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x86/ftrace: Use text_poke()
Move ftrace over to using the generic x86 text_poke functions; this avoids having a second/different copy of that code around. This also avoids ftrace violating the (new) W^X rule and avoids fragmenting the kernel text page-tables, due to no longer having to toggle them RW. Tested-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191111132457.761255803@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
Ingo Molnar
parent
63f62addb8
commit
768ae4406a
@ -34,8 +34,6 @@ struct dyn_arch_ftrace {
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/* No extra data needed for x86 */
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};
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int ftrace_int3_handler(struct pt_regs *regs);
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#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR
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#endif /* CONFIG_DYNAMIC_FTRACE */
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@ -949,7 +949,7 @@ static struct bp_patching_desc {
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int nr_entries;
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} bp_patching;
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static int patch_cmp(const void *key, const void *elt)
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static int notrace patch_cmp(const void *key, const void *elt)
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{
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struct text_poke_loc *tp = (struct text_poke_loc *) elt;
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@ -961,7 +961,7 @@ static int patch_cmp(const void *key, const void *elt)
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}
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NOKPROBE_SYMBOL(patch_cmp);
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int poke_int3_handler(struct pt_regs *regs)
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int notrace poke_int3_handler(struct pt_regs *regs)
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{
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struct text_poke_loc *tp;
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void *ip;
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@ -1209,10 +1209,15 @@ void text_poke_finish(void)
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text_poke_flush(NULL);
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}
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void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate)
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void __ref text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate)
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{
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struct text_poke_loc *tp;
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if (unlikely(system_state == SYSTEM_BOOTING)) {
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text_poke_early(addr, opcode, len);
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return;
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}
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text_poke_flush(addr);
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tp = &tp_vec[tp_vec_nr++];
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@ -1230,10 +1235,15 @@ void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emu
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* dynamically allocated memory. This function should be used when it is
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* not possible to allocate memory.
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*/
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void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate)
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void __ref text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate)
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{
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struct text_poke_loc tp;
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if (unlikely(system_state == SYSTEM_BOOTING)) {
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text_poke_early(addr, opcode, len);
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return;
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}
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text_poke_loc_init(&tp, addr, opcode, len, emulate);
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text_poke_bp_batch(&tp, 1);
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}
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@ -34,6 +34,8 @@
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#ifdef CONFIG_DYNAMIC_FTRACE
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static int ftrace_poke_late = 0;
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int ftrace_arch_code_modify_prepare(void)
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__acquires(&text_mutex)
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{
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@ -43,16 +45,20 @@ int ftrace_arch_code_modify_prepare(void)
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* ftrace has it set to "read/write".
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*/
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mutex_lock(&text_mutex);
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set_kernel_text_rw();
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set_all_modules_text_rw();
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ftrace_poke_late = 1;
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return 0;
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}
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int ftrace_arch_code_modify_post_process(void)
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__releases(&text_mutex)
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{
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set_all_modules_text_ro();
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set_kernel_text_ro();
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/*
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* ftrace_make_{call,nop}() may be called during
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* module load, and we need to finish the text_poke_queue()
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* that they do, here.
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*/
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text_poke_finish();
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ftrace_poke_late = 0;
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mutex_unlock(&text_mutex);
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return 0;
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}
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@ -60,67 +66,34 @@ int ftrace_arch_code_modify_post_process(void)
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union ftrace_code_union {
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char code[MCOUNT_INSN_SIZE];
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struct {
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unsigned char op;
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char op;
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int offset;
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} __attribute__((packed));
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};
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static int ftrace_calc_offset(long ip, long addr)
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{
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return (int)(addr - ip);
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}
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static unsigned char *
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ftrace_text_replace(unsigned char op, unsigned long ip, unsigned long addr)
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static const char *ftrace_text_replace(char op, unsigned long ip, unsigned long addr)
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{
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static union ftrace_code_union calc;
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calc.op = op;
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calc.offset = ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr);
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calc.op = op;
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calc.offset = (int)(addr - (ip + MCOUNT_INSN_SIZE));
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return calc.code;
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}
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static unsigned char *
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ftrace_call_replace(unsigned long ip, unsigned long addr)
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{
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return ftrace_text_replace(0xe8, ip, addr);
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}
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static inline int
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within(unsigned long addr, unsigned long start, unsigned long end)
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{
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return addr >= start && addr < end;
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}
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static unsigned long text_ip_addr(unsigned long ip)
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{
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/*
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* On x86_64, kernel text mappings are mapped read-only, so we use
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* the kernel identity mapping instead of the kernel text mapping
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* to modify the kernel text.
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*
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* For 32bit kernels, these mappings are same and we can use
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* kernel identity mapping to modify code.
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*/
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if (within(ip, (unsigned long)_text, (unsigned long)_etext))
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ip = (unsigned long)__va(__pa_symbol(ip));
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return ip;
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}
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static const unsigned char *ftrace_nop_replace(void)
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static const char *ftrace_nop_replace(void)
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{
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return ideal_nops[NOP_ATOMIC5];
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}
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static int
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ftrace_modify_code_direct(unsigned long ip, unsigned const char *old_code,
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unsigned const char *new_code)
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static const char *ftrace_call_replace(unsigned long ip, unsigned long addr)
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{
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unsigned char replaced[MCOUNT_INSN_SIZE];
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return ftrace_text_replace(CALL_INSN_OPCODE, ip, addr);
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}
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ftrace_expected = old_code;
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static int ftrace_verify_code(unsigned long ip, const char *old_code)
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{
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char cur_code[MCOUNT_INSN_SIZE];
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/*
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* Note:
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@ -129,31 +102,41 @@ ftrace_modify_code_direct(unsigned long ip, unsigned const char *old_code,
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* Carefully read and modify the code with probe_kernel_*(), and make
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* sure what we read is what we expected it to be before modifying it.
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*/
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/* read the text we want to modify */
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if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
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if (probe_kernel_read(cur_code, (void *)ip, MCOUNT_INSN_SIZE)) {
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WARN_ON(1);
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return -EFAULT;
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}
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/* Make sure it is what we expect it to be */
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if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
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if (memcmp(cur_code, old_code, MCOUNT_INSN_SIZE) != 0) {
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WARN_ON(1);
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return -EINVAL;
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ip = text_ip_addr(ip);
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/* replace the text with the new text */
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if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
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return -EPERM;
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sync_core();
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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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static int
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ftrace_modify_code_direct(unsigned long ip, const char *old_code,
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const char *new_code)
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{
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int ret = ftrace_verify_code(ip, old_code);
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if (ret)
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return ret;
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/* replace the text with the new text */
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if (ftrace_poke_late)
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text_poke_queue((void *)ip, new_code, MCOUNT_INSN_SIZE, NULL);
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else
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text_poke_early((void *)ip, new_code, MCOUNT_INSN_SIZE);
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return 0;
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}
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int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned const char *new, *old;
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unsigned long ip = rec->ip;
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const char *new, *old;
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old = ftrace_call_replace(ip, addr);
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new = ftrace_nop_replace();
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@ -167,19 +150,20 @@ int ftrace_make_nop(struct module *mod,
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* just modify the code directly.
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*/
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if (addr == MCOUNT_ADDR)
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return ftrace_modify_code_direct(rec->ip, old, new);
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return ftrace_modify_code_direct(ip, old, new);
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ftrace_expected = NULL;
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/* Normal cases use add_brk_on_nop */
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/*
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* x86 overrides ftrace_replace_code -- this function will never be used
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* in this case.
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*/
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WARN_ONCE(1, "invalid use of ftrace_make_nop");
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return -EINVAL;
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}
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int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned const char *new, *old;
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unsigned long ip = rec->ip;
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const char *new, *old;
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old = ftrace_nop_replace();
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new = ftrace_call_replace(ip, addr);
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@ -188,43 +172,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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return ftrace_modify_code_direct(rec->ip, old, new);
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}
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/*
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* The modifying_ftrace_code is used to tell the breakpoint
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* handler to call ftrace_int3_handler(). If it fails to
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* call this handler for a breakpoint added by ftrace, then
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* the kernel may crash.
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*
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* As atomic_writes on x86 do not need a barrier, we do not
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* need to add smp_mb()s for this to work. It is also considered
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* that we can not read the modifying_ftrace_code before
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* executing the breakpoint. That would be quite remarkable if
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* it could do that. Here's the flow that is required:
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*
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* CPU-0 CPU-1
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*
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* atomic_inc(mfc);
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* write int3s
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* <trap-int3> // implicit (r)mb
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* if (atomic_read(mfc))
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* call ftrace_int3_handler()
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*
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* Then when we are finished:
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*
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* atomic_dec(mfc);
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*
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* If we hit a breakpoint that was not set by ftrace, it does not
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* matter if ftrace_int3_handler() is called or not. It will
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* simply be ignored. But it is crucial that a ftrace nop/caller
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* breakpoint is handled. No other user should ever place a
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* breakpoint on an ftrace nop/caller location. It must only
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* be done by this code.
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*/
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atomic_t modifying_ftrace_code __read_mostly;
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static int
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ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
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unsigned const char *new_code);
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/*
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* Should never be called:
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* As it is only called by __ftrace_replace_code() which is called by
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@ -237,452 +184,84 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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unsigned long addr)
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{
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WARN_ON(1);
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ftrace_expected = NULL;
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return -EINVAL;
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}
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static unsigned long ftrace_update_func;
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static unsigned long ftrace_update_func_call;
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static int update_ftrace_func(unsigned long ip, void *new)
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{
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unsigned char old[MCOUNT_INSN_SIZE];
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int ret;
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memcpy(old, (void *)ip, MCOUNT_INSN_SIZE);
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ftrace_update_func = ip;
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/* Make sure the breakpoints see the ftrace_update_func update */
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smp_wmb();
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/* See comment above by declaration of modifying_ftrace_code */
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atomic_inc(&modifying_ftrace_code);
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ret = ftrace_modify_code(ip, old, new);
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atomic_dec(&modifying_ftrace_code);
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return ret;
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}
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int ftrace_update_ftrace_func(ftrace_func_t func)
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{
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unsigned long ip = (unsigned long)(&ftrace_call);
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unsigned char *new;
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int ret;
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ftrace_update_func_call = (unsigned long)func;
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new = ftrace_call_replace(ip, (unsigned long)func);
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ret = update_ftrace_func(ip, new);
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/* Also update the regs callback function */
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if (!ret) {
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ip = (unsigned long)(&ftrace_regs_call);
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new = ftrace_call_replace(ip, (unsigned long)func);
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ret = update_ftrace_func(ip, new);
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}
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return ret;
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}
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static nokprobe_inline int is_ftrace_caller(unsigned long ip)
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{
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if (ip == ftrace_update_func)
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return 1;
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return 0;
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}
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/*
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* A breakpoint was added to the code address we are about to
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* modify, and this is the handle that will just skip over it.
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* We are either changing a nop into a trace call, or a trace
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* call to a nop. While the change is taking place, we treat
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* it just like it was a nop.
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*/
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int ftrace_int3_handler(struct pt_regs *regs)
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{
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unsigned long ip;
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const char *new;
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if (WARN_ON_ONCE(!regs))
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return 0;
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ip = (unsigned long)(&ftrace_call);
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new = ftrace_call_replace(ip, (unsigned long)func);
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text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
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ip = regs->ip - INT3_INSN_SIZE;
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if (ftrace_location(ip)) {
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int3_emulate_call(regs, (unsigned long)ftrace_regs_caller);
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return 1;
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} else if (is_ftrace_caller(ip)) {
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if (!ftrace_update_func_call) {
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int3_emulate_jmp(regs, ip + CALL_INSN_SIZE);
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return 1;
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}
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int3_emulate_call(regs, ftrace_update_func_call);
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return 1;
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}
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ip = (unsigned long)(&ftrace_regs_call);
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new = ftrace_call_replace(ip, (unsigned long)func);
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text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
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return 0;
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}
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NOKPROBE_SYMBOL(ftrace_int3_handler);
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static int ftrace_write(unsigned long ip, const char *val, int size)
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{
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ip = text_ip_addr(ip);
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if (probe_kernel_write((void *)ip, val, size))
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return -EPERM;
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return 0;
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}
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static int add_break(unsigned long ip, const char *old)
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{
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unsigned char replaced[MCOUNT_INSN_SIZE];
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unsigned char brk = BREAKPOINT_INSTRUCTION;
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if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
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return -EFAULT;
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ftrace_expected = old;
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/* Make sure it is what we expect it to be */
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if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
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return -EINVAL;
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return ftrace_write(ip, &brk, 1);
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}
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static int add_brk_on_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned const char *old;
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unsigned long ip = rec->ip;
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old = ftrace_call_replace(ip, addr);
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return add_break(rec->ip, old);
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}
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static int add_brk_on_nop(struct dyn_ftrace *rec)
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{
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unsigned const char *old;
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old = ftrace_nop_replace();
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return add_break(rec->ip, old);
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}
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static int add_breakpoints(struct dyn_ftrace *rec, bool enable)
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{
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unsigned long ftrace_addr;
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int ret;
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ftrace_addr = ftrace_get_addr_curr(rec);
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ret = ftrace_test_record(rec, enable);
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switch (ret) {
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case FTRACE_UPDATE_IGNORE:
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return 0;
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case FTRACE_UPDATE_MAKE_CALL:
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/* converting nop to call */
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return add_brk_on_nop(rec);
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|
||||
case FTRACE_UPDATE_MODIFY_CALL:
|
||||
case FTRACE_UPDATE_MAKE_NOP:
|
||||
/* converting a call to a nop */
|
||||
return add_brk_on_call(rec, ftrace_addr);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* On error, we need to remove breakpoints. This needs to
|
||||
* be done caefully. If the address does not currently have a
|
||||
* breakpoint, we know we are done. Otherwise, we look at the
|
||||
* remaining 4 bytes of the instruction. If it matches a nop
|
||||
* we replace the breakpoint with the nop. Otherwise we replace
|
||||
* it with the call instruction.
|
||||
*/
|
||||
static int remove_breakpoint(struct dyn_ftrace *rec)
|
||||
{
|
||||
unsigned char ins[MCOUNT_INSN_SIZE];
|
||||
unsigned char brk = BREAKPOINT_INSTRUCTION;
|
||||
const unsigned char *nop;
|
||||
unsigned long ftrace_addr;
|
||||
unsigned long ip = rec->ip;
|
||||
|
||||
/* If we fail the read, just give up */
|
||||
if (probe_kernel_read(ins, (void *)ip, MCOUNT_INSN_SIZE))
|
||||
return -EFAULT;
|
||||
|
||||
/* If this does not have a breakpoint, we are done */
|
||||
if (ins[0] != brk)
|
||||
return 0;
|
||||
|
||||
nop = ftrace_nop_replace();
|
||||
|
||||
/*
|
||||
* If the last 4 bytes of the instruction do not match
|
||||
* a nop, then we assume that this is a call to ftrace_addr.
|
||||
*/
|
||||
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0) {
|
||||
/*
|
||||
* For extra paranoidism, we check if the breakpoint is on
|
||||
* a call that would actually jump to the ftrace_addr.
|
||||
* If not, don't touch the breakpoint, we make just create
|
||||
* a disaster.
|
||||
*/
|
||||
ftrace_addr = ftrace_get_addr_new(rec);
|
||||
nop = ftrace_call_replace(ip, ftrace_addr);
|
||||
|
||||
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) == 0)
|
||||
goto update;
|
||||
|
||||
/* Check both ftrace_addr and ftrace_old_addr */
|
||||
ftrace_addr = ftrace_get_addr_curr(rec);
|
||||
nop = ftrace_call_replace(ip, ftrace_addr);
|
||||
|
||||
ftrace_expected = nop;
|
||||
|
||||
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0)
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
update:
|
||||
return ftrace_write(ip, nop, 1);
|
||||
}
|
||||
|
||||
static int add_update_code(unsigned long ip, unsigned const char *new)
|
||||
{
|
||||
/* skip breakpoint */
|
||||
ip++;
|
||||
new++;
|
||||
return ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1);
|
||||
}
|
||||
|
||||
static int add_update_call(struct dyn_ftrace *rec, unsigned long addr)
|
||||
{
|
||||
unsigned long ip = rec->ip;
|
||||
unsigned const char *new;
|
||||
|
||||
new = ftrace_call_replace(ip, addr);
|
||||
return add_update_code(ip, new);
|
||||
}
|
||||
|
||||
static int add_update_nop(struct dyn_ftrace *rec)
|
||||
{
|
||||
unsigned long ip = rec->ip;
|
||||
unsigned const char *new;
|
||||
|
||||
new = ftrace_nop_replace();
|
||||
return add_update_code(ip, new);
|
||||
}
|
||||
|
||||
static int add_update(struct dyn_ftrace *rec, bool enable)
|
||||
{
|
||||
unsigned long ftrace_addr;
|
||||
int ret;
|
||||
|
||||
ret = ftrace_test_record(rec, enable);
|
||||
|
||||
ftrace_addr = ftrace_get_addr_new(rec);
|
||||
|
||||
switch (ret) {
|
||||
case FTRACE_UPDATE_IGNORE:
|
||||
return 0;
|
||||
|
||||
case FTRACE_UPDATE_MODIFY_CALL:
|
||||
case FTRACE_UPDATE_MAKE_CALL:
|
||||
/* converting nop to call */
|
||||
return add_update_call(rec, ftrace_addr);
|
||||
|
||||
case FTRACE_UPDATE_MAKE_NOP:
|
||||
/* converting a call to a nop */
|
||||
return add_update_nop(rec);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int finish_update_call(struct dyn_ftrace *rec, unsigned long addr)
|
||||
{
|
||||
unsigned long ip = rec->ip;
|
||||
unsigned const char *new;
|
||||
|
||||
new = ftrace_call_replace(ip, addr);
|
||||
|
||||
return ftrace_write(ip, new, 1);
|
||||
}
|
||||
|
||||
static int finish_update_nop(struct dyn_ftrace *rec)
|
||||
{
|
||||
unsigned long ip = rec->ip;
|
||||
unsigned const char *new;
|
||||
|
||||
new = ftrace_nop_replace();
|
||||
|
||||
return ftrace_write(ip, new, 1);
|
||||
}
|
||||
|
||||
static int finish_update(struct dyn_ftrace *rec, bool enable)
|
||||
{
|
||||
unsigned long ftrace_addr;
|
||||
int ret;
|
||||
|
||||
ret = ftrace_update_record(rec, enable);
|
||||
|
||||
ftrace_addr = ftrace_get_addr_new(rec);
|
||||
|
||||
switch (ret) {
|
||||
case FTRACE_UPDATE_IGNORE:
|
||||
return 0;
|
||||
|
||||
case FTRACE_UPDATE_MODIFY_CALL:
|
||||
case FTRACE_UPDATE_MAKE_CALL:
|
||||
/* converting nop to call */
|
||||
return finish_update_call(rec, ftrace_addr);
|
||||
|
||||
case FTRACE_UPDATE_MAKE_NOP:
|
||||
/* converting a call to a nop */
|
||||
return finish_update_nop(rec);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void do_sync_core(void *data)
|
||||
{
|
||||
sync_core();
|
||||
}
|
||||
|
||||
static void run_sync(void)
|
||||
{
|
||||
int enable_irqs;
|
||||
|
||||
/* No need to sync if there's only one CPU */
|
||||
if (num_online_cpus() == 1)
|
||||
return;
|
||||
|
||||
enable_irqs = irqs_disabled();
|
||||
|
||||
/* We may be called with interrupts disabled (on bootup). */
|
||||
if (enable_irqs)
|
||||
local_irq_enable();
|
||||
on_each_cpu(do_sync_core, NULL, 1);
|
||||
if (enable_irqs)
|
||||
local_irq_disable();
|
||||
}
|
||||
|
||||
void ftrace_replace_code(int enable)
|
||||
{
|
||||
struct ftrace_rec_iter *iter;
|
||||
struct dyn_ftrace *rec;
|
||||
const char *report = "adding breakpoints";
|
||||
int count = 0;
|
||||
const char *new, *old;
|
||||
int ret;
|
||||
|
||||
for_ftrace_rec_iter(iter) {
|
||||
rec = ftrace_rec_iter_record(iter);
|
||||
|
||||
ret = add_breakpoints(rec, enable);
|
||||
if (ret)
|
||||
goto remove_breakpoints;
|
||||
count++;
|
||||
switch (ftrace_test_record(rec, enable)) {
|
||||
case FTRACE_UPDATE_IGNORE:
|
||||
default:
|
||||
continue;
|
||||
|
||||
case FTRACE_UPDATE_MAKE_CALL:
|
||||
old = ftrace_nop_replace();
|
||||
break;
|
||||
|
||||
case FTRACE_UPDATE_MODIFY_CALL:
|
||||
case FTRACE_UPDATE_MAKE_NOP:
|
||||
old = ftrace_call_replace(rec->ip, ftrace_get_addr_curr(rec));
|
||||
break;
|
||||
}
|
||||
|
||||
ret = ftrace_verify_code(rec->ip, old);
|
||||
if (ret) {
|
||||
ftrace_bug(ret, rec);
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
run_sync();
|
||||
|
||||
report = "updating code";
|
||||
count = 0;
|
||||
|
||||
for_ftrace_rec_iter(iter) {
|
||||
rec = ftrace_rec_iter_record(iter);
|
||||
|
||||
ret = add_update(rec, enable);
|
||||
if (ret)
|
||||
goto remove_breakpoints;
|
||||
count++;
|
||||
switch (ftrace_test_record(rec, enable)) {
|
||||
case FTRACE_UPDATE_IGNORE:
|
||||
default:
|
||||
continue;
|
||||
|
||||
case FTRACE_UPDATE_MAKE_CALL:
|
||||
case FTRACE_UPDATE_MODIFY_CALL:
|
||||
new = ftrace_call_replace(rec->ip, ftrace_get_addr_new(rec));
|
||||
break;
|
||||
|
||||
case FTRACE_UPDATE_MAKE_NOP:
|
||||
new = ftrace_nop_replace();
|
||||
break;
|
||||
}
|
||||
|
||||
text_poke_queue((void *)rec->ip, new, MCOUNT_INSN_SIZE, NULL);
|
||||
ftrace_update_record(rec, enable);
|
||||
}
|
||||
|
||||
run_sync();
|
||||
|
||||
report = "removing breakpoints";
|
||||
count = 0;
|
||||
|
||||
for_ftrace_rec_iter(iter) {
|
||||
rec = ftrace_rec_iter_record(iter);
|
||||
|
||||
ret = finish_update(rec, enable);
|
||||
if (ret)
|
||||
goto remove_breakpoints;
|
||||
count++;
|
||||
}
|
||||
|
||||
run_sync();
|
||||
|
||||
return;
|
||||
|
||||
remove_breakpoints:
|
||||
pr_warn("Failed on %s (%d):\n", report, count);
|
||||
ftrace_bug(ret, rec);
|
||||
for_ftrace_rec_iter(iter) {
|
||||
rec = ftrace_rec_iter_record(iter);
|
||||
/*
|
||||
* Breakpoints are handled only when this function is in
|
||||
* progress. The system could not work with them.
|
||||
*/
|
||||
if (remove_breakpoint(rec))
|
||||
BUG();
|
||||
}
|
||||
run_sync();
|
||||
}
|
||||
|
||||
static int
|
||||
ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
|
||||
unsigned const char *new_code)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = add_break(ip, old_code);
|
||||
if (ret)
|
||||
goto out;
|
||||
|
||||
run_sync();
|
||||
|
||||
ret = add_update_code(ip, new_code);
|
||||
if (ret)
|
||||
goto fail_update;
|
||||
|
||||
run_sync();
|
||||
|
||||
ret = ftrace_write(ip, new_code, 1);
|
||||
/*
|
||||
* The breakpoint is handled only when this function is in progress.
|
||||
* The system could not work if we could not remove it.
|
||||
*/
|
||||
BUG_ON(ret);
|
||||
out:
|
||||
run_sync();
|
||||
return ret;
|
||||
|
||||
fail_update:
|
||||
/* Also here the system could not work with the breakpoint */
|
||||
if (ftrace_write(ip, old_code, 1))
|
||||
BUG();
|
||||
goto out;
|
||||
text_poke_finish();
|
||||
}
|
||||
|
||||
void arch_ftrace_update_code(int command)
|
||||
{
|
||||
/* See comment above by declaration of modifying_ftrace_code */
|
||||
atomic_inc(&modifying_ftrace_code);
|
||||
|
||||
ftrace_modify_all_code(command);
|
||||
|
||||
atomic_dec(&modifying_ftrace_code);
|
||||
}
|
||||
|
||||
int __init ftrace_dyn_arch_init(void)
|
||||
@ -747,6 +326,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
|
||||
unsigned long start_offset;
|
||||
unsigned long end_offset;
|
||||
unsigned long op_offset;
|
||||
unsigned long call_offset;
|
||||
unsigned long offset;
|
||||
unsigned long npages;
|
||||
unsigned long size;
|
||||
@ -763,10 +343,12 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
|
||||
start_offset = (unsigned long)ftrace_regs_caller;
|
||||
end_offset = (unsigned long)ftrace_regs_caller_end;
|
||||
op_offset = (unsigned long)ftrace_regs_caller_op_ptr;
|
||||
call_offset = (unsigned long)ftrace_regs_call;
|
||||
} else {
|
||||
start_offset = (unsigned long)ftrace_caller;
|
||||
end_offset = (unsigned long)ftrace_epilogue;
|
||||
op_offset = (unsigned long)ftrace_caller_op_ptr;
|
||||
call_offset = (unsigned long)ftrace_call;
|
||||
}
|
||||
|
||||
size = end_offset - start_offset;
|
||||
@ -823,16 +405,21 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
|
||||
/* put in the new offset to the ftrace_ops */
|
||||
memcpy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
|
||||
|
||||
/* put in the call to the function */
|
||||
mutex_lock(&text_mutex);
|
||||
call_offset -= start_offset;
|
||||
memcpy(trampoline + call_offset,
|
||||
text_gen_insn(CALL_INSN_OPCODE,
|
||||
trampoline + call_offset,
|
||||
ftrace_ops_get_func(ops)), CALL_INSN_SIZE);
|
||||
mutex_unlock(&text_mutex);
|
||||
|
||||
/* ALLOC_TRAMP flags lets us know we created it */
|
||||
ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
|
||||
|
||||
set_vm_flush_reset_perms(trampoline);
|
||||
|
||||
/*
|
||||
* Module allocation needs to be completed by making the page
|
||||
* executable. The page is still writable, which is a security hazard,
|
||||
* but anyhow ftrace breaks W^X completely.
|
||||
*/
|
||||
set_memory_ro((unsigned long)trampoline, npages);
|
||||
set_memory_x((unsigned long)trampoline, npages);
|
||||
return (unsigned long)trampoline;
|
||||
fail:
|
||||
@ -859,43 +446,35 @@ static unsigned long calc_trampoline_call_offset(bool save_regs)
|
||||
void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
|
||||
{
|
||||
ftrace_func_t func;
|
||||
unsigned char *new;
|
||||
unsigned long offset;
|
||||
unsigned long ip;
|
||||
unsigned int size;
|
||||
int ret, npages;
|
||||
const char *new;
|
||||
|
||||
if (ops->trampoline) {
|
||||
/*
|
||||
* The ftrace_ops caller may set up its own trampoline.
|
||||
* In such a case, this code must not modify it.
|
||||
*/
|
||||
if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
|
||||
return;
|
||||
npages = PAGE_ALIGN(ops->trampoline_size) >> PAGE_SHIFT;
|
||||
set_memory_rw(ops->trampoline, npages);
|
||||
} else {
|
||||
if (!ops->trampoline) {
|
||||
ops->trampoline = create_trampoline(ops, &size);
|
||||
if (!ops->trampoline)
|
||||
return;
|
||||
ops->trampoline_size = size;
|
||||
npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
|
||||
return;
|
||||
}
|
||||
|
||||
/*
|
||||
* The ftrace_ops caller may set up its own trampoline.
|
||||
* In such a case, this code must not modify it.
|
||||
*/
|
||||
if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
|
||||
return;
|
||||
|
||||
offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS);
|
||||
ip = ops->trampoline + offset;
|
||||
|
||||
func = ftrace_ops_get_func(ops);
|
||||
|
||||
ftrace_update_func_call = (unsigned long)func;
|
||||
|
||||
mutex_lock(&text_mutex);
|
||||
/* Do a safe modify in case the trampoline is executing */
|
||||
new = ftrace_call_replace(ip, (unsigned long)func);
|
||||
ret = update_ftrace_func(ip, new);
|
||||
set_memory_ro(ops->trampoline, npages);
|
||||
|
||||
/* The update should never fail */
|
||||
WARN_ON(ret);
|
||||
text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
|
||||
mutex_unlock(&text_mutex);
|
||||
}
|
||||
|
||||
/* Return the address of the function the trampoline calls */
|
||||
@ -981,19 +560,18 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
|
||||
#ifdef CONFIG_DYNAMIC_FTRACE
|
||||
extern void ftrace_graph_call(void);
|
||||
|
||||
static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
|
||||
static const char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
|
||||
{
|
||||
return ftrace_text_replace(0xe9, ip, addr);
|
||||
return ftrace_text_replace(JMP32_INSN_OPCODE, ip, addr);
|
||||
}
|
||||
|
||||
static int ftrace_mod_jmp(unsigned long ip, void *func)
|
||||
{
|
||||
unsigned char *new;
|
||||
const char *new;
|
||||
|
||||
ftrace_update_func_call = 0UL;
|
||||
new = ftrace_jmp_replace(ip, (unsigned long)func);
|
||||
|
||||
return update_ftrace_func(ip, new);
|
||||
text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
|
||||
return 0;
|
||||
}
|
||||
|
||||
int ftrace_enable_ftrace_graph_caller(void)
|
||||
@ -1019,10 +597,9 @@ int ftrace_disable_ftrace_graph_caller(void)
|
||||
void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
|
||||
unsigned long frame_pointer)
|
||||
{
|
||||
unsigned long return_hooker = (unsigned long)&return_to_handler;
|
||||
unsigned long old;
|
||||
int faulted;
|
||||
unsigned long return_hooker = (unsigned long)
|
||||
&return_to_handler;
|
||||
|
||||
/*
|
||||
* When resuming from suspend-to-ram, this function can be indirectly
|
||||
|
||||
@ -563,15 +563,6 @@ NOKPROBE_SYMBOL(do_general_protection);
|
||||
|
||||
dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
|
||||
{
|
||||
#ifdef CONFIG_DYNAMIC_FTRACE
|
||||
/*
|
||||
* ftrace must be first, everything else may cause a recursive crash.
|
||||
* See note by declaration of modifying_ftrace_code in ftrace.c
|
||||
*/
|
||||
if (unlikely(atomic_read(&modifying_ftrace_code)) &&
|
||||
ftrace_int3_handler(regs))
|
||||
return;
|
||||
#endif
|
||||
if (poke_int3_handler(regs))
|
||||
return;
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user