Re: More info for DSM w/r/t sunffb on 2.6.15-rc6

From: David S. Miller
Date: Tue Mar 21 2006 - 05:25:34 EST


From: Hugh Dickins <hugh@xxxxxxxxxxx>
Date: Sat, 24 Dec 2005 09:07:29 +0000 (GMT)

> I was wondering your estimation of the likelihood of problems if we
> change sparc and sparc64 io_remap_pfn_range to respect the distinction
> between shared and private, readonly and writable, early in 2.6.16,
> or early in 2.6.17.

I don't anticipate any, what they are doing is clearly broken.

I'll push the following fix soon.

Thanks for pointing all of this stuff out Hugh.

diff --git a/arch/sparc/mm/generic.c b/arch/sparc/mm/generic.c
index 2cb0728..1ef7fa0 100644
--- a/arch/sparc/mm/generic.c
+++ b/arch/sparc/mm/generic.c
@@ -76,7 +76,6 @@ int io_remap_pfn_range(struct vm_area_st
vma->vm_pgoff = (offset >> PAGE_SHIFT) |
((unsigned long)space << 28UL);

- prot = __pgprot(pg_iobits);
offset -= from;
dir = pgd_offset(mm, from);
flush_cache_range(vma, beg, end);
diff --git a/arch/sparc/mm/loadmmu.c b/arch/sparc/mm/loadmmu.c
index e9f9571..36b4d24 100644
--- a/arch/sparc/mm/loadmmu.c
+++ b/arch/sparc/mm/loadmmu.c
@@ -22,8 +22,6 @@ struct ctx_list *ctx_list_pool;
struct ctx_list ctx_free;
struct ctx_list ctx_used;

-unsigned int pg_iobits;
-
extern void ld_mmu_sun4c(void);
extern void ld_mmu_srmmu(void);

diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index c664b96..27b0e0b 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -2130,6 +2130,13 @@ static unsigned long srmmu_pte_to_pgoff(
return pte_val(pte) >> SRMMU_PTE_FILE_SHIFT;
}

+static pgprot_t srmmu_pgprot_noncached(pgprot_t prot)
+{
+ prot &= ~__pgprot(SRMMU_CACHE);
+
+ return prot;
+}
+
/* Load up routines and constants for sun4m and sun4d mmu */
void __init ld_mmu_srmmu(void)
{
@@ -2150,9 +2157,9 @@ void __init ld_mmu_srmmu(void)
BTFIXUPSET_INT(page_readonly, pgprot_val(SRMMU_PAGE_RDONLY));
BTFIXUPSET_INT(page_kernel, pgprot_val(SRMMU_PAGE_KERNEL));
page_kernel = pgprot_val(SRMMU_PAGE_KERNEL);
- pg_iobits = SRMMU_VALID | SRMMU_WRITE | SRMMU_REF;

/* Functions */
+ BTFIXUPSET_CALL(pgprot_noncached, srmmu_pgprot_noncached, BTFIXUPCALL_NORM);
#ifndef CONFIG_SMP
BTFIXUPSET_CALL(___xchg32, ___xchg32_sun4md, BTFIXUPCALL_SWAPG1G2);
#endif
diff --git a/arch/sparc/mm/sun4c.c b/arch/sparc/mm/sun4c.c
index 731f196..49f28c1 100644
--- a/arch/sparc/mm/sun4c.c
+++ b/arch/sparc/mm/sun4c.c
@@ -1589,7 +1589,10 @@ static void sun4c_flush_tlb_page(struct

static inline void sun4c_mapioaddr(unsigned long physaddr, unsigned long virt_addr)
{
- unsigned long page_entry;
+ unsigned long page_entry, pg_iobits;
+
+ pg_iobits = _SUN4C_PAGE_PRESENT | _SUN4C_READABLE | _SUN4C_WRITEABLE |
+ _SUN4C_PAGE_IO | _SUN4C_PAGE_NOCACHE;

page_entry = ((physaddr >> PAGE_SHIFT) & SUN4C_PFN_MASK);
page_entry |= ((pg_iobits | _SUN4C_PAGE_PRIV) & ~(_SUN4C_PAGE_PRESENT));
@@ -2134,6 +2137,13 @@ void __init sun4c_paging_init(void)
printk("SUN4C: %d mmu entries for the kernel\n", cnt);
}

+static pgprot_t sun4c_pgprot_noncached(pgprot_t prot)
+{
+ prot |= __pgprot(_SUN4C_PAGE_IO | _SUN4C_PAGE_NOCACHE);
+
+ return prot;
+}
+
/* Load up routines and constants for sun4c mmu */
void __init ld_mmu_sun4c(void)
{
@@ -2156,10 +2166,9 @@ void __init ld_mmu_sun4c(void)
BTFIXUPSET_INT(page_readonly, pgprot_val(SUN4C_PAGE_READONLY));
BTFIXUPSET_INT(page_kernel, pgprot_val(SUN4C_PAGE_KERNEL));
page_kernel = pgprot_val(SUN4C_PAGE_KERNEL);
- pg_iobits = _SUN4C_PAGE_PRESENT | _SUN4C_READABLE | _SUN4C_WRITEABLE |
- _SUN4C_PAGE_IO | _SUN4C_PAGE_NOCACHE;

/* Functions */
+ BTFIXUPSET_CALL(pgprot_noncached, sun4c_pgprot_noncached, BTFIXUPCALL_NORM);
BTFIXUPSET_CALL(___xchg32, ___xchg32_sun4c, BTFIXUPCALL_NORM);
BTFIXUPSET_CALL(do_check_pgt_cache, sun4c_check_pgt_cache, BTFIXUPCALL_NORM);

diff --git a/arch/sparc64/kernel/pci.c b/arch/sparc64/kernel/pci.c
index 95ffa94..dfccff2 100644
--- a/arch/sparc64/kernel/pci.c
+++ b/arch/sparc64/kernel/pci.c
@@ -656,6 +656,7 @@ int pci_mmap_page_range(struct pci_dev *
__pci_mmap_set_flags(dev, vma, mmap_state);
__pci_mmap_set_pgprot(dev, vma, mmap_state);

+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
ret = io_remap_pfn_range(vma, vma->vm_start,
vma->vm_pgoff,
vma->vm_end - vma->vm_start,
@@ -663,7 +664,6 @@ int pci_mmap_page_range(struct pci_dev *
if (ret)
return ret;

- vma->vm_flags |= VM_IO;
return 0;
}

diff --git a/arch/sparc64/mm/generic.c b/arch/sparc64/mm/generic.c
index 5fc5c57..8cb0620 100644
--- a/arch/sparc64/mm/generic.c
+++ b/arch/sparc64/mm/generic.c
@@ -140,7 +140,6 @@ int io_remap_pfn_range(struct vm_area_st
vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
vma->vm_pgoff = phys_base >> PAGE_SHIFT;

- prot = __pgprot(pg_iobits);
offset -= from;
dir = pgd_offset(mm, from);
flush_cache_range(vma, beg, end);
diff --git a/drivers/char/drm/drm_vm.c b/drivers/char/drm/drm_vm.c
index 0291cd6..ffd0800 100644
--- a/drivers/char/drm/drm_vm.c
+++ b/drivers/char/drm/drm_vm.c
@@ -619,6 +619,7 @@ int drm_mmap(struct file *filp, struct v
#endif
offset = dev->driver->get_reg_ofs(dev);
#ifdef __sparc__
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
if (io_remap_pfn_range(DRM_RPR_ARG(vma) vma->vm_start,
(map->offset + offset) >> PAGE_SHIFT,
vma->vm_end - vma->vm_start,
diff --git a/drivers/sbus/char/flash.c b/drivers/sbus/char/flash.c
index 6bdd768..2beb3dd 100644
--- a/drivers/sbus/char/flash.c
+++ b/drivers/sbus/char/flash.c
@@ -71,9 +71,8 @@ flash_mmap(struct file *file, struct vm_
if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));

- pgprot_val(vma->vm_page_prot) &= ~(_PAGE_CACHE);
- pgprot_val(vma->vm_page_prot) |= _PAGE_E;
vma->vm_flags |= (VM_SHM | VM_LOCKED);
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
return -EAGAIN;
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 996c7b5..07d882b 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1169,11 +1169,6 @@ fb_mmap(struct file *file, struct vm_are
vma->vm_pgoff = off >> PAGE_SHIFT;
/* This is an IO map - tell maydump to skip this VMA */
vma->vm_flags |= VM_IO | VM_RESERVED;
-#if defined(__sparc_v9__)
- if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
- vma->vm_end - vma->vm_start, vma->vm_page_prot))
- return -EAGAIN;
-#else
#if defined(__mc68000__)
#if defined(CONFIG_SUN3)
pgprot_val(vma->vm_page_prot) |= SUN3_PAGE_NOCACHE;
@@ -1195,7 +1190,7 @@ fb_mmap(struct file *file, struct vm_are
#elif defined(__i386__) || defined(__x86_64__)
if (boot_cpu_data.x86 > 3)
pgprot_val(vma->vm_page_prot) |= _PAGE_PCD;
-#elif defined(__mips__)
+#elif defined(__mips__) || defined(__sparc_v9__)
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
#elif defined(__hppa__)
pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
@@ -1212,7 +1207,6 @@ fb_mmap(struct file *file, struct vm_are
if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
vma->vm_end - vma->vm_start, vma->vm_page_prot))
return -EAGAIN;
-#endif /* !__sparc_v9__ */
return 0;
#endif /* !sparc32 */
}
diff --git a/drivers/video/sbuslib.c b/drivers/video/sbuslib.c
index a4d7cc5..34ef859 100644
--- a/drivers/video/sbuslib.c
+++ b/drivers/video/sbuslib.c
@@ -58,6 +58,8 @@ int sbusfb_mmap_helper(struct sbus_mmap_
/* To stop the swapper from even considering these pages */
vma->vm_flags |= (VM_IO | VM_RESERVED);

+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
/* Each page, see which map applies */
for (page = 0; page < size; ){
map_size = 0;
diff --git a/include/asm-sparc/pgtable.h b/include/asm-sparc/pgtable.h
index b33c354..9eea8f4 100644
--- a/include/asm-sparc/pgtable.h
+++ b/include/asm-sparc/pgtable.h
@@ -269,11 +269,14 @@ BTFIXUPDEF_CALL_CONST(pte_t, mk_pte, str

BTFIXUPDEF_CALL_CONST(pte_t, mk_pte_phys, unsigned long, pgprot_t)
BTFIXUPDEF_CALL_CONST(pte_t, mk_pte_io, unsigned long, pgprot_t, int)
+BTFIXUPDEF_CALL_CONST(pgprot_t, pgprot_noncached, pgprot_t)

#define mk_pte(page,pgprot) BTFIXUP_CALL(mk_pte)(page,pgprot)
#define mk_pte_phys(page,pgprot) BTFIXUP_CALL(mk_pte_phys)(page,pgprot)
#define mk_pte_io(page,pgprot,space) BTFIXUP_CALL(mk_pte_io)(page,pgprot,space)

+#define pgprot_noncached(pgprot) BTFIXUP_CALL(pgprot_noncached)(pgprot)
+
BTFIXUPDEF_INT(pte_modify_mask)

static pte_t pte_modify(pte_t pte, pgprot_t newprot) __attribute_const__;
@@ -309,9 +312,6 @@ BTFIXUPDEF_CALL(pte_t *, pte_offset_kern
#define pte_unmap(pte) do{}while(0)
#define pte_unmap_nested(pte) do{}while(0)

-/* The permissions for pgprot_val to make a page mapped on the obio space */
-extern unsigned int pg_iobits;
-
/* Certain architectures need to do special things when pte's
* within a page table are directly modified. Thus, the following
* hook is made available.
-
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