Re: [GIT PULL tip/x86/mm] xen/x86 fixes ===> fix sp5100_tco mmio checking.

[Yinghai Lu <yinghai@kernel.org>]

On 03/16/2011 11:02 AM, Stefano Stabellini wrote:
> On Wed, 16 Mar 2011, Yinghai Lu wrote:
>> On 03/16/2011 07:43 AM, Stefano Stabellini wrote:
>>> actually attach the logs :)
>>>
>>> On Wed, 16 Mar 2011, Stefano Stabellini wrote:
>>>> On Fri, 11 Mar 2011, Konrad Rzeszutek Wilk wrote:
>>>>> On Fri, Mar 11, 2011 at 01:17:23PM +0000, Stefano Stabellini wrote:
>>>>>> Hello,
>>>>>> recently we had a couple of long discussions with Yinghai about boot
>>>>>> crashes on xen, related to pagetable initialization.
>>>>>> As a result we came up with three patches, two of them fix the first [1]
>>>>>> boot crash and provide a nice cleanup on native:
>>>>>
>>>>> I don't know why this is happening now, but it could be very well
>>>>> related to the build config. Smaller builds don't seem to encounter this, while
>>>>> this is a distro type build. If I use:
>>>>>
>>>>>> Stefano Stabellini (1):
>>>>>>         xen: set max_pfn_mapped to the last pfn mapped
>>>>>
>>>>> it hangs during bootup. The machine hangs during the box (no keyboard interaction)
>>>>> and I can see this in the bootup.
>>>>
>>>> Konrad sent me few other logs offline: log1 is the log of the hang and
>>>> log2 is a successful boot (reverting the problematic patch).
>>>> It looks like the SP5100 TCO WatchDog Timer Driver is using ioremap on
>>>> an address (0xb8fe00) that belongs to the memory range used for the
>>>> pagetable (0x9fc000-0xf43fff).
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000] found SMP MP-table at [ffff8800000ff780] ff780
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]     memblock_x86_reserve_range: [0x000ff780-0x000ff78f]   * MP-table mpf
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]     memblock_x86_reserve_range: [0x000fd240-0x000fd423]   * MP-table mpc
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]     memblock_x86_reserve_range: [0x01cfd000-0x01d1c0e4]              BRK
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000] MEMBLOCK configuration:
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  memory size = 0x23fe39000
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  memory.cnt  = 0x3
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  memory[0x0]      [0x00000000010000-0x0000000009afff], 0x8b000 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  memory[0x1]      [0x00000000100000-0x000000bffaffff], 0xbfeb0000 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  memory[0x2]      [0x00000100000000-0x0000027fefdfff], 0x17fefe000 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  reserved.cnt  = 0x5
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  reserved[0x0]    [0x000000000fd240-0x000000000fd423], 0x1e4 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  reserved[0x1]    [0x000000000ff780-0x000000000ff78f], 0x10 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  reserved[0x2]    [0x00000001000000-0x00000001d1c0e4], 0xd1c0e5 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  reserved[0x3]    [0x00000001e33000-0x00000016a36fff], 0x14c04000 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]  reserved[0x4]    [0x000001f0f7e000-0x0000027fefdfff], 0x8ef80000 bytes
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000] Scanning 0 areas for low memory corruption
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]     memblock_x86_reserve_range: [0x00099000-0x0009afff]       TRAMPOLINE
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]     memblock_x86_reserve_range: [0x00095000-0x00098fff]      ACPI WAKEUP
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000] init_memory_mapping: 0000000000000000-00000000bffb0000
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000] DEBUG find_early_table_space: _text=1000000 _end=1e33000 pgtable_start=9fc000 pgtable_end=9fc000
>>
>> Mar 15 16:09:04 phenom kernel: [    0.000000]     memblock_x86_reserve_range: [0x009fc000-0x00f43fff]          PGTABLE
>>
>> e820 said that range is ram and usable. so it is right for memblock to use it.
>>
>> why TCO watchdog try to use ioremap with RAM?  BIOS put wrong mmio in that BAR?
>>
>> could do some sanitary check in that driver.
>>
>
> Yeah, I think the max_pfn_mapped patch might be exposing bugs in the
> drivers.
> Do you remember this patch:
>
> https://lkml.org/lkml/2011/2/4/60
>
> would you be happy with it as a safer alternative?

we should fix tco driver

Mar 15 16:09:04 phenom kernel: [    9.148536] SP5100 TCO timer: SP5100 TCO WatchDog Timer Driver v0.01

Mar 15 16:09:04 phenom kernel: [    9.148628] DEBUG __ioremap_caller WARNING address=b8fe00 size=8 valid=1 reserved=1

so BIOS program wrong MMIO info.

need some checking in that driver like

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 8083728..2fac643 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -42,6 +42,7 @@
  #define PFX TCO_MODULE_NAME ": "
  
  /* internal variables */
+static u32 tcobase_phys;
  static void __iomem *tcobase;
  static unsigned int pm_iobase;
  static DEFINE_SPINLOCK(tco_lock);	/* Guards the hardware */
@@ -305,6 +306,12 @@ static unsigned char __devinit sp5100_tco_setupdevice(void)
  	/* Low three bits of BASE0 are reserved. */
  	val = val << 8 | (inb(SP5100_IO_PM_DATA_REG) & 0xf8);
  
+	if (request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE, "SP5100 TCO")) {
+		printk(KERN_ERR PFX "mmio address 0x%04x already in use\n", val);
+		goto unreg_region;
+	}
+	tcobase_phys = val;
+
  	tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
  	if (tcobase == 0) {
  		printk(KERN_ERR PFX "failed to get tcobase address\n");
@@ -414,6 +421,7 @@ static void __devexit sp5100_tco_cleanup(void)
  	/* Deregister */
  	misc_deregister(&sp5100_tco_miscdev);
  	iounmap(tcobase);
+	release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
  	release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
  }