Re: [BUG] 2.5.63: ESR killed my box!

[Linus Torvalds]

Ok, can people agree on this simplified version of Mikaels patch, which 
doesn't BUG_ON(), and doesn't reset 'boot_cpu_physical_apicid' 
unnecessarily..

Does this work for people?

			Linus

---
# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.1087  -> 1.1088 
#	arch/i386/kernel/apic.c	1.33    -> 1.34   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/02/26	[e-mail]	1.1088
# [PATCH] APIC ID fixes
# 
# 1) apic_write_around(APIC_ID, boot_cpu_physical_apicid) places the APIC
# value in the lower 8 bits of APIC_ID, when it should be in the upper 8. As
# as result, it effectively forces the APIC id to always be 0 for the boot
# CPU, which is fatal on SMP AMD boxes.
# 
#  Fix: don't do the write at all. The APIC_ID value should be right already.
# 
# 2) phys_cpu_present_map = 1 means we always set bit 0, but later on
#    in setup_local_APIC() we do
#         if (!clustered_apic_mode &&
#             !test_bit(GET_APIC_ID(apic_read(APIC_ID)), &phys_cpu_present_map))
#                 BUG();
# and the bug is triggered if the APIC_ID is not zero.
# 
#  Fix: initialize 'phys_cpu_present_map' correctly.
# --------------------------------------------
#
diff -Nru a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
--- a/arch/i386/kernel/apic.c	Wed Feb 26 16:00:18 2003
+++ b/arch/i386/kernel/apic.c	Wed Feb 26 16:00:18 2003
@@ -665,7 +665,6 @@
 	}
 	set_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
-	boot_cpu_physical_apicid = 0;
 	if (nmi_watchdog != NMI_NONE)
 		nmi_watchdog = NMI_LOCAL_APIC;
 
@@ -1154,8 +1153,7 @@
 
 	connect_bsp_APIC();
 
-	phys_cpu_present_map = 1;
-	apic_write_around(APIC_ID, boot_cpu_physical_apicid);
+	phys_cpu_present_map = 1 << boot_cpu_physical_apicid;
 
 	apic_pm_init2();