This patch fixes the broken evaluation of the E801 EISA memory map. The
shift was too much, the high word is already shifted :-) The bug was
hidden until the E820 memory map evaluation was broken due to the struct
packing issue fixed in my last patch.
The extra handling of "0x3C00" case is IMO not necessary. Regions are
merged a few lines later.
During testing, I added a primitive memory to detect such problems
early. It was difficult to find why grub crashes during module load.
Christian
2007-10-23 Christian Franke <[EMAIL PROTECTED]>
* kern/i386/pc/init.c (addr_is_valid): New function.
(add_mem_region): Add memory existence check.
(grub_machine_init): Fix evaluation of eisa_mmap.
--- grub2.orig/kern/i386/pc/init.c 2007-10-22 22:22:51.359375000 +0200
+++ grub2/kern/i386/pc/init.c 2007-10-22 22:25:44.546875000 +0200
@@ -83,6 +83,19 @@ make_install_device (void)
return grub_prefix;
}
+/* Check memory address */
+static int
+addr_is_valid (grub_addr_t addr)
+{
+ volatile unsigned char * p = (volatile unsigned char *)addr;
+ unsigned char x, y;
+ x = *p;
+ *p = x ^ 0xcf;
+ y = *p;
+ *p = x;
+ return y == (x ^ 0xcf);
+}
+
/* Add a memory region. */
static void
add_mem_region (grub_addr_t addr, grub_size_t size)
@@ -91,6 +104,9 @@ add_mem_region (grub_addr_t addr, grub_s
/* Ignore. */
return;
+ if (!(addr + size > addr && addr_is_valid (addr) && addr_is_valid (addr+size-1)))
+ grub_fatal ("invalid memory region %p - %p", (char*)addr, (char*)addr+size-1);
+
mem_regions[num_regions].addr = addr;
mem_regions[num_regions].size = size;
num_regions++;
@@ -199,13 +215,8 @@ grub_machine_init (void)
if (eisa_mmap)
{
- if ((eisa_mmap & 0xFFFF) == 0x3C00)
- add_mem_region (0x100000, (eisa_mmap << 16) + 0x100000 * 15);
- else
- {
- add_mem_region (0x100000, (eisa_mmap & 0xFFFF) << 10);
- add_mem_region (0x1000000, eisa_mmap << 16);
- }
+ add_mem_region (0x100000, (eisa_mmap & 0xFFFF) << 10);
+ add_mem_region (0x1000000, eisa_mmap & ~0xFFFF);
}
else
add_mem_region (0x100000, grub_get_memsize (1) << 10);
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