995 lines
24 KiB
C
995 lines
24 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/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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#include <asm/inst.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 ppc_inst_t
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ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
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{
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ppc_inst_t 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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create_branch(&op, (u32 *)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, ppc_inst_t old, ppc_inst_t new)
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{
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ppc_inst_t 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 (copy_inst_from_kernel_nofault(&replaced, (void *)ip))
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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 (!ppc_inst_equal(replaced, old)) {
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pr_err("%p: replaced (%s) != old (%s)",
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(void *)ip, ppc_inst_as_str(replaced), ppc_inst_as_str(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((u32 *)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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ppc_inst_t op;
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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(&op, (u32 *)ip, addr, 0) == 0;
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}
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static int is_bl_op(ppc_inst_t op)
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{
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return (ppc_inst_val(op) & 0xfc000003) == 0x48000001;
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}
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static int is_b_op(ppc_inst_t op)
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{
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return (ppc_inst_val(op) & 0xfc000003) == 0x48000000;
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}
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static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op)
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{
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int offset;
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offset = (ppc_inst_val(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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ppc_inst_t op, pop;
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/* read where this goes */
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if (copy_inst_from_kernel_nofault(&op, (void *)ip)) {
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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 %s\n", ppc_inst_as_str(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(PPC_RAW_NOP());
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if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 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 (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) &&
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!ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) {
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pr_err("Unexpected instruction %s around bl _mcount\n",
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ppc_inst_as_str(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(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 (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) {
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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 (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) {
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pr_err("Expected %08lx found %s\n", PPC_INST_LD_TOC, ppc_inst_as_str(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((u32 *)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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ppc_inst_t op;
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unsigned long ip = rec->ip;
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unsigned long tramp, ptr;
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if (copy_from_kernel_nofault(&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 %s\n", ppc_inst_as_str(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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/* Find where the trampoline jumps to */
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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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if (ptr != 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(PPC_RAW_NOP());
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if (patch_instruction((u32 *)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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ppc_inst_t instr;
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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(&instr, (void *)ip,
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ftrace_tramps[i], 0) == 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;
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ppc_inst_t op;
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unsigned long ptr;
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ppc_inst_t instr;
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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] == 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 (copy_inst_from_kernel_nofault(&op, (void *)tramp)) {
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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(&instr, (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((u32 *)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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ppc_inst_t op;
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/* Read where this goes */
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if (copy_inst_from_kernel_nofault(&op, (void *)ip)) {
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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 %s\n", ppc_inst_as_str(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((u32 *)ip, ppc_inst(PPC_RAW_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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ppc_inst_t 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(PPC_RAW_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, ppc_inst_t op0, ppc_inst_t 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 (!ppc_inst_equal(op0, ppc_inst(0x48000008)) ||
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(ppc_inst_val(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, ppc_inst_t op0, ppc_inst_t op1)
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{
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/* look for patched "NOP" on ppc64 with -mprofile-kernel */
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if (!ppc_inst_equal(op0, ppc_inst(PPC_RAW_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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ppc_inst_t op[2];
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ppc_inst_t instr;
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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 (copy_inst_from_kernel_nofault(op, ip))
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return -EFAULT;
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if (copy_inst_from_kernel_nofault(op + 1, ip + 4))
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return -EFAULT;
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if (!expected_nop_sequence(ip, op[0], op[1])) {
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pr_err("Unexpected call sequence at %p: %s %s\n",
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ip, ppc_inst_as_str(op[0]), ppc_inst_as_str(op[1]));
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return -EINVAL;
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}
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/* If we never set up ftrace trampoline(s), then bail */
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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if (!mod->arch.tramp || !mod->arch.tramp_regs) {
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#else
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if (!mod->arch.tramp) {
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#endif
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pr_err("No ftrace trampoline\n");
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return -EINVAL;
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}
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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if (rec->flags & FTRACE_FL_REGS)
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tramp = mod->arch.tramp_regs;
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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(&instr, 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)
|
|
{
|
|
int err;
|
|
ppc_inst_t op;
|
|
u32 *ip = (u32 *)rec->ip;
|
|
struct module *mod = rec->arch.mod;
|
|
unsigned long tramp;
|
|
|
|
/* read where this goes */
|
|
if (copy_inst_from_kernel_nofault(&op, ip))
|
|
return -EFAULT;
|
|
|
|
/* It should be pointing to a nop */
|
|
if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) {
|
|
pr_err("Expected NOP but have %s\n", ppc_inst_as_str(op));
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* If we never set up a trampoline to ftrace_caller, 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;
|
|
/* create the branch to the trampoline */
|
|
err = create_branch(&op, ip, tramp, BRANCH_SET_LINK);
|
|
if (err) {
|
|
pr_err("REL24 out of range!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
pr_devel("write to %lx\n", rec->ip);
|
|
|
|
if (patch_instruction(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)
|
|
{
|
|
ppc_inst_t 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 (copy_inst_from_kernel_nofault(&op, ip)) {
|
|
pr_err("Unable to read ftrace location %p\n", ip);
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) {
|
|
pr_err("Unexpected call sequence at %p: %s\n", ip, ppc_inst_as_str(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;
|
|
ppc_inst_t 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(PPC_RAW_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)
|
|
{
|
|
ppc_inst_t 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 (copy_inst_from_kernel_nofault(&op, (void *)ip)) {
|
|
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 %s\n", ppc_inst_as_str(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((u32 *)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(&op, (u32 *)ip, tramp, BRANCH_SET_LINK)) {
|
|
pr_err("Branch out of range\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (patch_branch((u32 *)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;
|
|
ppc_inst_t 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);
|
|
ppc_inst_t old, new;
|
|
int ret;
|
|
|
|
old = ppc_inst_read((u32 *)&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 = ppc_inst_read((u32 *)&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)
|
|
|
|
extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[];
|
|
|
|
void ftrace_free_init_tramp(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++)
|
|
if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) {
|
|
ftrace_tramps[i] = 0;
|
|
return;
|
|
}
|
|
}
|
|
|
|
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);
|
|
|
|
static int ftrace_modify_ftrace_graph_caller(bool enable)
|
|
{
|
|
unsigned long ip = (unsigned long)(&ftrace_graph_call);
|
|
unsigned long addr = (unsigned long)(&ftrace_graph_caller);
|
|
unsigned long stub = (unsigned long)(&ftrace_graph_stub);
|
|
ppc_inst_t old, new;
|
|
|
|
if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS))
|
|
return 0;
|
|
|
|
old = ftrace_call_replace(ip, enable ? stub : addr, 0);
|
|
new = ftrace_call_replace(ip, enable ? addr : stub, 0);
|
|
|
|
return ftrace_modify_code(ip, old, new);
|
|
}
|
|
|
|
int ftrace_enable_ftrace_graph_caller(void)
|
|
{
|
|
return ftrace_modify_ftrace_graph_caller(true);
|
|
}
|
|
|
|
int ftrace_disable_ftrace_graph_caller(void)
|
|
{
|
|
return ftrace_modify_ftrace_graph_caller(false);
|
|
}
|
|
|
|
/*
|
|
* 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 sp)
|
|
{
|
|
unsigned long return_hooker;
|
|
int bit;
|
|
|
|
if (unlikely(ftrace_graph_is_dead()))
|
|
goto out;
|
|
|
|
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
|
|
goto out;
|
|
|
|
bit = ftrace_test_recursion_trylock(ip, parent);
|
|
if (bit < 0)
|
|
goto out;
|
|
|
|
return_hooker = ppc_function_entry(return_to_handler);
|
|
|
|
if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp))
|
|
parent = return_hooker;
|
|
|
|
ftrace_test_recursion_unlock(bit);
|
|
out:
|
|
return parent;
|
|
}
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
|
|
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
|
|
struct ftrace_ops *op, struct ftrace_regs *fregs)
|
|
{
|
|
fregs->regs.link = prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]);
|
|
}
|
|
#endif
|
|
#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 */
|