Add a utility to map a perf register number to a dwarf register number for a particular ELF machine type.
Create a generic unwind-libdw initial register initialization routine that uses this function and thereby avoids arch specific initialization. The unwind-libdw code does: 1) compute the maximum dwarf register from the set of sampled user registers, 2) allocates a set of dwarf registers, 3) copies the sample registers into the appropriate dwarf registers. This generic solution is initially implemented for use with x86 as only get_dwarf_regnum_for_perf_regnum support for x86 is currently present. Signed-off-by: Ian Rogers <[email protected]> --- .../util/dwarf-regs-arch/dwarf-regs-x86.c | 95 +++++++++++++++++++ tools/perf/util/dwarf-regs.c | 55 +++++++++++ tools/perf/util/include/dwarf-regs.h | 8 ++ tools/perf/util/unwind-libdw-arch/Build | 1 - .../util/unwind-libdw-arch/unwind-libdw-x86.c | 54 ----------- tools/perf/util/unwind-libdw.c | 70 ++++++++++++-- tools/perf/util/unwind-libdw.h | 2 +- 7 files changed, 222 insertions(+), 63 deletions(-) delete mode 100644 tools/perf/util/unwind-libdw-arch/unwind-libdw-x86.c diff --git a/tools/perf/util/dwarf-regs-arch/dwarf-regs-x86.c b/tools/perf/util/dwarf-regs-arch/dwarf-regs-x86.c index f0c42e4d7423..cadef120aeb4 100644 --- a/tools/perf/util/dwarf-regs-arch/dwarf-regs-x86.c +++ b/tools/perf/util/dwarf-regs-arch/dwarf-regs-x86.c @@ -10,6 +10,7 @@ #include <string.h> /* for strcmp */ #include <linux/kernel.h> /* for ARRAY_SIZE */ #include <dwarf-regs.h> +#include "../../../arch/x86/include/uapi/asm/perf_regs.h" struct dwarf_regs_idx { const char *name; @@ -163,3 +164,97 @@ int __get_dwarf_regnum_x86_64(const char *name) { return get_regnum(x86_64_regidx_table, ARRAY_SIZE(x86_64_regidx_table), name); } + +int __get_dwarf_regnum_for_perf_regnum_i386(int perf_regnum) +{ + static const int dwarf_i386_regnums[] = { + [PERF_REG_X86_AX] = 0, + [PERF_REG_X86_BX] = 3, + [PERF_REG_X86_CX] = 1, + [PERF_REG_X86_DX] = 2, + [PERF_REG_X86_SI] = 6, + [PERF_REG_X86_DI] = 7, + [PERF_REG_X86_BP] = 5, + [PERF_REG_X86_SP] = 4, + [PERF_REG_X86_IP] = 8, + [PERF_REG_X86_FLAGS] = 9, + [PERF_REG_X86_CS] = 41, + [PERF_REG_X86_SS] = 42, + [PERF_REG_X86_DS] = 43, + [PERF_REG_X86_ES] = 40, + [PERF_REG_X86_FS] = 44, + [PERF_REG_X86_GS] = 45, + [PERF_REG_X86_XMM0] = 21, + [PERF_REG_X86_XMM1] = 22, + [PERF_REG_X86_XMM2] = 23, + [PERF_REG_X86_XMM3] = 24, + [PERF_REG_X86_XMM4] = 25, + [PERF_REG_X86_XMM5] = 26, + [PERF_REG_X86_XMM6] = 27, + [PERF_REG_X86_XMM7] = 28, + }; + + if (perf_regnum == 0) + return 0; + + if (perf_regnum < 0 || perf_regnum > (int)ARRAY_SIZE(dwarf_i386_regnums) || + dwarf_i386_regnums[perf_regnum] == 0) + return -ENOENT; + + return dwarf_i386_regnums[perf_regnum]; +} + +int __get_dwarf_regnum_for_perf_regnum_x86_64(int perf_regnum) +{ + static const int dwarf_x86_64_regnums[] = { + [PERF_REG_X86_AX] = 0, + [PERF_REG_X86_BX] = 3, + [PERF_REG_X86_CX] = 2, + [PERF_REG_X86_DX] = 1, + [PERF_REG_X86_SI] = 4, + [PERF_REG_X86_DI] = 5, + [PERF_REG_X86_BP] = 6, + [PERF_REG_X86_SP] = 7, + [PERF_REG_X86_IP] = 16, + [PERF_REG_X86_FLAGS] = 49, + [PERF_REG_X86_CS] = 51, + [PERF_REG_X86_SS] = 52, + [PERF_REG_X86_DS] = 53, + [PERF_REG_X86_ES] = 50, + [PERF_REG_X86_FS] = 54, + [PERF_REG_X86_GS] = 55, + [PERF_REG_X86_R8] = 8, + [PERF_REG_X86_R9] = 9, + [PERF_REG_X86_R10] = 10, + [PERF_REG_X86_R11] = 11, + [PERF_REG_X86_R12] = 12, + [PERF_REG_X86_R13] = 13, + [PERF_REG_X86_R14] = 14, + [PERF_REG_X86_R15] = 15, + [PERF_REG_X86_XMM0] = 17, + [PERF_REG_X86_XMM1] = 18, + [PERF_REG_X86_XMM2] = 19, + [PERF_REG_X86_XMM3] = 20, + [PERF_REG_X86_XMM4] = 21, + [PERF_REG_X86_XMM5] = 22, + [PERF_REG_X86_XMM6] = 23, + [PERF_REG_X86_XMM7] = 24, + [PERF_REG_X86_XMM8] = 25, + [PERF_REG_X86_XMM9] = 26, + [PERF_REG_X86_XMM10] = 27, + [PERF_REG_X86_XMM11] = 28, + [PERF_REG_X86_XMM12] = 29, + [PERF_REG_X86_XMM13] = 30, + [PERF_REG_X86_XMM14] = 31, + [PERF_REG_X86_XMM15] = 32, + }; + + if (perf_regnum == 0) + return 0; + + if (perf_regnum < 0 || perf_regnum > (int)ARRAY_SIZE(dwarf_x86_64_regnums) || + dwarf_x86_64_regnums[perf_regnum] == 0) + return -ENOENT; + + return dwarf_x86_64_regnums[perf_regnum]; +} diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c index ef249dd589e3..1f7d892612df 100644 --- a/tools/perf/util/dwarf-regs.c +++ b/tools/perf/util/dwarf-regs.c @@ -103,3 +103,58 @@ int get_dwarf_regnum(const char *name, unsigned int machine, unsigned int flags free(regname); return reg; } + +static int get_libdw_frame_nregs(unsigned int machine, unsigned int flags __maybe_unused) +{ + switch (machine) { + case EM_X86_64: + return 17; + case EM_386: + return 9; + case EM_ARM: + return 16; + case EM_AARCH64: + return 97; + case EM_CSKY: + return 38; + case EM_S390: + return 32; + case EM_PPC: + case EM_PPC64: + return 145; + case EM_RISCV: + return 66; + case EM_SPARC: + case EM_SPARCV9: + return 103; + case EM_LOONGARCH: + return 74; + default: + return 0; + } +} + +int get_dwarf_regnum_for_perf_regnum(int perf_regnum, unsigned int machine, + unsigned int flags, bool only_libdw_supported) +{ + int reg; + + switch (machine) { + case EM_X86_64: + reg = __get_dwarf_regnum_for_perf_regnum_x86_64(perf_regnum); + break; + case EM_386: + reg = __get_dwarf_regnum_for_perf_regnum_i386(perf_regnum); + break; + default: + pr_err("ELF MACHINE %x is not supported.\n", machine); + return -ENOENT; + } + if (reg >= 0 && only_libdw_supported) { + int nregs = get_libdw_frame_nregs(machine, flags); + + if (reg >= nregs) + reg = -ENOENT; + } + return reg; +} diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h index bb5413b0fee4..00881f1d45d6 100644 --- a/tools/perf/util/include/dwarf-regs.h +++ b/tools/perf/util/include/dwarf-regs.h @@ -101,6 +101,8 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int int __get_dwarf_regnum_i386(const char *name); int __get_dwarf_regnum_x86_64(const char *name); +int __get_dwarf_regnum_for_perf_regnum_i386(int perf_regnum); +int __get_dwarf_regnum_for_perf_regnum_x86_64(int perf_regnum); /* * get_dwarf_regnum - Returns DWARF regnum from register name @@ -109,6 +111,12 @@ int __get_dwarf_regnum_x86_64(const char *name); */ int get_dwarf_regnum(const char *name, unsigned int machine, unsigned int flags); +/* + * get_dwarf_regnum - Returns DWARF regnum from perf register number. + */ +int get_dwarf_regnum_for_perf_regnum(int perf_regnum, unsigned int machine, unsigned int flags, + bool only_libdw_supported); + void get_powerpc_regs(u32 raw_insn, int is_source, struct annotated_op_loc *op_loc); #else /* HAVE_LIBDW_SUPPORT */ diff --git a/tools/perf/util/unwind-libdw-arch/Build b/tools/perf/util/unwind-libdw-arch/Build index ef17a83a7813..5b5682029953 100644 --- a/tools/perf/util/unwind-libdw-arch/Build +++ b/tools/perf/util/unwind-libdw-arch/Build @@ -1,4 +1,3 @@ -perf-util-y += unwind-libdw-x86.o perf-util-y += unwind-libdw-arm.o perf-util-y += unwind-libdw-arm64.o perf-util-y += unwind-libdw-csky.o diff --git a/tools/perf/util/unwind-libdw-arch/unwind-libdw-x86.c b/tools/perf/util/unwind-libdw-arch/unwind-libdw-x86.c deleted file mode 100644 index dd27545a4a68..000000000000 --- a/tools/perf/util/unwind-libdw-arch/unwind-libdw-x86.c +++ /dev/null @@ -1,54 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include <elfutils/libdwfl.h> -#include "../arch/x86/include/uapi/asm/perf_regs.h" -#include "util/unwind-libdw.h" -#include "util/perf_regs.h" -#include "util/sample.h" - -bool libdw_set_initial_registers_x86(Dwfl_Thread *thread, void *arg) -{ - struct unwind_info *ui = arg; - struct regs_dump *user_regs = perf_sample__user_regs(ui->sample); - Dwarf_Word dwarf_regs[17]; - unsigned nregs; - -#define REG(r) ({ \ - Dwarf_Word val = 0; \ - perf_reg_value(&val, user_regs, PERF_REG_X86_##r); \ - val; \ -}) - - if (user_regs->abi == PERF_SAMPLE_REGS_ABI_32) { - dwarf_regs[0] = REG(AX); - dwarf_regs[1] = REG(CX); - dwarf_regs[2] = REG(DX); - dwarf_regs[3] = REG(BX); - dwarf_regs[4] = REG(SP); - dwarf_regs[5] = REG(BP); - dwarf_regs[6] = REG(SI); - dwarf_regs[7] = REG(DI); - dwarf_regs[8] = REG(IP); - nregs = 9; - } else { - dwarf_regs[0] = REG(AX); - dwarf_regs[1] = REG(DX); - dwarf_regs[2] = REG(CX); - dwarf_regs[3] = REG(BX); - dwarf_regs[4] = REG(SI); - dwarf_regs[5] = REG(DI); - dwarf_regs[6] = REG(BP); - dwarf_regs[7] = REG(SP); - dwarf_regs[8] = REG(R8); - dwarf_regs[9] = REG(R9); - dwarf_regs[10] = REG(R10); - dwarf_regs[11] = REG(R11); - dwarf_regs[12] = REG(R12); - dwarf_regs[13] = REG(R13); - dwarf_regs[14] = REG(R14); - dwarf_regs[15] = REG(R15); - dwarf_regs[16] = REG(IP); - nregs = 17; - } - - return dwfl_thread_state_registers(thread, 0, nregs, dwarf_regs); -} diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c index c25190cdceb4..055dab921442 100644 --- a/tools/perf/util/unwind-libdw.c +++ b/tools/perf/util/unwind-libdw.c @@ -6,6 +6,7 @@ #include <errno.h> #include "debug.h" #include "dso.h" +#include <dwarf-regs.h> #include "unwind.h" #include "unwind-libdw.h" #include "machine.h" @@ -225,6 +226,59 @@ static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word * return true; } +static bool libdw_set_initial_registers_generic(Dwfl_Thread *thread, void *arg) +{ + struct unwind_info *ui = arg; + struct regs_dump *user_regs = perf_sample__user_regs(ui->sample); + Dwarf_Word *dwarf_regs; + int max_dwarf_reg = 0; + bool ret; + uint16_t e_machine = ui->e_machine; + int e_flags = 0; + uint64_t ip_perf_reg = perf_arch_reg_ip(e_machine); + Dwarf_Word val = 0; + + + /* + * For every possible perf register in the bitmap determine the dwarf + * register and use to compute the max. + */ + for (int perf_reg = 0; perf_reg < 64; perf_reg++) { + if (user_regs->mask & (1ULL << perf_reg)) { + int dwarf_reg = + get_dwarf_regnum_for_perf_regnum(perf_reg, e_machine, + e_flags, + /*only_libdw_supported=*/true); + if (dwarf_reg > max_dwarf_reg) + max_dwarf_reg = dwarf_reg; + } + } + + dwarf_regs = calloc(max_dwarf_reg + 1, sizeof(*dwarf_regs)); + if (!dwarf_regs) + return false; + + for (int perf_reg = 0; perf_reg < 64; perf_reg++) { + if (user_regs->mask & (1ULL << perf_reg)) { + int dwarf_reg = + get_dwarf_regnum_for_perf_regnum(perf_reg, e_machine, + e_flags, + /*only_libdw_supported=*/true); + if (dwarf_reg >= 0) { + val = 0; + if (perf_reg_value(&val, user_regs, perf_reg) == 0) + dwarf_regs[dwarf_reg] = val; + } + } + } + if (perf_reg_value(&val, user_regs, ip_perf_reg) == 0) + dwfl_thread_state_register_pc(thread, val); + + ret = dwfl_thread_state_registers(thread, 0, max_dwarf_reg + 1, dwarf_regs); + free(dwarf_regs); + return ret; +} + #define DEFINE_DWFL_THREAD_CALLBACKS(arch) \ static const Dwfl_Thread_Callbacks callbacks_##arch = { \ .next_thread = next_thread, \ @@ -232,7 +286,12 @@ static const Dwfl_Thread_Callbacks callbacks_##arch = { \ .set_initial_registers = libdw_set_initial_registers_##arch, \ } -DEFINE_DWFL_THREAD_CALLBACKS(x86); +static const Dwfl_Thread_Callbacks callbacks_generic = { + .next_thread = next_thread, + .memory_read = memory_read, + .set_initial_registers = libdw_set_initial_registers_generic, +}; + DEFINE_DWFL_THREAD_CALLBACKS(arm); DEFINE_DWFL_THREAD_CALLBACKS(arm64); DEFINE_DWFL_THREAD_CALLBACKS(csky); @@ -257,12 +316,8 @@ static const Dwfl_Thread_Callbacks *get_thread_callbacks(const char *arch) return &callbacks_riscv; else if (!strcmp(arch, "s390")) return &callbacks_s390; - else if (!strcmp(arch, "x86")) - return &callbacks_x86; - pr_err("Fail to get thread callbacks for arch %s, returns NULL\n", - arch); - return NULL; + return &callbacks_generic; } static int @@ -301,6 +356,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, bool best_effort) { struct machine *machine = maps__machine(thread__maps(thread)); + uint16_t e_machine = thread__e_machine(thread, machine); struct unwind_info *ui, ui_buf = { .sample = data, .thread = thread, @@ -308,9 +364,9 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, .cb = cb, .arg = arg, .max_stack = max_stack, + .e_machine = e_machine, .best_effort = best_effort }; - uint16_t e_machine = thread__e_machine(thread, machine); const char *arch = perf_env__arch(machine->env); Dwarf_Word ip; int err = -EINVAL, i; diff --git a/tools/perf/util/unwind-libdw.h b/tools/perf/util/unwind-libdw.h index 574b29848cce..496e5898e7ef 100644 --- a/tools/perf/util/unwind-libdw.h +++ b/tools/perf/util/unwind-libdw.h @@ -9,7 +9,6 @@ struct machine; struct perf_sample; struct thread; -bool libdw_set_initial_registers_x86(Dwfl_Thread *thread, void *arg); bool libdw_set_initial_registers_arm(Dwfl_Thread *thread, void *arg); bool libdw_set_initial_registers_arm64(Dwfl_Thread *thread, void *arg); bool libdw_set_initial_registers_csky(Dwfl_Thread *thread, void *arg); @@ -28,6 +27,7 @@ struct unwind_info { void *arg; int max_stack; int idx; + uint16_t e_machine; bool best_effort; struct unwind_entry entries[]; }; -- 2.52.0.457.g6b5491de43-goog
