linux/arch/sparc/mm/highmem.c
Mike Rapoport 7235db268a sparc32: use pgtable-nopud instead of 4level-fixup
32-bit version of sparc has three-level page tables and can use
pgtable-nopud and folding of the upper layers.

Replace usage of include/asm-generic/4level-fixup.h with
include/asm-generic/pgtable-nopud.h and adjust page table manipulation
macros and functions accordingly.

Link: http://lkml.kernel.org/r/1572938135-31886-11-git-send-email-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Tested-by: Anatoly Pugachev <matorola@gmail.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Peter Rosin <peda@axentia.se>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:15 -08:00

138 lines
3.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* highmem.c: virtual kernel memory mappings for high memory
*
* Provides kernel-static versions of atomic kmap functions originally
* found as inlines in include/asm-sparc/highmem.h. These became
* needed as kmap_atomic() and kunmap_atomic() started getting
* called from within modules.
* -- Tomas Szepe <szepe@pinerecords.com>, September 2002
*
* But kmap_atomic() and kunmap_atomic() cannot be inlined in
* modules because they are loaded with btfixup-ped functions.
*/
/*
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
* gives a more generic (and caching) interface. But kmap_atomic can
* be used in IRQ contexts, so in some (very limited) cases we need it.
*
* XXX This is an old text. Actually, it's good to use atomic kmaps,
* provided you remember that they are atomic and not try to sleep
* with a kmap taken, much like a spinlock. Non-atomic kmaps are
* shared by CPUs, and so precious, and establishing them requires IPI.
* Atomic kmaps are lightweight and we may have NCPUS more of them.
*/
#include <linux/highmem.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/vaddrs.h>
pgprot_t kmap_prot;
static pte_t *kmap_pte;
void __init kmap_init(void)
{
unsigned long address;
p4d_t *p4d;
pud_t *pud;
pmd_t *dir;
address = __fix_to_virt(FIX_KMAP_BEGIN);
p4d = p4d_offset(pgd_offset_k(address), address);
pud = pud_offset(p4d, address);
dir = pmd_offset(pud, address);
/* cache the first kmap pte */
kmap_pte = pte_offset_kernel(dir, address);
kmap_prot = __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE);
}
void *kmap_atomic(struct page *page)
{
unsigned long vaddr;
long idx, type;
preempt_disable();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
/* XXX Fix - Anton */
#if 0
__flush_cache_one(vaddr);
#else
flush_cache_all();
#endif
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(kmap_pte-idx)));
#endif
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
/* XXX Fix - Anton */
#if 0
__flush_tlb_one(vaddr);
#else
flush_tlb_all();
#endif
return (void*) vaddr;
}
EXPORT_SYMBOL(kmap_atomic);
void __kunmap_atomic(void *kvaddr)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
int type;
if (vaddr < FIXADDR_START) { // FIXME
pagefault_enable();
preempt_enable();
return;
}
type = kmap_atomic_idx();
#ifdef CONFIG_DEBUG_HIGHMEM
{
unsigned long idx;
idx = type + KM_TYPE_NR * smp_processor_id();
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
/* XXX Fix - Anton */
#if 0
__flush_cache_one(vaddr);
#else
flush_cache_all();
#endif
/*
* force other mappings to Oops if they'll try to access
* this pte without first remap it
*/
pte_clear(&init_mm, vaddr, kmap_pte-idx);
/* XXX Fix - Anton */
#if 0
__flush_tlb_one(vaddr);
#else
flush_tlb_all();
#endif
}
#endif
kmap_atomic_idx_pop();
pagefault_enable();
preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);