[PATCH] x86: Apm is on cpu zero only
APM BIOS code has a protective wrapper that runs it only on CPU zero. Thus,
no need to set APM BIOS segments in the GDT for other CPUs.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Acked-by: "Seth, Rohit" <rohit.seth@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index 45199bb..d0b4880 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -2222,8 +2222,8 @@
static int __init apm_init(void)
{
struct proc_dir_entry *apm_proc;
+ struct desc_struct *gdt;
int ret;
- int i;
dmi_check_system(apm_dmi_table);
@@ -2314,18 +2314,17 @@
* not restrict themselves to their claimed limit. When this happens,
* they will cause a segmentation violation in the kernel at boot time.
* Most BIOS's, however, will respect a 64k limit, so we use that.
+ *
+ * Note we only set APM segments on CPU zero, since we pin the APM
+ * code to that CPU.
*/
- for (i = 0; i < NR_CPUS; i++) {
- struct desc_struct *gdt = get_cpu_gdt_table(i);
- if (!gdt)
- continue;
- set_base(gdt[APM_CS >> 3],
- __va((unsigned long)apm_info.bios.cseg << 4));
- set_base(gdt[APM_CS_16 >> 3],
- __va((unsigned long)apm_info.bios.cseg_16 << 4));
- set_base(gdt[APM_DS >> 3],
- __va((unsigned long)apm_info.bios.dseg << 4));
- }
+ gdt = get_cpu_gdt_table(0);
+ set_base(gdt[APM_CS >> 3],
+ __va((unsigned long)apm_info.bios.cseg << 4));
+ set_base(gdt[APM_CS_16 >> 3],
+ __va((unsigned long)apm_info.bios.cseg_16 << 4));
+ set_base(gdt[APM_DS >> 3],
+ __va((unsigned long)apm_info.bios.dseg << 4));
apm_proc = create_proc_info_entry("apm", 0, NULL, apm_get_info);
if (apm_proc)
