hm, page 000f0000 reserved twice ?

hm, page 000f0000 reserved twice ?

[Stephan von Krawczynski]

Hello all,

Can any kind soul please tell me what "hm, page xxxx reserved twice" means? And
additionally: is there any magic involved in getting a serial console working?
There seems no way to make it work on below system. All "echo >/dev/ttyS0 test"
do work, but no console output whatsoever visible...

Regards,
Stephan

dmesg:

Inspecting /boot/System.map-2.4.21-pre5
Loaded 17206 symbols from /boot/System.map-2.4.21-pre5.
Symbols match kernel version 2.4.21.
No module symbols loaded.
klogd 1.4.1, log source = ksyslog started.
<4>Linux version 2.4.21-pre5 (root@admin) (gcc version 3.2) #8 SMP Sat Mar 8
17:20:05 CET 2003
<6>BIOS-provided physical RAM map:
<4> BIOS-e820: 0000000000000000 - 000000000009e800 (usable)   
<4> BIOS-e820: 000000000009e800 - 00000000000a0000 (reserved) 
<4> BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved) 
<4> BIOS-e820: 0000000000100000 - 000000001fffb000 (usable)
<4> BIOS-e820: 000000001fffb000 - 000000001ffff000 (ACPI data)
<4> BIOS-e820: 000000001ffff000 - 0000000020000000 (ACPI NVS)
<4> BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
<4> BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
<4> BIOS-e820: 00000000ffff0000 - 0000000100000000 (reserved)
<5>0MB HIGHMEM available.
<5>511MB LOWMEM available.
<4>found SMP MP-table at 000f0410
<4>hm, page 000f0000 reserved twice.
<4>hm, page 000f1000 reserved twice.
<4>hm, page 000f0000 reserved twice.      
<4>On node 0 totalpages: 131067
<4>zone(0): 4096 pages.
<4>zone(1): 126971 pages.
<4>zone(2): 0 pages.
<4>Intel MultiProcessor Specification v1.4
<4>    Virtual Wire compatibility mode. 
<4>OEM ID: ASUS     Product ID: PROD00000000 APIC at: 0xFEE00000
<4>Processor #3 Pentium(tm) Pro APIC version 17
<4>Processor #0 Pentium(tm) Pro APIC version 17
<4>I/O APIC #4 Version 17 at 0xFEC00000.
<4>I/O APIC #5 Version 17 at 0xFEC01000.
<4>I/O APIC #6 Version 17 at 0xFEC02000.
<4>Enabling APIC mode: Flat.    Using 3 I/O APICs
<4>Processors: 2
<4>Kernel command line: root=/dev/sda3  hda=none hdb=none hdc=ide-scsi
console=ttyS0,9600

Re: hm, page 000f0000 reserved twice ?

[Alan Cox]

On Sat, 2003-03-08 at 17:18, Stephan von Krawczynski wrote:
> Hello all,
> 
> Can any kind soul please tell me what "hm, page xxxx reserved twice" means? And
> additionally: is there any magic involved in getting a serial console working?
> There seems no way to make it work on below system. All "echo >/dev/ttyS0 test"
> do work, but no console output whatsoever visible...

The page reserved twice is just a warning, in this case its harmless and really
its code that wants tidying up

Re: hm, page 000f0000 reserved twice ?

[Stephan von Krawczynski]

On 08 Mar 2003 18:46:22 +0000
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Sat, 2003-03-08 at 17:18, Stephan von Krawczynski wrote:
> > Hello all,
> > 
> > Can any kind soul please tell me what "hm, page xxxx reserved twice" means?
> > And additionally: is there any magic involved in getting a serial console
> > working? There seems no way to make it work on below system. All "echo
> > >/dev/ttyS0 test"
> > do work, but no console output whatsoever visible...
> 
> The page reserved twice is just a warning, in this case its harmless and
> really its code that wants tidying up

Hm, from looking at the code (mm/bootmem.c), I would say, that:

static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long
addr, unsigned long size)
{
        unsigned long i;
        /*
         * round up, partially reserved pages are considered
         * fully reserved.
         */
        unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;
        unsigned long eidx = (addr + size - bdata->node_boot_start + 
                                                        PAGE_SIZE-1)/PAGE_SIZE;
        unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE;





        if (!size) BUG();

        if (sidx < 0)    
                BUG();   

Can sidx < 0 happen? sidx is unsigned long... Shouldn't "(addr <
bdata->node_boot_start)" be checked instead which would implicitely check eidx,
too. Or not?


        if (eidx < 0)    
                BUG();   

s.a. ...

        if (sidx >= eidx)
                BUG();
        if ((addr >> PAGE_SHIFT) >= bdata->node_low_pfn)
                BUG();
        if (end > bdata->node_low_pfn)
                BUG();
        for (i = sidx; i < eidx; i++)
                if (test_and_set_bit(i, bdata->node_bootmem_map))
                        printk("hm, page %08lx reserved twice.\n",
i*PAGE_SIZE);
}


Just as a note ... not really important, though.

Regards,
Stephan