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Date: Wed, 28 Oct 2015 16:53:11 +0530
From: Vineet Gupta <Vineet.Gupta1@...opsys.com>
To: Max Filippov <jcmvbkbc@...il.com>, Joonsoo Kim <js1304@...il.com>,
"Mel Gorman" <mgorman@...e.de>, Minchan Kim <minchan@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>
CC: <linux-arch@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-mm@...ck.org>, <linux-snps-arc@...ts.infraded.org>,
Alexey Brodkin <Alexey.Brodkin@...opsys.com>,
Vineet Gupta <Vineet.Gupta1@...opsys.com>
Subject: [PATCH 1/3] ARC: mm: preps ahead of HIGHMEM support
Before we plug in highmem support, some of code needs to be ready for it
- copy_user_highpage() needs to be using the kmap_atomic API
- max_low_pfn can't be assumed to be same as max_pfn
- mk_pte() can't assume page_address()
- do_page_fault() can't assume VMALLOC_END is end of kernel vaddr space
Signed-off-by: Alexey Brodkin <abrodkin@...opsys.com>
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
---
arch/arc/include/asm/pgtable.h | 9 +--------
arch/arc/mm/cache.c | 16 +++++++++++-----
arch/arc/mm/fault.c | 13 ++++++++++---
arch/arc/mm/init.c | 2 +-
4 files changed, 23 insertions(+), 17 deletions(-)
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index f7c7273cd537..bd771351a1d1 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -270,13 +270,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
(unsigned long)(((pte_val(x) - CONFIG_LINUX_LINK_BASE) >> \
PAGE_SHIFT)))
-#define mk_pte(page, pgprot) \
-({ \
- pte_t pte; \
- pte_val(pte) = __pa(page_address(page)) + pgprot_val(pgprot); \
- pte; \
-})
-
+#define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot)
#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
#define pfn_pte(pfn, prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
#define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
@@ -360,7 +354,6 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
#define pgd_offset_fast(mm, addr) pgd_offset(mm, addr)
#endif
-extern void paging_init(void);
extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
pte_t *ptep);
diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index 27d255d3dc5d..08a7cc0ac100 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -813,8 +813,8 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page,
void copy_user_highpage(struct page *to, struct page *from,
unsigned long u_vaddr, struct vm_area_struct *vma)
{
- unsigned long kfrom = (unsigned long)page_address(from);
- unsigned long kto = (unsigned long)page_address(to);
+ void *kfrom = kmap_atomic(from);
+ void *kto = kmap_atomic(to);
int clean_src_k_mappings = 0;
/*
@@ -824,13 +824,16 @@ void copy_user_highpage(struct page *to, struct page *from,
*
* Note that while @u_vaddr refers to DST page's userspace vaddr, it is
* equally valid for SRC page as well
+ *
+ * For !VIPT cache, all of this gets compiled out as
+ * addr_not_cache_congruent() is 0
*/
if (page_mapped(from) && addr_not_cache_congruent(kfrom, u_vaddr)) {
- __flush_dcache_page(kfrom, u_vaddr);
+ __flush_dcache_page((unsigned long)kfrom, u_vaddr);
clean_src_k_mappings = 1;
}
- copy_page((void *)kto, (void *)kfrom);
+ copy_page(kto, kfrom);
/*
* Mark DST page K-mapping as dirty for a later finalization by
@@ -847,11 +850,14 @@ void copy_user_highpage(struct page *to, struct page *from,
* sync the kernel mapping back to physical page
*/
if (clean_src_k_mappings) {
- __flush_dcache_page(kfrom, kfrom);
+ __flush_dcache_page((unsigned long)kfrom, (unsigned long)kfrom);
set_bit(PG_dc_clean, &from->flags);
} else {
clear_bit(PG_dc_clean, &from->flags);
}
+
+ kunmap_atomic(kto);
+ kunmap_atomic(kfrom);
}
void clear_user_page(void *to, unsigned long u_vaddr, struct page *page)
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index d948e4e9d89c..af63f4a13e60 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -18,7 +18,14 @@
#include <asm/pgalloc.h>
#include <asm/mmu.h>
-static int handle_vmalloc_fault(unsigned long address)
+/*
+ * kernel virtual address is required to implement vmalloc/pkmap/fixmap
+ * Refer to asm/processor.h for System Memory Map
+ *
+ * It simply copies the PMD entry (pointer to 2nd level page table or hugepage)
+ * from swapper pgdir to task pgdir. The 2nd level table/page is thus shared
+ */
+noinline static int handle_kernel_vaddr_fault(unsigned long address)
{
/*
* Synchronize this task's top level page-table
@@ -72,8 +79,8 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
* only copy the information from the master page table,
* nothing more.
*/
- if (address >= VMALLOC_START && address <= VMALLOC_END) {
- ret = handle_vmalloc_fault(address);
+ if (address >= VMALLOC_START) {
+ ret = handle_kernel_vaddr_fault(address);
if (unlikely(ret))
goto bad_area_nosemaphore;
else
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 5121b9b16ba8..5256765d5db0 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -97,7 +97,7 @@ void __init setup_arch_memory(void)
/* Last usable page of low mem (no HIGHMEM yet for ARC port) */
max_low_pfn = max_pfn = PFN_DOWN(end_mem);
- max_mapnr = max_low_pfn - min_low_pfn;
+ max_mapnr = max_pfn - min_low_pfn;
/*------------- reserve kernel image -----------------------*/
memblock_reserve(CONFIG_LINUX_LINK_BASE,
--
1.9.1
--
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