[tip: perf/core] perf/x86: Move branch classifier
From: tip-bot2 for Sandipan Das
Date: Fri Aug 26 2022 - 18:17:07 EST
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 4462fbfe6ec1bfe2196b977010f6ce7b43a32f2c
Gitweb: https://git.kernel.org/tip/4462fbfe6ec1bfe2196b977010f6ce7b43a32f2c
Author: Sandipan Das <sandipan.das@xxxxxxx>
AuthorDate: Thu, 11 Aug 2022 17:59:56 +05:30
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Sat, 27 Aug 2022 00:05:44 +02:00
perf/x86: Move branch classifier
Commit 3e702ff6d1ea ("perf/x86: Add LBR software filter support for Intel
CPUs") introduces a software branch filter which complements the hardware
branch filter and adds an x86 branch classifier.
Move the branch classifier to arch/x86/events/ so that it can be utilized
by other vendors for branch record filtering.
Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/bae5b95470d6bd49f40954bd379f414f5afcb965.1660211399.git.sandipan.das@xxxxxxx
---
arch/x86/events/Makefile | 2 +-
arch/x86/events/intel/lbr.c | 273 +----------------------------------
arch/x86/events/perf_event.h | 62 ++++++++-
arch/x86/events/utils.c | 216 +++++++++++++++++++++++++++-
4 files changed, 279 insertions(+), 274 deletions(-)
create mode 100644 arch/x86/events/utils.c
diff --git a/arch/x86/events/Makefile b/arch/x86/events/Makefile
index 9933c0e..86a76ef 100644
--- a/arch/x86/events/Makefile
+++ b/arch/x86/events/Makefile
@@ -1,5 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
-obj-y += core.o probe.o
+obj-y += core.o probe.o utils.o
obj-$(CONFIG_PERF_EVENTS_INTEL_RAPL) += rapl.o
obj-y += amd/
obj-$(CONFIG_X86_LOCAL_APIC) += msr.o
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 4f70fb6..7dffc0c 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -4,7 +4,6 @@
#include <asm/perf_event.h>
#include <asm/msr.h>
-#include <asm/insn.h>
#include "../perf_event.h"
@@ -66,65 +65,6 @@
#define LBR_FROM_SIGNEXT_2MSB (BIT_ULL(60) | BIT_ULL(59))
/*
- * x86control flow change classification
- * x86control flow changes include branches, interrupts, traps, faults
- */
-enum {
- X86_BR_NONE = 0, /* unknown */
-
- X86_BR_USER = 1 << 0, /* branch target is user */
- X86_BR_KERNEL = 1 << 1, /* branch target is kernel */
-
- X86_BR_CALL = 1 << 2, /* call */
- X86_BR_RET = 1 << 3, /* return */
- X86_BR_SYSCALL = 1 << 4, /* syscall */
- X86_BR_SYSRET = 1 << 5, /* syscall return */
- X86_BR_INT = 1 << 6, /* sw interrupt */
- X86_BR_IRET = 1 << 7, /* return from interrupt */
- X86_BR_JCC = 1 << 8, /* conditional */
- X86_BR_JMP = 1 << 9, /* jump */
- X86_BR_IRQ = 1 << 10,/* hw interrupt or trap or fault */
- X86_BR_IND_CALL = 1 << 11,/* indirect calls */
- X86_BR_ABORT = 1 << 12,/* transaction abort */
- X86_BR_IN_TX = 1 << 13,/* in transaction */
- X86_BR_NO_TX = 1 << 14,/* not in transaction */
- X86_BR_ZERO_CALL = 1 << 15,/* zero length call */
- X86_BR_CALL_STACK = 1 << 16,/* call stack */
- X86_BR_IND_JMP = 1 << 17,/* indirect jump */
-
- X86_BR_TYPE_SAVE = 1 << 18,/* indicate to save branch type */
-
-};
-
-#define X86_BR_PLM (X86_BR_USER | X86_BR_KERNEL)
-#define X86_BR_ANYTX (X86_BR_NO_TX | X86_BR_IN_TX)
-
-#define X86_BR_ANY \
- (X86_BR_CALL |\
- X86_BR_RET |\
- X86_BR_SYSCALL |\
- X86_BR_SYSRET |\
- X86_BR_INT |\
- X86_BR_IRET |\
- X86_BR_JCC |\
- X86_BR_JMP |\
- X86_BR_IRQ |\
- X86_BR_ABORT |\
- X86_BR_IND_CALL |\
- X86_BR_IND_JMP |\
- X86_BR_ZERO_CALL)
-
-#define X86_BR_ALL (X86_BR_PLM | X86_BR_ANY)
-
-#define X86_BR_ANY_CALL \
- (X86_BR_CALL |\
- X86_BR_IND_CALL |\
- X86_BR_ZERO_CALL |\
- X86_BR_SYSCALL |\
- X86_BR_IRQ |\
- X86_BR_INT)
-
-/*
* Intel LBR_CTL bits
*
* Hardware branch filter for Arch LBR
@@ -1143,219 +1083,6 @@ int intel_pmu_setup_lbr_filter(struct perf_event *event)
return ret;
}
-/*
- * return the type of control flow change at address "from"
- * instruction is not necessarily a branch (in case of interrupt).
- *
- * The branch type returned also includes the priv level of the
- * target of the control flow change (X86_BR_USER, X86_BR_KERNEL).
- *
- * If a branch type is unknown OR the instruction cannot be
- * decoded (e.g., text page not present), then X86_BR_NONE is
- * returned.
- */
-static int branch_type(unsigned long from, unsigned long to, int abort)
-{
- struct insn insn;
- void *addr;
- int bytes_read, bytes_left;
- int ret = X86_BR_NONE;
- int ext, to_plm, from_plm;
- u8 buf[MAX_INSN_SIZE];
- int is64 = 0;
-
- to_plm = kernel_ip(to) ? X86_BR_KERNEL : X86_BR_USER;
- from_plm = kernel_ip(from) ? X86_BR_KERNEL : X86_BR_USER;
-
- /*
- * maybe zero if lbr did not fill up after a reset by the time
- * we get a PMU interrupt
- */
- if (from == 0 || to == 0)
- return X86_BR_NONE;
-
- if (abort)
- return X86_BR_ABORT | to_plm;
-
- if (from_plm == X86_BR_USER) {
- /*
- * can happen if measuring at the user level only
- * and we interrupt in a kernel thread, e.g., idle.
- */
- if (!current->mm)
- return X86_BR_NONE;
-
- /* may fail if text not present */
- bytes_left = copy_from_user_nmi(buf, (void __user *)from,
- MAX_INSN_SIZE);
- bytes_read = MAX_INSN_SIZE - bytes_left;
- if (!bytes_read)
- return X86_BR_NONE;
-
- addr = buf;
- } else {
- /*
- * The LBR logs any address in the IP, even if the IP just
- * faulted. This means userspace can control the from address.
- * Ensure we don't blindly read any address by validating it is
- * a known text address.
- */
- if (kernel_text_address(from)) {
- addr = (void *)from;
- /*
- * Assume we can get the maximum possible size
- * when grabbing kernel data. This is not
- * _strictly_ true since we could possibly be
- * executing up next to a memory hole, but
- * it is very unlikely to be a problem.
- */
- bytes_read = MAX_INSN_SIZE;
- } else {
- return X86_BR_NONE;
- }
- }
-
- /*
- * decoder needs to know the ABI especially
- * on 64-bit systems running 32-bit apps
- */
-#ifdef CONFIG_X86_64
- 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;
-
- 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;
- 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;
- break;
- case 4:
- case 5:
- ret = X86_BR_IND_JMP;
- break;
- }
- break;
- default:
- ret = X86_BR_NONE;
- }
- /*
- * interrupts, traps, faults (and thus ring transition) may
- * occur on any instructions. Thus, to classify them correctly,
- * we need to first look at the from and to priv levels. If they
- * are different and to is in the kernel, then it indicates
- * a ring transition. If the from instruction is not a ring
- * transition instr (syscall, systenter, int), then it means
- * it was a irq, trap or fault.
- *
- * we have no way of detecting kernel to kernel faults.
- */
- if (from_plm == X86_BR_USER && to_plm == X86_BR_KERNEL
- && ret != X86_BR_SYSCALL && ret != X86_BR_INT)
- ret = X86_BR_IRQ;
-
- /*
- * branch priv level determined by target as
- * is done by HW when LBR_SELECT is implemented
- */
- if (ret != X86_BR_NONE)
- ret |= to_plm;
-
- return ret;
-}
-
-#define X86_BR_TYPE_MAP_MAX 16
-
-static int branch_map[X86_BR_TYPE_MAP_MAX] = {
- PERF_BR_CALL, /* X86_BR_CALL */
- PERF_BR_RET, /* X86_BR_RET */
- PERF_BR_SYSCALL, /* X86_BR_SYSCALL */
- PERF_BR_SYSRET, /* X86_BR_SYSRET */
- PERF_BR_UNKNOWN, /* X86_BR_INT */
- PERF_BR_ERET, /* X86_BR_IRET */
- PERF_BR_COND, /* X86_BR_JCC */
- PERF_BR_UNCOND, /* X86_BR_JMP */
- PERF_BR_IRQ, /* X86_BR_IRQ */
- PERF_BR_IND_CALL, /* X86_BR_IND_CALL */
- PERF_BR_UNKNOWN, /* X86_BR_ABORT */
- PERF_BR_UNKNOWN, /* X86_BR_IN_TX */
- PERF_BR_UNKNOWN, /* X86_BR_NO_TX */
- PERF_BR_CALL, /* X86_BR_ZERO_CALL */
- PERF_BR_UNKNOWN, /* X86_BR_CALL_STACK */
- PERF_BR_IND, /* X86_BR_IND_JMP */
-};
-
-static int
-common_branch_type(int type)
-{
- int i;
-
- type >>= 2; /* skip X86_BR_USER and X86_BR_KERNEL */
-
- if (type) {
- i = __ffs(type);
- if (i < X86_BR_TYPE_MAP_MAX)
- return branch_map[i];
- }
-
- return PERF_BR_UNKNOWN;
-}
-
enum {
ARCH_LBR_BR_TYPE_JCC = 0,
ARCH_LBR_BR_TYPE_NEAR_IND_JMP = 1,
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index e893041..2de9cd6 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -1210,6 +1210,68 @@ static inline void set_linear_ip(struct pt_regs *regs, unsigned long ip)
regs->ip = ip;
}
+/*
+ * x86control flow change classification
+ * x86control flow changes include branches, interrupts, traps, faults
+ */
+enum {
+ X86_BR_NONE = 0, /* unknown */
+
+ X86_BR_USER = 1 << 0, /* branch target is user */
+ X86_BR_KERNEL = 1 << 1, /* branch target is kernel */
+
+ X86_BR_CALL = 1 << 2, /* call */
+ X86_BR_RET = 1 << 3, /* return */
+ X86_BR_SYSCALL = 1 << 4, /* syscall */
+ X86_BR_SYSRET = 1 << 5, /* syscall return */
+ X86_BR_INT = 1 << 6, /* sw interrupt */
+ X86_BR_IRET = 1 << 7, /* return from interrupt */
+ X86_BR_JCC = 1 << 8, /* conditional */
+ X86_BR_JMP = 1 << 9, /* jump */
+ X86_BR_IRQ = 1 << 10,/* hw interrupt or trap or fault */
+ X86_BR_IND_CALL = 1 << 11,/* indirect calls */
+ X86_BR_ABORT = 1 << 12,/* transaction abort */
+ X86_BR_IN_TX = 1 << 13,/* in transaction */
+ X86_BR_NO_TX = 1 << 14,/* not in transaction */
+ X86_BR_ZERO_CALL = 1 << 15,/* zero length call */
+ X86_BR_CALL_STACK = 1 << 16,/* call stack */
+ X86_BR_IND_JMP = 1 << 17,/* indirect jump */
+
+ X86_BR_TYPE_SAVE = 1 << 18,/* indicate to save branch type */
+
+};
+
+#define X86_BR_PLM (X86_BR_USER | X86_BR_KERNEL)
+#define X86_BR_ANYTX (X86_BR_NO_TX | X86_BR_IN_TX)
+
+#define X86_BR_ANY \
+ (X86_BR_CALL |\
+ X86_BR_RET |\
+ X86_BR_SYSCALL |\
+ X86_BR_SYSRET |\
+ X86_BR_INT |\
+ X86_BR_IRET |\
+ X86_BR_JCC |\
+ X86_BR_JMP |\
+ X86_BR_IRQ |\
+ X86_BR_ABORT |\
+ X86_BR_IND_CALL |\
+ X86_BR_IND_JMP |\
+ X86_BR_ZERO_CALL)
+
+#define X86_BR_ALL (X86_BR_PLM | X86_BR_ANY)
+
+#define X86_BR_ANY_CALL \
+ (X86_BR_CALL |\
+ X86_BR_IND_CALL |\
+ X86_BR_ZERO_CALL |\
+ X86_BR_SYSCALL |\
+ X86_BR_IRQ |\
+ X86_BR_INT)
+
+int common_branch_type(int type);
+int branch_type(unsigned long from, unsigned long to, int abort);
+
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
new file mode 100644
index 0000000..a323689
--- /dev/null
+++ b/arch/x86/events/utils.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/insn.h>
+
+#include "perf_event.h"
+
+/*
+ * return the type of control flow change at address "from"
+ * instruction is not necessarily a branch (in case of interrupt).
+ *
+ * The branch type returned also includes the priv level of the
+ * target of the control flow change (X86_BR_USER, X86_BR_KERNEL).
+ *
+ * If a branch type is unknown OR the instruction cannot be
+ * decoded (e.g., text page not present), then X86_BR_NONE is
+ * returned.
+ */
+int branch_type(unsigned long from, unsigned long to, int abort)
+{
+ struct insn insn;
+ void *addr;
+ int bytes_read, bytes_left;
+ int ret = X86_BR_NONE;
+ int ext, to_plm, from_plm;
+ u8 buf[MAX_INSN_SIZE];
+ int is64 = 0;
+
+ to_plm = kernel_ip(to) ? X86_BR_KERNEL : X86_BR_USER;
+ from_plm = kernel_ip(from) ? X86_BR_KERNEL : X86_BR_USER;
+
+ /*
+ * maybe zero if lbr did not fill up after a reset by the time
+ * we get a PMU interrupt
+ */
+ if (from == 0 || to == 0)
+ return X86_BR_NONE;
+
+ if (abort)
+ return X86_BR_ABORT | to_plm;
+
+ if (from_plm == X86_BR_USER) {
+ /*
+ * can happen if measuring at the user level only
+ * and we interrupt in a kernel thread, e.g., idle.
+ */
+ if (!current->mm)
+ return X86_BR_NONE;
+
+ /* may fail if text not present */
+ bytes_left = copy_from_user_nmi(buf, (void __user *)from,
+ MAX_INSN_SIZE);
+ bytes_read = MAX_INSN_SIZE - bytes_left;
+ if (!bytes_read)
+ return X86_BR_NONE;
+
+ addr = buf;
+ } else {
+ /*
+ * The LBR logs any address in the IP, even if the IP just
+ * faulted. This means userspace can control the from address.
+ * Ensure we don't blindly read any address by validating it is
+ * a known text address.
+ */
+ if (kernel_text_address(from)) {
+ addr = (void *)from;
+ /*
+ * Assume we can get the maximum possible size
+ * when grabbing kernel data. This is not
+ * _strictly_ true since we could possibly be
+ * executing up next to a memory hole, but
+ * it is very unlikely to be a problem.
+ */
+ bytes_read = MAX_INSN_SIZE;
+ } else {
+ return X86_BR_NONE;
+ }
+ }
+
+ /*
+ * decoder needs to know the ABI especially
+ * on 64-bit systems running 32-bit apps
+ */
+#ifdef CONFIG_X86_64
+ 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;
+
+ 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;
+ 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;
+ break;
+ case 4:
+ case 5:
+ ret = X86_BR_IND_JMP;
+ break;
+ }
+ break;
+ default:
+ ret = X86_BR_NONE;
+ }
+ /*
+ * interrupts, traps, faults (and thus ring transition) may
+ * occur on any instructions. Thus, to classify them correctly,
+ * we need to first look at the from and to priv levels. If they
+ * are different and to is in the kernel, then it indicates
+ * a ring transition. If the from instruction is not a ring
+ * transition instr (syscall, systenter, int), then it means
+ * it was a irq, trap or fault.
+ *
+ * we have no way of detecting kernel to kernel faults.
+ */
+ if (from_plm == X86_BR_USER && to_plm == X86_BR_KERNEL
+ && ret != X86_BR_SYSCALL && ret != X86_BR_INT)
+ ret = X86_BR_IRQ;
+
+ /*
+ * branch priv level determined by target as
+ * is done by HW when LBR_SELECT is implemented
+ */
+ if (ret != X86_BR_NONE)
+ ret |= to_plm;
+
+ return ret;
+}
+
+#define X86_BR_TYPE_MAP_MAX 16
+
+static int branch_map[X86_BR_TYPE_MAP_MAX] = {
+ PERF_BR_CALL, /* X86_BR_CALL */
+ PERF_BR_RET, /* X86_BR_RET */
+ PERF_BR_SYSCALL, /* X86_BR_SYSCALL */
+ PERF_BR_SYSRET, /* X86_BR_SYSRET */
+ PERF_BR_UNKNOWN, /* X86_BR_INT */
+ PERF_BR_ERET, /* X86_BR_IRET */
+ PERF_BR_COND, /* X86_BR_JCC */
+ PERF_BR_UNCOND, /* X86_BR_JMP */
+ PERF_BR_IRQ, /* X86_BR_IRQ */
+ PERF_BR_IND_CALL, /* X86_BR_IND_CALL */
+ PERF_BR_UNKNOWN, /* X86_BR_ABORT */
+ PERF_BR_UNKNOWN, /* X86_BR_IN_TX */
+ PERF_BR_UNKNOWN, /* X86_BR_NO_TX */
+ PERF_BR_CALL, /* X86_BR_ZERO_CALL */
+ PERF_BR_UNKNOWN, /* X86_BR_CALL_STACK */
+ PERF_BR_IND, /* X86_BR_IND_JMP */
+};
+
+int common_branch_type(int type)
+{
+ int i;
+
+ type >>= 2; /* skip X86_BR_USER and X86_BR_KERNEL */
+
+ if (type) {
+ i = __ffs(type);
+ if (i < X86_BR_TYPE_MAP_MAX)
+ return branch_map[i];
+ }
+
+ return PERF_BR_UNKNOWN;
+}