[PATCH] x86, PCI: support mmio more than 44 bits on 32bit/PAE mode

From: Yinghai Lu
Date: Fri Nov 21 2014 - 14:38:14 EST


Aaron reported 32bit/PAE mode, has problem with 64bit resource.

[ 6.610012] pci 0000:03:00.0: reg 0x10: [mem 0x383fffc00000-0x383fffdfffff 64bit pref]
[ 6.622195] pci 0000:03:00.0: reg 0x20: [mem 0x383fffe04000-0x383fffe07fff 64bit pref]
[ 6.656112] pci 0000:03:00.1: reg 0x10: [mem 0x383fffa00000-0x383fffbfffff 64bit pref]
[ 6.668293] pci 0000:03:00.1: reg 0x20: [mem 0x383fffe00000-0x383fffe03fff 64bit pref]
...
[ 12.374143] calling ixgbe_init_module+0x0/0x51 @ 1
[ 12.378130] ixgbe: Intel(R) 10 Gigabit PCI Express Network Driver - version 3.19.1-k
[ 12.385318] ixgbe: Copyright (c) 1999-2014 Intel Corporation.
[ 12.390578] ixgbe 0000:03:00.0: Adapter removed
[ 12.394247] ixgbe: probe of 0000:03:00.0 failed with error -5
[ 12.399369] ixgbe 0000:03:00.1: Adapter removed
[ 12.403036] ixgbe: probe of 0000:03:00.1 failed with error -5
[ 12.408017] initcall ixgbe_init_module+0x0/0x51 returned 0 after 29200 usecs

root cause: ioremap can not handle mmio range that is more than 44bits on
32bit PAE mode.

We are using pfn with unsigned long like pfn_pte(), so those 0x383fffc00000 will
overflow in pfn format with unsigned long (that is 32 bits in 32bit x86 kernel,
and pfn only can support 44bits).

| static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
| {
| return __pte(((phys_addr_t)page_nr << PAGE_SHIFT) |
| massage_pgprot(pgprot));
| }

We could limit iomem to 44 bits so we can reject them early from root bus.
but xhci is not happy with resource allocation (hang...)

Change phys_addr_t for pfn_pte, and add overflow check to skip ram checking,
as the mmio is too big to be ram.
At last, don't use PHYSICAL_PAGE_MASK to get aligned phys_addr, that will
cut off bits above 44bits.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=88131
Reported-by: Aaron Ma <mapengyu@xxxxxxxxx>
Tested-by: Aaron Ma <mapengyu@xxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

---
arch/x86/include/asm/page.h | 8 ++++++++
arch/x86/include/asm/pgtable.h | 4 ++--
arch/x86/mm/ioremap.c | 6 ++++--
arch/x86/mm/pat.c | 3 +++
4 files changed, 17 insertions(+), 4 deletions(-)

Index: linux-2.6/arch/x86/include/asm/page.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/page.h
+++ linux-2.6/arch/x86/include/asm/page.h
@@ -15,6 +15,14 @@

#ifndef __ASSEMBLY__

+static inline int pfn_overflow(dma_addr_t phy_addr)
+{
+ dma_addr_t real_pfn = phy_addr >> PAGE_SHIFT;
+ unsigned long pfn = (unsigned long)real_pfn;
+
+ return pfn != real_pfn;
+}
+
struct page;

#include <linux/range.h>
Index: linux-2.6/arch/x86/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/pgtable.h
+++ linux-2.6/arch/x86/include/asm/pgtable.h
@@ -355,9 +355,9 @@ static inline pgprotval_t massage_pgprot
return protval;
}

-static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
+static inline pte_t pfn_pte(phys_addr_t page_nr, pgprot_t pgprot)
{
- return __pte(((phys_addr_t)page_nr << PAGE_SHIFT) |
+ return __pte((page_nr << PAGE_SHIFT) |
massage_pgprot(pgprot));
}

Index: linux-2.6/arch/x86/mm/ioremap.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/ioremap.c
+++ linux-2.6/arch/x86/mm/ioremap.c
@@ -122,7 +122,9 @@ static void __iomem *__ioremap_caller(re
if (ram_region < 0) {
pfn = phys_addr >> PAGE_SHIFT;
last_pfn = last_addr >> PAGE_SHIFT;
- if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
+ /* pfn overflow, don't need to check */
+ if (!pfn_overflow(last_addr) &&
+ walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
__ioremap_check_ram) == 1)
return NULL;
}
@@ -130,7 +132,7 @@ static void __iomem *__ioremap_caller(re
* Mappings have to be page-aligned
*/
offset = phys_addr & ~PAGE_MASK;
- phys_addr &= PHYSICAL_PAGE_MASK;
+ phys_addr -= offset;
size = PAGE_ALIGN(last_addr+1) - phys_addr;

retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
Index: linux-2.6/arch/x86/mm/pat.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/pat.c
+++ linux-2.6/arch/x86/mm/pat.c
@@ -299,6 +299,9 @@ static int pat_pagerange_is_ram(resource
unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
struct pagerange_state state = {start_pfn, 0, 0};

+ /* pfn overflow, don't need to check */
+ if (pfn_overflow(end + PAGE_SIZE - 1))
+ return 0;
/*
* For legacy reasons, physical address range in the legacy ISA
* region is tracked as non-RAM. This will allow users of
--
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