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authorIngo Molnar <mingo@elte.hu>2008-07-08 11:14:58 +0200
committerIngo Molnar <mingo@elte.hu>2008-07-08 11:14:58 +0200
commit3de352bbd86f890dd0c5e1c09a6a1b0b29e0f8ce (patch)
treed4c5eba8cd2abefd7c9f16d089393f0f5999cf63 /arch/x86/kernel/head.c
parent1b8ba39a3fad9c58532f6dad12c94d6e675be656 (diff)
parent9340e1ccdf7b9b22a2be7f51cd74e8b5e11961bf (diff)
Merge branch 'x86/mpparse' into x86/devel
Conflicts: arch/x86/Kconfig arch/x86/kernel/io_apic_32.c arch/x86/kernel/setup_64.c arch/x86/mm/init_32.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/head.c')
-rw-r--r--arch/x86/kernel/head.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/arch/x86/kernel/head.c b/arch/x86/kernel/head.c
new file mode 100644
index 00000000000..a727c0b9819
--- /dev/null
+++ b/arch/x86/kernel/head.c
@@ -0,0 +1,73 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+#include <asm/setup.h>
+#include <asm/bios_ebda.h>
+
+#define BIOS_LOWMEM_KILOBYTES 0x413
+
+/*
+ * 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.
+ */
+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();
+
+ /* Fixup: bios puts an EBDA in the top 64K segment */
+ /* of conventional memory, but does not adjust lowmem. */
+ if ((lowmem - ebda_addr) <= 0x10000)
+ lowmem = ebda_addr;
+
+ /* Fixup: bios does not report an EBDA at all. */
+ /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
+ if ((ebda_addr == 0) && (lowmem >= 0x9f000))
+ lowmem = 0x9f000;
+
+ /* Paranoia: should never happen, but... */
+ if ((lowmem == 0) || (lowmem >= 0x100000))
+ lowmem = 0x9f000;
+
+ /* reserve all memory between lowmem and the 1MB mark */
+ reserve_early(lowmem, 0x100000, "BIOS reserved");
+}
+
+void __init reserve_setup_data(void)
+{
+ struct setup_data *data;
+ u64 pa_data;
+ char buf[32];
+
+ if (boot_params.hdr.version < 0x0209)
+ return;
+ pa_data = boot_params.hdr.setup_data;
+ while (pa_data) {
+ data = early_ioremap(pa_data, sizeof(*data));
+ sprintf(buf, "setup data %x", data->type);
+ reserve_early(pa_data, pa_data+sizeof(*data)+data->len, buf);
+ pa_data = data->next;
+ early_iounmap(data, sizeof(*data));
+ }
+}