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ARM: highmem: Switch to generic kmap atomic

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No reason having the same code in every architecture.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20201103095857.582196476@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-11-03 10:27:22 +01:00
parent 39cac191ff
commit 2a15ba82fa
6 changed files with 26 additions and 144 deletions
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1
arch/arm/Kconfig
View File

@ -1498,6 +1498,7 @@ config HAVE_ARCH_PFN_VALID
config HIGHMEM
bool "High Memory Support"
depends on MMU
select KMAP_LOCAL
help
The address space of ARM processors is only 4 Gigabytes large
and it has to accommodate user address space, kernel address

4
arch/arm/include/asm/fixmap.h
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@ -7,14 +7,14 @@
#define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE)
#include <linux/pgtable.h>
#include <asm/kmap_types.h>
#include <asm/kmap_size.h>
enum fixed_addresses {
FIX_EARLYCON_MEM_BASE,
__end_of_permanent_fixed_addresses,
FIX_KMAP_BEGIN = __end_of_permanent_fixed_addresses,
FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
/* Support writing RO kernel text via kprobes, jump labels, etc. */
FIX_TEXT_POKE0,

33
arch/arm/include/asm/highmem.h
View File

@ -2,7 +2,7 @@
#ifndef _ASM_HIGHMEM_H
#define _ASM_HIGHMEM_H
#include <asm/kmap_types.h>
#include <asm/fixmap.h>
#define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE)
#define LAST_PKMAP PTRS_PER_PTE
@ -46,19 +46,32 @@ extern pte_t *pkmap_page_table;
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
extern void *kmap_high_get(struct page *page);
#else
static inline void *arch_kmap_local_high_get(struct page *page)
{
if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !cache_is_vivt())
return NULL;
return kmap_high_get(page);
}
#define arch_kmap_local_high_get arch_kmap_local_high_get
#else /* ARCH_NEEDS_KMAP_HIGH_GET */
static inline void *kmap_high_get(struct page *page)
{
return NULL;
}
#endif
#endif /* !ARCH_NEEDS_KMAP_HIGH_GET */
/*
* The following functions are already defined by <linux/highmem.h>
* when CONFIG_HIGHMEM is not set.
*/
#ifdef CONFIG_HIGHMEM
extern void *kmap_atomic_pfn(unsigned long pfn);
#endif
#define arch_kmap_local_post_map(vaddr, pteval) \
local_flush_tlb_kernel_page(vaddr)
#define arch_kmap_local_pre_unmap(vaddr) \
do { \
if (cache_is_vivt()) \
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); \
} while (0)
#define arch_kmap_local_post_unmap(vaddr) \
local_flush_tlb_kernel_page(vaddr)
#endif

10
arch/arm/include/asm/kmap_types.h
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@ -1,10 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ARM_KMAP_TYPES_H
#define __ARM_KMAP_TYPES_H
/*
* This is the "bare minimum". AIO seems to require this.
*/
#define KM_TYPE_NR 16
#endif

1
arch/arm/mm/Makefile
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@ -19,7 +19,6 @@ obj-$(CONFIG_MODULES) += proc-syms.o
obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o
obj-$(CONFIG_ALIGNMENT_TRAP) += alignment.o
obj-$(CONFIG_HIGHMEM) += highmem.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_ARM_PV_FIXUP) += pv-fixup-asm.o

121
arch/arm/mm/highmem.c
View File

@ -1,121 +0,0 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* arch/arm/mm/highmem.c -- ARM highmem support
*
* Author: Nicolas Pitre
* Created: september 8, 2008
* Copyright: Marvell Semiconductors Inc.
*/
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <asm/fixmap.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include "mm.h"
static inline void set_fixmap_pte(int idx, pte_t pte)
{
unsigned long vaddr = __fix_to_virt(idx);
pte_t *ptep = virt_to_kpte(vaddr);
set_pte_ext(ptep, pte, 0);
local_flush_tlb_kernel_page(vaddr);
}
static inline pte_t get_fixmap_pte(unsigned long vaddr)
{
pte_t *ptep = virt_to_kpte(vaddr);
return *ptep;
}
void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
{
unsigned int idx;
unsigned long vaddr;
void *kmap;
int type;
#ifdef CONFIG_DEBUG_HIGHMEM
/*
* There is no cache coherency issue when non VIVT, so force the
* dedicated kmap usage for better debugging purposes in that case.
*/
if (!cache_is_vivt())
kmap = NULL;
else
#endif
kmap = kmap_high_get(page);
if (kmap)
return kmap;
type = kmap_atomic_idx_push();
idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
/*
* With debugging enabled, kunmap_atomic forces that entry to 0.
* Make sure it was indeed properly unmapped.
*/
BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
#endif
/*
* When debugging is off, kunmap_atomic leaves the previous mapping
* in place, so the contained TLB flush ensures the TLB is updated
* with the new mapping.
*/
set_fixmap_pte(idx, mk_pte(page, prot));
return (void *)vaddr;
}
EXPORT_SYMBOL(kmap_atomic_high_prot);
void kunmap_atomic_high(void *kvaddr)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
int idx, type;
if (kvaddr >= (void *)FIXADDR_START) {
type = kmap_atomic_idx();
idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
if (cache_is_vivt())
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(vaddr != __fix_to_virt(idx));
set_fixmap_pte(idx, __pte(0));
#else
(void) idx; /* to kill a warning */
#endif
kmap_atomic_idx_pop();
} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
/* this address was obtained through kmap_high_get() */
kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
}
}
EXPORT_SYMBOL(kunmap_atomic_high);
void *kmap_atomic_pfn(unsigned long pfn)
{
unsigned long vaddr;
int idx, type;
struct page *page = pfn_to_page(pfn);
preempt_disable();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
type = kmap_atomic_idx_push();
idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
#endif
set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
return (void *)vaddr;
}