diff options
| -rw-r--r-- | arch/x86/events/perf_event.h | 2 | ||||
| -rw-r--r-- | arch/x86/events/utils.c | 169 |
2 files changed, 102 insertions, 69 deletions
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 2de9cd66347e..93263b98cd6e 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1271,6 +1271,8 @@ enum { int common_branch_type(int type); int branch_type(unsigned long from, unsigned long to, int abort); +int branch_type_fused(unsigned long from, unsigned long to, int abort, + int *offset); ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event); ssize_t intel_event_sysfs_show(char *page, u64 config); diff --git a/arch/x86/events/utils.c b/arch/x86/events/utils.c index a32368945462..e013243f360c 100644 --- a/arch/x86/events/utils.c +++ b/arch/x86/events/utils.c @@ -3,6 +3,68 @@ #include "perf_event.h" +static int decode_branch_type(struct insn *insn) +{ + int ext; + + if (insn_get_opcode(insn)) + return X86_BR_ABORT; + + switch (insn->opcode.bytes[0]) { + case 0xf: + switch (insn->opcode.bytes[1]) { + case 0x05: /* syscall */ + case 0x34: /* sysenter */ + return X86_BR_SYSCALL; + case 0x07: /* sysret */ + case 0x35: /* sysexit */ + return X86_BR_SYSRET; + case 0x80 ... 0x8f: /* conditional */ + return X86_BR_JCC; + } + return X86_BR_NONE; + case 0x70 ... 0x7f: /* conditional */ + return X86_BR_JCC; + case 0xc2: /* near ret */ + case 0xc3: /* near ret */ + case 0xca: /* far ret */ + case 0xcb: /* far ret */ + return X86_BR_RET; + case 0xcf: /* iret */ + return X86_BR_IRET; + case 0xcc ... 0xce: /* int */ + return X86_BR_INT; + case 0xe8: /* call near rel */ + if (insn_get_immediate(insn) || insn->immediate1.value == 0) { + /* zero length call */ + return X86_BR_ZERO_CALL; + } + fallthrough; + case 0x9a: /* call far absolute */ + return X86_BR_CALL; + case 0xe0 ... 0xe3: /* loop jmp */ + return X86_BR_JCC; + case 0xe9 ... 0xeb: /* jmp */ + return X86_BR_JMP; + case 0xff: /* call near absolute, call far absolute ind */ + if (insn_get_modrm(insn)) + return X86_BR_ABORT; + + ext = (insn->modrm.bytes[0] >> 3) & 0x7; + switch (ext) { + case 2: /* near ind call */ + case 3: /* far ind call */ + return X86_BR_IND_CALL; + case 4: + case 5: + return X86_BR_IND_JMP; + } + return X86_BR_NONE; + } + + return X86_BR_NONE; +} + /* * return the type of control flow change at address "from" * instruction is not necessarily a branch (in case of interrupt). @@ -13,14 +75,22 @@ * If a branch type is unknown OR the instruction cannot be * decoded (e.g., text page not present), then X86_BR_NONE is * returned. + * + * While recording branches, some processors can report the "from" + * address to be that of an instruction preceding the actual branch + * when instruction fusion occurs. If fusion is expected, attempt to + * find the type of the first branch instruction within the next + * MAX_INSN_SIZE bytes and if found, provide the offset between the + * reported "from" address and the actual branch instruction address. */ -int branch_type(unsigned long from, unsigned long to, int abort) +static int get_branch_type(unsigned long from, unsigned long to, int abort, + bool fused, int *offset) { struct insn insn; void *addr; - int bytes_read, bytes_left; + int bytes_read, bytes_left, insn_offset; int ret = X86_BR_NONE; - int ext, to_plm, from_plm; + int to_plm, from_plm; u8 buf[MAX_INSN_SIZE]; int is64 = 0; @@ -83,77 +153,27 @@ int branch_type(unsigned long from, unsigned long to, int abort) is64 = kernel_ip((unsigned long)addr) || any_64bit_mode(current_pt_regs()); #endif insn_init(&insn, addr, bytes_read, is64); - if (insn_get_opcode(&insn)) - return X86_BR_ABORT; + ret = decode_branch_type(&insn); + insn_offset = 0; - switch (insn.opcode.bytes[0]) { - case 0xf: - switch (insn.opcode.bytes[1]) { - case 0x05: /* syscall */ - case 0x34: /* sysenter */ - ret = X86_BR_SYSCALL; - break; - case 0x07: /* sysret */ - case 0x35: /* sysexit */ - ret = X86_BR_SYSRET; - break; - case 0x80 ... 0x8f: /* conditional */ - ret = X86_BR_JCC; - break; - default: - ret = X86_BR_NONE; - } - break; - case 0x70 ... 0x7f: /* conditional */ - ret = X86_BR_JCC; - break; - case 0xc2: /* near ret */ - case 0xc3: /* near ret */ - case 0xca: /* far ret */ - case 0xcb: /* far ret */ - ret = X86_BR_RET; - break; - case 0xcf: /* iret */ - ret = X86_BR_IRET; - break; - case 0xcc ... 0xce: /* int */ - ret = X86_BR_INT; - break; - case 0xe8: /* call near rel */ - if (insn_get_immediate(&insn) || insn.immediate1.value == 0) { - /* zero length call */ - ret = X86_BR_ZERO_CALL; + /* Check for the possibility of branch fusion */ + while (fused && ret == X86_BR_NONE) { + /* Check for decoding errors */ + if (insn_get_length(&insn) || !insn.length) break; - } - fallthrough; - case 0x9a: /* call far absolute */ - ret = X86_BR_CALL; - break; - case 0xe0 ... 0xe3: /* loop jmp */ - ret = X86_BR_JCC; - break; - case 0xe9 ... 0xeb: /* jmp */ - ret = X86_BR_JMP; - break; - case 0xff: /* call near absolute, call far absolute ind */ - if (insn_get_modrm(&insn)) - return X86_BR_ABORT; - ext = (insn.modrm.bytes[0] >> 3) & 0x7; - switch (ext) { - case 2: /* near ind call */ - case 3: /* far ind call */ - ret = X86_BR_IND_CALL; + insn_offset += insn.length; + bytes_read -= insn.length; + if (bytes_read < 0) break; - case 4: - case 5: - ret = X86_BR_IND_JMP; - break; - } - break; - default: - ret = X86_BR_NONE; + + insn_init(&insn, addr + insn_offset, bytes_read, is64); + ret = decode_branch_type(&insn); } + + if (offset) + *offset = insn_offset; + /* * interrupts, traps, faults (and thus ring transition) may * occur on any instructions. Thus, to classify them correctly, @@ -179,6 +199,17 @@ int branch_type(unsigned long from, unsigned long to, int abort) return ret; } +int branch_type(unsigned long from, unsigned long to, int abort) +{ + return get_branch_type(from, to, abort, false, NULL); +} + +int branch_type_fused(unsigned long from, unsigned long to, int abort, + int *offset) +{ + return get_branch_type(from, to, abort, true, offset); +} + #define X86_BR_TYPE_MAP_MAX 16 static int branch_map[X86_BR_TYPE_MAP_MAX] = { |