[patch RFC 08/15] mips/mm/highmem: Switch to generic kmap atomic

Thomas Gleixner
2020-09-19T09:50:23Z

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
---
Note: Completely untested
---
arch/mips/Kconfig | 1
arch/mips/include/asm/highmem.h | 4 +-
arch/mips/mm/highmem.c | 77 ----------------------------------------
arch/mips/mm/init.c | 3 -
4 files changed, 3 insertions(+), 82 deletions(-)

--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2654,6 +2654,7 @@ config MIPS_CRC_SUPPORT
config HIGHMEM
bool "High Memory Support"
depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA
+ select KMAP_ATOMIC_GENERIC

config CPU_SUPPORTS_HIGHMEM
bool
--- a/arch/mips/include/asm/highmem.h
+++ b/arch/mips/include/asm/highmem.h
@@ -48,11 +48,11 @@ extern pte_t *pkmap_page_table;

#define ARCH_HAS_KMAP_FLUSH_TLB
extern void kmap_flush_tlb(unsigned long addr);
-extern void *kmap_atomic_pfn(unsigned long pfn);

#define flush_cache_kmaps() BUG_ON(cpu_has_dc_aliases)

-extern void kmap_init(void);
+#define arch_kmap_temp_post_map(vaddr, pteval) local_flush_tlb_one(vaddr)
+#define arch_kmap_temp_post_unmap(vaddr) local_flush_tlb_one(vaddr)

#endif /* __KERNEL__ */

--- a/arch/mips/mm/highmem.c
+++ b/arch/mips/mm/highmem.c
@@ -8,8 +8,6 @@
#include <asm/fixmap.h>
#include <asm/tlbflush.h>

-static pte_t *kmap_pte;
-
unsigned long highstart_pfn, highend_pfn;

void kmap_flush_tlb(unsigned long addr)
@@ -17,78 +15,3 @@ void kmap_flush_tlb(unsigned long addr)
flush_tlb_one(addr);
}
EXPORT_SYMBOL(kmap_flush_tlb);
-
-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
-{
- unsigned long vaddr;
- int idx, type;
-
- type = kmap_atomic_idx_push();
- idx = type + KM_TYPE_NR*smp_processor_id();
- 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, prot));
- local_flush_tlb_one((unsigned long)vaddr);
-
- 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 __maybe_unused;
-
- if (vaddr < FIXADDR_START)
- return;
-
- type = kmap_atomic_idx();
-#ifdef CONFIG_DEBUG_HIGHMEM
- {
- int idx = type + KM_TYPE_NR * smp_processor_id();
-
- BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
-
- /*
- * 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);
- local_flush_tlb_one(vaddr);
- }
-#endif
- kmap_atomic_idx_pop();
-}
-EXPORT_SYMBOL(kunmap_atomic_high);
-
-/*
- * This is the same as kmap_atomic() but can map memory that doesn't
- * have a struct page associated with it.
- */
-void *kmap_atomic_pfn(unsigned long pfn)
-{
- unsigned long vaddr;
- int idx, type;
-
- preempt_disable();
- pagefault_disable();
-
- type = kmap_atomic_idx_push();
- idx = type + KM_TYPE_NR*smp_processor_id();
- vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
- set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
- flush_tlb_one(vaddr);
-
- return (void*) vaddr;
-}
-
-void __init kmap_init(void)
-{
- unsigned long kmap_vstart;
-
- /* cache the first kmap pte */
- kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
- kmap_pte = virt_to_kpte(kmap_vstart);
-}
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -402,9 +402,6 @@ void __init paging_init(void)

pagetable_init();

-#ifdef CONFIG_HIGHMEM
- kmap_init();
-#endif
#ifdef CONFIG_ZONE_DMA
max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
#endif