nds32/mm/highmem: Switch to generic kmap atomic

The mapping code is odd and looks broken. See FIXME in the comment.

Also fix the harmless off by one in the FIX_KMAP_END define.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20201103095857.980576055@linutronix.de

diff --git a/arch/nds32/Kconfig.cpu b/arch/nds32/Kconfig.cpu
index f88a12f..c107599 100644 (file)
--- a/arch/nds32/Kconfig.cpu
+++ b/arch/nds32/Kconfig.cpu
@@ -157,6 +157,7 @@ config HW_SUPPORT_UNALIGNMENT_ACCESS
 config HIGHMEM
        bool "High Memory Support"
        depends on MMU && !CPU_CACHE_ALIASING
+       select KMAP_LOCAL
        help
          The address space of Andes processors is only 4 Gigabytes large
          and it has to accommodate user address space, kernel address

diff --git a/arch/nds32/include/asm/fixmap.h b/arch/nds32/include/asm/fixmap.h
index 5a4bf11..2fa09a2 100644 (file)
--- a/arch/nds32/include/asm/fixmap.h
+++ b/arch/nds32/include/asm/fixmap.h
@@ -6,7 +6,7 @@
 
 #ifdef CONFIG_HIGHMEM
 #include <linux/threads.h>
-#include <asm/kmap_types.h>
+#include <asm/kmap_size.h>
 #endif
 
 enum fixed_addresses {
@@ -14,7 +14,7 @@ enum fixed_addresses {
        FIX_KMAP_RESERVED,
        FIX_KMAP_BEGIN,
 #ifdef CONFIG_HIGHMEM
-       FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS),
+       FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
 #endif
        FIX_EARLYCON_MEM_BASE,
        __end_of_fixed_addresses

diff --git a/arch/nds32/include/asm/highmem.h b/arch/nds32/include/asm/highmem.h
index fe986d0..16159a8 100644 (file)
--- a/arch/nds32/include/asm/highmem.h
+++ b/arch/nds32/include/asm/highmem.h
@@ -5,7 +5,6 @@
 #define _ASM_HIGHMEM_H
 
 #include <asm/proc-fns.h>
-#include <asm/kmap_types.h>
 #include <asm/fixmap.h>
 
 /*
@@ -45,11 +44,22 @@ extern pte_t *pkmap_page_table;
 extern void kmap_init(void);
 
 /*
- * The following functions are already defined by <linux/highmem.h>
- * when CONFIG_HIGHMEM is not set.
+ * FIXME: The below looks broken vs. a kmap_atomic() in task context which
+ * is interupted and another kmap_atomic() happens in interrupt context.
+ * But what do I know about nds32. -- tglx
  */
-#ifdef CONFIG_HIGHMEM
-extern void *kmap_atomic_pfn(unsigned long pfn);
-#endif
+#define arch_kmap_local_post_map(vaddr, pteval)                        \
+       do {                                                    \
+               __nds32__tlbop_inv(vaddr);                      \
+               __nds32__mtsr_dsb(vaddr, NDS32_SR_TLB_VPN);     \
+               __nds32__tlbop_rwr(pteval);                     \
+               __nds32__isb();                                 \
+       } while (0)
+
+#define arch_kmap_local_pre_unmap(vaddr)                       \
+       do {                                                    \
+               __nds32__tlbop_inv(vaddr);                      \
+               __nds32__isb();                                 \
+       } while (0)
 
 #endif

diff --git a/arch/nds32/mm/Makefile b/arch/nds32/mm/Makefile
index 897ecaf..14fb2e8 100644 (file)
--- a/arch/nds32/mm/Makefile
+++ b/arch/nds32/mm/Makefile
@@ -3,7 +3,6 @@ obj-y                           := extable.o tlb.o fault.o init.o mmap.o \
                                    mm-nds32.o cacheflush.o proc.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)   += alignment.o
-obj-$(CONFIG_HIGHMEM)           += highmem.o
 
 ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_proc.o     = $(CC_FLAGS_FTRACE)

diff --git a/arch/nds32/mm/highmem.c b/arch/nds32/mm/highmem.c
deleted file mode 100644 (file)
index 4284cd5..0000000
--- a/arch/nds32/mm/highmem.c
+++ /dev/null
@@ -1,48 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/export.h>
-#include <linux/highmem.h>
-#include <linux/sched.h>
-#include <linux/smp.h>
-#include <linux/interrupt.h>
-#include <linux/memblock.h>
-#include <asm/fixmap.h>
-#include <asm/tlbflush.h>
-
-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
-{
-       unsigned int idx;
-       unsigned long vaddr, pte;
-       int type;
-       pte_t *ptep;
-
-       type = kmap_atomic_idx_push();
-
-       idx = type + KM_TYPE_NR * smp_processor_id();
-       vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-       pte = (page_to_pfn(page) << PAGE_SHIFT) | prot;
-       ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
-       set_pte(ptep, pte);
-
-       __nds32__tlbop_inv(vaddr);
-       __nds32__mtsr_dsb(vaddr, NDS32_SR_TLB_VPN);
-       __nds32__tlbop_rwr(pte);
-       __nds32__isb();
-       return (void *)vaddr;
-}
-EXPORT_SYMBOL(kmap_atomic_high_prot);
-
-void kunmap_atomic_high(void *kvaddr)
-{
-       if (kvaddr >= (void *)FIXADDR_START) {
-               unsigned long vaddr = (unsigned long)kvaddr;
-               pte_t *ptep;
-               kmap_atomic_idx_pop();
-               __nds32__tlbop_inv(vaddr);
-               __nds32__isb();
-               ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
-               set_pte(ptep, 0);
-       }
-}
-EXPORT_SYMBOL(kunmap_atomic_high);