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authorThomas Gleixner <tglx@linutronix.de>2020-11-03 10:27:21 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-11-06 23:14:55 +0100
commit39cac191ff37939544af80d5d2af6b870fd94c9b (patch)
treeb693f7450c7c336161489022b1a36bab6ba67811 /arch/arc/include/asm/highmem.h
parentx86/mm/highmem: Use generic kmap atomic implementation (diff)
downloadlinux-39cac191ff37939544af80d5d2af6b870fd94c9b.tar.xz
linux-39cac191ff37939544af80d5d2af6b870fd94c9b.zip
arc/mm/highmem: Use generic kmap atomic implementation
Adopt the map ordering to match the other architectures and the generic code. Also make the maximum entries limited and not dependend on the number of CPUs. With the original implementation did the following calculation: nr_slots = mapsize >> PAGE_SHIFT; The results in either 512 or 1024 total slots depending on configuration. The total slots have to be divided by the number of CPUs to get the number of slots per CPU (former KM_TYPE_NR). ARC supports up to 4k CPUs, so this just falls apart in random ways depending on the number of CPUs and the actual kmap (atomic) nesting. The comment in highmem.c: * - 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). is just wrong. KM_TYPE_NR (now KM_MAX_IDX) is the number of slots per CPU because kmap_local/atomic() needs to support nested mappings (thread, softirq, interrupt). While KM_MAX_IDX might be overestimated, the above reasoning is just wrong and clearly the highmem code was never tested with any system with more than a few CPUs. Use the default number of slots and fail the build when it does not fit. Randomly failing at runtime is not a really good option. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20201103095857.472289952@linutronix.de
Diffstat (limited to 'arch/arc/include/asm/highmem.h')
-rw-r--r--arch/arc/include/asm/highmem.h26
1 files changed, 20 insertions, 6 deletions
diff --git a/arch/arc/include/asm/highmem.h b/arch/arc/include/asm/highmem.h
index 6e5eafb3afdd..a6b8e2c352c4 100644
--- a/arch/arc/include/asm/highmem.h
+++ b/arch/arc/include/asm/highmem.h
@@ -9,17 +9,29 @@
#ifdef CONFIG_HIGHMEM
#include <uapi/asm/page.h>
-#include <asm/kmap_types.h>
+#include <asm/kmap_size.h>
+
+#define FIXMAP_SIZE PGDIR_SIZE
+#define PKMAP_SIZE PGDIR_SIZE
/* start after vmalloc area */
#define FIXMAP_BASE (PAGE_OFFSET - FIXMAP_SIZE - PKMAP_SIZE)
-#define FIXMAP_SIZE PGDIR_SIZE /* only 1 PGD worth */
-#define KM_TYPE_NR ((FIXMAP_SIZE >> PAGE_SHIFT)/NR_CPUS)
-#define FIXMAP_ADDR(nr) (FIXMAP_BASE + ((nr) << PAGE_SHIFT))
+
+#define FIX_KMAP_SLOTS (KM_MAX_IDX * NR_CPUS)
+#define FIX_KMAP_BEGIN (0UL)
+#define FIX_KMAP_END ((FIX_KMAP_BEGIN + FIX_KMAP_SLOTS) - 1)
+
+#define FIXADDR_TOP (FIXMAP_BASE + (FIX_KMAP_END << PAGE_SHIFT))
+
+/*
+ * This should be converted to the asm-generic version, but of course this
+ * is needlessly different from all other architectures. Sigh - tglx
+ */
+#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
+#define __virt_to_fix(x) (((FIXADDR_TOP - ((x) & PAGE_MASK))) >> PAGE_SHIFT)
/* start after fixmap area */
#define PKMAP_BASE (FIXMAP_BASE + FIXMAP_SIZE)
-#define PKMAP_SIZE PGDIR_SIZE
#define LAST_PKMAP (PKMAP_SIZE >> PAGE_SHIFT)
#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
@@ -29,11 +41,13 @@
extern void kmap_init(void);
+#define arch_kmap_local_post_unmap(vaddr) \
+ local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE)
+
static inline void flush_cache_kmaps(void)
{
flush_cache_all();
}
-
#endif
#endif