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989 lines
24 KiB
989 lines
24 KiB
// 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 <[email protected]> |
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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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|
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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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#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 struct ppc_inst |
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ftrace_call_replace(unsigned long ip, unsigned long addr, int link) |
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{ |
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struct ppc_inst 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, (struct ppc_inst *)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, struct ppc_inst old, struct ppc_inst new) |
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{ |
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struct ppc_inst 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_inst(&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((struct ppc_inst *)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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struct ppc_inst 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, (struct ppc_inst *)ip, addr, 0) == 0; |
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} |
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static int is_bl_op(struct ppc_inst 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(struct ppc_inst 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, struct ppc_inst 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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struct ppc_inst op, pop; |
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/* read where this goes */ |
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if (probe_kernel_read_inst(&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_INST_NOP); |
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if (probe_kernel_read_inst(&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_INST_MFLR)) && |
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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 (probe_kernel_read_inst(&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 %08x 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((struct ppc_inst *)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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struct ppc_inst 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 (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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/* |
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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 (copy_from_kernel_nofault(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(PPC_INST_NOP); |
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if (patch_instruction((struct ppc_inst *)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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struct ppc_inst 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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struct ppc_inst op; |
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unsigned long ptr; |
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struct ppc_inst 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]) |
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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_inst(&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((struct ppc_inst *)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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struct ppc_inst op; |
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/* Read where this goes */ |
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if (probe_kernel_read_inst(&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((struct ppc_inst *)ip, ppc_inst(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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struct ppc_inst 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_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, struct ppc_inst op0, struct ppc_inst 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, struct ppc_inst op0, struct ppc_inst 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_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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struct ppc_inst op[2]; |
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struct ppc_inst 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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|
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/* read where this goes */ |
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if (probe_kernel_read_inst(op, ip)) |
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return -EFAULT; |
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if (probe_kernel_read_inst(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 |
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#endif |
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tramp = mod->arch.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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|
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/* Ensure branch is within 24 bits */ |
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if (create_branch(&instr, ip, tramp, BRANCH_SET_LINK)) { |
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pr_err("Branch out of range\n"); |
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return -EINVAL; |
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} |
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|
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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; |
|
struct ppc_inst op; |
|
unsigned long ip = rec->ip; |
|
|
|
/* read where this goes */ |
|
if (probe_kernel_read_inst(&op, (void *)ip)) |
|
return -EFAULT; |
|
|
|
/* It should be pointing to a nop */ |
|
if (!ppc_inst_equal(op, ppc_inst(PPC_INST_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 */ |
|
if (!rec->arch.mod->arch.tramp) { |
|
pr_err("No ftrace trampoline\n"); |
|
return -EINVAL; |
|
} |
|
|
|
/* create the branch to the trampoline */ |
|
err = create_branch(&op, (struct ppc_inst *)ip, |
|
rec->arch.mod->arch.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((struct ppc_inst *)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) |
|
{ |
|
struct ppc_inst 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_inst(&op, ip)) { |
|
pr_err("Unable to read ftrace location %p\n", ip); |
|
return -EFAULT; |
|
} |
|
|
|
if (!ppc_inst_equal(op, ppc_inst(PPC_INST_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; |
|
struct ppc_inst 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_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) |
|
{ |
|
struct ppc_inst 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_inst(&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((struct ppc_inst *)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, (struct ppc_inst *)ip, tramp, BRANCH_SET_LINK)) { |
|
pr_err("Branch out of range\n"); |
|
return -EINVAL; |
|
} |
|
|
|
if (patch_branch((struct ppc_inst *)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; |
|
struct ppc_inst 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); |
|
struct ppc_inst old, new; |
|
int ret; |
|
|
|
old = ppc_inst_read((struct ppc_inst *)&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((struct ppc_inst *)&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[]; |
|
|
|
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); |
|
struct ppc_inst 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); |
|
struct ppc_inst 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 sp) |
|
{ |
|
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, (unsigned long *)sp)) |
|
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 */
|
|
|