From 6778948f9de86c3cfaf36725a7c87dcff9ba247f Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 08:20:59 +0000
Subject: [PATCH] kernel_5.10 no rt

---
 kernel/arch/riscv/include/asm/mmu_context.h |   69 +---------------------------------
 1 files changed, 3 insertions(+), 66 deletions(-)

diff --git a/kernel/arch/riscv/include/asm/mmu_context.h b/kernel/arch/riscv/include/asm/mmu_context.h
index 336d60e..67c4638 100644
--- a/kernel/arch/riscv/include/asm/mmu_context.h
+++ b/kernel/arch/riscv/include/asm/mmu_context.h
@@ -1,15 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (C) 2012 Regents of the University of California
  * Copyright (C) 2017 SiFive
- *
- *   This program is free software; you can redistribute it and/or
- *   modify it under the terms of the GNU General Public License
- *   as published by the Free Software Foundation, version 2.
- *
- *   This program is distributed in the hope that it will be useful,
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *   GNU General Public License for more details.
  */
 
 #ifndef _ASM_RISCV_MMU_CONTEXT_H
@@ -20,8 +12,6 @@
 
 #include <linux/mm.h>
 #include <linux/sched.h>
-#include <asm/tlbflush.h>
-#include <asm/cacheflush.h>
 
 static inline void enter_lazy_tlb(struct mm_struct *mm,
 	struct task_struct *task)
@@ -39,61 +29,8 @@
 {
 }
 
-/*
- * When necessary, performs a deferred icache flush for the given MM context,
- * on the local CPU.  RISC-V has no direct mechanism for instruction cache
- * shoot downs, so instead we send an IPI that informs the remote harts they
- * need to flush their local instruction caches.  To avoid pathologically slow
- * behavior in a common case (a bunch of single-hart processes on a many-hart
- * machine, ie 'make -j') we avoid the IPIs for harts that are not currently
- * executing a MM context and instead schedule a deferred local instruction
- * cache flush to be performed before execution resumes on each hart.  This
- * actually performs that local instruction cache flush, which implicitly only
- * refers to the current hart.
- */
-static inline void flush_icache_deferred(struct mm_struct *mm)
-{
-#ifdef CONFIG_SMP
-	unsigned int cpu = smp_processor_id();
-	cpumask_t *mask = &mm->context.icache_stale_mask;
-
-	if (cpumask_test_cpu(cpu, mask)) {
-		cpumask_clear_cpu(cpu, mask);
-		/*
-		 * Ensure the remote hart's writes are visible to this hart.
-		 * This pairs with a barrier in flush_icache_mm.
-		 */
-		smp_mb();
-		local_flush_icache_all();
-	}
-#endif
-}
-
-static inline void switch_mm(struct mm_struct *prev,
-	struct mm_struct *next, struct task_struct *task)
-{
-	if (likely(prev != next)) {
-		/*
-		 * Mark the current MM context as inactive, and the next as
-		 * active.  This is at least used by the icache flushing
-		 * routines in order to determine who should
-		 */
-		unsigned int cpu = smp_processor_id();
-
-		cpumask_clear_cpu(cpu, mm_cpumask(prev));
-		cpumask_set_cpu(cpu, mm_cpumask(next));
-
-		/*
-		 * Use the old spbtr name instead of using the current satp
-		 * name to support binutils 2.29 which doesn't know about the
-		 * privileged ISA 1.10 yet.
-		 */
-		csr_write(sptbr, virt_to_pfn(next->pgd) | SATP_MODE);
-		local_flush_tlb_all();
-
-		flush_icache_deferred(next);
-	}
-}
+void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+	struct task_struct *task);
 
 static inline void activate_mm(struct mm_struct *prev,
 			       struct mm_struct *next)

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