From: Dave Anderson <anderson@redhat.com>
Date: Fri, 2 Nov 2007 13:23:39 -0500
Subject: [x86_64] update IO-APIC dest field to 8-bit for xAPIC
Message-id: 472B6B2B.20604@redhat.com
O-Subject: [RHEL5.2 PATCH] BZ #224373: kexec or kdump hangs on ES7000/ONE
Bugzilla: 224373

BZ #224373: kexec or kdump hangs on ES7000/ONE
   https://bugzilla.redhat.com/show_bug.cgi?id=224373

Description:
   Backport of a 2.6.21 patch that addresses the increase in size of
   the x86_64 physical dest field from 4-bits in the legacy APIC to
   8-bits in the xAPIC.  The 4-bit physical_dest and 8-bit logical_dest
   fields in the IO_APIC_route_entry dest union were replaced by a common
   8-bit dest field, i.e., from this:

         union {         struct { __u32
                                         __reserved_1    : 24,
                                         physical_dest   :  4,
                                         __reserved_2    :  4;
                         } physical;

                         struct { __u32
                                         __reserved_1    : 24,
                                         logical_dest    :  8;
                         } logical;
         } dest;

   to this:

        __u32    __reserved_3    : 24,
                 dest            : 8;

   The kexec/kdump problem was tracked to old code in the io_apic.c file.
   Inside of disable_IO_APIC(), the obsolete 4-bit field physical.physical_dest
   was being used.  As of the xAPIC spec this field was expanded to 8 bits.
   The old code cuts the upper 4 bits off of the APIC ID, and on the
   ES7000 this causes the timer interrupt to fail on any cell above cell 0
   (the cell number ends up being the top 4 bits of the APIC ID).

Upstream status:
   commit ee4eff6ff6cbfc8ce38131058a18802bf6206879
   Author: Benjamin Romer <benjamin.romer@unisys.com>
   Date:   Tue Feb 13 13:26:25 2007 +0100

   [PATCH] x86-64: update IO-APIC dest field to 8-bit for xAPIC

   On the Unisys ES7000/ONE system, we encountered a problem where performing
   a kexec reboot or dump on any cell other than cell 0 causes the system
   timer to stop working, resulting in a hang during timer calibration in the
   new kernel.

   We traced the problem to one line of code in disable_IO_APIC(), which needs
   to restore the timer's IO-APIC configuration before rebooting.  The code is
   currently using the 4-bit physical destination field, rather than using the
   8-bit logical destination field, and it cuts off the upper 4 bits of the
   timer's APIC ID.  If we change this to use the logical destination field,
   the timer works and we can kexec on the upper cells.  This was tested on
   two different cells (0 and 2) in an ES7000/ONE system.

   For reference, the relevant Intel xAPIC spec is kept at
   ftp://download.intel.com/design/chipsets/e8501/datashts/30962001.pdf,
   specifically on page 334.

   Signed-off-by: Benjamin M Romer <benjamin.romer@unisys.com>
   Signed-off-by: Andi Kleen <ak@suse.de>
   Cc: Andi Kleen <ak@suse.de>
   Cc: "Eric W. Biederman" <ebiederm@xmission.com>
   Cc: Vivek Goyal <vgoyal@in.ibm.com>
   Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Testing:
   Brew-built with no KABI issues.
   Tested by Unisys, and by Jeff Burke on our in-house ES7000/ONE system.

RHEL-5 Patch:

Acked-by: Brian Maly <bmaly@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Jarod Wilson <jwilson@redhat.com>
Acked-by: Neil Horman <nhorman@redhat.com>
---
 arch/x86_64/kernel/io_apic-xen.c |   20 +++++++++-----------
 arch/x86_64/kernel/io_apic.c     |   20 +++++++++-----------
 include/asm-x86_64/io_apic.h     |   15 ++-------------
 3 files changed, 20 insertions(+), 35 deletions(-)

diff --git a/arch/x86_64/kernel/io_apic-xen.c b/arch/x86_64/kernel/io_apic-xen.c
index 9ba203b..bc894fa 100644
--- a/arch/x86_64/kernel/io_apic-xen.c
+++ b/arch/x86_64/kernel/io_apic-xen.c
@@ -956,7 +956,7 @@ static void __init setup_IO_APIC_irqs(void)
 		entry.delivery_mode = INT_DELIVERY_MODE;
 		entry.dest_mode = INT_DEST_MODE;
 		entry.mask = 0;				/* enable IRQ */
-		entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+		entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 
 		idx = find_irq_entry(apic,pin,mp_INT);
 		if (idx == -1) {
@@ -974,7 +974,7 @@ static void __init setup_IO_APIC_irqs(void)
 		if (irq_trigger(idx)) {
 			entry.trigger = 1;
 			entry.mask = 1;
-			entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+			entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 		}
 
 		irq = pin_2_irq(idx, apic, pin);
@@ -1026,7 +1026,7 @@ static void __init setup_ExtINT_IRQ0_pin(unsigned int apic, unsigned int pin, in
 	 */
 	entry.dest_mode = INT_DEST_MODE;
 	entry.mask = 0;					/* unmask IRQ now */
-	entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+	entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 	entry.delivery_mode = INT_DELIVERY_MODE;
 	entry.polarity = 0;
 	entry.trigger = 0;
@@ -1126,7 +1126,7 @@ void __apicdebuginit print_IO_APIC(void)
 
 	printk(KERN_DEBUG ".... IRQ redirection table:\n");
 
-	printk(KERN_DEBUG " NR Log Phy Mask Trig IRR Pol"
+	printk(KERN_DEBUG " NR Dst Mask Trig IRR Pol"
 			  " Stat Dest Deli Vect:   \n");
 
 	for (i = 0; i <= reg_01.bits.entries; i++) {
@@ -1137,10 +1137,9 @@ void __apicdebuginit print_IO_APIC(void)
 		*(((int *)&entry)+1) = io_apic_read(apic, 0x11+i*2);
 		spin_unlock_irqrestore(&ioapic_lock, flags);
 
-		printk(KERN_DEBUG " %02x %03X %02X  ",
+		printk(KERN_DEBUG " %02x %03X ",
 			i,
-			entry.dest.logical.logical_dest,
-			entry.dest.physical.physical_dest
+			entry.dest
 		);
 
 		printk("%1d    %1d    %1d   %1d   %1d    %1d    %1d    %02X\n",
@@ -1424,8 +1423,7 @@ void disable_IO_APIC(void)
 		entry.dest_mode       = 0; /* Physical */
 		entry.delivery_mode   = dest_ExtINT; /* ExtInt */
 		entry.vector          = 0;
-		entry.dest.physical.physical_dest =
-					GET_APIC_ID(apic_read(APIC_ID));
+		entry.dest            = GET_APIC_ID(apic_read(APIC_ID));
 
 		/*
 		 * Add it to the IO-APIC irq-routing table:
@@ -1846,7 +1844,7 @@ static inline void unlock_ExtINT_logic(void)
 
 	entry1.dest_mode = 0;			/* physical delivery */
 	entry1.mask = 0;			/* unmask IRQ now */
-	entry1.dest.physical.physical_dest = hard_smp_processor_id();
+	entry1.dest = hard_smp_processor_id();
 	entry1.delivery_mode = dest_ExtINT;
 	entry1.polarity = entry0.polarity;
 	entry1.trigger = 0;
@@ -2198,7 +2196,7 @@ int io_apic_set_pci_routing (int ioapic, int pin, int irq, int edge_level, int a
 
 	entry.delivery_mode = INT_DELIVERY_MODE;
 	entry.dest_mode = INT_DEST_MODE;
-	entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+	entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 	entry.trigger = edge_level;
 	entry.polarity = active_high_low;
 	entry.mask = 1;					 /* Disabled (masked) */
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 924a4a3..610d316 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -908,7 +908,7 @@ static void __init setup_IO_APIC_irqs(void)
 		entry.delivery_mode = INT_DELIVERY_MODE;
 		entry.dest_mode = INT_DEST_MODE;
 		entry.mask = 0;				/* enable IRQ */
-		entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+		entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 
 		idx = find_irq_entry(apic,pin,mp_INT);
 		if (idx == -1) {
@@ -926,7 +926,7 @@ static void __init setup_IO_APIC_irqs(void)
 		if (irq_trigger(idx)) {
 			entry.trigger = 1;
 			entry.mask = 1;
-			entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+			entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 		}
 
 		irq = pin_2_irq(idx, apic, pin);
@@ -977,7 +977,7 @@ static void __init setup_ExtINT_IRQ0_pin(unsigned int apic, unsigned int pin, in
 	 */
 	entry.dest_mode = INT_DEST_MODE;
 	entry.mask = 0;					/* unmask IRQ now */
-	entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+	entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 	entry.delivery_mode = INT_DELIVERY_MODE;
 	entry.polarity = 0;
 	entry.trigger = 0;
@@ -1077,7 +1077,7 @@ void __apicdebuginit print_IO_APIC(void)
 
 	printk(KERN_DEBUG ".... IRQ redirection table:\n");
 
-	printk(KERN_DEBUG " NR Log Phy Mask Trig IRR Pol"
+	printk(KERN_DEBUG " NR Dst Mask Trig IRR Pol"
 			  " Stat Dest Deli Vect:   \n");
 
 	for (i = 0; i <= reg_01.bits.entries; i++) {
@@ -1088,10 +1088,9 @@ void __apicdebuginit print_IO_APIC(void)
 		*(((int *)&entry)+1) = io_apic_read(apic, 0x11+i*2);
 		spin_unlock_irqrestore(&ioapic_lock, flags);
 
-		printk(KERN_DEBUG " %02x %03X %02X  ",
+		printk(KERN_DEBUG " %02x %03X ",
 			i,
-			entry.dest.logical.logical_dest,
-			entry.dest.physical.physical_dest
+			entry.dest
 		);
 
 		printk("%1d    %1d    %1d   %1d   %1d    %1d    %1d    %02X\n",
@@ -1366,8 +1365,7 @@ void disable_IO_APIC(void)
 		entry.dest_mode       = 0; /* Physical */
 		entry.delivery_mode   = dest_ExtINT; /* ExtInt */
 		entry.vector          = 0;
-		entry.dest.physical.physical_dest =
-					GET_APIC_ID(apic_read(APIC_ID));
+		entry.dest            = GET_APIC_ID(apic_read(APIC_ID));
 
 		/*
 		 * Add it to the IO-APIC irq-routing table:
@@ -1778,7 +1776,7 @@ static inline void unlock_ExtINT_logic(void)
 
 	entry1.dest_mode = 0;			/* physical delivery */
 	entry1.mask = 0;			/* unmask IRQ now */
-	entry1.dest.physical.physical_dest = hard_smp_processor_id();
+	entry1.dest = hard_smp_processor_id();
 	entry1.delivery_mode = dest_ExtINT;
 	entry1.polarity = entry0.polarity;
 	entry1.trigger = 0;
@@ -2124,7 +2122,7 @@ int io_apic_set_pci_routing (int ioapic, int pin, int irq, int triggering, int p
 
 	entry.delivery_mode = INT_DELIVERY_MODE;
 	entry.dest_mode = INT_DEST_MODE;
-	entry.dest.logical.logical_dest = cpu_mask_to_apicid(TARGET_CPUS);
+	entry.dest = cpu_mask_to_apicid(TARGET_CPUS);
 	entry.trigger = triggering;
 	entry.polarity = polarity;
 	entry.mask = 1;					 /* Disabled (masked) */
diff --git a/include/asm-x86_64/io_apic.h b/include/asm-x86_64/io_apic.h
index fb7a090..21fff71 100644
--- a/include/asm-x86_64/io_apic.h
+++ b/include/asm-x86_64/io_apic.h
@@ -130,19 +130,8 @@ struct IO_APIC_route_entry {
 		trigger		:  1,	/* 0: edge, 1: level */
 		mask		:  1,	/* 0: enabled, 1: disabled */
 		__reserved_2	: 15;
-
-	union {		struct { __u32
-					__reserved_1	: 24,
-					physical_dest	:  4,
-					__reserved_2	:  4;
-			} physical;
-
-			struct { __u32
-					__reserved_1	: 24,
-					logical_dest	:  8;
-			} logical;
-	} dest;
-
+       __u32	__reserved_3	: 24,
+		dest		: 8;
 } __attribute__ ((packed));
 
 /*
-- 
1.5.3.5.645.gbb47