mirror of
https://github.com/torvalds/linux.git
synced 2024-12-11 05:33:09 +00:00
090e77e166
Most architectures define kmap_prot to be PAGE_KERNEL. Let sparc and xtensa define there own and define PAGE_KERNEL as the default if not overridden. [akpm@linux-foundation.org: coding style fixes] Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christian König <christian.koenig@amd.com> Cc: Chris Zankel <chris@zankel.net> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Helge Deller <deller@gmx.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200507150004.1423069-16-ira.weiny@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
125 lines
2.9 KiB
C
125 lines
2.9 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>
|
|
|
|
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);
|
|
}
|
|
|
|
void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
|
|
{
|
|
unsigned long vaddr;
|
|
long idx, type;
|
|
|
|
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, prot));
|
|
/* XXX Fix - Anton */
|
|
#if 0
|
|
__flush_tlb_one(vaddr);
|
|
#else
|
|
flush_tlb_all();
|
|
#endif
|
|
|
|
return (void*) vaddr;
|
|
}
|
|
EXPORT_SYMBOL(kmap_atomic_high_prot);
|
|
|
|
void kunmap_atomic_high(void *kvaddr)
|
|
{
|
|
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
|
|
int type;
|
|
|
|
if (vaddr < FIXADDR_START)
|
|
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();
|
|
}
|
|
EXPORT_SYMBOL(kunmap_atomic_high);
|