[PATCH 1/2] arm: use generic fixmap.h
Leif Lindholm
leif.lindholm at linaro.org
Fri Jul 18 07:33:08 PDT 2014
On Wed, Jul 09, 2014 at 04:49:02PM -0400, Mark Salter wrote:
> On Wed, 2014-07-09 at 10:39 +0100, Leif Lindholm wrote:
> > diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
> > index 45aeaac..3c59cdf 100644
> > --- a/arch/arm/mm/highmem.c
> > +++ b/arch/arm/mm/highmem.c
> > @@ -20,16 +20,19 @@
> >
> > pte_t *fixmap_page_table;
> >
> > +#define __kmap_fix_to_virt(x) (__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
>
> FIX_KMAP_END - (x) ?
>
> > +#define __kmap_virt_to_fix(x) (FIX_KMAP_NR_PTES - 1 - __fix_to_virt(x))
>
> shouldn't this use __virt_to_fix(x)?
Err, clearly.
Good thing I managed to mess up the end of the interface that actually
isn't used anywhere in the kernel(!).
Fixed in the below.
/
Leif
>From d0a82cd19000139d32232f415bcf46f476c16561 Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter at redhat.com>
Date: Thu, 14 Nov 2013 11:37:32 -0500
Subject: [PATCH 1/2] arm: use generic fixmap.h
ARM is different from other architectures in that fixmap pages are
indexed with a positive offset from FIXADDR_START. Other architectures
index with a negative offset from FIXADDR_TOP. In order to use the
generic fixmap.h definitions, this patch redefines FIXADDR_TOP to be
inclusive of the useable range. That is, FIXADDR_TOP is the virtual
address of the topmost fixed page. The newly defined FIXADDR_END is
the first virtual address past the fixed mappings.
The patch also introduces local helper macros in highmem.c to reverse
the iteration order of fixmap pages.
Signed-off-by: Mark Salter <msalter at redhat.com>
[Rebased to 3.16-rc4, reverse kmap fixmap traversal]
Signed-off-by: Leif Lindholm <leif.lindholm at linaro.org>
---
arch/arm/include/asm/fixmap.h | 45 ++++++++++++++++++++++++++---------------
arch/arm/mm/highmem.c | 13 +++++++-----
arch/arm/mm/init.c | 2 +-
3 files changed, 38 insertions(+), 22 deletions(-)
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index 74124b0..8992431 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -1,28 +1,41 @@
#ifndef _ASM_FIXMAP_H
#define _ASM_FIXMAP_H
+#include <asm/pgtable.h>
+
#define FIXADDR_START 0xffc00000UL
-#define FIXADDR_TOP 0xffe00000UL
-#define FIXADDR_SIZE (FIXADDR_TOP - FIXADDR_START)
+#define FIXADDR_END 0xffe00000UL
+#define FIXADDR_SIZE (FIXADDR_END - FIXADDR_START)
+#define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE)
#define FIX_KMAP_NR_PTES (FIXADDR_SIZE >> PAGE_SHIFT)
-#define __fix_to_virt(x) (FIXADDR_START + ((x) << PAGE_SHIFT))
-#define __virt_to_fix(x) (((x) - FIXADDR_START) >> PAGE_SHIFT)
+enum fixed_addresses {
+ FIX_KMAP_BEGIN,
+ FIX_KMAP_END = FIX_KMAP_NR_PTES - 1,
+ __end_of_fixed_addresses
+};
+
+/*
+ * Temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the last pmd of the FIXADDR region, which is used for
+ * highmem later on, and statically aligned to 1MB.
+ * Growing down from FIXADDR_TOP
+ */
+#define NR_FIX_BTMAPS 32
+#define FIX_BTMAPS_SLOTS (PTRS_PER_PTE / NR_FIX_BTMAPS)
+#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+#define FIX_BTMAP_END FIX_KMAP_BEGIN
+#define FIX_BTMAP_BEGIN (FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
-extern void __this_fixmap_does_not_exist(void);
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
-static inline unsigned long fix_to_virt(const unsigned int idx)
-{
- if (idx >= FIX_KMAP_NR_PTES)
- __this_fixmap_does_not_exist();
- return __fix_to_virt(idx);
-}
+extern void __early_set_fixmap(enum fixed_addresses idx,
+ phys_addr_t phys, pgprot_t flags);
-static inline unsigned int virt_to_fix(const unsigned long vaddr)
-{
- BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
- return __virt_to_fix(vaddr);
-}
+#include <asm-generic/fixmap.h>
#endif
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index 45aeaac..2e5b773 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -20,16 +20,19 @@
pte_t *fixmap_page_table;
+#define __kmap_fix_to_virt(x) (__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
+#define __kmap_virt_to_fix(x) (FIX_KMAP_NR_PTES - 1 - __virt_to_fix(x))
+
static inline void set_fixmap_pte(int idx, pte_t pte)
{
- unsigned long vaddr = __fix_to_virt(idx);
+ unsigned long vaddr = __kmap_fix_to_virt(idx);
set_pte_ext(fixmap_page_table + idx, pte, 0);
local_flush_tlb_kernel_page(vaddr);
}
static inline pte_t get_fixmap_pte(unsigned long vaddr)
{
- unsigned long idx = __virt_to_fix(vaddr);
+ unsigned long idx = __kmap_virt_to_fix(vaddr);
return *(fixmap_page_table + idx);
}
@@ -78,7 +81,7 @@ void *kmap_atomic(struct page *page)
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR * smp_processor_id();
- vaddr = __fix_to_virt(idx);
+ vaddr = __kmap_fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
/*
* With debugging enabled, kunmap_atomic forces that entry to 0.
@@ -109,7 +112,7 @@ void __kunmap_atomic(void *kvaddr)
if (cache_is_vivt())
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
#ifdef CONFIG_DEBUG_HIGHMEM
- BUG_ON(vaddr != __fix_to_virt(idx));
+ BUG_ON(vaddr != __kmap_fix_to_virt(idx));
set_fixmap_pte(idx, __pte(0));
#else
(void) idx; /* to kill a warning */
@@ -132,7 +135,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR * smp_processor_id();
- vaddr = __fix_to_virt(idx);
+ vaddr = __kmap_fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(fixmap_page_table + idx)));
#endif
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 659c75d..ad82c05 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -570,7 +570,7 @@ void __init mem_init(void)
MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
MLK(ITCM_OFFSET, (unsigned long) itcm_end),
#endif
- MLK(FIXADDR_START, FIXADDR_TOP),
+ MLK(FIXADDR_START, FIXADDR_END),
MLM(VMALLOC_START, VMALLOC_END),
MLM(PAGE_OFFSET, (unsigned long)high_memory),
#ifdef CONFIG_HIGHMEM
--
1.7.10.4
More information about the linux-arm-kernel
mailing list