diff options
Diffstat (limited to 'arch/powerpc/kernel/trace')
| -rw-r--r-- | arch/powerpc/kernel/trace/Makefile | 26 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace.c | 846 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_64_pg.S | 67 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_low.S | 78 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace_mprofile.S | 256 | ||||
| -rw-r--r-- | arch/powerpc/kernel/trace/trace_clock.c | 13 |
6 files changed, 1286 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile new file mode 100644 index 000000000..af8527538 --- /dev/null +++ b/arch/powerpc/kernel/trace/Makefile @@ -0,0 +1,26 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the powerpc trace subsystem +# + +ifdef CONFIG_FUNCTION_TRACER +# do not trace tracer code +CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) +endif + +obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o +ifdef CONFIG_MPROFILE_KERNEL +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o +else +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o +endif +obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o ftrace.o +obj-$(CONFIG_TRACING) += trace_clock.o + +obj-$(CONFIG_PPC64) += $(obj64-y) +obj-$(CONFIG_PPC32) += $(obj32-y) + +# Disable GCOV, KCOV & sanitizers in odd or sensitive code +GCOV_PROFILE_ftrace.o := n +KCOV_INSTRUMENT_ftrace.o := n +UBSAN_SANITIZE_ftrace.o := n diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c new file mode 100644 index 000000000..7b85c3b46 --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -0,0 +1,846 @@ +// 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/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_64_pg.S b/arch/powerpc/kernel/trace/ftrace_64_pg.S new file mode 100644 index 000000000..6708e24db --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace_64_pg.S @@ -0,0 +1,67 @@ +/* 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_low.S b/arch/powerpc/kernel/trace/ftrace_low.S new file mode 100644 index 000000000..294d1e059 --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace_low.S @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Split from entry_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> + +#ifdef CONFIG_PPC64 +.pushsection ".tramp.ftrace.text","aw",@progbits; +.globl ftrace_tramp_text +ftrace_tramp_text: + .space 64 +.popsection + +.pushsection ".tramp.ftrace.init","aw",@progbits; +.globl ftrace_tramp_init +ftrace_tramp_init: + .space 64 +.popsection +#endif + +_GLOBAL(mcount) +_GLOBAL(_mcount) +EXPORT_SYMBOL(_mcount) + mflr r12 + mtctr r12 + mtlr r0 + bctr + +#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 */ diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S new file mode 100644 index 000000000..f4a72b384 --- /dev/null +++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S @@ -0,0 +1,256 @@ +/* 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> +#include <asm/thread_info.h> +#include <asm/bug.h> +#include <asm/ptrace.h> + +/* + * + * ftrace_caller()/ftrace_regs_caller() is the function that replaces _mcount() + * when ftrace is active. + * + * We arrive here after a function A calls function B, and we are the trace + * function for B. When we enter r1 points to A's stack frame, B has not yet + * had a chance to allocate one yet. + * + * Additionally r2 may point either to the TOC for A, or B, depending on + * whether B did a TOC setup sequence before calling us. + * + * On entry the LR points back to the _mcount() call site, and r0 holds the + * saved LR as it was on entry to B, ie. the original return address at the + * call site in A. + * + * Our job is to save the register state into a struct pt_regs (on the stack) + * and then arrange for the ftrace function to be called. + */ +.macro ftrace_regs_entry allregs + /* Create a minimal stack frame for representing B */ + PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) + + /* Create our stack frame + pt_regs */ + PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) + + /* Save all gprs to pt_regs */ + SAVE_GPR(0, r1) + SAVE_GPRS(3, 10, r1) + +#ifdef CONFIG_PPC64 + /* Save the original return address in A's stack frame */ + std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) + /* Ok to continue? */ + lbz r3, PACA_FTRACE_ENABLED(r13) + cmpdi r3, 0 + beq ftrace_no_trace +#endif + + .if \allregs == 1 + SAVE_GPR(2, r1) + SAVE_GPRS(11, 31, r1) + .else +#ifdef CONFIG_LIVEPATCH_64 + SAVE_GPR(14, r1) +#endif + .endif + + /* Save previous stack pointer (r1) */ + addi r8, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE + PPC_STL r8, GPR1(r1) + + .if \allregs == 1 + /* Load special regs for save below */ + mfmsr r8 + mfctr r9 + mfxer r10 + mfcr r11 + .else + /* Clear MSR to flag as ftrace_caller versus frace_regs_caller */ + li r8, 0 + .endif + + /* Get the _mcount() call site out of LR */ + mflr r7 + /* Save it as pt_regs->nip */ + PPC_STL r7, _NIP(r1) + /* Also save it in B's stackframe header for proper unwind */ + PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) + /* Save the read LR in pt_regs->link */ + PPC_STL r0, _LINK(r1) + +#ifdef CONFIG_PPC64 + /* Save callee's TOC in the ABI compliant location */ + std r2, STK_GOT(r1) + LOAD_PACA_TOC() /* get kernel TOC in r2 */ + LOAD_REG_ADDR(r3, function_trace_op) + ld r5,0(r3) +#else + lis r3,function_trace_op@ha + lwz r5,function_trace_op@l(r3) +#endif + +#ifdef CONFIG_LIVEPATCH_64 + mr r14, r7 /* remember old NIP */ +#endif + + /* Calculate ip from nip-4 into r3 for call below */ + subi r3, r7, MCOUNT_INSN_SIZE + + /* Put the original return address in r4 as parent_ip */ + mr r4, r0 + + /* Save special regs */ + PPC_STL r8, _MSR(r1) + .if \allregs == 1 + PPC_STL r9, _CTR(r1) + PPC_STL r10, _XER(r1) + PPC_STL r11, _CCR(r1) + .endif + + /* Load &pt_regs in r6 for call below */ + addi r6, r1, STACK_FRAME_OVERHEAD +.endm + +.macro ftrace_regs_exit allregs + /* Load ctr with the possibly modified NIP */ + PPC_LL r3, _NIP(r1) + mtctr r3 + +#ifdef CONFIG_LIVEPATCH_64 + cmpd r14, r3 /* has NIP been altered? */ +#endif + + /* Restore gprs */ + .if \allregs == 1 + REST_GPRS(2, 31, r1) + .else + REST_GPRS(3, 10, r1) +#ifdef CONFIG_LIVEPATCH_64 + REST_GPR(14, r1) +#endif + .endif + + /* Restore possibly modified LR */ + PPC_LL r0, _LINK(r1) + mtlr r0 + +#ifdef CONFIG_PPC64 + /* Restore callee's TOC */ + ld r2, STK_GOT(r1) +#endif + + /* Pop our stack frame */ + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE + +#ifdef CONFIG_LIVEPATCH_64 + /* Based on the cmpd above, if the NIP was altered handle livepatch */ + bne- livepatch_handler +#endif + bctr /* jump after _mcount site */ +.endm + +_GLOBAL(ftrace_regs_caller) + ftrace_regs_entry 1 + /* ftrace_call(r3, r4, r5, r6) */ +.globl ftrace_regs_call +ftrace_regs_call: + bl ftrace_stub + nop + ftrace_regs_exit 1 + +_GLOBAL(ftrace_caller) + ftrace_regs_entry 0 + /* ftrace_call(r3, r4, r5, r6) */ +.globl ftrace_call +ftrace_call: + bl ftrace_stub + nop + ftrace_regs_exit 0 + +_GLOBAL(ftrace_stub) + blr + +#ifdef CONFIG_PPC64 +ftrace_no_trace: + mflr r3 + mtctr r3 + REST_GPR(3, r1) + addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE + mtlr r0 + bctr +#endif + +#ifdef CONFIG_LIVEPATCH_64 + /* + * This function runs in the mcount context, between two functions. As + * such it can only clobber registers which are volatile and used in + * function linkage. + * + * We get here when a function A, calls another function B, but B has + * been live patched with a new function C. + * + * On entry: + * - we have no stack frame and can not allocate one + * - LR points back to the original caller (in A) + * - CTR holds the new NIP in C + * - r0, r11 & r12 are free + */ +livepatch_handler: + ld r12, PACA_THREAD_INFO(r13) + + /* Allocate 3 x 8 bytes */ + ld r11, TI_livepatch_sp(r12) + addi r11, r11, 24 + std r11, TI_livepatch_sp(r12) + + /* Save toc & real LR on livepatch stack */ + std r2, -24(r11) + mflr r12 + std r12, -16(r11) + + /* Store stack end marker */ + lis r12, STACK_END_MAGIC@h + ori r12, r12, STACK_END_MAGIC@l + std r12, -8(r11) + + /* Put ctr in r12 for global entry and branch there */ + mfctr r12 + bctrl + + /* + * Now we are returning from the patched function to the original + * caller A. We are free to use r11, r12 and we can use r2 until we + * restore it. + */ + + ld r12, PACA_THREAD_INFO(r13) + + ld r11, TI_livepatch_sp(r12) + + /* Check stack marker hasn't been trashed */ + lis r2, STACK_END_MAGIC@h + ori r2, r2, STACK_END_MAGIC@l + ld r12, -8(r11) +1: tdne r12, r2 + EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0 + + /* Restore LR & toc from livepatch stack */ + ld r12, -16(r11) + mtlr r12 + ld r2, -24(r11) + + /* Pop livepatch stack frame */ + ld r12, PACA_THREAD_INFO(r13) + subi r11, r11, 24 + std r11, TI_livepatch_sp(r12) + + /* Return to original caller of live patched function */ + blr +#endif /* CONFIG_LIVEPATCH */ diff --git a/arch/powerpc/kernel/trace/trace_clock.c b/arch/powerpc/kernel/trace/trace_clock.c new file mode 100644 index 000000000..b0143a313 --- /dev/null +++ b/arch/powerpc/kernel/trace/trace_clock.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (C) 2015 Naveen N. Rao, IBM Corporation + */ + +#include <asm/trace_clock.h> +#include <asm/time.h> + +u64 notrace trace_clock_ppc_tb(void) +{ + return get_tb(); +} |