[RFC PATCH v2 01/34] x86/msr: Move rdtsc{,_ordered}() to

Xin Li (Intel)
2025-04-22T08:23:49Z

Relocate rdtsc{,_ordered}() from <asm/msr.h> to <asm/tsc.h>, and
subsequently remove the inclusion of <asm/msr.h> in <asm/tsc.h>.
Consequently, <asm/msr.h> must be included in several source files
that previously did not require it.

Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---
arch/x86/boot/startup/sme.c | 1 +
arch/x86/events/msr.c | 3 +
arch/x86/events/perf_event.h | 1 +
arch/x86/events/probe.c | 2 +
arch/x86/hyperv/ivm.c | 1 +
arch/x86/include/asm/fred.h | 1 +
arch/x86/include/asm/microcode.h | 2 +
arch/x86/include/asm/mshyperv.h | 1 +
arch/x86/include/asm/msr.h | 55 +-------------
arch/x86/include/asm/suspend_32.h | 1 +
arch/x86/include/asm/suspend_64.h | 1 +
arch/x86/include/asm/switch_to.h | 2 +
arch/x86/include/asm/tsc.h | 76 ++++++++++++++++++-
arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 1 +
arch/x86/kernel/fpu/xstate.h | 1 +
arch/x86/kernel/hpet.c | 1 +
arch/x86/kernel/process_64.c | 1 +
arch/x86/kernel/trace_clock.c | 2 +-
arch/x86/kernel/tsc_sync.c | 1 +
arch/x86/lib/kaslr.c | 2 +-
arch/x86/realmode/init.c | 1 +
drivers/acpi/processor_perflib.c | 1 +
drivers/acpi/processor_throttling.c | 3 +-
drivers/cpufreq/amd-pstate-ut.c | 2 +
drivers/hwmon/hwmon-vid.c | 4 +
drivers/net/vmxnet3/vmxnet3_drv.c | 4 +
.../intel/speed_select_if/isst_if_common.c | 1 +
drivers/platform/x86/intel/turbo_max_3.c | 1 +
28 files changed, 115 insertions(+), 58 deletions(-)

diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
index 5738b31c8e60..591d6a4d2e59 100644
--- a/arch/x86/boot/startup/sme.c
+++ b/arch/x86/boot/startup/sme.c
@@ -44,6 +44,7 @@
#include <asm/sections.h>
#include <asm/coco.h>
#include <asm/sev.h>
+#include <asm/msr.h>

#define PGD_FLAGS _KERNPG_TABLE_NOENC
#define P4D_FLAGS _KERNPG_TABLE_NOENC
diff --git a/arch/x86/events/msr.c b/arch/x86/events/msr.c
index 8970ecef87c5..c39e49cecace 100644
--- a/arch/x86/events/msr.c
+++ b/arch/x86/events/msr.c
@@ -3,6 +3,9 @@
#include <linux/sysfs.h>
#include <linux/nospec.h>
#include <asm/cpu_device_id.h>
+#include <asm/msr.h>
+#include <asm/tsc.h>
+
#include "probe.h"

enum perf_msr_id {
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index b29b452b1187..53ef48b4c65c 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -17,6 +17,7 @@
#include <asm/fpu/xstate.h>
#include <asm/intel_ds.h>
#include <asm/cpu.h>
+#include <asm/msr.h>

/* To enable MSR tracing please use the generic trace points. */

diff --git a/arch/x86/events/probe.c b/arch/x86/events/probe.c
index fda35cf25528..bb719d0d3f0b 100644
--- a/arch/x86/events/probe.c
+++ b/arch/x86/events/probe.c
@@ -2,6 +2,8 @@
#include <linux/export.h>
#include <linux/types.h>
#include <linux/bits.h>
+
+#include <asm/msr.h>
#include "probe.h"

static umode_t
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 1b8a2415183b..8209de792388 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -22,6 +22,7 @@
#include <asm/realmode.h>
#include <asm/e820/api.h>
#include <asm/desc.h>
+#include <asm/msr.h>
#include <uapi/asm/vmx.h>

#ifdef CONFIG_AMD_MEM_ENCRYPT
diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h
index 2a29e5216881..12b34d5b2953 100644
--- a/arch/x86/include/asm/fred.h
+++ b/arch/x86/include/asm/fred.h
@@ -9,6 +9,7 @@
#include <linux/const.h>

#include <asm/asm.h>
+#include <asm/msr.h>
#include <asm/trapnr.h>

/*
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 263ea3dd0001..107a1aaa211b 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -2,6 +2,8 @@
#ifndef _ASM_X86_MICROCODE_H
#define _ASM_X86_MICROCODE_H

+#include <asm/msr.h>
+
struct cpu_signature {
unsigned int sig;
unsigned int pf;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index bab5ccfc60a7..15d00dace70f 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -8,6 +8,7 @@
#include <linux/io.h>
#include <asm/nospec-branch.h>
#include <asm/paravirt.h>
+#include <asm/msr.h>
#include <hyperv/hvhdk.h>

/*
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 2ccc78ebc3d7..2caa13830e11 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -12,6 +12,7 @@
#include <uapi/asm/msr.h>
#include <asm/shared/msr.h>

+#include <linux/types.h>
#include <linux/percpu.h>

struct msr_info {
@@ -169,60 +170,6 @@ native_write_msr_safe(u32 msr, u32 low, u32 high)
extern int rdmsr_safe_regs(u32 regs[8]);
extern int wrmsr_safe_regs(u32 regs[8]);

-/**
- * rdtsc() - returns the current TSC without ordering constraints
- *
- * rdtsc() returns the result of RDTSC as a 64-bit integer. The
- * only ordering constraint it supplies is the ordering implied by
- * "asm volatile": it will put the RDTSC in the place you expect. The
- * CPU can and will speculatively execute that RDTSC, though, so the
- * results can be non-monotonic if compared on different CPUs.
- */
-static __always_inline u64 rdtsc(void)
-{
- DECLARE_ARGS(val, low, high);
-
- asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
-
- return EAX_EDX_VAL(val, low, high);
-}
-
-/**
- * rdtsc_ordered() - read the current TSC in program order
- *
- * rdtsc_ordered() returns the result of RDTSC as a 64-bit integer.
- * It is ordered like a load to a global in-memory counter. It should
- * be impossible to observe non-monotonic rdtsc_unordered() behavior
- * across multiple CPUs as long as the TSC is synced.
- */
-static __always_inline u64 rdtsc_ordered(void)
-{
- DECLARE_ARGS(val, low, high);
-
- /*
- * The RDTSC instruction is not ordered relative to memory
- * access. The Intel SDM and the AMD APM are both vague on this
- * point, but empirically an RDTSC instruction can be
- * speculatively executed before prior loads. An RDTSC
- * immediately after an appropriate barrier appears to be
- * ordered as a normal load, that is, it provides the same
- * ordering guarantees as reading from a global memory location
- * that some other imaginary CPU is updating continuously with a
- * time stamp.
- *
- * Thus, use the preferred barrier on the respective CPU, aiming for
- * RDTSCP as the default.
- */
- asm volatile(ALTERNATIVE_2("rdtsc",
- "lfence; rdtsc", X86_FEATURE_LFENCE_RDTSC,
- "rdtscp", X86_FEATURE_RDTSCP)
- : EAX_EDX_RET(val, low, high)
- /* RDTSCP clobbers ECX with MSR_TSC_AUX. */
- :: "ecx");
-
- return EAX_EDX_VAL(val, low, high);
-}
-
static inline u64 native_read_pmc(int counter)
{
DECLARE_ARGS(val, low, high);
diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h
index d8416b3bf832..e8e5aab06255 100644
--- a/arch/x86/include/asm/suspend_32.h
+++ b/arch/x86/include/asm/suspend_32.h
@@ -9,6 +9,7 @@

#include <asm/desc.h>
#include <asm/fpu/api.h>
+#include <asm/msr.h>

/* image of the saved processor state */
struct saved_context {
diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h
index 54df06687d83..b512f9665f78 100644
--- a/arch/x86/include/asm/suspend_64.h
+++ b/arch/x86/include/asm/suspend_64.h
@@ -9,6 +9,7 @@

#include <asm/desc.h>
#include <asm/fpu/api.h>
+#include <asm/msr.h>

/*
* Image of the saved processor state, used by the low level ACPI suspend to
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index 75248546403d..4f21df7af715 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -52,6 +52,8 @@ do { \
} while (0)

#ifdef CONFIG_X86_32
+#include <asm/msr.h>
+
static inline void refresh_sysenter_cs(struct thread_struct *thread)
{
/* Only happens when SEP is enabled, no need to test "SEP"arately: */
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 94408a784c8e..13335a130edf 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -7,7 +7,81 @@

#include <asm/cpufeature.h>
#include <asm/processor.h>
-#include <asm/msr.h>
+
+/*
+ * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"
+ * constraint has different meanings. For i386, "A" means exactly
+ * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead,
+ * it means rax *or* rdx.
+ */
+#ifdef CONFIG_X86_64
+/* Using 64-bit values saves one instruction clearing the high half of low */
+#define DECLARE_ARGS(val, low, high) unsigned long low, high
+#define EAX_EDX_VAL(val, low, high) ((low) | (high) << 32)
+#define EAX_EDX_RET(val, low, high) "=a" (low), "=d" (high)
+#else
+#define DECLARE_ARGS(val, low, high) u64 val
+#define EAX_EDX_VAL(val, low, high) (val)
+#define EAX_EDX_RET(val, low, high) "=A" (val)
+#endif
+
+/**
+ * rdtsc() - returns the current TSC without ordering constraints
+ *
+ * rdtsc() returns the result of RDTSC as a 64-bit integer. The
+ * only ordering constraint it supplies is the ordering implied by
+ * "asm volatile": it will put the RDTSC in the place you expect. The
+ * CPU can and will speculatively execute that RDTSC, though, so the
+ * results can be non-monotonic if compared on different CPUs.
+ */
+static __always_inline u64 rdtsc(void)
+{
+ DECLARE_ARGS(val, low, high);
+
+ asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
+
+ return EAX_EDX_VAL(val, low, high);
+}
+
+/**
+ * rdtsc_ordered() - read the current TSC in program order
+ *
+ * rdtsc_ordered() returns the result of RDTSC as a 64-bit integer.
+ * It is ordered like a load to a global in-memory counter. It should
+ * be impossible to observe non-monotonic rdtsc_unordered() behavior
+ * across multiple CPUs as long as the TSC is synced.
+ */
+static __always_inline u64 rdtsc_ordered(void)
+{
+ DECLARE_ARGS(val, low, high);
+
+ /*
+ * The RDTSC instruction is not ordered relative to memory
+ * access. The Intel SDM and the AMD APM are both vague on this
+ * point, but empirically an RDTSC instruction can be
+ * speculatively executed before prior loads. An RDTSC
+ * immediately after an appropriate barrier appears to be
+ * ordered as a normal load, that is, it provides the same
+ * ordering guarantees as reading from a global memory location
+ * that some other imaginary CPU is updating continuously with a
+ * time stamp.
+ *
+ * Thus, use the preferred barrier on the respective CPU, aiming for
+ * RDTSCP as the default.
+ */
+ asm volatile(ALTERNATIVE_2("rdtsc",
+ "lfence; rdtsc", X86_FEATURE_LFENCE_RDTSC,
+ "rdtscp", X86_FEATURE_RDTSCP)
+ : EAX_EDX_RET(val, low, high)
+ /* RDTSCP clobbers ECX with MSR_TSC_AUX. */
+ :: "ecx");
+
+ return EAX_EDX_VAL(val, low, high);
+}
+
+#undef DECLARE_ARGS
+#undef EAX_EDX_VAL
+#undef EAX_EDX_RET

/*
* Standard way to access the cycle counter.
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index 2a82eb6a0376..26c354bdea07 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -25,6 +25,7 @@
#include <asm/cpu_device_id.h>
#include <asm/resctrl.h>
#include <asm/perf_event.h>
+#include <asm/msr.h>

#include "../../events/perf_event.h" /* For X86_CONFIG() */
#include "internal.h"
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index a3b7dcbdb060..52ce19289989 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -5,6 +5,7 @@
#include <asm/cpufeature.h>
#include <asm/fpu/xstate.h>
#include <asm/fpu/xcr.h>
+#include <asm/msr.h>

#ifdef CONFIG_X86_64
DECLARE_PER_CPU(u64, xfd_state);
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index cc5d12232216..c9982a7c9536 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -12,6 +12,7 @@
#include <asm/hpet.h>
#include <asm/time.h>
#include <asm/mwait.h>
+#include <asm/msr.h>

#undef pr_fmt
#define pr_fmt(fmt) "hpet: " fmt
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 24e1ccf22912..cfa9c031de91 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -57,6 +57,7 @@
#include <asm/unistd.h>
#include <asm/fsgsbase.h>
#include <asm/fred.h>
+#include <asm/msr.h>
#ifdef CONFIG_IA32_EMULATION
/* Not included via unistd.h */
#include <asm/unistd_32_ia32.h>
diff --git a/arch/x86/kernel/trace_clock.c b/arch/x86/kernel/trace_clock.c
index b8e7abe00b06..708d61743d15 100644
--- a/arch/x86/kernel/trace_clock.c
+++ b/arch/x86/kernel/trace_clock.c
@@ -4,7 +4,7 @@
*/
#include <asm/trace_clock.h>
#include <asm/barrier.h>
-#include <asm/msr.h>
+#include <asm/tsc.h>

/*
* trace_clock_x86_tsc(): A clock that is just the cycle counter.
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index f1c7a86dbf49..ec3aa340d351 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -21,6 +21,7 @@
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/nmi.h>
+#include <asm/msr.h>
#include <asm/tsc.h>

struct tsc_adjust {
diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c
index a58f451a7dd3..b5893928d55c 100644
--- a/arch/x86/lib/kaslr.c
+++ b/arch/x86/lib/kaslr.c
@@ -8,7 +8,7 @@
*/
#include <asm/asm.h>
#include <asm/kaslr.h>
-#include <asm/msr.h>
+#include <asm/tsc.h>
#include <asm/archrandom.h>
#include <asm/e820/api.h>
#include <asm/shared/io.h>
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 263787b4800c..ed5c63c0b4e5 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -9,6 +9,7 @@
#include <asm/realmode.h>
#include <asm/tlbflush.h>
#include <asm/crash.h>
+#include <asm/msr.h>
#include <asm/sev.h>

struct real_mode_header *real_mode_header;
diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 53996f1a2d80..64b8d1e19594 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -20,6 +20,7 @@
#include <acpi/processor.h>
#ifdef CONFIG_X86
#include <asm/cpufeature.h>
+#include <asm/msr.h>
#endif

#define ACPI_PROCESSOR_FILE_PERFORMANCE "performance"
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 00d045e5f524..8482e9a8a7aa 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -18,9 +18,10 @@
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/acpi.h>
+#include <linux/uaccess.h>
#include <acpi/processor.h>
#include <asm/io.h>
-#include <linux/uaccess.h>
+#include <asm/asm.h>

/* ignore_tpc:
* 0 -> acpi processor driver doesn't ignore _TPC values
diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
index 707fa81c749f..c8d031b297d2 100644
--- a/drivers/cpufreq/amd-pstate-ut.c
+++ b/drivers/cpufreq/amd-pstate-ut.c
@@ -31,6 +31,8 @@

#include <acpi/cppc_acpi.h>

+#include <asm/msr.h>
+
#include "amd-pstate.h"

diff --git a/drivers/hwmon/hwmon-vid.c b/drivers/hwmon/hwmon-vid.c
index 6d1175a51832..2df4956296ed 100644
--- a/drivers/hwmon/hwmon-vid.c
+++ b/drivers/hwmon/hwmon-vid.c
@@ -15,6 +15,10 @@
#include <linux/kernel.h>
#include <linux/hwmon-vid.h>

+#ifdef CONFIG_X86
+#include <asm/msr.h>
+#endif
+
/*
* Common code for decoding VID pins.
*
diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 3df6aabc7e33..7edd0b5e0e77 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -27,6 +27,10 @@
#include <linux/module.h>
#include <net/ip6_checksum.h>

+#ifdef CONFIG_X86
+#include <asm/msr.h>
+#endif
+
#include "vmxnet3_int.h"
#include "vmxnet3_xdp.h"

diff --git a/drivers/platform/x86/intel/speed_select_if/isst_if_common.c b/drivers/platform/x86/intel/speed_select_if/isst_if_common.c
index 44dcd165b4c0..8a5713593811 100644
--- a/drivers/platform/x86/intel/speed_select_if/isst_if_common.c
+++ b/drivers/platform/x86/intel/speed_select_if/isst_if_common.c
@@ -21,6 +21,7 @@

#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
+#include <asm/msr.h>

#include "isst_if_common.h"

diff --git a/drivers/platform/x86/intel/turbo_max_3.c b/drivers/platform/x86/intel/turbo_max_3.c
index 7e538bbd5b50..b5af3e91ba04 100644
--- a/drivers/platform/x86/intel/turbo_max_3.c
+++ b/drivers/platform/x86/intel/turbo_max_3.c
@@ -17,6 +17,7 @@

#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
+#include <asm/msr.h>

#define MSR_OC_MAILBOX 0x150
#define MSR_OC_MAILBOX_CMD_OFFSET 32
--
2.49.0