mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
2cb7c9cb42
The existing code relies on pagefault_disable() implicitly disabling preemption, so that no schedule will happen between kmap_atomic() and kunmap_atomic(). Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
96 lines
2.3 KiB
C
96 lines
2.3 KiB
C
/*
|
|
* High memory support for Xtensa architecture
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General
|
|
* Public License. See the file "COPYING" in the main directory of
|
|
* this archive for more details.
|
|
*
|
|
* Copyright (C) 2014 Cadence Design Systems Inc.
|
|
*/
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/highmem.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
static pte_t *kmap_pte;
|
|
|
|
#if DCACHE_WAY_SIZE > PAGE_SIZE
|
|
unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS];
|
|
wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS];
|
|
|
|
static void __init kmap_waitqueues_init(void)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i)
|
|
init_waitqueue_head(pkmap_map_wait_arr + i);
|
|
}
|
|
#else
|
|
static inline void kmap_waitqueues_init(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
|
|
{
|
|
return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS +
|
|
color;
|
|
}
|
|
|
|
void *kmap_atomic(struct page *page)
|
|
{
|
|
enum fixed_addresses idx;
|
|
unsigned long vaddr;
|
|
|
|
preempt_disable();
|
|
pagefault_disable();
|
|
if (!PageHighMem(page))
|
|
return page_address(page);
|
|
|
|
idx = kmap_idx(kmap_atomic_idx_push(),
|
|
DCACHE_ALIAS(page_to_phys(page)));
|
|
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
|
BUG_ON(!pte_none(*(kmap_pte + idx)));
|
|
#endif
|
|
set_pte(kmap_pte + idx, mk_pte(page, PAGE_KERNEL_EXEC));
|
|
|
|
return (void *)vaddr;
|
|
}
|
|
EXPORT_SYMBOL(kmap_atomic);
|
|
|
|
void __kunmap_atomic(void *kvaddr)
|
|
{
|
|
if (kvaddr >= (void *)FIXADDR_START &&
|
|
kvaddr < (void *)FIXADDR_TOP) {
|
|
int idx = kmap_idx(kmap_atomic_idx(),
|
|
DCACHE_ALIAS((unsigned long)kvaddr));
|
|
|
|
/*
|
|
* Force other mappings to Oops if they'll try to access this
|
|
* pte without first remap it. Keeping stale mappings around
|
|
* is a bad idea also, in case the page changes cacheability
|
|
* attributes or becomes a protected page in a hypervisor.
|
|
*/
|
|
pte_clear(&init_mm, kvaddr, kmap_pte + idx);
|
|
local_flush_tlb_kernel_range((unsigned long)kvaddr,
|
|
(unsigned long)kvaddr + PAGE_SIZE);
|
|
|
|
kmap_atomic_idx_pop();
|
|
}
|
|
|
|
pagefault_enable();
|
|
preempt_enable();
|
|
}
|
|
EXPORT_SYMBOL(__kunmap_atomic);
|
|
|
|
void __init kmap_init(void)
|
|
{
|
|
unsigned long kmap_vstart;
|
|
|
|
/* cache the first kmap pte */
|
|
kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
|
|
kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
|
|
kmap_waitqueues_init();
|
|
}
|