u64 dummy5:3;
		u64 i:1;
		u64 dummy6:4;
		};

		static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
		{
		struct ftrace_call_insn code = (void )ftrace_call_code;
		unsigned long offset = addr - (ip + 0x10);

		code->imm39_l = offset >> 24;
		code->imm39_h = offset >> 40;
		code->imm20 = offset >> 4;
		code->i = offset >> 63;
		return ftrace_call_code;
		}

		static int
		ftrace_modify_code(unsigned long ip, unsigned char *old_code,
		unsigned char *new_code, int do_check)
		{
		unsigned char replaced[MCOUNT_INSN_SIZE];

		/*
		* Note: Due to modules and __init, code can
		* disappear and change, we need to protect against faulting
		* as well as code changing. We do this by using the
		* probe_kernel_* functions.
		*
		* No real locking needed, this code is run through
		* kstop_machine, or before SMP starts.
		*/

		if (!do_check)
		goto skip_check;

		/* read the text we want to modify */
		if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
		return -EFAULT;

		/* Make sure it is what we expect it to be */
		if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
		return -EINVAL;

		skip_check:
		/* replace the text with the new text */
		if (probe_kernel_write(((void *)ip), new_code, MCOUNT_INSN_SIZE))
		return -EPERM;
		flush_icache_range(ip, ip + MCOUNT_INSN_SIZE);

		return 0;
		}

		static int ftrace_make_nop_check(struct dyn_ftrace *rec, unsigned long addr)
		{
		unsigned char __attribute__((aligned(8))) replaced[MCOUNT_INSN_SIZE];
		unsigned long ip = rec->ip;

		if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
		return -EFAULT;
		if (rec->flags & FTRACE_FL_CONVERTED) {
		struct ftrace_call_insn call_insn, tmp_call;

		call_insn = (void *)ftrace_call_code;
		tmp_call = (void *)replaced;
		call_insn->imm39_l = tmp_call->imm39_l;
		call_insn->imm39_h = tmp_call->imm39_h;
		call_insn->imm20 = tmp_call->imm20;
		call_insn->i = tmp_call->i;
		if (memcmp(replaced, ftrace_call_code, MCOUNT_INSN_SIZE) != 0)
		return -EINVAL;
		return 0;
		} else {
		struct ftrace_orig_insn call_insn, tmp_call;

		call_insn = (void *)ftrace_orig_code;
		tmp_call = (void *)replaced;
		call_insn->sign = tmp_call->sign;
		call_insn->imm20 = tmp_call->imm20;
		if (memcmp(replaced, ftrace_orig_code, MCOUNT_INSN_SIZE) != 0)
		return -EINVAL;
		return 0;
		}
		}

		int ftrace_make_nop(struct module *mod,
		struct dyn_ftrace *rec, unsigned long addr)
		{
		int ret;
		char *new;

		ret = ftrace_make_nop_check(rec, addr);
		if (ret)
		return ret;
		new = ftrace_nop_replace();
		return ftrace_modify_code(rec->ip, NULL, new, 0);
		}

		int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
		{
		unsigned long ip = rec->ip;
		unsigned char old, new;

		old= ftrace_nop_replace();
		new = ftrace_call_replace(ip, addr);
		return ftrace_modify_code(ip, old, new, 1);
		}

		/* in IA64, _mcount can't directly call ftrace_stub. Only jump is ok */
		int ftrace_update_ftrace_func(ftrace_func_t func)
		{
		unsigned long ip;
		unsigned long addr = ((struct fnptr *)ftrace_call)->ip;

		if (func == ftrace_stub)
		return 0;
		ip = ((struct fnptr *)func)->ip;

		ia64_patch_imm64(addr + 2, ip);

		flush_icache_range(addr, addr + 16);
		return 0;
		}

		/* run from kstop_machine */
		int __init ftrace_dyn_arch_init(void *data)
		{
		(unsigned long )data = 0;

		return 0;
		}

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