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nds32/mm/highmem: Switch to generic kmap atomic

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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
This commit is contained in:
Thomas Gleixner 2020-11-03 10:27:26 +01:00
parent a4c33e83bc
commit 5f037ea3b2
5 changed files with 19 additions and 57 deletions
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1
arch/nds32/Kconfig.cpu
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@ -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

4
arch/nds32/include/asm/fixmap.h
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@ -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

22
arch/nds32/include/asm/highmem.h
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@ -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

1
arch/nds32/mm/Makefile
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@ -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)

48
arch/nds32/mm/highmem.c
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@ -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);