linux-kernel - Re: [PATCH 2/3]: x86-64: Handle SRAT v1 and v2 consistently

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Date:	Mon, 18 May 2009 13:04:58 -0700
From:	Yinghai Lu <yhlu.kernel@...il.com>
To:	Kurt Garloff <garloff@...e.de>,
	Linux kernel list <linux-kernel@...r.kernel.org>,
	Norbert Eicker <N.Eicker@...juelich.de>,
	Greg Kroah-Hartman <GregKH@...e.de>,
	Alexey Starikovskiy <AStarikovskiy@...e.cz>,
	Len Brown <LenB@...nel.org>, xb <xavier.bru@...l.net>
Cc:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2/3]: x86-64: Handle SRAT v1 and v2 consistently

On Mon, May 18, 2009 at 2:47 AM, Kurt Garloff <garloff@...e.de> wrote:
> Hi,
>
> x86-64 was rather inconsistent prior to this patch; it used 8 bits
> for the pxm field in cpu_affinity, but 32 bits in mem_affinity.
> This patch makes it consistent: Either use 8 bits consistently (SRAT
> rev 1 or lower) or 32 bits (SRAT rev 2 or higher).
>
> This is patch 2/3.
> --
> Kurt Garloff, VP OPS Partner Engineering -- Novell Inc.
>
From: Kurt Garloff <garloff@...e.de>
Subject: Use SRAT table rev to use 8bit or 32bit PXM fields (x86-64)
References: bnc#503038

In SRAT v1, we had 8bit proximity domain (PXM) fields; SRAT v2 provides
32bits for these. The new fields were reserved before.
According to the ACPI spec, the OS must disregrard reserved fields.

x86-64 was rather inconsistent prior to this patch; it used 8 bits
for the pxm field in cpu_affinity, but 32 bits in mem_affinity.
This patch makes it consistent: Either use 8 bits consistently (SRAT
rev 1 or lower) or 32 bits (SRAT rev 2 or higher).

This is patch 2/3.

Signed-off-by: Kurt Garloff <garloff@...e.de>

---
 arch/x86/mm/srat_64.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6/arch/x86/mm/srat_64.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/srat_64.c
+++ linux-2.6/arch/x86/mm/srat_64.c
@@ -154,6 +154,8 @@ acpi_numa_processor_affinity_init(struct
 	if ((pa->flags & ACPI_SRAT_CPU_ENABLED) == 0)
 		return;
 	pxm = pa->proximity_domain_lo;
+	if (acpi_srat_revision >= 2)
+		pxm |= *((unsigned int*)pa->proximity_domain_hi) << 8;
 	node = setup_node(pxm);
 	if (node < 0) {
 		printk(KERN_ERR "SRAT: Too many proximity domains %x\n", pxm);
@@ -255,6 +257,8 @@ acpi_numa_memory_affinity_init(struct ac
 	start = ma->base_address;
 	end = start + ma->length;
 	pxm = ma->proximity_domain;
+	if (acpi_srat_revision <= 1)
+		pxm &= 0xff;
 	node = setup_node(pxm);
 	if (node < 0) {
 		printk(KERN_ERR "SRAT: Too many proximity domains.\n");


Acked-by: Yinghai Lu <yinghai@...nel.org>
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