Commit 5f037ea3 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: default avatarThomas 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
parent a4c33e83

arch/nds32/Kconfig.cpu

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/nds32/include/asm/fixmap.h

+2 −2
Original line number Diff line number Diff line
@@ -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

arch/nds32/include/asm/highmem.h

+16 −6
Original line number Diff line number Diff line
@@ -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

arch/nds32/mm/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -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)

arch/nds32/mm/highmem.c

deleted100644 → 0
+0 −48
Original line number Diff line number Diff line 
// 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);