aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/head64.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/head64.c')
-rw-r--r--arch/x86/kernel/head64.c50
1 files changed, 0 insertions, 50 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index e25c57b8aa84..f1773c8ee21e 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -51,56 +51,6 @@ static void __init copy_bootdata(char *real_mode_data)
51 } 51 }
52} 52}
53 53
54#define BIOS_LOWMEM_KILOBYTES 0x413
55
56/*
57 * The BIOS places the EBDA/XBDA at the top of conventional
58 * memory, and usually decreases the reported amount of
59 * conventional memory (int 0x12) too. This also contains a
60 * workaround for Dell systems that neglect to reserve EBDA.
61 * The same workaround also avoids a problem with the AMD768MPX
62 * chipset: reserve a page before VGA to prevent PCI prefetch
63 * into it (errata #56). Usually the page is reserved anyways,
64 * unless you have no PS/2 mouse plugged in.
65 */
66static void __init reserve_ebda_region(void)
67{
68 unsigned int lowmem, ebda_addr;
69
70 /* To determine the position of the EBDA and the */
71 /* end of conventional memory, we need to look at */
72 /* the BIOS data area. In a paravirtual environment */
73 /* that area is absent. We'll just have to assume */
74 /* that the paravirt case can handle memory setup */
75 /* correctly, without our help. */
76 if (paravirt_enabled())
77 return;
78
79 /* end of low (conventional) memory */
80 lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
81 lowmem <<= 10;
82
83 /* start of EBDA area */
84 ebda_addr = get_bios_ebda();
85
86 /* Fixup: bios puts an EBDA in the top 64K segment */
87 /* of conventional memory, but does not adjust lowmem. */
88 if ((lowmem - ebda_addr) <= 0x10000)
89 lowmem = ebda_addr;
90
91 /* Fixup: bios does not report an EBDA at all. */
92 /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
93 if ((ebda_addr == 0) && (lowmem >= 0x9f000))
94 lowmem = 0x9f000;
95
96 /* Paranoia: should never happen, but... */
97 if ((lowmem == 0) || (lowmem >= 0x100000))
98 lowmem = 0x9f000;
99
100 /* reserve all memory between lowmem and the 1MB mark */
101 reserve_early(lowmem, 0x100000, "BIOS reserved");
102}
103
104static void __init reserve_setup_data(void) 54static void __init reserve_setup_data(void)
105{ 55{
106 struct setup_data *data; 56 struct setup_data *data;