// SPDX-License-Identifier: GPL-2.0 #include <linux/spinlock.h> #include <linux/hardirq.h> #include <linux/ftrace.h> #include <linux/percpu.h> #include <linux/init.h> #include <linux/list.h> #include <trace/syscall.h> #include <asm/ftrace.h> #ifdef CONFIG_DYNAMIC_FTRACE static const u32 ftrace_nop = 0x01000000; static u32 ftrace_call_replace(unsigned long ip, unsigned long addr) { u32 call; s32 off; off = ((s32)addr - (s32)ip); call = 0x40000000 | ((u32)off >> 2); return call; } static int ftrace_modify_code(unsigned long ip, u32 old, u32 new) { u32 replaced; int faulted; __asm__ __volatile__( "1: cas [%[ip]], %[old], %[new]\n" " flush %[ip]\n" " mov 0, %[faulted]\n" "2:\n" " .section .fixup,#alloc,#execinstr\n" " .align 4\n" "3: sethi %%hi(2b), %[faulted]\n" " jmpl %[faulted] + %%lo(2b), %%g0\n" " mov 1, %[faulted]\n" " .previous\n" " .section __ex_table,\"a\"\n" " .align 4\n" " .word 1b, 3b\n" " .previous\n" : "=r" (replaced), [faulted] "=r" (faulted) : [new] "0" (new), [old] "r" (old), [ip] "r" (ip) : "memory"); if (replaced != old && replaced != new) faulted = 2; return faulted; } int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { unsigned long ip = rec->ip; u32 old, new; old = ftrace_call_replace(ip, addr); new = ftrace_nop; return ftrace_modify_code(ip, old, new); } int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { unsigned long ip = rec->ip; u32 old, new; old = ftrace_nop; new = ftrace_call_replace(ip, addr); return ftrace_modify_code(ip, old, new); } int ftrace_update_ftrace_func(ftrace_func_t func) { unsigned long ip = (unsigned long)(&ftrace_call); u32 old, new; old = *(u32 *) &ftrace_call; new = ftrace_call_replace(ip, (unsigned long)func); return ftrace_modify_code(ip, old, new); } int __init ftrace_dyn_arch_init(void) { return 0; } #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER #ifdef CONFIG_DYNAMIC_FTRACE extern void ftrace_graph_call(void); int ftrace_enable_ftrace_graph_caller(void) { unsigned long ip = (unsigned long)(&ftrace_graph_call); u32 old, new; old = *(u32 *) &ftrace_graph_call; new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller); return ftrace_modify_code(ip, old, new); } int ftrace_disable_ftrace_graph_caller(void) { unsigned long ip = (unsigned long)(&ftrace_graph_call); u32 old, new; old = *(u32 *) &ftrace_graph_call; new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub); return ftrace_modify_code(ip, old, new); } #endif /* !CONFIG_DYNAMIC_FTRACE */ /* * Hook the return address and push it in the stack of return addrs * in current thread info. */ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long self_addr, unsigned long frame_pointer) { unsigned long return_hooker = (unsigned long) &return_to_handler; if (unlikely(atomic_read(¤t->tracing_graph_pause))) return parent + 8UL; if (function_graph_enter(parent, self_addr, frame_pointer, NULL)) return parent + 8UL; return return_hooker; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */