Re: [PATCH] x86,pci: detect end_bus_number according to acpi/e820reserved

From: Ingo Molnar
Date: Fri Jul 18 2008 - 16:48:39 EST



* Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:

> for MacBookPro2
>
> change the mconf bus range from [0,0xff] to to [0, 0x3f]
> to match range [0xf0000000, 0xf4000000) in e820 tables.
>
> Signed-off-by: Yinghai Lu <yhlu.kernel@xxxxxxxxx>

pushed the commit below into tip/pci-for-jesse.

Jack, could you check whether the end result in tip/master boots fine on
your 3GB MacBook by default:

http://people.redhat.com/mingo/x86.git/README

... and let us know if there are any other problems/weirdnesses.

Ingo

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git pci-for-jesse

------------------------->
commit 473e6a3881ed2b5903252cb6a759d55aecff8611
Author: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
Date: Fri Jul 18 13:22:36 2008 -0700

x86, pci: detect end_bus_number according to acpi/e820 reserved

Jack Howarth reported that 2.6.26-rc9-git9 doesn't boot on MacBookPro2.

the reason is a faulty BIOS update that reportes faulty resources.

Nevertheless it's possible for Linux to be more resolent about this
situation (and similar situations) and work around this bug, by
cross-checking the mmconf range against the e820 table and ACPI resources.

Change the mconf bus range from [0,0xff] to to [0, 0x3f]
to match range [0xf0000000, 0xf4000000) in e820 tables.

Reported-by: Jack Howarth <howarth@xxxxxxxxxxxxxxxxx>
Signed-off-by: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
Cc: jbarnes@xxxxxxxxxxxxxxxx
Cc: Jack Howarth <howarth@xxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/pci/mmconfig-shared.c | 64 +++++++++++++++++++++++++++++----------
1 files changed, 47 insertions(+), 17 deletions(-)

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 23faaa8..9297882 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -293,7 +293,7 @@ static acpi_status __init find_mboard_resource(acpi_handle handle, u32 lvl,
return AE_OK;
}

-static int __init is_acpi_reserved(unsigned long start, unsigned long end)
+static int __init is_acpi_reserved(u64 start, u64 end, unsigned not_used)
{
struct resource mcfg_res;

@@ -310,6 +310,41 @@ static int __init is_acpi_reserved(unsigned long start, unsigned long end)
return mcfg_res.flags;
}

+typedef int (*check_reserved_t)(u64 start, u64 end, unsigned type);
+
+static int __init is_mmconf_reserved(check_reserved_t is_reserved,
+ u64 addr, u64 size, int i,
+ typeof(pci_mmcfg_config[0]) *cfg, int with_e820)
+{
+ u64 old_size = size;
+ int valid = 0;
+
+ while (!is_reserved(addr, addr + size - 1, E820_RESERVED)) {
+ size >>= 1;
+ if (size < (16UL<<20))
+ break;
+ }
+
+ if (size >= (16UL<<20) || size == old_size) {
+ printk(KERN_NOTICE
+ "PCI: MCFG area at %Lx reserved in %s\n",
+ addr, with_e820?"E820":"ACPI motherboard resources");
+ valid = 1;
+
+ if (old_size != size) {
+ /* update end_bus_number */
+ cfg->end_bus_number = cfg->start_bus_number + ((size>>20) - 1);
+ printk(KERN_NOTICE "PCI: updated MCFG configuration %d: base %lx "
+ "segment %hu buses %u - %u\n",
+ i, (unsigned long)cfg->address, cfg->pci_segment,
+ (unsigned int)cfg->start_bus_number,
+ (unsigned int)cfg->end_bus_number);
+ }
+ }
+
+ return valid;
+}
+
static void __init pci_mmcfg_reject_broken(int early)
{
typeof(pci_mmcfg_config[0]) *cfg;
@@ -324,21 +359,21 @@ static void __init pci_mmcfg_reject_broken(int early)

for (i = 0; i < pci_mmcfg_config_num; i++) {
int valid = 0;
- u32 size = (cfg->end_bus_number + 1) << 20;
+ u64 addr, size;
+
cfg = &pci_mmcfg_config[i];
+ addr = cfg->start_bus_number;
+ addr <<= 20;
+ size = cfg->end_bus_number + 1 - cfg->start_bus_number;
+ size <<= 20;
printk(KERN_NOTICE "PCI: MCFG configuration %d: base %lx "
"segment %hu buses %u - %u\n",
i, (unsigned long)cfg->address, cfg->pci_segment,
(unsigned int)cfg->start_bus_number,
(unsigned int)cfg->end_bus_number);

- if (!early &&
- is_acpi_reserved(cfg->address, cfg->address + size - 1)) {
- printk(KERN_NOTICE "PCI: MCFG area at %Lx reserved "
- "in ACPI motherboard resources\n",
- cfg->address);
- valid = 1;
- }
+ if (!early)
+ valid = is_mmconf_reserved(is_acpi_reserved, addr, size, i, cfg, 0);

if (valid)
continue;
@@ -347,16 +382,11 @@ static void __init pci_mmcfg_reject_broken(int early)
printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %Lx is not"
" reserved in ACPI motherboard resources\n",
cfg->address);
+
/* Don't try to do this check unless configuration
type 1 is available. how about type 2 ?*/
- if (raw_pci_ops && e820_all_mapped(cfg->address,
- cfg->address + size - 1,
- E820_RESERVED)) {
- printk(KERN_NOTICE
- "PCI: MCFG area at %Lx reserved in E820\n",
- cfg->address);
- valid = 1;
- }
+ if (raw_pci_ops)
+ valid = is_mmconf_reserved(e820_all_mapped, addr, size, i, cfg, 1);

if (!valid)
goto reject;
--
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