From 748e4f3d702def1a4bff191e0cf93b6a05340f01 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:41:34 +0000
Subject: [PATCH] add gpio led uart
---
kernel/arch/sparc/mm/highmem.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 115 insertions(+), 0 deletions(-)
diff --git a/kernel/arch/sparc/mm/highmem.c b/kernel/arch/sparc/mm/highmem.c
new file mode 100644
index 0000000..8f2a2af
--- /dev/null
+++ b/kernel/arch/sparc/mm/highmem.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * highmem.c: virtual kernel memory mappings for high memory
+ *
+ * Provides kernel-static versions of atomic kmap functions originally
+ * found as inlines in include/asm-sparc/highmem.h. These became
+ * needed as kmap_atomic() and kunmap_atomic() started getting
+ * called from within modules.
+ * -- Tomas Szepe <szepe@pinerecords.com>, September 2002
+ *
+ * But kmap_atomic() and kunmap_atomic() cannot be inlined in
+ * modules because they are loaded with btfixup-ped functions.
+ */
+
+/*
+ * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+ * gives a more generic (and caching) interface. But kmap_atomic can
+ * be used in IRQ contexts, so in some (very limited) cases we need it.
+ *
+ * XXX This is an old text. Actually, it's good to use atomic kmaps,
+ * provided you remember that they are atomic and not try to sleep
+ * with a kmap taken, much like a spinlock. Non-atomic kmaps are
+ * shared by CPUs, and so precious, and establishing them requires IPI.
+ * Atomic kmaps are lightweight and we may have NCPUS more of them.
+ */
+#include <linux/highmem.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/vaddrs.h>
+
+static pte_t *kmap_pte;
+
+void __init kmap_init(void)
+{
+ unsigned long address = __fix_to_virt(FIX_KMAP_BEGIN);
+
+ /* cache the first kmap pte */
+ kmap_pte = virt_to_kpte(address);
+}
+
+void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+{
+ unsigned long vaddr;
+ long idx, type;
+
+ type = kmap_atomic_idx_push();
+ idx = type + KM_TYPE_NR*smp_processor_id();
+ vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+
+/* XXX Fix - Anton */
+#if 0
+ __flush_cache_one(vaddr);
+#else
+ flush_cache_all();
+#endif
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+ BUG_ON(!pte_none(*(kmap_pte-idx)));
+#endif
+ set_pte(kmap_pte-idx, mk_pte(page, prot));
+/* XXX Fix - Anton */
+#if 0
+ __flush_tlb_one(vaddr);
+#else
+ flush_tlb_all();
+#endif
+
+ return (void*) vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic_high_prot);
+
+void kunmap_atomic_high(void *kvaddr)
+{
+ unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+ int type;
+
+ if (vaddr < FIXADDR_START)
+ return;
+
+ type = kmap_atomic_idx();
+
+#ifdef CONFIG_DEBUG_HIGHMEM
+ {
+ unsigned long idx;
+
+ idx = type + KM_TYPE_NR * smp_processor_id();
+ BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
+
+ /* XXX Fix - Anton */
+#if 0
+ __flush_cache_one(vaddr);
+#else
+ flush_cache_all();
+#endif
+
+ /*
+ * force other mappings to Oops if they'll try to access
+ * this pte without first remap it
+ */
+ pte_clear(&init_mm, vaddr, kmap_pte-idx);
+ /* XXX Fix - Anton */
+#if 0
+ __flush_tlb_one(vaddr);
+#else
+ flush_tlb_all();
+#endif
+ }
+#endif
+
+ kmap_atomic_idx_pop();
+}
+EXPORT_SYMBOL(kunmap_atomic_high);
--
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