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7bea7ac0ca
Recently in commitfbf508da74("powerpc: split compat syscall table out from native table") we changed the layout of the system call table. Instead of having two entries for each syscall number, one for the regular entry point and one for the compat entry point, we now have separate tables for regular and compat entry points. This inadvertently broke syscall tracing (CONFIG_FTRACE_SYSCALLS), because our implementation of arch_syscall_addr() knew about the layout of the table (it did nr * 2). We can fix it just by dropping our version of arch_syscall_addr() and using the generic version which does: return (unsigned long)sys_call_table[nr]; Fixes:fbf508da74("powerpc: split compat syscall table out from native table") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
979 lines
23 KiB
C
979 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Code for replacing ftrace calls with jumps.
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*
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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*
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* Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
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*
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* Added function graph tracer code, taken from x86 that was written
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* by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
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*
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*/
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#define pr_fmt(fmt) "ftrace-powerpc: " fmt
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#include <linux/spinlock.h>
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#include <linux/hardirq.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/ftrace.h>
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#include <linux/percpu.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <asm/asm-prototypes.h>
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#include <asm/cacheflush.h>
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#include <asm/code-patching.h>
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#include <asm/ftrace.h>
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#include <asm/syscall.h>
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#ifdef CONFIG_DYNAMIC_FTRACE
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/*
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* We generally only have a single long_branch tramp and at most 2 or 3 plt
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* tramps generated. But, we don't use the plt tramps currently. We also allot
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* 2 tramps after .text and .init.text. So, we only end up with around 3 usable
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* tramps in total. Set aside 8 just to be sure.
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*/
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#define NUM_FTRACE_TRAMPS 8
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static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
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static unsigned int
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ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
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{
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unsigned int op;
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addr = ppc_function_entry((void *)addr);
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/* if (link) set op to 'bl' else 'b' */
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op = create_branch((unsigned int *)ip, addr, link ? 1 : 0);
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return op;
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}
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static int
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ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
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{
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unsigned int replaced;
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/*
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* Note:
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* We are paranoid about modifying text, as if a bug was to happen, it
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* could cause us to read or write to someplace that could cause harm.
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* Carefully read and modify the code with probe_kernel_*(), and make
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* sure what we read is what we expected it to be before modifying it.
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*/
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/* read the text we want to modify */
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if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE))
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return -EFAULT;
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/* Make sure it is what we expect it to be */
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if (replaced != old) {
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pr_err("%p: replaced (%#x) != old (%#x)",
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(void *)ip, replaced, old);
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return -EINVAL;
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}
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/* replace the text with the new text */
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if (patch_instruction((unsigned int *)ip, new))
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return -EPERM;
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return 0;
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}
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/*
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* Helper functions that are the same for both PPC64 and PPC32.
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*/
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static int test_24bit_addr(unsigned long ip, unsigned long addr)
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{
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addr = ppc_function_entry((void *)addr);
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/* use the create_branch to verify that this offset can be branched */
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return create_branch((unsigned int *)ip, addr, 0);
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}
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static int is_bl_op(unsigned int op)
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{
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return (op & 0xfc000003) == 0x48000001;
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}
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static int is_b_op(unsigned int op)
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{
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return (op & 0xfc000003) == 0x48000000;
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}
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static unsigned long find_bl_target(unsigned long ip, unsigned int op)
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{
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int offset;
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offset = (op & 0x03fffffc);
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/* make it signed */
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if (offset & 0x02000000)
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offset |= 0xfe000000;
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return ip + (long)offset;
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}
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#ifdef CONFIG_MODULES
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#ifdef CONFIG_PPC64
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static int
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__ftrace_make_nop(struct module *mod,
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struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned long entry, ptr, tramp;
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unsigned long ip = rec->ip;
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unsigned int op, pop;
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/* read where this goes */
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if (probe_kernel_read(&op, (void *)ip, sizeof(int))) {
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pr_err("Fetching opcode failed.\n");
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return -EFAULT;
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}
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/* Make sure that that this is still a 24bit jump */
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if (!is_bl_op(op)) {
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pr_err("Not expected bl: opcode is %x\n", op);
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return -EINVAL;
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}
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/* lets find where the pointer goes */
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tramp = find_bl_target(ip, op);
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pr_devel("ip:%lx jumps to %lx", ip, tramp);
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if (module_trampoline_target(mod, tramp, &ptr)) {
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pr_err("Failed to get trampoline target\n");
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return -EFAULT;
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}
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pr_devel("trampoline target %lx", ptr);
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entry = ppc_global_function_entry((void *)addr);
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/* This should match what was called */
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if (ptr != entry) {
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pr_err("addr %lx does not match expected %lx\n", ptr, entry);
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return -EINVAL;
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}
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#ifdef CONFIG_MPROFILE_KERNEL
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/* When using -mkernel_profile there is no load to jump over */
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pop = PPC_INST_NOP;
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if (probe_kernel_read(&op, (void *)(ip - 4), 4)) {
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pr_err("Fetching instruction at %lx failed.\n", ip - 4);
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return -EFAULT;
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}
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/* We expect either a mflr r0, or a std r0, LRSAVE(r1) */
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if (op != PPC_INST_MFLR && op != PPC_INST_STD_LR) {
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pr_err("Unexpected instruction %08x around bl _mcount\n", op);
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return -EINVAL;
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}
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#else
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/*
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* Our original call site looks like:
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*
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* bl <tramp>
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* ld r2,XX(r1)
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*
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* Milton Miller pointed out that we can not simply nop the branch.
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* If a task was preempted when calling a trace function, the nops
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* will remove the way to restore the TOC in r2 and the r2 TOC will
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* get corrupted.
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*
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* Use a b +8 to jump over the load.
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*/
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pop = PPC_INST_BRANCH | 8; /* b +8 */
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/*
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* Check what is in the next instruction. We can see ld r2,40(r1), but
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* on first pass after boot we will see mflr r0.
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*/
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if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) {
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pr_err("Fetching op failed.\n");
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return -EFAULT;
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}
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if (op != PPC_INST_LD_TOC) {
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pr_err("Expected %08x found %08x\n", PPC_INST_LD_TOC, op);
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return -EINVAL;
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}
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#endif /* CONFIG_MPROFILE_KERNEL */
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if (patch_instruction((unsigned int *)ip, pop)) {
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pr_err("Patching NOP failed.\n");
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return -EPERM;
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}
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return 0;
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}
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#else /* !PPC64 */
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static int
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__ftrace_make_nop(struct module *mod,
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struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned int op;
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unsigned int jmp[4];
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unsigned long ip = rec->ip;
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unsigned long tramp;
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if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
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return -EFAULT;
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/* Make sure that that this is still a 24bit jump */
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if (!is_bl_op(op)) {
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pr_err("Not expected bl: opcode is %x\n", op);
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return -EINVAL;
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}
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/* lets find where the pointer goes */
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tramp = find_bl_target(ip, op);
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/*
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* On PPC32 the trampoline looks like:
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* 0x3d, 0x80, 0x00, 0x00 lis r12,sym@ha
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* 0x39, 0x8c, 0x00, 0x00 addi r12,r12,sym@l
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* 0x7d, 0x89, 0x03, 0xa6 mtctr r12
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* 0x4e, 0x80, 0x04, 0x20 bctr
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*/
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pr_devel("ip:%lx jumps to %lx", ip, tramp);
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/* Find where the trampoline jumps to */
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if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
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pr_err("Failed to read %lx\n", tramp);
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return -EFAULT;
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}
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pr_devel(" %08x %08x ", jmp[0], jmp[1]);
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/* verify that this is what we expect it to be */
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if (((jmp[0] & 0xffff0000) != 0x3d800000) ||
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((jmp[1] & 0xffff0000) != 0x398c0000) ||
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(jmp[2] != 0x7d8903a6) ||
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(jmp[3] != 0x4e800420)) {
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pr_err("Not a trampoline\n");
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return -EINVAL;
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}
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tramp = (jmp[1] & 0xffff) |
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((jmp[0] & 0xffff) << 16);
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if (tramp & 0x8000)
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tramp -= 0x10000;
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pr_devel(" %lx ", tramp);
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if (tramp != addr) {
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pr_err("Trampoline location %08lx does not match addr\n",
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tramp);
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return -EINVAL;
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}
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op = PPC_INST_NOP;
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if (patch_instruction((unsigned int *)ip, op))
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return -EPERM;
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return 0;
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}
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#endif /* PPC64 */
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#endif /* CONFIG_MODULES */
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static unsigned long find_ftrace_tramp(unsigned long ip)
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{
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int i;
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/*
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* We have the compiler generated long_branch tramps at the end
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* and we prefer those
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*/
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for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--)
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if (!ftrace_tramps[i])
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continue;
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else if (create_branch((void *)ip, ftrace_tramps[i], 0))
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return ftrace_tramps[i];
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return 0;
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}
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static int add_ftrace_tramp(unsigned long tramp)
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{
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int i;
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for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
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if (!ftrace_tramps[i]) {
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ftrace_tramps[i] = tramp;
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return 0;
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}
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return -1;
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}
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/*
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* If this is a compiler generated long_branch trampoline (essentially, a
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* trampoline that has a branch to _mcount()), we re-write the branch to
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* instead go to ftrace_[regs_]caller() and note down the location of this
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* trampoline.
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*/
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static int setup_mcount_compiler_tramp(unsigned long tramp)
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{
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int i, op;
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unsigned long ptr;
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static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS];
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/* Is this a known long jump tramp? */
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for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
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if (!ftrace_tramps[i])
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break;
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else if (ftrace_tramps[i] == tramp)
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return 0;
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/* Is this a known plt tramp? */
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for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
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if (!ftrace_plt_tramps[i])
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break;
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else if (ftrace_plt_tramps[i] == tramp)
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return -1;
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/* New trampoline -- read where this goes */
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if (probe_kernel_read(&op, (void *)tramp, sizeof(int))) {
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pr_debug("Fetching opcode failed.\n");
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return -1;
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}
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/* Is this a 24 bit branch? */
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if (!is_b_op(op)) {
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pr_debug("Trampoline is not a long branch tramp.\n");
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return -1;
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}
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/* lets find where the pointer goes */
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ptr = find_bl_target(tramp, op);
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if (ptr != ppc_global_function_entry((void *)_mcount)) {
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pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr);
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return -1;
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}
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/* Let's re-write the tramp to go to ftrace_[regs_]caller */
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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ptr = ppc_global_function_entry((void *)ftrace_regs_caller);
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#else
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ptr = ppc_global_function_entry((void *)ftrace_caller);
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#endif
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if (!create_branch((void *)tramp, ptr, 0)) {
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pr_debug("%ps is not reachable from existing mcount tramp\n",
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(void *)ptr);
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return -1;
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}
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if (patch_branch((unsigned int *)tramp, ptr, 0)) {
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pr_debug("REL24 out of range!\n");
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return -1;
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}
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if (add_ftrace_tramp(tramp)) {
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pr_debug("No tramp locations left\n");
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return -1;
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}
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return 0;
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}
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static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned long tramp, ip = rec->ip;
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unsigned int op;
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/* Read where this goes */
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if (probe_kernel_read(&op, (void *)ip, sizeof(int))) {
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pr_err("Fetching opcode failed.\n");
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return -EFAULT;
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}
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/* Make sure that that this is still a 24bit jump */
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if (!is_bl_op(op)) {
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pr_err("Not expected bl: opcode is %x\n", op);
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return -EINVAL;
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}
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/* Let's find where the pointer goes */
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tramp = find_bl_target(ip, op);
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pr_devel("ip:%lx jumps to %lx", ip, tramp);
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if (setup_mcount_compiler_tramp(tramp)) {
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/* Are other trampolines reachable? */
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if (!find_ftrace_tramp(ip)) {
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pr_err("No ftrace trampolines reachable from %ps\n",
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(void *)ip);
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return -EINVAL;
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}
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}
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if (patch_instruction((unsigned int *)ip, PPC_INST_NOP)) {
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pr_err("Patching NOP failed.\n");
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return -EPERM;
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}
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return 0;
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}
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int ftrace_make_nop(struct module *mod,
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struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned long ip = rec->ip;
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unsigned int old, new;
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/*
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* If the calling address is more that 24 bits away,
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* then we had to use a trampoline to make the call.
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* Otherwise just update the call site.
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*/
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if (test_24bit_addr(ip, addr)) {
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/* within range */
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old = ftrace_call_replace(ip, addr, 1);
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new = PPC_INST_NOP;
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return ftrace_modify_code(ip, old, new);
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} else if (core_kernel_text(ip))
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return __ftrace_make_nop_kernel(rec, addr);
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#ifdef CONFIG_MODULES
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/*
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* Out of range jumps are called from modules.
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* We should either already have a pointer to the module
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* or it has been passed in.
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*/
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if (!rec->arch.mod) {
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if (!mod) {
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pr_err("No module loaded addr=%lx\n", addr);
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return -EFAULT;
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}
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rec->arch.mod = mod;
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} else if (mod) {
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if (mod != rec->arch.mod) {
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pr_err("Record mod %p not equal to passed in mod %p\n",
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rec->arch.mod, mod);
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return -EINVAL;
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}
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/* nothing to do if mod == rec->arch.mod */
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} else
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mod = rec->arch.mod;
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return __ftrace_make_nop(mod, rec, addr);
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#else
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/* We should not get here without modules */
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return -EINVAL;
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#endif /* CONFIG_MODULES */
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}
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#ifdef CONFIG_MODULES
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#ifdef CONFIG_PPC64
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/*
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* Examine the existing instructions for __ftrace_make_call.
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* They should effectively be a NOP, and follow formal constraints,
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* depending on the ABI. Return false if they don't.
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*/
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#ifndef CONFIG_MPROFILE_KERNEL
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static int
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expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1)
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{
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/*
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* We expect to see:
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*
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* b +8
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* ld r2,XX(r1)
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*
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* The load offset is different depending on the ABI. For simplicity
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* just mask it out when doing the compare.
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*/
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if ((op0 != 0x48000008) || ((op1 & 0xffff0000) != 0xe8410000))
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return 0;
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return 1;
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}
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#else
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static int
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expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1)
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{
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/* look for patched "NOP" on ppc64 with -mprofile-kernel */
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if (op0 != PPC_INST_NOP)
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return 0;
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return 1;
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}
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#endif
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static int
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__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned int op[2];
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void *ip = (void *)rec->ip;
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unsigned long entry, ptr, tramp;
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struct module *mod = rec->arch.mod;
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/* read where this goes */
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if (probe_kernel_read(op, ip, sizeof(op)))
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return -EFAULT;
|
|
|
|
if (!expected_nop_sequence(ip, op[0], op[1])) {
|
|
pr_err("Unexpected call sequence at %p: %x %x\n",
|
|
ip, op[0], op[1]);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* If we never set up ftrace trampoline(s), then bail */
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
if (!mod->arch.tramp || !mod->arch.tramp_regs) {
|
|
#else
|
|
if (!mod->arch.tramp) {
|
|
#endif
|
|
pr_err("No ftrace trampoline\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
if (rec->flags & FTRACE_FL_REGS)
|
|
tramp = mod->arch.tramp_regs;
|
|
else
|
|
#endif
|
|
tramp = mod->arch.tramp;
|
|
|
|
if (module_trampoline_target(mod, tramp, &ptr)) {
|
|
pr_err("Failed to get trampoline target\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
pr_devel("trampoline target %lx", ptr);
|
|
|
|
entry = ppc_global_function_entry((void *)addr);
|
|
/* This should match what was called */
|
|
if (ptr != entry) {
|
|
pr_err("addr %lx does not match expected %lx\n", ptr, entry);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Ensure branch is within 24 bits */
|
|
if (!create_branch(ip, tramp, BRANCH_SET_LINK)) {
|
|
pr_err("Branch out of range\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
|
|
pr_err("REL24 out of range!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#else /* !CONFIG_PPC64: */
|
|
static int
|
|
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
unsigned int op;
|
|
unsigned long ip = rec->ip;
|
|
|
|
/* read where this goes */
|
|
if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
|
|
return -EFAULT;
|
|
|
|
/* It should be pointing to a nop */
|
|
if (op != PPC_INST_NOP) {
|
|
pr_err("Expected NOP but have %x\n", op);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* If we never set up a trampoline to ftrace_caller, then bail */
|
|
if (!rec->arch.mod->arch.tramp) {
|
|
pr_err("No ftrace trampoline\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* create the branch to the trampoline */
|
|
op = create_branch((unsigned int *)ip,
|
|
rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
|
|
if (!op) {
|
|
pr_err("REL24 out of range!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
pr_devel("write to %lx\n", rec->ip);
|
|
|
|
if (patch_instruction((unsigned int *)ip, op))
|
|
return -EPERM;
|
|
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_PPC64 */
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
unsigned int op;
|
|
void *ip = (void *)rec->ip;
|
|
unsigned long tramp, entry, ptr;
|
|
|
|
/* Make sure we're being asked to patch branch to a known ftrace addr */
|
|
entry = ppc_global_function_entry((void *)ftrace_caller);
|
|
ptr = ppc_global_function_entry((void *)addr);
|
|
|
|
if (ptr != entry) {
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
entry = ppc_global_function_entry((void *)ftrace_regs_caller);
|
|
if (ptr != entry) {
|
|
#endif
|
|
pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr);
|
|
return -EINVAL;
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* Make sure we have a nop */
|
|
if (probe_kernel_read(&op, ip, sizeof(op))) {
|
|
pr_err("Unable to read ftrace location %p\n", ip);
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (op != PPC_INST_NOP) {
|
|
pr_err("Unexpected call sequence at %p: %x\n", ip, op);
|
|
return -EINVAL;
|
|
}
|
|
|
|
tramp = find_ftrace_tramp((unsigned long)ip);
|
|
if (!tramp) {
|
|
pr_err("No ftrace trampolines reachable from %ps\n", ip);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
|
|
pr_err("Error patching branch to ftrace tramp!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
unsigned long ip = rec->ip;
|
|
unsigned int old, new;
|
|
|
|
/*
|
|
* If the calling address is more that 24 bits away,
|
|
* then we had to use a trampoline to make the call.
|
|
* Otherwise just update the call site.
|
|
*/
|
|
if (test_24bit_addr(ip, addr)) {
|
|
/* within range */
|
|
old = PPC_INST_NOP;
|
|
new = ftrace_call_replace(ip, addr, 1);
|
|
return ftrace_modify_code(ip, old, new);
|
|
} else if (core_kernel_text(ip))
|
|
return __ftrace_make_call_kernel(rec, addr);
|
|
|
|
#ifdef CONFIG_MODULES
|
|
/*
|
|
* Out of range jumps are called from modules.
|
|
* Being that we are converting from nop, it had better
|
|
* already have a module defined.
|
|
*/
|
|
if (!rec->arch.mod) {
|
|
pr_err("No module loaded\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return __ftrace_make_call(rec, addr);
|
|
#else
|
|
/* We should not get here without modules */
|
|
return -EINVAL;
|
|
#endif /* CONFIG_MODULES */
|
|
}
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
#ifdef CONFIG_MODULES
|
|
static int
|
|
__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
|
|
unsigned long addr)
|
|
{
|
|
unsigned int op;
|
|
unsigned long ip = rec->ip;
|
|
unsigned long entry, ptr, tramp;
|
|
struct module *mod = rec->arch.mod;
|
|
|
|
/* If we never set up ftrace trampolines, then bail */
|
|
if (!mod->arch.tramp || !mod->arch.tramp_regs) {
|
|
pr_err("No ftrace trampoline\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* read where this goes */
|
|
if (probe_kernel_read(&op, (void *)ip, sizeof(int))) {
|
|
pr_err("Fetching opcode failed.\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
/* Make sure that that this is still a 24bit jump */
|
|
if (!is_bl_op(op)) {
|
|
pr_err("Not expected bl: opcode is %x\n", op);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* lets find where the pointer goes */
|
|
tramp = find_bl_target(ip, op);
|
|
entry = ppc_global_function_entry((void *)old_addr);
|
|
|
|
pr_devel("ip:%lx jumps to %lx", ip, tramp);
|
|
|
|
if (tramp != entry) {
|
|
/* old_addr is not within range, so we must have used a trampoline */
|
|
if (module_trampoline_target(mod, tramp, &ptr)) {
|
|
pr_err("Failed to get trampoline target\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
pr_devel("trampoline target %lx", ptr);
|
|
|
|
/* This should match what was called */
|
|
if (ptr != entry) {
|
|
pr_err("addr %lx does not match expected %lx\n", ptr, entry);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* The new target may be within range */
|
|
if (test_24bit_addr(ip, addr)) {
|
|
/* within range */
|
|
if (patch_branch((unsigned int *)ip, addr, BRANCH_SET_LINK)) {
|
|
pr_err("REL24 out of range!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
if (rec->flags & FTRACE_FL_REGS)
|
|
tramp = mod->arch.tramp_regs;
|
|
else
|
|
tramp = mod->arch.tramp;
|
|
|
|
if (module_trampoline_target(mod, tramp, &ptr)) {
|
|
pr_err("Failed to get trampoline target\n");
|
|
return -EFAULT;
|
|
}
|
|
|
|
pr_devel("trampoline target %lx", ptr);
|
|
|
|
entry = ppc_global_function_entry((void *)addr);
|
|
/* This should match what was called */
|
|
if (ptr != entry) {
|
|
pr_err("addr %lx does not match expected %lx\n", ptr, entry);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Ensure branch is within 24 bits */
|
|
if (!create_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) {
|
|
pr_err("Branch out of range\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (patch_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) {
|
|
pr_err("REL24 out of range!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
|
|
unsigned long addr)
|
|
{
|
|
unsigned long ip = rec->ip;
|
|
unsigned int old, new;
|
|
|
|
/*
|
|
* If the calling address is more that 24 bits away,
|
|
* then we had to use a trampoline to make the call.
|
|
* Otherwise just update the call site.
|
|
*/
|
|
if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) {
|
|
/* within range */
|
|
old = ftrace_call_replace(ip, old_addr, 1);
|
|
new = ftrace_call_replace(ip, addr, 1);
|
|
return ftrace_modify_code(ip, old, new);
|
|
} else if (core_kernel_text(ip)) {
|
|
/*
|
|
* We always patch out of range locations to go to the regs
|
|
* variant, so there is nothing to do here
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
/*
|
|
* Out of range jumps are called from modules.
|
|
*/
|
|
if (!rec->arch.mod) {
|
|
pr_err("No module loaded\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return __ftrace_modify_call(rec, old_addr, addr);
|
|
#else
|
|
/* We should not get here without modules */
|
|
return -EINVAL;
|
|
#endif /* CONFIG_MODULES */
|
|
}
|
|
#endif
|
|
|
|
int ftrace_update_ftrace_func(ftrace_func_t func)
|
|
{
|
|
unsigned long ip = (unsigned long)(&ftrace_call);
|
|
unsigned int old, new;
|
|
int ret;
|
|
|
|
old = *(unsigned int *)&ftrace_call;
|
|
new = ftrace_call_replace(ip, (unsigned long)func, 1);
|
|
ret = ftrace_modify_code(ip, old, new);
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
/* Also update the regs callback function */
|
|
if (!ret) {
|
|
ip = (unsigned long)(&ftrace_regs_call);
|
|
old = *(unsigned int *)&ftrace_regs_call;
|
|
new = ftrace_call_replace(ip, (unsigned long)func, 1);
|
|
ret = ftrace_modify_code(ip, old, new);
|
|
}
|
|
#endif
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Use the default ftrace_modify_all_code, but without
|
|
* stop_machine().
|
|
*/
|
|
void arch_ftrace_update_code(int command)
|
|
{
|
|
ftrace_modify_all_code(command);
|
|
}
|
|
|
|
#ifdef CONFIG_PPC64
|
|
#define PACATOC offsetof(struct paca_struct, kernel_toc)
|
|
|
|
#define PPC_LO(v) ((v) & 0xffff)
|
|
#define PPC_HI(v) (((v) >> 16) & 0xffff)
|
|
#define PPC_HA(v) PPC_HI ((v) + 0x8000)
|
|
|
|
extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[];
|
|
|
|
int __init ftrace_dyn_arch_init(void)
|
|
{
|
|
int i;
|
|
unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
|
|
u32 stub_insns[] = {
|
|
0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */
|
|
0x3d8c0000, /* addis r12,r12,<high> */
|
|
0x398c0000, /* addi r12,r12,<low> */
|
|
0x7d8903a6, /* mtctr r12 */
|
|
0x4e800420, /* bctr */
|
|
};
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
unsigned long addr = ppc_global_function_entry((void *)ftrace_regs_caller);
|
|
#else
|
|
unsigned long addr = ppc_global_function_entry((void *)ftrace_caller);
|
|
#endif
|
|
long reladdr = addr - kernel_toc_addr();
|
|
|
|
if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
|
|
pr_err("Address of %ps out of range of kernel_toc.\n",
|
|
(void *)addr);
|
|
return -1;
|
|
}
|
|
|
|
for (i = 0; i < 2; i++) {
|
|
memcpy(tramp[i], stub_insns, sizeof(stub_insns));
|
|
tramp[i][1] |= PPC_HA(reladdr);
|
|
tramp[i][2] |= PPC_LO(reladdr);
|
|
add_ftrace_tramp((unsigned long)tramp[i]);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
int __init ftrace_dyn_arch_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
|
|
extern void ftrace_graph_call(void);
|
|
extern void ftrace_graph_stub(void);
|
|
|
|
int ftrace_enable_ftrace_graph_caller(void)
|
|
{
|
|
unsigned long ip = (unsigned long)(&ftrace_graph_call);
|
|
unsigned long addr = (unsigned long)(&ftrace_graph_caller);
|
|
unsigned long stub = (unsigned long)(&ftrace_graph_stub);
|
|
unsigned int old, new;
|
|
|
|
old = ftrace_call_replace(ip, stub, 0);
|
|
new = ftrace_call_replace(ip, addr, 0);
|
|
|
|
return ftrace_modify_code(ip, old, new);
|
|
}
|
|
|
|
int ftrace_disable_ftrace_graph_caller(void)
|
|
{
|
|
unsigned long ip = (unsigned long)(&ftrace_graph_call);
|
|
unsigned long addr = (unsigned long)(&ftrace_graph_caller);
|
|
unsigned long stub = (unsigned long)(&ftrace_graph_stub);
|
|
unsigned int old, new;
|
|
|
|
old = ftrace_call_replace(ip, addr, 0);
|
|
new = ftrace_call_replace(ip, stub, 0);
|
|
|
|
return ftrace_modify_code(ip, old, new);
|
|
}
|
|
|
|
/*
|
|
* Hook the return address and push it in the stack of return addrs
|
|
* in current thread info. Return the address we want to divert to.
|
|
*/
|
|
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
|
|
{
|
|
unsigned long return_hooker;
|
|
|
|
if (unlikely(ftrace_graph_is_dead()))
|
|
goto out;
|
|
|
|
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
|
|
goto out;
|
|
|
|
return_hooker = ppc_function_entry(return_to_handler);
|
|
|
|
if (!function_graph_enter(parent, ip, 0, NULL))
|
|
parent = return_hooker;
|
|
out:
|
|
return parent;
|
|
}
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
|
|
#ifdef PPC64_ELF_ABI_v1
|
|
char *arch_ftrace_match_adjust(char *str, const char *search)
|
|
{
|
|
if (str[0] == '.' && search[0] != '.')
|
|
return str + 1;
|
|
else
|
|
return str;
|
|
}
|
|
#endif /* PPC64_ELF_ABI_v1 */
|