Le 19/06/2023 à 11:47, Naveen N Rao a écrit : > ELFv1 support is deprecated and on the way out. Pre -mprofile-kernel > ftrace support (-pg only) is very limited and is retained primarily for > clang builds. It won't be necessary once clang lands support for > -fpatchable-function-entry. > > Copy the existing ftrace code supporting these into ftrace_pg.c. > ftrace.c can then be refactored and enhanced with a focus on ppc32 and > ppc64 ELFv2. > > Signed-off-by: Naveen N Rao <nav...@kernel.org>
Reviewed-by: Christophe Leroy <christophe.le...@csgroup.eu> > --- > arch/powerpc/kernel/trace/Makefile | 13 +- > arch/powerpc/kernel/trace/ftrace.c | 10 - > arch/powerpc/kernel/trace/ftrace_pg.c | 846 ++++++++++++++++++++++++++ > 3 files changed, 855 insertions(+), 14 deletions(-) > create mode 100644 arch/powerpc/kernel/trace/ftrace_pg.c > > diff --git a/arch/powerpc/kernel/trace/Makefile > b/arch/powerpc/kernel/trace/Makefile > index b16a9f9c0b35f2..342a2d1ae86cd0 100644 > --- a/arch/powerpc/kernel/trace/Makefile > +++ b/arch/powerpc/kernel/trace/Makefile > @@ -6,15 +6,16 @@ > ifdef CONFIG_FUNCTION_TRACER > # do not trace tracer code > CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) > +CFLAGS_REMOVE_ftrace_pg.o = $(CC_FLAGS_FTRACE) > endif > > -obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o > +obj32-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o ftrace.o > ifdef CONFIG_MPROFILE_KERNEL > -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o > +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_mprofile.o ftrace.o > else > -obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o > +obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_pg.o > endif > -obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o ftrace.o > +obj-$(CONFIG_FUNCTION_TRACER) += ftrace_low.o > obj-$(CONFIG_TRACING) += trace_clock.o > > obj-$(CONFIG_PPC64) += $(obj64-y) > @@ -25,3 +26,7 @@ GCOV_PROFILE_ftrace.o := n > KCOV_INSTRUMENT_ftrace.o := n > KCSAN_SANITIZE_ftrace.o := n > UBSAN_SANITIZE_ftrace.o := n > +GCOV_PROFILE_ftrace_pg.o := n > +KCOV_INSTRUMENT_ftrace_pg.o := n > +KCSAN_SANITIZE_ftrace_pg.o := n > +UBSAN_SANITIZE_ftrace_pg.o := n > diff --git a/arch/powerpc/kernel/trace/ftrace.c > b/arch/powerpc/kernel/trace/ftrace.c > index a47f303734233b..81a121b56c4d7f 100644 > --- a/arch/powerpc/kernel/trace/ftrace.c > +++ b/arch/powerpc/kernel/trace/ftrace.c > @@ -864,13 +864,3 @@ unsigned long prepare_ftrace_return(unsigned long > parent, unsigned long ip, > } > #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_pg.c > b/arch/powerpc/kernel/trace/ftrace_pg.c > new file mode 100644 > index 00000000000000..7b85c3b460a3c0 > --- /dev/null > +++ b/arch/powerpc/kernel/trace/ftrace_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 <srost...@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 */