Re: MPTable can not be high-memory on Linux

From: Kevin O'Connor
Date: Sat Feb 28 2009 - 18:41:41 EST


On Sun, Feb 22, 2009 at 10:14:56PM -0800, Yinghai Lu wrote:
> please check
>
> [PATCH] x86: check physptr with max_low_pfn on 32bit

Thanks for looking at this issue.

Unfortunately, the kernel still does not work with the applied patch.
Neither 32bit nor 64bit kernels boot. (Note, I applied the patch to
Linus' git, and I had to replace mpf->physptr with mpf->mpf_physptr.)

The error messages from before and after patching appear to be the
same.


In order to aid in testing, I modified SeaBIOS to force the mptable
into high memory even in qemu mode. A modified bios.bin file can be
found at:

http://linuxtogo.org/~kevin/SeaBIOS/bios.bin-high-mptable

To use it with qemu, the steps are roughly:

mkdir testbios
cp /usr/share/qemu/*.bin testbios/
cp bios.bin-high-mptable testbios/bios.bin
qemu -L testbios/ -hda mytestlinux.img -serial file:mylog


The modified bios.bin can also be built manually by running:

git clone git://linuxtogo.org/home/kevin/seabios.git
cd seabios
patch -p1 < patch-from-below
make
cp out/bios.bin ../bios.bin-high-mptable

-Kevin


diff --git a/src/config.h b/src/config.h
index 56e5302..1ecc86f 100644
--- a/src/config.h
+++ b/src/config.h
@@ -21,7 +21,7 @@
#define CONFIG_DEBUG_LEVEL 1

// Send debugging information to serial port
-#define CONFIG_DEBUG_SERIAL 0
+#define CONFIG_DEBUG_SERIAL 1

// Support for int13 floppy drive access
#define CONFIG_FLOPPY_SUPPORT 1
@@ -77,7 +77,7 @@
// Support finding a UUID (for smbios) via "magic" outl sequence.
#define CONFIG_UUID_BACKDOOR 1
// Support generation of ACPI tables (for emulators)
-#define CONFIG_ACPI 1
+#define CONFIG_ACPI 0
// Support bios callbacks specific to via vgabios.
#define CONFIG_VGAHOOKS 0
// Support S3 resume handler.
diff --git a/src/mptable.c b/src/mptable.c
index 9e030fe..79cc7ba 100644
--- a/src/mptable.c
+++ b/src/mptable.c
@@ -19,7 +19,7 @@ mptable_init(void)
dprintf(3, "init MPTable\n");

int smp_cpus = smp_probe();
- if (smp_cpus <= 1)
+ if (0 && smp_cpus <= 1)
// Building an mptable on uniprocessor machines confuses some OSes.
return;

@@ -39,7 +39,9 @@ mptable_init(void)
/* floating pointer structure */
struct mptable_floating_s *floating = (void*)start;
memset(floating, 0, sizeof(*floating));
- struct mptable_config_s *config = (void*)&floating[1];
+// struct mptable_config_s *config = (void*)&floating[1];
+ struct mptable_config_s *config = (void*)(RamSize - 64*1024);
+ add_e820((u32)config, 64*1024, E820_RESERVED);
floating->signature = MPTABLE_SIGNATURE;
floating->physaddr = (u32)config;
floating->length = 1;
--
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