[PATCH v4] arch/x86: port I/O tracing on x86
From: Dan Raymond
Date: Fri Oct 06 2023 - 17:32:51 EST
Add support for port I/O tracing on x86. Memory mapped I/O tracing is
available on x86 via CONFIG_MMIOTRACE but that relies on page faults
so it doesn't work with port I/O. This feature uses tracepoints in a
similar manner as CONFIG_TRACE_MMIO_ACCESS.
Signed-off-by: Dan Raymond <raymod2@xxxxxxxxx>
Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
V1 -> V2:
- create header file for prototypes to silence new compiler warning
- reduce CPU overhead to 2 instructions (no branching) when tracing disabled
- fix imprecise IP logging by retrieving the IP off the stack instead of using
compile time labels
V2 -> V3:
- restore missing semicolon
V3 -> V4:
- make GPL licenses consistent
- change pointer arguments from (long) to (void *)
- eliminate include guard checks and use -DDISABLE_TRACEPOINTS instead to
disable tracepoints in arch/x86/boot/*
- fix compiler warnings due to signed/unsigned mismatch in arch_cmpxchg64()
arch/x86/boot/Makefile | 1 +
arch/x86/boot/compressed/Makefile | 1 +
arch/x86/include/asm/cmpxchg_32.h | 13 ++++----
arch/x86/include/asm/shared/io.h | 9 ++++++
arch/x86/lib/Makefile | 1 +
arch/x86/lib/trace_portio.c | 21 +++++++++++++
include/linux/trace_portio.h | 6 ++++
include/linux/tracepoint-defs.h | 2 +-
include/trace/events/portio.h | 49 +++++++++++++++++++++++++++++++
9 files changed, 97 insertions(+), 6 deletions(-)
create mode 100644 arch/x86/lib/trace_portio.c
create mode 100644 include/linux/trace_portio.h
create mode 100644 include/trace/events/portio.h
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index ffec8bb01ba8..6cec531be03b 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -70,6 +70,7 @@ KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP
KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
+KBUILD_CFLAGS += -DDISABLE_TRACEPOINTS
GCOV_PROFILE := n
UBSAN_SANITIZE := n
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 35ce1a64068b..c368bcc008eb 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -51,6 +51,7 @@ KBUILD_CFLAGS += -D__DISABLE_EXPORTS
# Disable relocation relaxation in case the link is not PIE.
KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no)
KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h
+KBUILD_CFLAGS += -DDISABLE_TRACEPOINTS
# sev.c indirectly inludes inat-table.h which is generated during
# compilation and stored in $(objtree). Add the directory to the includes so
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 215f5a65790f..054a2906eefd 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -37,13 +37,16 @@ static inline void set_64bit(volatile u64 *ptr, u64 value)
#ifdef CONFIG_X86_CMPXCHG64
#define arch_cmpxchg64(ptr, o, n) \
- ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \
+ ((__typeof__(*(ptr)))__cmpxchg64((unsigned long long *)(ptr), \
+ (unsigned long long)(o), \
(unsigned long long)(n)))
-#define arch_cmpxchg64_local(ptr, o, n) \
- ((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o), \
+#define arch_cmpxchg64_local(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg64_local((unsigned long long *)(ptr), \
+ (unsigned long long)(o), \
(unsigned long long)(n)))
-#define arch_try_cmpxchg64(ptr, po, n) \
- __try_cmpxchg64((ptr), (unsigned long long *)(po), \
+#define arch_try_cmpxchg64(ptr, po, n) \
+ __try_cmpxchg64((unsigned long long *)(ptr), \
+ (unsigned long long *)(po), \
(unsigned long long)(n))
#endif
diff --git a/arch/x86/include/asm/shared/io.h b/arch/x86/include/asm/shared/io.h
index c0ef921c0586..82664956ce41 100644
--- a/arch/x86/include/asm/shared/io.h
+++ b/arch/x86/include/asm/shared/io.h
@@ -2,13 +2,20 @@
#ifndef _ASM_X86_SHARED_IO_H
#define _ASM_X86_SHARED_IO_H
+#include <linux/tracepoint-defs.h>
+#include <linux/trace_portio.h>
#include <linux/types.h>
+DECLARE_TRACEPOINT(portio_write);
+DECLARE_TRACEPOINT(portio_read);
+
#define BUILDIO(bwl, bw, type) \
static inline void __out##bwl(type value, u16 port) \
{ \
asm volatile("out" #bwl " %" #bw "0, %w1" \
: : "a"(value), "Nd"(port)); \
+ if (tracepoint_enabled(portio_write)) \
+ do_trace_portio_write(value, port, #bwl[0]); \
} \
\
static inline type __in##bwl(u16 port) \
@@ -16,6 +23,8 @@ static inline type __in##bwl(u16 port) \
type value; \
asm volatile("in" #bwl " %w1, %" #bw "0" \
: "=a"(value) : "Nd"(port)); \
+ if (tracepoint_enabled(portio_read)) \
+ do_trace_portio_read(value, port, #bwl[0]); \
return value; \
}
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f76747862bd2..254f223c025d 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -40,6 +40,7 @@ $(obj)/inat.o: $(obj)/inat-tables.c
clean-files := inat-tables.c
obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
+obj-$(CONFIG_TRACEPOINTS) += trace_portio.o
lib-y := delay.o misc.o cmdline.o cpu.o
lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
diff --git a/arch/x86/lib/trace_portio.c b/arch/x86/lib/trace_portio.c
new file mode 100644
index 000000000000..b5f62dfd85a0
--- /dev/null
+++ b/arch/x86/lib/trace_portio.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/instruction_pointer.h>
+#include <linux/trace_portio.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/portio.h>
+
+void do_trace_portio_read(u32 value, u16 port, char width)
+{
+ trace_portio_read(value, port, width, (void *)_RET_IP_);
+}
+EXPORT_SYMBOL_GPL(do_trace_portio_read);
+EXPORT_TRACEPOINT_SYMBOL_GPL(portio_read);
+
+void do_trace_portio_write(u32 value, u16 port, char width)
+{
+ trace_portio_write(value, port, width, (void *)_RET_IP_);
+}
+EXPORT_SYMBOL_GPL(do_trace_portio_write);
+EXPORT_TRACEPOINT_SYMBOL_GPL(portio_write);
diff --git a/include/linux/trace_portio.h b/include/linux/trace_portio.h
new file mode 100644
index 000000000000..2324d62e6c9e
--- /dev/null
+++ b/include/linux/trace_portio.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/types.h>
+
+extern void do_trace_portio_read(u32 value, u16 port, char width);
+extern void do_trace_portio_write(u32 value, u16 port, char width);
diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
index e7c2276be33e..bfe70e17b2aa 100644
--- a/include/linux/tracepoint-defs.h
+++ b/include/linux/tracepoint-defs.h
@@ -80,7 +80,7 @@ struct bpf_raw_event_map {
#define DECLARE_TRACEPOINT(tp) \
extern struct tracepoint __tracepoint_##tp
-#ifdef CONFIG_TRACEPOINTS
+#if defined(CONFIG_TRACEPOINTS) && !defined(DISABLE_TRACEPOINTS)
# define tracepoint_enabled(tp) \
static_key_false(&(__tracepoint_##tp).key)
#else
diff --git a/include/trace/events/portio.h b/include/trace/events/portio.h
new file mode 100644
index 000000000000..7bac3ed197a8
--- /dev/null
+++ b/include/trace/events/portio.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM portio
+
+#if !defined(_TRACE_PORTIO_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PORTIO_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(portio_class,
+ TP_PROTO(u32 value, u16 port, char width, void *ip_addr),
+
+ TP_ARGS(value, port, width, ip_addr),
+
+ TP_STRUCT__entry(
+ __field(u32, value)
+ __field(u16, port)
+ __field(char, width)
+ __field(void *, ip_addr)
+ ),
+
+ TP_fast_assign(
+ __entry->value = value;
+ __entry->port = port;
+ __entry->width = width;
+ __entry->ip_addr = ip_addr;
+ ),
+
+ TP_printk("port=0x%04x value=0x%0*x %pS",
+ __entry->port,
+ __entry->width == 'b' ? 2 :
+ __entry->width == 'w' ? 4 : 8,
+ __entry->value, __entry->ip_addr)
+);
+
+DEFINE_EVENT(portio_class, portio_read,
+ TP_PROTO(u32 value, u16 port, char width, void *ip_addr),
+ TP_ARGS(value, port, width, ip_addr)
+);
+
+DEFINE_EVENT(portio_class, portio_write,
+ TP_PROTO(u32 value, u16 port, char width, void *ip_addr),
+ TP_ARGS(value, port, width, ip_addr)
+);
+
+#endif /* _TRACE_PORTIO_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
base-commit: be8b93b5cc7d533eb8c9b0590cdac055ecafe13a
--
2.25.1