kernel_5.10 no rt

hc

2023-12-11 6778948f9de86c3cfaf36725a7c87dcff9ba247f

 kernel/arch/riscv/include/asm/timex.h
..
..
@@ -1,56 +1,87 @@
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+/* SPDX-License-Identifier: GPL-2.0-only */
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 /*
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  * Copyright (C) 2012 Regents of the University of California
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- *
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- *   This program is free software; you can redistribute it and/or
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- *   modify it under the terms of the GNU General Public License
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- *   as published by the Free Software Foundation, version 2.
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- *
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- *   This program is distributed in the hope that it will be useful,
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- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
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- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- *   GNU General Public License for more details.
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  */
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 #ifndef _ASM_RISCV_TIMEX_H
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 #define _ASM_RISCV_TIMEX_H
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8
 
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-#include <asm/param.h>
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+#include <asm/csr.h>
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 typedef unsigned long cycles_t;
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12
 
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-static inline cycles_t get_cycles_inline(void)
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-{
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-	cycles_t n;
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+#ifdef CONFIG_RISCV_M_MODE
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-	__asm__ __volatile__ (
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-		"rdtime %0"
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-		: "=r" (n));
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-	return n;
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-}
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-#define get_cycles get_cycles_inline
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+#include <asm/clint.h>
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 #ifdef CONFIG_64BIT
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-static inline uint64_t get_cycles64(void)
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+static inline cycles_t get_cycles(void)
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 {
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-        return get_cycles();
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+	return readq_relaxed(clint_time_val);
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 }
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-#else
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-static inline uint64_t get_cycles64(void)
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+#else /* !CONFIG_64BIT */
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+static inline u32 get_cycles(void)
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 {
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-	u32 lo, hi, tmp;
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-	__asm__ __volatile__ (
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-		"1:\n"
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-		"rdtimeh %0\n"
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-		"rdtime %1\n"
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-		"rdtimeh %2\n"
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-		"bne %0, %2, 1b"
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-		: "=&r" (hi), "=&r" (lo), "=&r" (tmp));
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+	return readl_relaxed(((u32 *)clint_time_val));
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+}
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+#define get_cycles get_cycles
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+
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+static inline u32 get_cycles_hi(void)
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+{
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+	return readl_relaxed(((u32 *)clint_time_val) + 1);
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+}
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+#define get_cycles_hi get_cycles_hi
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+#endif /* CONFIG_64BIT */
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+
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+/*
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+ * Much like MIPS, we may not have a viable counter to use at an early point
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+ * in the boot process. Unfortunately we don't have a fallback, so instead
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+ * we just return 0.
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+ */
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+static inline unsigned long random_get_entropy(void)
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+{
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+	if (unlikely(clint_time_val == NULL))
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+		return random_get_entropy_fallback();
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+	return get_cycles();
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+}
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+#define random_get_entropy()	random_get_entropy()
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+
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+#else /* CONFIG_RISCV_M_MODE */
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+
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+static inline cycles_t get_cycles(void)
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+{
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+	return csr_read(CSR_TIME);
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+}
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+#define get_cycles get_cycles
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+
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+static inline u32 get_cycles_hi(void)
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+{
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+	return csr_read(CSR_TIMEH);
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+}
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+#define get_cycles_hi get_cycles_hi
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+
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+#endif /* !CONFIG_RISCV_M_MODE */
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+
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+#ifdef CONFIG_64BIT
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+static inline u64 get_cycles64(void)
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+{
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+	return get_cycles();
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+}
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+#else /* CONFIG_64BIT */
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+static inline u64 get_cycles64(void)
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+{
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+	u32 hi, lo;
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+
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+	do {
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+		hi = get_cycles_hi();
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+		lo = get_cycles();
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+	} while (hi != get_cycles_hi());
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+
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 	return ((u64)hi << 32) | lo;
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 }
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-#endif
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+#endif /* CONFIG_64BIT */
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 #define ARCH_HAS_READ_CURRENT_TIMER
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-
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 static inline int read_current_timer(unsigned long *timer_val)
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 {
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 	*timer_val = get_cycles();