From: Noam Camus <noamca@xxxxxxxxxxxx>
This way FIXMAP can have 2 PTEs per CPU even for
NR_CPUS=4096
For the extreme case like in eznps platform We use
all gutter between kernel and user.
Signed-off-by: Noam Camus <noamca at mellanox.com>
---
arch/arc/Kconfig | 11 +++++++++++
arch/arc/include/asm/highmem.h | 8 +++++---
arch/arc/include/asm/pgtable.h | 9 +++++++++
arch/arc/include/asm/processor.h | 5 +++--
arch/arc/mm/fault.c | 8 ++++++++
arch/arc/mm/highmem.c | 16 +++++++++++-----
arch/arc/mm/tlbex.S | 31 +++++++++++++++++++++++++++++++
7 files changed, 78 insertions(+), 10 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index b759be1..54ba8e6 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -478,6 +478,17 @@ config ARC_HAS_PAE40
Enable access to physical memory beyond 4G, only supported on
ARC cores with 40 bit Physical Addressing support
+config HIGHMEM_PGDS_SHIFT
+ int "log num of PGDs for HIGHMEM"
+ range 0 5
+ default "0" if !ARC_PLAT_EZNPS || !HIGHMEM
+ default "5" if ARC_PLAT_EZNPS
+ help
+ This way we can map more pages for HIGHMEM.
+ Single PGD (2M) is supporting 256 PTEs (8K PAGE_SIZE)
+ For FIXMAP where at least 2 PTEs are needed per CPU
+ large NR_CPUS e.g. 4096 will consume 32 PGDs
+
config ARCH_PHYS_ADDR_T_64BIT
def_bool ARC_HAS_PAE40
diff --git a/arch/arc/include/asm/highmem.h b/arch/arc/include/asm/highmem.h
index b1585c9..c5cb473 100644
--- a/arch/arc/include/asm/highmem.h
+++ b/arch/arc/include/asm/highmem.h
@@ -17,13 +17,13 @@
/* start after vmalloc area */
#define FIXMAP_BASE (PAGE_OFFSET - FIXMAP_SIZE - PKMAP_SIZE)
-#define FIXMAP_SIZE PGDIR_SIZE /* only 1 PGD worth */
-#define KM_TYPE_NR ((FIXMAP_SIZE >> PAGE_SHIFT)/NR_CPUS)
+#define FIXMAP_SIZE (PGDIR_SIZE * _BITUL(CONFIG_HIGHMEM_PGDS_SHIFT))
+#define KM_TYPE_NR (((FIXMAP_SIZE >> PAGE_SHIFT)/NR_CPUS) > 2 ?: 2)
#define FIXMAP_ADDR(nr) (FIXMAP_BASE + ((nr) << PAGE_SHIFT))
/* start after fixmap area */
#define PKMAP_BASE (FIXMAP_BASE + FIXMAP_SIZE)
-#define PKMAP_SIZE PGDIR_SIZE
+#define PKMAP_SIZE (PGDIR_SIZE * _BITUL(CONFIG_HIGHMEM_PGDS_SHIFT))
#define LAST_PKMAP (PKMAP_SIZE >> PAGE_SHIFT)
#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
@@ -32,6 +32,7 @@
#define kmap_prot PAGE_KERNEL
+#ifndef __ASSEMBLY__
#include <asm/cacheflush.h>
extern void *kmap(struct page *page);
@@ -54,6 +55,7 @@ static inline void kunmap(struct page *page)
return;
kunmap_high(page);
}
+#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 08fe338..d08e207 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -224,6 +224,8 @@
#define PTRS_PER_PTE _BITUL(BITS_FOR_PTE)
#define PTRS_PER_PGD _BITUL(BITS_FOR_PGD)
+#define PTRS_HMEM_PTE _BITUL(BITS_FOR_PTE + CONFIG_HIGHMEM_PGDS_SHIFT)
+
/*
* Number of entries a user land program use.
* TASK_SIZE is the maximum vaddr that can be used by a userland program.
@@ -285,7 +287,14 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
/* Don't use virt_to_pfn for macros below: could cause truncations for PAE40*/
#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
+#if CONFIG_HIGHMEM_PGDS_SHIFT
+#define __pte_index(addr) (((addr) >= VMALLOC_END) ? \
+ (((addr) >> PAGE_SHIFT) & (PTRS_HMEM_PTE - 1)) \
+ : \
+ (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)))
+#else
#define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
+#endif
/*
* pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system)
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 6e1242d..fd7bdfa 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -121,8 +121,9 @@ extern void start_thread(struct pt_regs * regs, unsigned long pc,
#define VMALLOC_START (PAGE_OFFSET - (CONFIG_ARC_KVADDR_SIZE << 20))
-/* 1 PGDIR_SIZE each for fixmap/pkmap, 2 PGDIR_SIZE gutter (see asm/highmem.h) */
-#define VMALLOC_SIZE ((CONFIG_ARC_KVADDR_SIZE << 20) - PGDIR_SIZE * 4)
+/* 1 << CONFIG_HIGHMEM_PGDS_SHIFT PGDIR_SIZE each for fixmap/pkmap */
+#define VMALLOC_SIZE ((CONFIG_ARC_KVADDR_SIZE << 20) - \
+ PGDIR_SIZE * _BITUL(CONFIG_HIGHMEM_PGDS_SHIFT) * 2)
#define VMALLOC_END (VMALLOC_START + VMALLOC_SIZE)
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index a0b7bd6..fd89c9a 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -17,6 +17,7 @@
#include <linux/perf_event.h>
#include <asm/pgalloc.h>
#include <asm/mmu.h>
+#include <asm/highmem.h>
/*
* kernel virtual address is required to implement vmalloc/pkmap/fixmap
@@ -35,6 +36,13 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address)
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
+#if defined(CONFIG_HIGHMEM) && (CONFIG_HIGHMEM_PGDS_SHIFT)
+ if (address > FIXMAP_BASE && address < (FIXMAP_BASE + FIXMAP_SIZE))
+ address = FIXMAP_BASE;
+ else if (address > PKMAP_BASE && address < (PKMAP_BASE + PKMAP_SIZE))
+ address = PKMAP_BASE;
+#endif
+
pgd = pgd_offset_fast(current->active_mm, address);
pgd_k = pgd_offset_k(address);
diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
index 77ff64a..1d4804d 100644
--- a/arch/arc/mm/highmem.c
+++ b/arch/arc/mm/highmem.c
@@ -112,7 +112,8 @@ void __kunmap_atomic(void *kv)
}
EXPORT_SYMBOL(__kunmap_atomic);
-static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
+static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr,
+ unsigned long pgnum)
{
pgd_t *pgd_k;
pud_t *pud_k;
@@ -123,19 +124,24 @@ void __kunmap_atomic(void *kv)
pud_k = pud_offset(pgd_k, kvaddr);
pmd_k = pmd_offset(pud_k, kvaddr);
- pte_k = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+ pte_k = (pte_t *)alloc_bootmem_low_pages(pgnum * PAGE_SIZE);
pmd_populate_kernel(&init_mm, pmd_k, pte_k);
return pte_k;
}
void __init kmap_init(void)
{
+ unsigned int pgnum;
+
/* Due to recursive include hell, we can't do this in processor.h */
BUILD_BUG_ON(PAGE_OFFSET < (VMALLOC_END + FIXMAP_SIZE + PKMAP_SIZE));
BUILD_BUG_ON(KM_TYPE_NR > PTRS_PER_PTE);
- pkmap_page_table = alloc_kmap_pgtable(PKMAP_BASE);
+ pgnum = DIV_ROUND_UP(PKMAP_SIZE, PAGE_SIZE * PTRS_PER_PTE);
+ pkmap_page_table = alloc_kmap_pgtable(PKMAP_BASE, pgnum);
- BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE);
- fixmap_page_table = alloc_kmap_pgtable(FIXMAP_BASE);
+ BUILD_BUG_ON(LAST_PKMAP > (PTRS_PER_PTE *
+ _BITUL(CONFIG_HIGHMEM_PGDS_SHIFT)));
+ pgnum = DIV_ROUND_UP(FIXMAP_SIZE, PAGE_SIZE * PTRS_PER_PTE);
+ fixmap_page_table = alloc_kmap_pgtable(FIXMAP_BASE, pgnum);
}
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index 0e1e47a..e21aecc 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -43,6 +43,7 @@
#include <asm/cache.h>
#include <asm/processor.h>
#include <asm/tlb-mmu1.h>
+#include <asm/highmem.h>
#ifdef CONFIG_ISA_ARCOMPACT
;-----------------------------------------------------------------
@@ -204,6 +205,12 @@ ex_saved_reg1:
ld r1, [r1, MM_PGD]
#endif
+#if defined(CONFIG_HIGHMEM) && defined(CONFIG_HIGHMEM_PGDS_SHIFT)
+ ; handle pkmap/fixmap with more then on pte table
+ cmp_s r2, VMALLOC_END
+ b.hs 4f
+#endif
+
lsr r0, r2, PGDIR_SHIFT ; Bits for indexing into PGD
ld.as r3, [r1, r0] ; PGD entry corresp to faulting addr
tst r3, r3
@@ -237,6 +244,30 @@ ex_saved_reg1:
2:
+#if defined(CONFIG_HIGHMEM) && defined(CONFIG_HIGHMEM_PGDS_SHIFT)
+ b 6f
+
+4:
+ lsr r0, r2, PGDIR_SHIFT ; Bits for indexing into KMAP_PGD
+ and r0, r0, ~(_BITUL(CONFIG_HIGHMEM_PGDS_SHIFT) - 1)
+ ld.as r1, [r1, r0] ; PGD entry corresp to faulting addr
+ tst r1, r1
+ bz do_slow_path_pf ; if no Page Table, do page fault
+ and r1, r1, PAGE_MASK
+
+ cmp_s r2, PKMAP_BASE
+ mov.hs r0, ( PKMAP_BASE >> PAGE_SHIFT )
+ b.hs 5f
+ mov r0, ( FIXMAP_BASE >> PAGE_SHIFT )
+
+5:
+ lsr r3, r2, PAGE_SHIFT
+ sub r0, r3, r0
+ asl r0, r0, PTE_SIZE_LOG
+ ld.aw r0, [r1, r0]
+6:
+#endif
+
.endm
;-----------------------------------------------------------------
--
1.7.1
