diff options
Diffstat (limited to 'arch/powerpc/kernel/trace')
| -rw-r--r-- | arch/powerpc/kernel/trace/Makefile | 12 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace.c | 858 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_64_pg.S | 67 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_64_pg.c | 846 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_64_pg_entry.S (renamed from arch/powerpc/kernel/trace/ftrace_low.S) | 66 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_entry.S (renamed from arch/powerpc/kernel/trace/ftrace_mprofile.S) | 69 |
6 files changed, 1189 insertions, 729 deletions
diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile index b16a9f9c0b35..125f4ca588b9 100644 --- a/arch/powerpc/kernel/trace/Makefile +++ b/arch/powerpc/kernel/trace/Makefile @@ -6,15 +6,15 @@ ifdef CONFIG_FUNCTION_TRACER # do not trace tracer code CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_ftrace_64_pg.o = $(CC_FLAGS_FTRACE) endif -obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o +obj32-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o ifdef CONFIG_MPROFILE_KERNEL -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o else -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_64_pg_entry.o endif -obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o ftrace.o obj-$(CONFIG_TRACING) += trace_clock.o obj-$(CONFIG_PPC64) += $(obj64-y) @@ -25,3 +25,7 @@ GCOV_PROFILE_ftrace.o := n KCOV_INSTRUMENT_ftrace.o := n KCSAN_SANITIZE_ftrace.o := n UBSAN_SANITIZE_ftrace.o := n +GCOV_PROFILE_ftrace_64_pg.o := n +KCOV_INSTRUMENT_ftrace_64_pg.o := n +KCSAN_SANITIZE_ftrace_64_pg.o := n +UBSAN_SANITIZE_ftrace_64_pg.o := n diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index a47f30373423..82010629cf88 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -28,203 +28,64 @@ #include <asm/syscall.h> #include <asm/inst.h> -/* - * 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 +#define NUM_FTRACE_TRAMPS 2 static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; -static ppc_inst_t -ftrace_call_replace(unsigned long ip, unsigned long addr, int link) +static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link) { ppc_inst_t op; - addr = ppc_function_entry((void *)addr); - - /* if (link) set op to 'bl' else 'b' */ + WARN_ON(!is_offset_in_branch_range(addr - ip)); create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); return op; } -static inline int -ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) +static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op) { - ppc_inst_t 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 (copy_inst_from_kernel_nofault(&replaced, (void *)ip)) + if (copy_inst_from_kernel_nofault(op, (void *)ip)) { + pr_err("0x%lx: fetching instruction failed\n", ip); return -EFAULT; - - /* Make sure it is what we expect it to be */ - if (!ppc_inst_equal(replaced, old)) { - pr_err("%p: replaced (%08lx) != old (%08lx)", (void *)ip, - ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old)); - return -EINVAL; } - /* replace the text with the new text */ - return patch_instruction((u32 *)ip, new); + return 0; } -/* - * Helper functions that are the same for both PPC64 and PPC32. - */ -static int test_24bit_addr(unsigned long ip, unsigned long addr) +static inline int ftrace_validate_inst(unsigned long ip, ppc_inst_t inst) { - addr = ppc_function_entry((void *)addr); - - return is_offset_in_branch_range(addr - ip); -} + ppc_inst_t op; + int ret; -static int is_bl_op(ppc_inst_t op) -{ - return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); -} + ret = ftrace_read_inst(ip, &op); + if (!ret && !ppc_inst_equal(op, inst)) { + pr_err("0x%lx: expected (%08lx) != found (%08lx)\n", + ip, ppc_inst_as_ulong(inst), ppc_inst_as_ulong(op)); + ret = -EINVAL; + } -static int is_b_op(ppc_inst_t op) -{ - return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0); + return ret; } -static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) +static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) { - int offset; + int ret = ftrace_validate_inst(ip, old); - offset = PPC_LI(ppc_inst_val(op)); - /* make it signed */ - if (offset & 0x02000000) - offset |= 0xfe000000; + if (!ret) + ret = patch_instruction((u32 *)ip, new); - return ip + (long)offset; + return ret; } -#ifdef CONFIG_MODULES -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; - ppc_inst_t op, pop; - - /* read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(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; - } - - if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { - if (copy_inst_from_kernel_nofault(&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_RAW_MFLR(_R0))) && - !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { - pr_err("Unexpected instruction %08lx around bl _mcount\n", - ppc_inst_as_ulong(op)); - return -EINVAL; - } - } else if (IS_ENABLED(CONFIG_PPC64)) { - /* - * 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 (copy_inst_from_kernel_nofault(&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 %08lx found %08lx\n", PPC_INST_LD_TOC, - ppc_inst_as_ulong(op)); - return -EINVAL; - } - } - - /* - * When using -mprofile-kernel or PPC32 there is no load to jump over. - * - * Otherwise 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. - * XXX: could make PCREL depend on MPROFILE_KERNEL - * XXX: check PCREL && MPROFILE_KERNEL calling sequence - */ - if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32)) - pop = ppc_inst(PPC_RAW_NOP()); - else - pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */ - - if (patch_instruction((u32 *)ip, pop)) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } - - return 0; -} -#else -static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) +static int is_bl_op(ppc_inst_t op) { - return 0; + return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); } -#endif /* CONFIG_MODULES */ static unsigned long find_ftrace_tramp(unsigned long ip) { int i; - /* - * We have the compiler generated long_branch tramps at the end - * and we prefer those - */ - for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) if (!ftrace_tramps[i]) continue; else if (is_offset_in_branch_range(ftrace_tramps[i] - ip)) @@ -233,449 +94,195 @@ static unsigned long find_ftrace_tramp(unsigned long ip) return 0; } -static int add_ftrace_tramp(unsigned long tramp) +static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst) { - int i; + unsigned long ip = rec->ip; + unsigned long stub; - for (i = 0; i < NUM_FTRACE_TRAMPS; i++) - if (!ftrace_tramps[i]) { - ftrace_tramps[i] = tramp; - return 0; + if (is_offset_in_branch_range(addr - ip)) { + /* Within range */ + stub = addr; +#ifdef CONFIG_MODULES + } else if (rec->arch.mod) { + /* Module code would be going to one of the module stubs */ + stub = (addr == (unsigned long)ftrace_caller ? rec->arch.mod->arch.tramp : + rec->arch.mod->arch.tramp_regs); +#endif + } else if (core_kernel_text(ip)) { + /* We would be branching to one of our ftrace stubs */ + stub = find_ftrace_tramp(ip); + if (!stub) { + pr_err("0x%lx: No ftrace stubs reachable\n", ip); + return -EINVAL; } - - 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; - ppc_inst_t op; - unsigned long ptr; - - /* Is this a known long jump tramp? */ - for (i = 0; i < NUM_FTRACE_TRAMPS; i++) - if (ftrace_tramps[i] == tramp) - return 0; - - /* New trampoline -- read where this goes */ - if (copy_inst_from_kernel_nofault(&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 */ - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - ptr = ppc_global_function_entry((void *)ftrace_regs_caller); - else - ptr = ppc_global_function_entry((void *)ftrace_caller); - - if (patch_branch((u32 *)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; + } else { + return -EINVAL; } + *call_inst = ftrace_create_branch_inst(ip, stub, 1); return 0; } -static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { - unsigned long tramp, ip = rec->ip; - ppc_inst_t op; - - /* Read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(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((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } - - return 0; + /* This should never be called since we override ftrace_replace_code() */ + WARN_ON(1); + return -EINVAL; } +#endif -int ftrace_make_nop(struct module *mod, - struct dyn_ftrace *rec, unsigned long addr) +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { - unsigned long ip = rec->ip; ppc_inst_t old, new; + int ret; - /* - * 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_RAW_NOP()); - return ftrace_modify_code(ip, old, new); - } else if (core_kernel_text(ip)) { - return __ftrace_make_nop_kernel(rec, addr); - } else if (!IS_ENABLED(CONFIG_MODULES)) { + /* This can only ever be called during module load */ + if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(rec->ip))) return -EINVAL; - } - /* - * 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; + old = ppc_inst(PPC_RAW_NOP()); + ret = ftrace_get_call_inst(rec, addr, &new); + if (ret) + return ret; - return __ftrace_make_nop(mod, rec, addr); + return ftrace_modify_code(rec->ip, old, new); } -#ifdef CONFIG_MODULES -/* - * 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. - */ -static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) -{ - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())); - else - return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) && - ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)); -} - -static int -__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) -{ - ppc_inst_t op[2]; - void *ip = (void *)rec->ip; - unsigned long entry, ptr, tramp; - struct module *mod = rec->arch.mod; - - /* read where this goes */ - if (copy_inst_from_kernel_nofault(op, ip)) - return -EFAULT; - - if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && - copy_inst_from_kernel_nofault(op + 1, ip + 4)) - return -EFAULT; - - if (!expected_nop_sequence(ip, op[0], op[1])) { - pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip, - ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1])); - return -EINVAL; - } - - /* If we never set up ftrace trampoline(s), then bail */ - if (!mod->arch.tramp || - (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) { - pr_err("No ftrace trampoline\n"); - return -EINVAL; - } - - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && 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; - } - - if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; -} -#else -static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { - return 0; + /* + * This should never be called since we override ftrace_replace_code(), + * as well as ftrace_init_nop() + */ + WARN_ON(1); + return -EINVAL; } -#endif /* CONFIG_MODULES */ -static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) +void ftrace_replace_code(int enable) { - ppc_inst_t op; - void *ip = (void *)rec->ip; - unsigned long tramp, entry, ptr; + ppc_inst_t old, new, call_inst, new_call_inst; + ppc_inst_t nop_inst = ppc_inst(PPC_RAW_NOP()); + unsigned long ip, new_addr, addr; + struct ftrace_rec_iter *iter; + struct dyn_ftrace *rec; + int ret = 0, update; - /* 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); + for_ftrace_rec_iter(iter) { + rec = ftrace_rec_iter_record(iter); + ip = rec->ip; - if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - entry = ppc_global_function_entry((void *)ftrace_regs_caller); - - if (ptr != entry) { - pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr); - return -EINVAL; - } - - /* Make sure we have a nop */ - if (copy_inst_from_kernel_nofault(&op, ip)) { - pr_err("Unable to read ftrace location %p\n", ip); - return -EFAULT; - } + if (rec->flags & FTRACE_FL_DISABLED && !(rec->flags & FTRACE_FL_ENABLED)) + continue; - if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) { - pr_err("Unexpected call sequence at %p: %08lx\n", - ip, ppc_inst_as_ulong(op)); - return -EINVAL; - } + addr = ftrace_get_addr_curr(rec); + new_addr = ftrace_get_addr_new(rec); + update = ftrace_update_record(rec, enable); - tramp = find_ftrace_tramp((unsigned long)ip); - if (!tramp) { - pr_err("No ftrace trampolines reachable from %ps\n", ip); - return -EINVAL; - } + switch (update) { + case FTRACE_UPDATE_IGNORE: + default: + continue; + case FTRACE_UPDATE_MODIFY_CALL: + ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst); + ret |= ftrace_get_call_inst(rec, addr, &call_inst); + old = call_inst; + new = new_call_inst; + break; + case FTRACE_UPDATE_MAKE_NOP: + ret = ftrace_get_call_inst(rec, addr, &call_inst); + old = call_inst; + new = nop_inst; + break; + case FTRACE_UPDATE_MAKE_CALL: + ret = ftrace_get_call_inst(rec, new_addr, &call_inst); + old = nop_inst; + new = call_inst; + break; + } - if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { - pr_err("Error patching branch to ftrace tramp!\n"); - return -EINVAL; + if (!ret) + ret = ftrace_modify_code(ip, old, new); + if (ret) + goto out; } - return 0; +out: + if (ret) + ftrace_bug(ret, rec); + return; } -int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { - unsigned long ip = rec->ip; + unsigned long addr, ip = rec->ip; ppc_inst_t 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_RAW_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); - } else if (!IS_ENABLED(CONFIG_MODULES)) { - /* We should not get here without modules */ - return -EINVAL; - } - - /* - * 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); -} - -#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) -{ - ppc_inst_t 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 (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); + int ret = 0; + + /* Verify instructions surrounding the ftrace location */ + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) { + /* Expect nops */ + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP())); + if (!ret) + ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP())); + } else if (IS_ENABLED(CONFIG_PPC32)) { + /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */ + ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); + if (!ret) + ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4))); + } else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { + /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */ + ret = ftrace_read_inst(ip - 4, &old); + if (!ret && !ppc_inst_equal(old, ppc_inst(PPC_RAW_MFLR(_R0)))) { + ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0))); + ret |= ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16))); + } + } else { 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 (ret) + return ret; - 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"); + if (!core_kernel_text(ip)) { + if (!mod) { + pr_err("0x%lx: No module provided for non-kernel address\n", ip); 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((u32 *)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; - } - - if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; + rec->arch.mod = mod; } - return 0; -} -#else -static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) -{ - return 0; -} -#endif - -int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, - unsigned long addr) -{ - unsigned long ip = rec->ip; - ppc_inst_t 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)) { + /* Nop-out the ftrace location */ + new = ppc_inst(PPC_RAW_NOP()); + addr = MCOUNT_ADDR; + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) { + /* we instead patch-in the 'mflr r0' */ + old = ppc_inst(PPC_RAW_NOP()); + new = ppc_inst(PPC_RAW_MFLR(_R0)); + ret = ftrace_modify_code(ip - 4, old, new); + } else if (is_offset_in_branch_range(addr - ip)) { + /* Within range */ + old = ftrace_create_branch_inst(ip, addr, 1); + ret = ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip) || (IS_ENABLED(CONFIG_MODULES) && mod)) { /* - * We always patch out of range locations to go to the regs - * variant, so there is nothing to do here + * We would be branching to a linker-generated stub, or to the module _mcount + * stub. Let's just confirm we have a 'bl' here. */ - return 0; - } else if (!IS_ENABLED(CONFIG_MODULES)) { - /* We should not get here without modules */ - return -EINVAL; - } - - /* - * Out of range jumps are called from modules. - */ - if (!rec->arch.mod) { - pr_err("No module loaded\n"); + ret = ftrace_read_inst(ip, &old); + if (ret) + return ret; + if (!is_bl_op(old)) { + pr_err("0x%lx: expected (bl) != found (%08lx)\n", ip, ppc_inst_as_ulong(old)); + return -EINVAL; + } + ret = patch_instruction((u32 *)ip, new); + } else { return -EINVAL; } - return __ftrace_modify_call(rec, old_addr, addr); + return ret; } -#endif int ftrace_update_ftrace_func(ftrace_func_t func) { @@ -684,14 +291,14 @@ int ftrace_update_ftrace_func(ftrace_func_t func) int ret; old = ppc_inst_read((u32 *)&ftrace_call); - new = ftrace_call_replace(ip, (unsigned long)func, 1); + new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1); ret = ftrace_modify_code(ip, old, new); /* Also update the regs callback function */ if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) { ip = (unsigned long)(&ftrace_regs_call); old = ppc_inst_read((u32 *)&ftrace_regs_call); - new = ftrace_call_replace(ip, (unsigned long)func, 1); + new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1); ret = ftrace_modify_code(ip, old, new); } @@ -707,11 +314,6 @@ 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; @@ -723,35 +325,43 @@ void ftrace_free_init_tramp(void) } } -int __init ftrace_dyn_arch_init(void) +static void __init 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; + } +} + +int __init ftrace_dyn_arch_init(void) +{ unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; -#ifdef CONFIG_PPC_KERNEL_PCREL + unsigned long addr = FTRACE_REGS_ADDR; + long reladdr; + int i; u32 stub_insns[] = { +#ifdef CONFIG_PPC_KERNEL_PCREL /* pla r12,addr */ PPC_PREFIX_MLS | __PPC_PRFX_R(1), PPC_INST_PADDI | ___PPC_RT(_R12), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR() - }; -#else - u32 stub_insns[] = { - PPC_RAW_LD(_R12, _R13, PACATOC), +#elif defined(CONFIG_PPC64) + PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), PPC_RAW_ADDIS(_R12, _R12, 0), PPC_RAW_ADDI(_R12, _R12, 0), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR() - }; +#else + PPC_RAW_LIS(_R12, 0), + PPC_RAW_ADDI(_R12, _R12, 0), + PPC_RAW_MTCTR(_R12), + PPC_RAW_BCTR() #endif - - unsigned long addr; - long reladdr; - - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) - addr = ppc_global_function_entry((void *)ftrace_regs_caller); - else - addr = ppc_global_function_entry((void *)ftrace_caller); + }; if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { for (i = 0; i < 2; i++) { @@ -768,10 +378,10 @@ int __init ftrace_dyn_arch_init(void) tramp[i][1] |= IMM_L(reladdr); add_ftrace_tramp((unsigned long)tramp[i]); } - } else { + } else if (IS_ENABLED(CONFIG_PPC64)) { reladdr = addr - kernel_toc_addr(); - if (reladdr >= (long)SZ_2G || reladdr < -(long)SZ_2G) { + if (reladdr >= (long)SZ_2G || reladdr < -(long long)SZ_2G) { pr_err("Address of %ps out of range of kernel_toc.\n", (void *)addr); return -1; @@ -783,51 +393,23 @@ int __init ftrace_dyn_arch_init(void) tramp[i][2] |= PPC_LO(reladdr); add_ftrace_tramp((unsigned long)tramp[i]); } + } else { + for (i = 0; i < 2; i++) { + memcpy(tramp[i], stub_insns, sizeof(stub_insns)); + tramp[i][0] |= PPC_HA(addr); + tramp[i][1] |= PPC_LO(addr); + add_ftrace_tramp((unsigned long)tramp[i]); + } } return 0; } -#endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER - -extern void ftrace_graph_call(void); -extern void ftrace_graph_stub(void); - -static int ftrace_modify_ftrace_graph_caller(bool enable) -{ - unsigned long ip = (unsigned long)(&ftrace_graph_call); - unsigned long addr = (unsigned long)(&ftrace_graph_caller); - unsigned long stub = (unsigned long)(&ftrace_graph_stub); - ppc_inst_t old, new; - - if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS)) - return 0; - - old = ftrace_call_replace(ip, enable ? stub : addr, 0); - new = ftrace_call_replace(ip, enable ? addr : stub, 0); - - return ftrace_modify_code(ip, old, new); -} - -int ftrace_enable_ftrace_graph_caller(void) -{ - return ftrace_modify_ftrace_graph_caller(true); -} - -int ftrace_disable_ftrace_graph_caller(void) -{ - return ftrace_modify_ftrace_graph_caller(false); -} - -/* - * 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. - */ -static unsigned long -__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp) +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) { - unsigned long return_hooker; + unsigned long sp = fregs->regs.gpr[1]; int bit; if (unlikely(ftrace_graph_is_dead())) @@ -836,41 +418,15 @@ __prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp if (unlikely(atomic_read(¤t->tracing_graph_pause))) goto out; - bit = ftrace_test_recursion_trylock(ip, parent); + bit = ftrace_test_recursion_trylock(ip, parent_ip); if (bit < 0) goto out; - return_hooker = ppc_function_entry(return_to_handler); - - if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp)) - parent = return_hooker; + if (!function_graph_enter(parent_ip, ip, 0, (unsigned long *)sp)) + parent_ip = ppc_function_entry(return_to_handler); ftrace_test_recursion_unlock(bit); out: - return parent; + fregs->regs.link = parent_ip; } - -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS -void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct ftrace_regs *fregs) -{ - fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]); -} -#else -unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, - unsigned long sp) -{ - return __prepare_ftrace_return(parent, ip, sp); -} -#endif #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -#ifdef CONFIG_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 /* CONFIG_PPC64_ELF_ABI_V1 */ diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.S b/arch/powerpc/kernel/trace/ftrace_64_pg.S deleted file mode 100644 index 6708e24db0ab..000000000000 --- a/arch/powerpc/kernel/trace/ftrace_64_pg.S +++ /dev/null @@ -1,67 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ -/* - * Split from ftrace_64.S - */ - -#include <linux/magic.h> -#include <asm/ppc_asm.h> -#include <asm/asm-offsets.h> -#include <asm/ftrace.h> -#include <asm/ppc-opcode.h> -#include <asm/export.h> - -_GLOBAL_TOC(ftrace_caller) - lbz r3, PACA_FTRACE_ENABLED(r13) - cmpdi r3, 0 - beqlr - - /* Taken from output of objdump from lib64/glibc */ - mflr r3 - ld r11, 0(r1) - stdu r1, -112(r1) - std r3, 128(r1) - ld r4, 16(r11) - subi r3, r3, MCOUNT_INSN_SIZE -.globl ftrace_call -ftrace_call: - bl ftrace_stub - nop -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -.globl ftrace_graph_call -ftrace_graph_call: - b ftrace_graph_stub -_GLOBAL(ftrace_graph_stub) -#endif - ld r0, 128(r1) - mtlr r0 - addi r1, r1, 112 - -_GLOBAL(ftrace_stub) - blr - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -_GLOBAL(ftrace_graph_caller) - addi r5, r1, 112 - /* load r4 with local address */ - ld r4, 128(r1) - subi r4, r4, MCOUNT_INSN_SIZE - - /* Grab the LR out of the caller stack frame */ - ld r11, 112(r1) - ld r3, 16(r11) - - bl prepare_ftrace_return - nop - - /* - * prepare_ftrace_return gives us the address we divert to. - * Change the LR in the callers stack frame to this. - */ - ld r11, 112(r1) - std r3, 16(r11) - - ld r0, 128(r1) - mtlr r0 - addi r1, r1, 112 - blr -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.c b/arch/powerpc/kernel/trace/ftrace_64_pg.c new file mode 100644 index 000000000000..7b85c3b460a3 --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c @@ -0,0 +1,846 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Code for replacing ftrace calls with jumps. + * + * Copyright (C) 2007-2008 Steven Rostedt <[email protected]> + * + * 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> +#include <asm/inst.h> + +/* + * 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 ppc_inst_t +ftrace_call_replace(unsigned long ip, unsigned long addr, int link) +{ + ppc_inst_t op; + + addr = ppc_function_entry((void *)addr); + + /* if (link) set op to 'bl' else 'b' */ + create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); + + return op; +} + +static inline int +ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) +{ + ppc_inst_t 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 (copy_inst_from_kernel_nofault(&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 (%08lx) != old (%08lx)", (void *)ip, + ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old)); + return -EINVAL; + } + + /* replace the text with the new text */ + return patch_instruction((u32 *)ip, new); +} + +/* + * 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); + + return is_offset_in_branch_range(addr - ip); +} + +static int is_bl_op(ppc_inst_t op) +{ + return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); +} + +static int is_b_op(ppc_inst_t op) +{ + return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0); +} + +static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) +{ + int offset; + + offset = PPC_LI(ppc_inst_val(op)); + /* make it signed */ + if (offset & 0x02000000) + offset |= 0xfe000000; + + return ip + (long)offset; +} + +#ifdef CONFIG_MODULES +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; + ppc_inst_t op, pop; + + /* read where this goes */ + if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { + pr_err("Fetching opcode failed.\n"); + return -EFAULT; + } + + /* Make sure that this is still a 24bit jump */ + if (!is_bl_op(op)) { + pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(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; + } + + if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { + if (copy_inst_from_kernel_nofault(&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_RAW_MFLR(_R0))) && + !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { + pr_err("Unexpected instruction %08lx around bl _mcount\n", + ppc_inst_as_ulong(op)); + return -EINVAL; + } + } else if (IS_ENABLED(CONFIG_PPC64)) { + /* + * 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 (copy_inst_from_kernel_nofault(&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 %08lx found %08lx\n", PPC_INST_LD_TOC, + ppc_inst_as_ulong(op)); + return -EINVAL; + } + } + + /* + * When using -mprofile-kernel or PPC32 there is no load to jump over. + * + * Otherwise 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. + */ + if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32)) + pop = ppc_inst(PPC_RAW_NOP()); + else + pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */ + + if (patch_instruction((u32 *)ip, pop)) { + pr_err("Patching NOP failed.\n"); + return -EPERM; + } + + return 0; +} +#else +static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) +{ + return 0; +} +#endif /* CONFIG_MODULES */ + +static unsigned long find_ftrace_tramp(unsigned long ip) +{ + int i; + + /* + * 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 (is_offset_in_branch_range(ftrace_tramps[i] - ip)) + 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; + ppc_inst_t op; + unsigned long ptr; + + /* Is this a known long jump tramp? */ + for (i = 0; i < NUM_FTRACE_TRAMPS; i++) + if (ftrace_tramps[i] == tramp) + return 0; + + /* New trampoline -- read where this goes */ + if (copy_inst_from_kernel_nofault(&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 */ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + ptr = ppc_global_function_entry((void *)ftrace_regs_caller); + else + ptr = ppc_global_function_entry((void *)ftrace_caller); + + if (patch_branch((u32 *)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; + ppc_inst_t op; + + /* Read where this goes */ + if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { + pr_err("Fetching opcode failed.\n"); + return -EFAULT; + } + + /* Make sure that this is still a 24bit jump */ + if (!is_bl_op(op)) { + pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(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((u32 *)ip, ppc_inst(PPC_RAW_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; + ppc_inst_t 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_RAW_NOP()); + return ftrace_modify_code(ip, old, new); + } else if (core_kernel_text(ip)) { + return __ftrace_make_nop_kernel(rec, addr); + } else if (!IS_ENABLED(CONFIG_MODULES)) { + return -EINVAL; + } + + /* + * 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); +} + +#ifdef CONFIG_MODULES +/* + * 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. + */ +static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) +{ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())); + else + return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) && + ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)); +} + +static int +__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + ppc_inst_t op[2]; + void *ip = (void *)rec->ip; + unsigned long entry, ptr, tramp; + struct module *mod = rec->arch.mod; + + /* read where this goes */ + if (copy_inst_from_kernel_nofault(op, ip)) + return -EFAULT; + + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && + copy_inst_from_kernel_nofault(op + 1, ip + 4)) + return -EFAULT; + + if (!expected_nop_sequence(ip, op[0], op[1])) { + pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip, + ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1])); + return -EINVAL; + } + + /* If we never set up ftrace trampoline(s), then bail */ + if (!mod->arch.tramp || + (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) { + pr_err("No ftrace trampoline\n"); + return -EINVAL; + } + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && 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; + } + + if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { + pr_err("REL24 out of range!\n"); + return -EINVAL; + } + + return 0; +} +#else +static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + return 0; +} +#endif /* CONFIG_MODULES */ + +static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) +{ + ppc_inst_t 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 && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + entry = ppc_global_function_entry((void *)ftrace_regs_caller); + + if (ptr != entry) { + pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr); + return -EINVAL; + } + + /* Make sure we have a nop */ + if (copy_inst_from_kernel_nofault(&op, ip)) { + pr_err("Unable to read ftrace location %p\n", ip); + return -EFAULT; + } + + if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) { + pr_err("Unexpected call sequence at %p: %08lx\n", + ip, ppc_inst_as_ulong(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; + ppc_inst_t 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_RAW_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); + } else if (!IS_ENABLED(CONFIG_MODULES)) { + /* We should not get here without modules */ + return -EINVAL; + } + + /* + * 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); +} + +#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) +{ + ppc_inst_t 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 (copy_inst_from_kernel_nofault(&op, (void *)ip)) { + pr_err("Fetching opcode failed.\n"); + return -EFAULT; + } + + /* Make sure that this is still a 24bit jump */ + if (!is_bl_op(op)) { + pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(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((u32 *)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; + } + + if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { + pr_err("REL24 out of range!\n"); + return -EINVAL; + } + + return 0; +} +#else +static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) +{ + return 0; +} +#endif + +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, + unsigned long addr) +{ + unsigned long ip = rec->ip; + ppc_inst_t 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; + } else if (!IS_ENABLED(CONFIG_MODULES)) { + /* We should not get here without modules */ + return -EINVAL; + } + + /* + * 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); +} +#endif + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long)(&ftrace_call); + ppc_inst_t old, new; + int ret; + + old = ppc_inst_read((u32 *)&ftrace_call); + new = ftrace_call_replace(ip, (unsigned long)func, 1); + ret = ftrace_modify_code(ip, old, new); + + /* Also update the regs callback function */ + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) { + ip = (unsigned long)(&ftrace_regs_call); + old = ppc_inst_read((u32 *)&ftrace_regs_call); + new = ftrace_call_replace(ip, (unsigned long)func, 1); + ret = ftrace_modify_code(ip, old, new); + } + + 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[] = { + PPC_RAW_LD(_R12, _R13, PACATOC), + PPC_RAW_ADDIS(_R12, _R12, 0), + PPC_RAW_ADDI(_R12, _R12, 0), + PPC_RAW_MTCTR(_R12), + PPC_RAW_BCTR() + }; + unsigned long addr; + long reladdr; + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) + addr = ppc_global_function_entry((void *)ftrace_regs_caller); + else + addr = ppc_global_function_entry((void *)ftrace_caller); + + reladdr = addr - kernel_toc_addr(); + + if (reladdr >= SZ_2G || reladdr < -(long)SZ_2G) { + 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; +} +#endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + +extern void ftrace_graph_call(void); +extern void ftrace_graph_stub(void); + +static int ftrace_modify_ftrace_graph_caller(bool enable) +{ + unsigned long ip = (unsigned long)(&ftrace_graph_call); + unsigned long addr = (unsigned long)(&ftrace_graph_caller); + unsigned long stub = (unsigned long)(&ftrace_graph_stub); + ppc_inst_t old, new; + + if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS)) + return 0; + + old = ftrace_call_replace(ip, enable ? stub : addr, 0); + new = ftrace_call_replace(ip, enable ? addr : stub, 0); + + return ftrace_modify_code(ip, old, new); +} + +int ftrace_enable_ftrace_graph_caller(void) +{ + return ftrace_modify_ftrace_graph_caller(true); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + return ftrace_modify_ftrace_graph_caller(false); +} + +/* + * 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. + */ +static unsigned long +__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp) +{ + unsigned long return_hooker; + int bit; + + if (unlikely(ftrace_graph_is_dead())) + goto out; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + goto out; + + bit = ftrace_test_recursion_trylock(ip, parent); + if (bit < 0) + goto out; + + return_hooker = ppc_function_entry(return_to_handler); + + if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp)) + parent = return_hooker; + + ftrace_test_recursion_unlock(bit); +out: + return parent; +} + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) +{ + fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]); +} +#else +unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, + unsigned long sp) +{ + return __prepare_ftrace_return(parent, ip, sp); +} +#endif +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_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 /* CONFIG_PPC64_ELF_ABI_V1 */ diff --git a/arch/powerpc/kernel/trace/ftrace_low.S b/arch/powerpc/kernel/trace/ftrace_64_pg_entry.S index 294d1e05958a..a8a7f28404c8 100644 --- a/arch/powerpc/kernel/trace/ftrace_low.S +++ b/arch/powerpc/kernel/trace/ftrace_64_pg_entry.S @@ -1,28 +1,82 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ /* - * Split from entry_64.S + * Split from ftrace_64.S */ +#include <linux/export.h> #include <linux/magic.h> #include <asm/ppc_asm.h> #include <asm/asm-offsets.h> #include <asm/ftrace.h> #include <asm/ppc-opcode.h> -#include <asm/export.h> -#ifdef CONFIG_PPC64 +_GLOBAL_TOC(ftrace_caller) + lbz r3, PACA_FTRACE_ENABLED(r13) + cmpdi r3, 0 + beqlr + + /* Taken from output of objdump from lib64/glibc */ + mflr r3 + ld r11, 0(r1) + stdu r1, -112(r1) + std r3, 128(r1) + ld r4, 16(r11) + subi r3, r3, MCOUNT_INSN_SIZE +.globl ftrace_call +ftrace_call: + bl ftrace_stub + nop +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +.globl ftrace_graph_call +ftrace_graph_call: + b ftrace_graph_stub +_GLOBAL(ftrace_graph_stub) +#endif + ld r0, 128(r1) + mtlr r0 + addi r1, r1, 112 + +_GLOBAL(ftrace_stub) + blr + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +_GLOBAL(ftrace_graph_caller) + addi r5, r1, 112 + /* load r4 with local address */ + ld r4, 128(r1) + subi r4, r4, MCOUNT_INSN_SIZE + + /* Grab the LR out of the caller stack frame */ + ld r11, 112(r1) + ld r3, 16(r11) + + bl prepare_ftrace_return + nop + + /* + * prepare_ftrace_return gives us the address we divert to. + * Change the LR in the callers stack frame to this. + */ + ld r11, 112(r1) + std r3, 16(r11) + + ld r0, 128(r1) + mtlr r0 + addi r1, r1, 112 + blr +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + .pushsection ".tramp.ftrace.text","aw",@progbits; .globl ftrace_tramp_text ftrace_tramp_text: - .space 64 + .space 32 .popsection .pushsection ".tramp.ftrace.init","aw",@progbits; .globl ftrace_tramp_init ftrace_tramp_init: - .space 64 + .space 32 .popsection -#endif _GLOBAL(mcount) _GLOBAL(_mcount) diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_entry.S index 1f7d86de1538..90701885762c 100644 --- a/arch/powerpc/kernel/trace/ftrace_mprofile.S +++ b/arch/powerpc/kernel/trace/ftrace_entry.S @@ -3,12 +3,12 @@ * Split from ftrace_64.S */ +#include <linux/export.h> #include <linux/magic.h> #include <asm/ppc_asm.h> #include <asm/asm-offsets.h> #include <asm/ftrace.h> #include <asm/ppc-opcode.h> -#include <asm/export.h> #include <asm/thread_info.h> #include <asm/bug.h> #include <asm/ptrace.h> @@ -254,3 +254,70 @@ livepatch_handler: /* Return to original caller of live patched function */ blr #endif /* CONFIG_LIVEPATCH */ + +#ifndef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY +_GLOBAL(mcount) +_GLOBAL(_mcount) +EXPORT_SYMBOL(_mcount) + mflr r12 + mtctr r12 + mtlr r0 + bctr +#endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +_GLOBAL(return_to_handler) + /* need to save return values */ +#ifdef CONFIG_PPC64 + std r4, -32(r1) + std r3, -24(r1) + /* save TOC */ + std r2, -16(r1) + std r31, -8(r1) + mr r31, r1 + stdu r1, -112(r1) + + /* + * We might be called from a module. + * Switch to our TOC to run inside the core kernel. + */ + LOAD_PACA_TOC() +#else + stwu r1, -16(r1) + stw r3, 8(r1) + stw r4, 12(r1) +#endif + + bl ftrace_return_to_handler + nop + + /* return value has real return address */ + mtlr r3 + +#ifdef CONFIG_PPC64 + ld r1, 0(r1) + ld r4, -32(r1) + ld r3, -24(r1) + ld r2, -16(r1) + ld r31, -8(r1) +#else + lwz r3, 8(r1) + lwz r4, 12(r1) + addi r1, r1, 16 +#endif + + /* Jump back to real return address */ + blr +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +.pushsection ".tramp.ftrace.text","aw",@progbits; +.globl ftrace_tramp_text +ftrace_tramp_text: + .space 32 +.popsection + +.pushsection ".tramp.ftrace.init","aw",@progbits; +.globl ftrace_tramp_init +ftrace_tramp_init: + .space 32 +.popsection |