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authorGlauber Costa <gcosta@redhat.com>2008-03-03 14:12:55 -0300
committerIngo Molnar <mingo@elte.hu>2008-04-17 17:40:56 +0200
commit0941ecb55fbfd2d8bcc62dfd2fcaba1b35f2f196 (patch)
tree1e5ab463fc747dcc1cf56c22df7c3c5b745ac981 /arch/x86/kernel/smp.c
parentc048fdfe6178e082be918d4062c86d9764979112 (diff)
downloadlinux-0941ecb55fbfd2d8bcc62dfd2fcaba1b35f2f196.tar.gz
x86: get rid of smp_32.c and smp_64.c
This patch merges the copyright notices, and valuable
comments that were left back on smp_{32,64}.c. With that,
files are empty, and are deleted

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/smp.c')
-rw-r--r--arch/x86/kernel/smp.c91
1 files changed, 91 insertions, 0 deletions
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index b662300a88f3..88c1e518a203 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -1,3 +1,16 @@
+/*
+ *	Intel SMP support routines.
+ *
+ *	(c) 1995 Alan Cox, Building #3 <alan@redhat.com>
+ *	(c) 1998-99, 2000 Ingo Molnar <mingo@redhat.com>
+ *      (c) 2002,2003 Andi Kleen, SuSE Labs.
+ *
+ *	i386 and x86_64 integration by Glauber Costa <gcosta@redhat.com>
+ *
+ *	This code is released under the GNU General Public License version 2 or
+ *	later.
+ */
+
 #include <linux/init.h>
 
 #include <linux/mm.h>
@@ -19,6 +32,84 @@
 #else
 #include <asm/mach_apic.h>
 #endif
+/*
+ *	Some notes on x86 processor bugs affecting SMP operation:
+ *
+ *	Pentium, Pentium Pro, II, III (and all CPUs) have bugs.
+ *	The Linux implications for SMP are handled as follows:
+ *
+ *	Pentium III / [Xeon]
+ *		None of the E1AP-E3AP errata are visible to the user.
+ *
+ *	E1AP.	see PII A1AP
+ *	E2AP.	see PII A2AP
+ *	E3AP.	see PII A3AP
+ *
+ *	Pentium II / [Xeon]
+ *		None of the A1AP-A3AP errata are visible to the user.
+ *
+ *	A1AP.	see PPro 1AP
+ *	A2AP.	see PPro 2AP
+ *	A3AP.	see PPro 7AP
+ *
+ *	Pentium Pro
+ *		None of 1AP-9AP errata are visible to the normal user,
+ *	except occasional delivery of 'spurious interrupt' as trap #15.
+ *	This is very rare and a non-problem.
+ *
+ *	1AP.	Linux maps APIC as non-cacheable
+ *	2AP.	worked around in hardware
+ *	3AP.	fixed in C0 and above steppings microcode update.
+ *		Linux does not use excessive STARTUP_IPIs.
+ *	4AP.	worked around in hardware
+ *	5AP.	symmetric IO mode (normal Linux operation) not affected.
+ *		'noapic' mode has vector 0xf filled out properly.
+ *	6AP.	'noapic' mode might be affected - fixed in later steppings
+ *	7AP.	We do not assume writes to the LVT deassering IRQs
+ *	8AP.	We do not enable low power mode (deep sleep) during MP bootup
+ *	9AP.	We do not use mixed mode
+ *
+ *	Pentium
+ *		There is a marginal case where REP MOVS on 100MHz SMP
+ *	machines with B stepping processors can fail. XXX should provide
+ *	an L1cache=Writethrough or L1cache=off option.
+ *
+ *		B stepping CPUs may hang. There are hardware work arounds
+ *	for this. We warn about it in case your board doesn't have the work
+ *	arounds. Basically that's so I can tell anyone with a B stepping
+ *	CPU and SMP problems "tough".
+ *
+ *	Specific items [From Pentium Processor Specification Update]
+ *
+ *	1AP.	Linux doesn't use remote read
+ *	2AP.	Linux doesn't trust APIC errors
+ *	3AP.	We work around this
+ *	4AP.	Linux never generated 3 interrupts of the same priority
+ *		to cause a lost local interrupt.
+ *	5AP.	Remote read is never used
+ *	6AP.	not affected - worked around in hardware
+ *	7AP.	not affected - worked around in hardware
+ *	8AP.	worked around in hardware - we get explicit CS errors if not
+ *	9AP.	only 'noapic' mode affected. Might generate spurious
+ *		interrupts, we log only the first one and count the
+ *		rest silently.
+ *	10AP.	not affected - worked around in hardware
+ *	11AP.	Linux reads the APIC between writes to avoid this, as per
+ *		the documentation. Make sure you preserve this as it affects
+ *		the C stepping chips too.
+ *	12AP.	not affected - worked around in hardware
+ *	13AP.	not affected - worked around in hardware
+ *	14AP.	we always deassert INIT during bootup
+ *	15AP.	not affected - worked around in hardware
+ *	16AP.	not affected - worked around in hardware
+ *	17AP.	not affected - worked around in hardware
+ *	18AP.	not affected - worked around in hardware
+ *	19AP.	not affected - worked around in BIOS
+ *
+ *	If this sounds worrying believe me these bugs are either ___RARE___,
+ *	or are signal timing bugs worked around in hardware and there's
+ *	about nothing of note with C stepping upwards.
+ */
 
 /*
  * this function sends a 'reschedule' IPI to another CPU.