From 10ebd8556b7990499c896a550e3d416b444211e6 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 02:23:07 +0000
Subject: [PATCH] add led
---
kernel/arch/arc/mm/highmem.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 49 insertions(+), 5 deletions(-)
diff --git a/kernel/arch/arc/mm/highmem.c b/kernel/arch/arc/mm/highmem.c
index c79912a..1b9f473 100644
--- a/kernel/arch/arc/mm/highmem.c
+++ b/kernel/arch/arc/mm/highmem.c
@@ -36,8 +36,9 @@
* This means each only has 1 PGDIR_SIZE worth of kvaddr mappings, which means
* 2M of kvaddr space for typical config (8K page and 11:8:13 traversal split)
*
- * - The fixed KMAP slots for kmap_local/atomic() require KM_MAX_IDX slots per
- * CPU. So the number of CPUs sharing a single PTE page is limited.
+ * - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE
+ * slots across NR_CPUS would be more than sufficient (generic code defines
+ * KM_TYPE_NR as 20).
*
* - pkmap being preemptible, in theory could do with more than 256 concurrent
* mappings. However, generic pkmap code: map_new_virtual(), doesn't traverse
@@ -46,6 +47,48 @@
*/
extern pte_t * pkmap_page_table;
+static pte_t * fixmap_page_table;
+
+void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+{
+ int idx, cpu_idx;
+ unsigned long vaddr;
+
+ cpu_idx = kmap_atomic_idx_push();
+ idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
+ vaddr = FIXMAP_ADDR(idx);
+
+ set_pte_at(&init_mm, vaddr, fixmap_page_table + idx,
+ mk_pte(page, prot));
+
+ return (void *)vaddr;
+}
+EXPORT_SYMBOL(kmap_atomic_high_prot);
+
+void kunmap_atomic_high(void *kv)
+{
+ unsigned long kvaddr = (unsigned long)kv;
+
+ if (kvaddr >= FIXMAP_BASE && kvaddr < (FIXMAP_BASE + FIXMAP_SIZE)) {
+
+ /*
+ * Because preemption is disabled, this vaddr can be associated
+ * with the current allocated index.
+ * But in case of multiple live kmap_atomic(), it still relies on
+ * callers to unmap in right order.
+ */
+ int cpu_idx = kmap_atomic_idx();
+ int idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
+
+ WARN_ON(kvaddr != FIXMAP_ADDR(idx));
+
+ pte_clear(&init_mm, kvaddr, fixmap_page_table + idx);
+ local_flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE);
+
+ kmap_atomic_idx_pop();
+ }
+}
+EXPORT_SYMBOL(kunmap_atomic_high);
static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
{
@@ -65,9 +108,10 @@
{
/* Due to recursive include hell, we can't do this in processor.h */
BUILD_BUG_ON(PAGE_OFFSET < (VMALLOC_END + FIXMAP_SIZE + PKMAP_SIZE));
- BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE);
- BUILD_BUG_ON(FIX_KMAP_SLOTS > PTRS_PER_PTE);
+ BUILD_BUG_ON(KM_TYPE_NR > PTRS_PER_PTE);
pkmap_page_table = alloc_kmap_pgtable(PKMAP_BASE);
- alloc_kmap_pgtable(FIXMAP_BASE);
+
+ BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE);
+ fixmap_page_table = alloc_kmap_pgtable(FIXMAP_BASE);
}
--
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