diff options
Diffstat (limited to 'arch/powerpc/kernel/trace/ftrace.c')
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace.c | 998 |
1 files changed, 998 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c new file mode 100644 index 000000000..d24aea4fe --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -0,0 +1,998 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/asm-prototypes.h> +#include <asm/cacheflush.h> +#include <asm/code-patching.h> +#include <asm/ftrace.h> +#include <asm/syscall.h> +#include <asm/inst.h> + + +#ifdef CONFIG_DYNAMIC_FTRACE + +/* + * We generally only have a single long_branch tramp and at most 2 or 3 plt + * tramps generated. But, we don't use the plt tramps currently. We also allot + * 2 tramps after .text and .init.text. So, we only end up with around 3 usable + * tramps in total. Set aside 8 just to be sure. + */ +#define NUM_FTRACE_TRAMPS 8 +static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; + +static struct ppc_inst +ftrace_call_replace(unsigned long ip, unsigned long addr, int link) +{ + struct ppc_inst op; + + addr = ppc_function_entry((void *)addr); + + /* if (link) set op to 'bl' else 'b' */ + create_branch(&op, (struct ppc_inst *)ip, addr, link ? 1 : 0); + + return op; +} + +static int +ftrace_modify_code(unsigned long ip, struct ppc_inst old, struct ppc_inst new) +{ + struct ppc_inst 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_inst(&replaced, (void *)ip)) + return -EFAULT; + + /* Make sure it is what we expect it to be */ + if (!ppc_inst_equal(replaced, old)) { + pr_err("%p: replaced (%s) != old (%s)", + (void *)ip, ppc_inst_as_str(replaced), ppc_inst_as_str(old)); + return -EINVAL; + } + + /* replace the text with the new text */ + if (patch_instruction((struct ppc_inst *)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) +{ + struct ppc_inst op; + addr = ppc_function_entry((void *)addr); + + /* use the create_branch to verify that this offset can be branched */ + return create_branch(&op, (struct ppc_inst *)ip, addr, 0) == 0; +} + +static int is_bl_op(struct ppc_inst op) +{ + return (ppc_inst_val(op) & 0xfc000003) == 0x48000001; +} + +static int is_b_op(struct ppc_inst op) +{ + return (ppc_inst_val(op) & 0xfc000003) == 0x48000000; +} + +static unsigned long find_bl_target(unsigned long ip, struct ppc_inst op) +{ + int offset; + + offset = (ppc_inst_val(op) & 0x03fffffc); + /* make it signed */ + if (offset & 0x02000000) + offset |= 0xfe000000; + + return ip + (long)offset; +} + +#ifdef CONFIG_MODULES +#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; + struct ppc_inst op, pop; + + /* 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); + + 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 CONFIG_MPROFILE_KERNEL + /* When using -mkernel_profile there is no load to jump over */ + pop = ppc_inst(PPC_INST_NOP); + + if (probe_kernel_read_inst(&op, (void *)(ip - 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 (!ppc_inst_equal(op, ppc_inst(PPC_INST_MFLR)) && + !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { + pr_err("Unexpected instruction %s around bl _mcount\n", + ppc_inst_as_str(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(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_inst(&op, (void *)(ip + 4))) { + pr_err("Fetching op failed.\n"); + return -EFAULT; + } + + if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) { + pr_err("Expected %08x found %s\n", PPC_INST_LD_TOC, ppc_inst_as_str(op)); + return -EINVAL; + } +#endif /* CONFIG_MPROFILE_KERNEL */ + + if (patch_instruction((struct ppc_inst *)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) +{ + struct ppc_inst op; + unsigned int jmp[4]; + unsigned long ip = rec->ip; + unsigned long tramp; + + if (copy_from_kernel_nofault(&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 %s\n", ppc_inst_as_str(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 (copy_from_kernel_nofault(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(PPC_INST_NOP); + + if (patch_instruction((struct ppc_inst *)ip, op)) + return -EPERM; + + return 0; +} +#endif /* PPC64 */ +#endif /* CONFIG_MODULES */ + +static unsigned long find_ftrace_tramp(unsigned long ip) +{ + int i; + struct ppc_inst instr; + + /* + * We have the compiler generated long_branch tramps at the end + * and we prefer those + */ + for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) + if (!ftrace_tramps[i]) + continue; + else if (create_branch(&instr, (void *)ip, + ftrace_tramps[i], 0) == 0) + return ftrace_tramps[i]; + + return 0; +} + +static int add_ftrace_tramp(unsigned long tramp) +{ + int i; + + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (!ftrace_tramps[i]) { + ftrace_tramps[i] = tramp; + return 0; + } + + return -1; +} + +/* + * If this is a compiler generated long_branch trampoline (essentially, a + * trampoline that has a branch to _mcount()), we re-write the branch to + * instead go to ftrace_[regs_]caller() and note down the location of this + * trampoline. + */ +static int setup_mcount_compiler_tramp(unsigned long tramp) +{ + int i; + struct ppc_inst op; + unsigned long ptr; + struct ppc_inst instr; + static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS]; + + /* Is this a known long jump tramp? */ + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (ftrace_tramps[i] == tramp) + return 0; + + /* Is this a known plt tramp? */ + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (!ftrace_plt_tramps[i]) + break; + else if (ftrace_plt_tramps[i] == tramp) + return -1; + + /* New trampoline -- read where this goes */ + if (probe_kernel_read_inst(&op, (void *)tramp)) { + pr_debug("Fetching opcode failed.\n"); + return -1; + } + + /* Is this a 24 bit branch? */ + if (!is_b_op(op)) { + pr_debug("Trampoline is not a long branch tramp.\n"); + return -1; + } + + /* lets find where the pointer goes */ + ptr = find_bl_target(tramp, op); + + if (ptr != ppc_global_function_entry((void *)_mcount)) { + pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr); + return -1; + } + + /* Let's re-write the tramp to go to ftrace_[regs_]caller */ +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + ptr = ppc_global_function_entry((void *)ftrace_regs_caller); +#else + ptr = ppc_global_function_entry((void *)ftrace_caller); +#endif + if (create_branch(&instr, (void *)tramp, ptr, 0)) { + pr_debug("%ps is not reachable from existing mcount tramp\n", + (void *)ptr); + return -1; + } + + if (patch_branch((struct ppc_inst *)tramp, ptr, 0)) { + pr_debug("REL24 out of range!\n"); + return -1; + } + + if (add_ftrace_tramp(tramp)) { + pr_debug("No tramp locations left\n"); + return -1; + } + + return 0; +} + +static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned long tramp, ip = rec->ip; + struct ppc_inst op; + + /* 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; + } + + /* Let's find where the pointer goes */ + tramp = find_bl_target(ip, op); + + pr_devel("ip:%lx jumps to %lx", ip, tramp); + + if (setup_mcount_compiler_tramp(tramp)) { + /* Are other trampolines reachable? */ + if (!find_ftrace_tramp(ip)) { + pr_err("No ftrace trampolines reachable from %ps\n", + (void *)ip); + return -EINVAL; + } + } + + if (patch_instruction((struct ppc_inst *)ip, ppc_inst(PPC_INST_NOP))) { + pr_err("Patching NOP failed.\n"); + return -EPERM; + } + + return 0; +} + +int ftrace_make_nop(struct module *mod, + 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 = ftrace_call_replace(ip, addr, 1); + new = ppc_inst(PPC_INST_NOP); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) + return __ftrace_make_nop_kernel(rec, addr); + +#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 CONFIG_MPROFILE_KERNEL +static int +expected_nop_sequence(void *ip, struct ppc_inst op0, struct ppc_inst 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 (!ppc_inst_equal(op0, ppc_inst(0x48000008)) || + (ppc_inst_val(op1) & 0xffff0000) != 0xe8410000) + return 0; + return 1; +} +#else +static int +expected_nop_sequence(void *ip, struct ppc_inst op0, struct ppc_inst op1) +{ + /* look for patched "NOP" on ppc64 with -mprofile-kernel */ + if (!ppc_inst_equal(op0, ppc_inst(PPC_INST_NOP))) + return 0; + return 1; +} +#endif + +static int +__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + struct ppc_inst op[2]; + struct ppc_inst instr; + void *ip = (void *)rec->ip; + unsigned long entry, ptr, tramp; + struct module *mod = rec->arch.mod; + + /* read where this goes */ + if (probe_kernel_read_inst(op, ip)) + return -EFAULT; + + if (probe_kernel_read_inst(op + 1, ip + 4)) + return -EFAULT; + + if (!expected_nop_sequence(ip, op[0], op[1])) { + pr_err("Unexpected call sequence at %p: %s %s\n", + ip, ppc_inst_as_str(op[0]), ppc_inst_as_str(op[1])); + return -EINVAL; + } + + /* If we never set up ftrace trampoline(s), then bail */ +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + if (!mod->arch.tramp || !mod->arch.tramp_regs) { +#else + if (!mod->arch.tramp) { +#endif + pr_err("No ftrace trampoline\n"); + return -EINVAL; + } + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + if (rec->flags & FTRACE_FL_REGS) + tramp = mod->arch.tramp_regs; + else +#endif + tramp = mod->arch.tramp; + + if (module_trampoline_target(mod, tramp, &ptr)) { + pr_err("Failed to get trampoline target\n"); + return -EFAULT; + } + + pr_devel("trampoline target %lx", ptr); + + entry = ppc_global_function_entry((void *)addr); + /* This should match what was called */ + if (ptr != entry) { + pr_err("addr %lx does not match expected %lx\n", ptr, entry); + return -EINVAL; + } + + /* Ensure branch is within 24 bits */ + if (create_branch(&instr, ip, tramp, BRANCH_SET_LINK)) { + pr_err("Branch out of range\n"); + return -EINVAL; + } + + if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { + pr_err("REL24 out of range!\n"); + return -EINVAL; + } + + return 0; +} + +#else /* !CONFIG_PPC64: */ +static int +__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + int err; + 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[]; + +void ftrace_free_init_tramp(void) +{ + int i; + + for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++) + if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) { + ftrace_tramps[i] = 0; + return; + } +} + +int __init ftrace_dyn_arch_init(void) +{ + int i; + unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; + u32 stub_insns[] = { + 0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */ + 0x3d8c0000, /* addis r12,r12,<high> */ + 0x398c0000, /* addi r12,r12,<low> */ + 0x7d8903a6, /* mtctr r12 */ + 0x4e800420, /* bctr */ + }; +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + unsigned long addr = ppc_global_function_entry((void *)ftrace_regs_caller); +#else + unsigned long addr = ppc_global_function_entry((void *)ftrace_caller); +#endif + long reladdr = addr - kernel_toc_addr(); + + if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { + pr_err("Address of %ps out of range of kernel_toc.\n", + (void *)addr); + return -1; + } + + for (i = 0; i < 2; i++) { + memcpy(tramp[i], stub_insns, sizeof(stub_insns)); + tramp[i][1] |= PPC_HA(reladdr); + tramp[i][2] |= PPC_LO(reladdr); + add_ftrace_tramp((unsigned long)tramp[i]); + } + + return 0; +} +#else +int __init ftrace_dyn_arch_init(void) +{ + return 0; +} +#endif +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + +extern void ftrace_graph_call(void); +extern void ftrace_graph_stub(void); + +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 */ |