diff options
Diffstat (limited to 'arch/x86/kernel/head.c')
-rw-r--r-- | arch/x86/kernel/head.c | 71 |
1 files changed, 0 insertions, 71 deletions
diff --git a/arch/x86/kernel/head.c b/arch/x86/kernel/head.c deleted file mode 100644 index 992f442ca..000000000 --- a/arch/x86/kernel/head.c +++ /dev/null @@ -1,71 +0,0 @@ -#include <linux/kernel.h> -#include <linux/init.h> -#include <linux/memblock.h> - -#include <asm/setup.h> -#include <asm/bios_ebda.h> - -/* - * The BIOS places the EBDA/XBDA at the top of conventional - * memory, and usually decreases the reported amount of - * conventional memory (int 0x12) too. This also contains a - * workaround for Dell systems that neglect to reserve EBDA. - * The same workaround also avoids a problem with the AMD768MPX - * chipset: reserve a page before VGA to prevent PCI prefetch - * into it (errata #56). Usually the page is reserved anyways, - * unless you have no PS/2 mouse plugged in. - * - * This functions is deliberately very conservative. Losing - * memory in the bottom megabyte is rarely a problem, as long - * as we have enough memory to install the trampoline. Using - * memory that is in use by the BIOS or by some DMA device - * the BIOS didn't shut down *is* a big problem. - */ - -#define BIOS_LOWMEM_KILOBYTES 0x413 -#define LOWMEM_CAP 0x9f000U /* Absolute maximum */ -#define INSANE_CUTOFF 0x20000U /* Less than this = insane */ - -void __init reserve_ebda_region(void) -{ - unsigned int lowmem, ebda_addr; - - /* - * To determine the position of the EBDA and the - * end of conventional memory, we need to look at - * the BIOS data area. In a paravirtual environment - * that area is absent. We'll just have to assume - * that the paravirt case can handle memory setup - * correctly, without our help. - */ - if (paravirt_enabled()) - return; - - /* end of low (conventional) memory */ - lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES); - lowmem <<= 10; - - /* start of EBDA area */ - ebda_addr = get_bios_ebda(); - - /* - * Note: some old Dells seem to need 4k EBDA without - * reporting so, so just consider the memory above 0x9f000 - * to be off limits (bugzilla 2990). - */ - - /* If the EBDA address is below 128K, assume it is bogus */ - if (ebda_addr < INSANE_CUTOFF) - ebda_addr = LOWMEM_CAP; - - /* If lowmem is less than 128K, assume it is bogus */ - if (lowmem < INSANE_CUTOFF) - lowmem = LOWMEM_CAP; - - /* Use the lower of the lowmem and EBDA markers as the cutoff */ - lowmem = min(lowmem, ebda_addr); - lowmem = min(lowmem, LOWMEM_CAP); /* Absolute cap */ - - /* reserve all memory between lowmem and the 1MB mark */ - memblock_reserve(lowmem, 0x100000 - lowmem); -} |