diff options
Diffstat (limited to 'arch/powerpc/kernel/ftrace.c')
| -rw-r--r-- | arch/powerpc/kernel/ftrace.c | 619 |
1 files changed, 0 insertions, 619 deletions
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c deleted file mode 100644 index 5c9f50c1aa99..000000000000 --- a/arch/powerpc/kernel/ftrace.c +++ /dev/null @@ -1,619 +0,0 @@ -/* - * Code for replacing ftrace calls with jumps. - * - * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> - * - * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. - * - * Added function graph tracer code, taken from x86 that was written - * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. - * - */ - -#define pr_fmt(fmt) "ftrace-powerpc: " fmt - -#include <linux/spinlock.h> -#include <linux/hardirq.h> -#include <linux/uaccess.h> -#include <linux/module.h> -#include <linux/ftrace.h> -#include <linux/percpu.h> -#include <linux/init.h> -#include <linux/list.h> - -#include <asm/cacheflush.h> -#include <asm/code-patching.h> -#include <asm/ftrace.h> -#include <asm/syscall.h> - - -#ifdef CONFIG_DYNAMIC_FTRACE -static unsigned int -ftrace_call_replace(unsigned long ip, unsigned long addr, int link) -{ - unsigned int op; - - addr = ppc_function_entry((void *)addr); - - /* if (link) set op to 'bl' else 'b' */ - op = create_branch((unsigned int *)ip, addr, link ? 1 : 0); - - return op; -} - -static int -ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new) -{ - unsigned int replaced; - - /* - * Note: - * We are paranoid about modifying text, as if a bug was to happen, it - * could cause us to read or write to someplace that could cause harm. - * Carefully read and modify the code with probe_kernel_*(), and make - * sure what we read is what we expected it to be before modifying it. - */ - - /* read the text we want to modify */ - if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE)) - return -EFAULT; - - /* Make sure it is what we expect it to be */ - if (replaced != old) { - pr_err("%p: replaced (%#x) != old (%#x)", - (void *)ip, replaced, old); - return -EINVAL; - } - - /* replace the text with the new text */ - if (patch_instruction((unsigned int *)ip, new)) - return -EPERM; - - return 0; -} - -/* - * Helper functions that are the same for both PPC64 and PPC32. - */ -static int test_24bit_addr(unsigned long ip, unsigned long addr) -{ - addr = ppc_function_entry((void *)addr); - - /* use the create_branch to verify that this offset can be branched */ - return create_branch((unsigned int *)ip, addr, 0); -} - -#ifdef CONFIG_MODULES - -static int is_bl_op(unsigned int op) -{ - return (op & 0xfc000003) == 0x48000001; -} - -static unsigned long find_bl_target(unsigned long ip, unsigned int op) -{ - static int offset; - - offset = (op & 0x03fffffc); - /* make it signed */ - if (offset & 0x02000000) - offset |= 0xfe000000; - - return ip + (long)offset; -} - -#ifdef CONFIG_PPC64 -static int -__ftrace_make_nop(struct module *mod, - struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long entry, ptr, tramp; - unsigned long ip = rec->ip; - unsigned int op, pop; - - /* read where this goes */ - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %x\n", op); - return -EINVAL; - } - - /* lets find where the pointer goes */ - tramp = find_bl_target(ip, op); - - pr_devel("ip:%lx jumps to %lx", ip, 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; - } - -#ifdef CC_USING_MPROFILE_KERNEL - /* When using -mkernel_profile there is no load to jump over */ - pop = PPC_INST_NOP; - - if (probe_kernel_read(&op, (void *)(ip - 4), 4)) { - pr_err("Fetching instruction at %lx failed.\n", ip - 4); - return -EFAULT; - } - - /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */ - if (op != PPC_INST_MFLR && op != PPC_INST_STD_LR) { - pr_err("Unexpected instruction %08x around bl _mcount\n", op); - return -EINVAL; - } -#else - /* - * Our original call site looks like: - * - * bl <tramp> - * ld r2,XX(r1) - * - * Milton Miller pointed out that we can not simply nop the branch. - * If a task was preempted when calling a trace function, the nops - * will remove the way to restore the TOC in r2 and the r2 TOC will - * get corrupted. - * - * Use a b +8 to jump over the load. - */ - - pop = PPC_INST_BRANCH | 8; /* b +8 */ - - /* - * Check what is in the next instruction. We can see ld r2,40(r1), but - * on first pass after boot we will see mflr r0. - */ - if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) { - pr_err("Fetching op failed.\n"); - return -EFAULT; - } - - if (op != PPC_INST_LD_TOC) { - pr_err("Expected %08x found %08x\n", PPC_INST_LD_TOC, op); - return -EINVAL; - } -#endif /* CC_USING_MPROFILE_KERNEL */ - - if (patch_instruction((unsigned int *)ip, pop)) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } - - return 0; -} - -#else /* !PPC64 */ -static int -__ftrace_make_nop(struct module *mod, - struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned int op; - unsigned int jmp[4]; - unsigned long ip = rec->ip; - unsigned long tramp; - - if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) - return -EFAULT; - - /* Make sure that that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %x\n", op); - return -EINVAL; - } - - /* lets find where the pointer goes */ - tramp = find_bl_target(ip, op); - - /* - * On PPC32 the trampoline looks like: - * 0x3d, 0x80, 0x00, 0x00 lis r12,sym@ha - * 0x39, 0x8c, 0x00, 0x00 addi r12,r12,sym@l - * 0x7d, 0x89, 0x03, 0xa6 mtctr r12 - * 0x4e, 0x80, 0x04, 0x20 bctr - */ - - pr_devel("ip:%lx jumps to %lx", ip, tramp); - - /* Find where the trampoline jumps to */ - if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { - pr_err("Failed to read %lx\n", tramp); - return -EFAULT; - } - - pr_devel(" %08x %08x ", jmp[0], jmp[1]); - - /* verify that this is what we expect it to be */ - if (((jmp[0] & 0xffff0000) != 0x3d800000) || - ((jmp[1] & 0xffff0000) != 0x398c0000) || - (jmp[2] != 0x7d8903a6) || - (jmp[3] != 0x4e800420)) { - pr_err("Not a trampoline\n"); - return -EINVAL; - } - - tramp = (jmp[1] & 0xffff) | - ((jmp[0] & 0xffff) << 16); - if (tramp & 0x8000) - tramp -= 0x10000; - - pr_devel(" %lx ", tramp); - - if (tramp != addr) { - pr_err("Trampoline location %08lx does not match addr\n", - tramp); - return -EINVAL; - } - - op = PPC_INST_NOP; - - if (patch_instruction((unsigned int *)ip, op)) - return -EPERM; - - return 0; -} -#endif /* PPC64 */ -#endif /* CONFIG_MODULES */ - -int ftrace_make_nop(struct module *mod, - struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long ip = rec->ip; - unsigned int old, new; - - /* - * If the calling address is more that 24 bits away, - * then we had to use a trampoline to make the call. - * Otherwise just update the call site. - */ - if (test_24bit_addr(ip, addr)) { - /* within range */ - old = ftrace_call_replace(ip, addr, 1); - new = PPC_INST_NOP; - return ftrace_modify_code(ip, old, new); - } - -#ifdef CONFIG_MODULES - /* - * Out of range jumps are called from modules. - * We should either already have a pointer to the module - * or it has been passed in. - */ - if (!rec->arch.mod) { - if (!mod) { - pr_err("No module loaded addr=%lx\n", addr); - return -EFAULT; - } - rec->arch.mod = mod; - } else if (mod) { - if (mod != rec->arch.mod) { - pr_err("Record mod %p not equal to passed in mod %p\n", - rec->arch.mod, mod); - return -EINVAL; - } - /* nothing to do if mod == rec->arch.mod */ - } else - mod = rec->arch.mod; - - return __ftrace_make_nop(mod, rec, addr); -#else - /* We should not get here without modules */ - return -EINVAL; -#endif /* CONFIG_MODULES */ -} - -#ifdef CONFIG_MODULES -#ifdef CONFIG_PPC64 -/* - * Examine the existing instructions for __ftrace_make_call. - * They should effectively be a NOP, and follow formal constraints, - * depending on the ABI. Return false if they don't. - */ -#ifndef CC_USING_MPROFILE_KERNEL -static int -expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1) -{ - /* - * We expect to see: - * - * b +8 - * ld r2,XX(r1) - * - * The load offset is different depending on the ABI. For simplicity - * just mask it out when doing the compare. - */ - if ((op0 != 0x48000008) || ((op1 & 0xffff0000) != 0xe8410000)) - return 0; - return 1; -} -#else -static int -expected_nop_sequence(void *ip, unsigned int op0, unsigned int op1) -{ - /* look for patched "NOP" on ppc64 with -mprofile-kernel */ - if (op0 != PPC_INST_NOP) - return 0; - return 1; -} -#endif - -static int -__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned int op[2]; - void *ip = (void *)rec->ip; - - /* read where this goes */ - if (probe_kernel_read(op, ip, sizeof(op))) - return -EFAULT; - - if (!expected_nop_sequence(ip, op[0], op[1])) { - pr_err("Unexpected call sequence at %p: %x %x\n", - ip, op[0], op[1]); - return -EINVAL; - } - - /* If we never set up a trampoline to ftrace_caller, then bail */ - if (!rec->arch.mod->arch.tramp) { - pr_err("No ftrace trampoline\n"); - return -EINVAL; - } - - /* Ensure branch is within 24 bits */ - if (!create_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) { - pr_err("Branch out of range\n"); - return -EINVAL; - } - - if (patch_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; -} - -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS -int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, - unsigned long addr) -{ - return ftrace_make_call(rec, addr); -} -#endif - -#else /* !CONFIG_PPC64: */ -static int -__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned int op; - unsigned long ip = rec->ip; - - /* read where this goes */ - if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) - return -EFAULT; - - /* It should be pointing to a nop */ - if (op != PPC_INST_NOP) { - pr_err("Expected NOP but have %x\n", op); - return -EINVAL; - } - - /* If we never set up a trampoline to ftrace_caller, then bail */ - if (!rec->arch.mod->arch.tramp) { - pr_err("No ftrace trampoline\n"); - return -EINVAL; - } - - /* create the branch to the trampoline */ - op = create_branch((unsigned int *)ip, - rec->arch.mod->arch.tramp, BRANCH_SET_LINK); - if (!op) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - pr_devel("write to %lx\n", rec->ip); - - if (patch_instruction((unsigned int *)ip, op)) - return -EPERM; - - return 0; -} -#endif /* CONFIG_PPC64 */ -#endif /* CONFIG_MODULES */ - -int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - unsigned long ip = rec->ip; - unsigned int old, new; - - /* - * If the calling address is more that 24 bits away, - * then we had to use a trampoline to make the call. - * Otherwise just update the call site. - */ - if (test_24bit_addr(ip, addr)) { - /* within range */ - old = PPC_INST_NOP; - new = ftrace_call_replace(ip, addr, 1); - return ftrace_modify_code(ip, old, new); - } - -#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 */ -} - -int ftrace_update_ftrace_func(ftrace_func_t func) -{ - unsigned long ip = (unsigned long)(&ftrace_call); - unsigned int old, new; - int ret; - - old = *(unsigned int *)&ftrace_call; - new = ftrace_call_replace(ip, (unsigned long)func, 1); - ret = ftrace_modify_code(ip, old, new); - - return ret; -} - -static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) -{ - unsigned long ftrace_addr = (unsigned long)FTRACE_ADDR; - int ret; - - ret = ftrace_update_record(rec, enable); - - switch (ret) { - case FTRACE_UPDATE_IGNORE: - return 0; - case FTRACE_UPDATE_MAKE_CALL: - return ftrace_make_call(rec, ftrace_addr); - case FTRACE_UPDATE_MAKE_NOP: - return ftrace_make_nop(NULL, rec, ftrace_addr); - } - - return 0; -} - -void ftrace_replace_code(int enable) -{ - struct ftrace_rec_iter *iter; - struct dyn_ftrace *rec; - int ret; - - for (iter = ftrace_rec_iter_start(); iter; - iter = ftrace_rec_iter_next(iter)) { - rec = ftrace_rec_iter_record(iter); - ret = __ftrace_replace_code(rec, enable); - if (ret) { - ftrace_bug(ret, rec); - return; - } - } -} - -/* - * Use the default ftrace_modify_all_code, but without - * stop_machine(). - */ -void arch_ftrace_update_code(int command) -{ - ftrace_modify_all_code(command); -} - -int __init ftrace_dyn_arch_init(void) -{ - return 0; -} -#endif /* CONFIG_DYNAMIC_FTRACE */ - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - -#ifdef CONFIG_DYNAMIC_FTRACE -extern void ftrace_graph_call(void); -extern void ftrace_graph_stub(void); - -int ftrace_enable_ftrace_graph_caller(void) -{ - unsigned long ip = (unsigned long)(&ftrace_graph_call); - unsigned long addr = (unsigned long)(&ftrace_graph_caller); - unsigned long stub = (unsigned long)(&ftrace_graph_stub); - unsigned int old, new; - - old = ftrace_call_replace(ip, stub, 0); - new = ftrace_call_replace(ip, addr, 0); - - return ftrace_modify_code(ip, old, new); -} - -int ftrace_disable_ftrace_graph_caller(void) -{ - unsigned long ip = (unsigned long)(&ftrace_graph_call); - unsigned long addr = (unsigned long)(&ftrace_graph_caller); - unsigned long stub = (unsigned long)(&ftrace_graph_stub); - unsigned int old, new; - - old = ftrace_call_replace(ip, addr, 0); - new = ftrace_call_replace(ip, stub, 0); - - return ftrace_modify_code(ip, old, new); -} -#endif /* CONFIG_DYNAMIC_FTRACE */ - -/* - * 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) -{ - struct ftrace_graph_ent trace; - 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); - - trace.func = ip; - trace.depth = current->curr_ret_stack + 1; - - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) - goto out; - - if (ftrace_push_return_trace(parent, ip, &trace.depth, 0, - NULL) == -EBUSY) - goto out; - - parent = return_hooker; -out: - return parent; -} -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) -unsigned long __init arch_syscall_addr(int nr) -{ - return sys_call_table[nr*2]; -} -#endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 */ - -#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 */ |