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Subject[tip: core/mm] nds32/mm/highmem: Switch to generic kmap atomic
The following commit has been merged into the core/mm branch of tip:

Commit-ID: 5f037ea3b26767e0b1bdc522948321b282268b49
Gitweb: https://git.kernel.org/tip/5f037ea3b26767e0b1bdc522948321b282268b49
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 03 Nov 2020 10:27:26 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 06 Nov 2020 23:14:57 +01:00

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

---
arch/nds32/Kconfig.cpu | 1 +-
arch/nds32/include/asm/fixmap.h | 4 +--
arch/nds32/include/asm/highmem.h | 22 ++++++++++----
arch/nds32/mm/Makefile | 1 +-
arch/nds32/mm/highmem.c | 48 +-------------------------------
5 files changed, 19 insertions(+), 57 deletions(-)
delete mode 100644 arch/nds32/mm/highmem.c

diff --git a/arch/nds32/Kconfig.cpu b/arch/nds32/Kconfig.cpu
index f88a12f..c107599 100644
--- 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
--- 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
--- 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
--- 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
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);
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