Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 151 insertions, 0 deletions

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
new file mode 100644
index 0000000000..bae8381050
--- /dev/null
+++ b/arch/x86/include/asm/mwait.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_MWAIT_H
+#define _ASM_X86_MWAIT_H
+
+#include <linux/sched.h>
+#include <linux/sched/idle.h>
+
+#include <asm/cpufeature.h>
+#include <asm/nospec-branch.h>
+
+#define MWAIT_SUBSTATE_MASK		0xf
+#define MWAIT_CSTATE_MASK		0xf
+#define MWAIT_SUBSTATE_SIZE		4
+#define MWAIT_HINT2CSTATE(hint)		(((hint) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK)
+#define MWAIT_HINT2SUBSTATE(hint)	((hint) & MWAIT_CSTATE_MASK)
+#define MWAIT_C1_SUBSTATE_MASK  0xf0
+
+#define CPUID_MWAIT_LEAF		5
+#define CPUID5_ECX_EXTENSIONS_SUPPORTED 0x1
+#define CPUID5_ECX_INTERRUPT_BREAK	0x2
+
+#define MWAIT_ECX_INTERRUPT_BREAK	0x1
+#define MWAITX_ECX_TIMER_ENABLE		BIT(1)
+#define MWAITX_MAX_WAIT_CYCLES		UINT_MAX
+#define MWAITX_DISABLE_CSTATES		0xf0
+#define TPAUSE_C01_STATE		1
+#define TPAUSE_C02_STATE		0
+
+static __always_inline void __monitor(const void *eax, unsigned long ecx,
+			     unsigned long edx)
+{
+	/* "monitor %eax, %ecx, %edx;" */
+	asm volatile(".byte 0x0f, 0x01, 0xc8;"
+		     :: "a" (eax), "c" (ecx), "d"(edx));
+}
+
+static __always_inline void __monitorx(const void *eax, unsigned long ecx,
+			      unsigned long edx)
+{
+	/* "monitorx %eax, %ecx, %edx;" */
+	asm volatile(".byte 0x0f, 0x01, 0xfa;"
+		     :: "a" (eax), "c" (ecx), "d"(edx));
+}
+
+static __always_inline void __mwait(unsigned long eax, unsigned long ecx)
+{
+	mds_idle_clear_cpu_buffers();
+
+	/* "mwait %eax, %ecx;" */
+	asm volatile(".byte 0x0f, 0x01, 0xc9;"
+		     :: "a" (eax), "c" (ecx));
+}
+
+/*
+ * MWAITX allows for a timer expiration to get the core out a wait state in
+ * addition to the default MWAIT exit condition of a store appearing at a
+ * monitored virtual address.
+ *
+ * Registers:
+ *
+ * MWAITX ECX[1]: enable timer if set
+ * MWAITX EBX[31:0]: max wait time expressed in SW P0 clocks. The software P0
+ * frequency is the same as the TSC frequency.
+ *
+ * Below is a comparison between MWAIT and MWAITX on AMD processors:
+ *
+ *                 MWAIT                           MWAITX
+ * opcode          0f 01 c9           |            0f 01 fb
+ * ECX[0]                  value of RFLAGS.IF seen by instruction
+ * ECX[1]          unused/#GP if set  |            enable timer if set
+ * ECX[31:2]                     unused/#GP if set
+ * EAX                           unused (reserve for hint)
+ * EBX[31:0]       unused             |            max wait time (P0 clocks)
+ *
+ *                 MONITOR                         MONITORX
+ * opcode          0f 01 c8           |            0f 01 fa
+ * EAX                     (logical) address to monitor
+ * ECX                     #GP if not zero
+ */
+static __always_inline void __mwaitx(unsigned long eax, unsigned long ebx,
+				     unsigned long ecx)
+{
+	/* No MDS buffer clear as this is AMD/HYGON only */
+
+	/* "mwaitx %eax, %ebx, %ecx;" */
+	asm volatile(".byte 0x0f, 0x01, 0xfb;"
+		     :: "a" (eax), "b" (ebx), "c" (ecx));
+}
+
+static __always_inline void __sti_mwait(unsigned long eax, unsigned long ecx)
+{
+	mds_idle_clear_cpu_buffers();
+	/* "mwait %eax, %ecx;" */
+	asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
+		     :: "a" (eax), "c" (ecx));
+}
+
+/*
+ * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
+ * which can obviate IPI to trigger checking of need_resched.
+ * We execute MONITOR against need_resched and enter optimized wait state
+ * through MWAIT. Whenever someone changes need_resched, we would be woken
+ * up from MWAIT (without an IPI).
+ *
+ * New with Core Duo processors, MWAIT can take some hints based on CPU
+ * capability.
+ */
+static __always_inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
+{
+	if (static_cpu_has_bug(X86_BUG_MONITOR) || !current_set_polling_and_test()) {
+		if (static_cpu_has_bug(X86_BUG_CLFLUSH_MONITOR)) {
+			mb();
+			clflush((void *)&current_thread_info()->flags);
+			mb();
+		}
+
+		__monitor((void *)&current_thread_info()->flags, 0, 0);
+
+		if (!need_resched()) {
+			if (ecx & 1) {
+				__mwait(eax, ecx);
+			} else {
+				__sti_mwait(eax, ecx);
+				raw_local_irq_disable();
+			}
+		}
+	}
+	current_clr_polling();
+}
+
+/*
+ * Caller can specify whether to enter C0.1 (low latency, less
+ * power saving) or C0.2 state (saves more power, but longer wakeup
+ * latency). This may be overridden by the IA32_UMWAIT_CONTROL MSR
+ * which can force requests for C0.2 to be downgraded to C0.1.
+ */
+static inline void __tpause(u32 ecx, u32 edx, u32 eax)
+{
+	/* "tpause %ecx, %edx, %eax;" */
+	#ifdef CONFIG_AS_TPAUSE
+	asm volatile("tpause %%ecx\n"
+		     :
+		     : "c"(ecx), "d"(edx), "a"(eax));
+	#else
+	asm volatile(".byte 0x66, 0x0f, 0xae, 0xf1\t\n"
+		     :
+		     : "c"(ecx), "d"(edx), "a"(eax));
+	#endif
+}
+
+#endif /* _ASM_X86_MWAIT_H */