linux-kernel - [PATCH] x86: UV2 BAU legacy mode

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Message-Id: <E1SccoO-0002Lh-Cb@eag09.americas.sgi.com>
Date:	Thu, 07 Jun 2012 08:31:40 -0500
From:	Cliff Wickman <cpw@....com>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...e.hu, x86@...nel.org
Subject: [PATCH] x86: UV2 BAU legacy mode

From: Cliff Wickman <cpw@....com>

The SGI Altix UV2 BAU (Broadcast Assist Unit) as used for tlb-shootdown
(selective broadcast mode) always uses UV2 broadcast descriptor format.
There is no need to clear the 'legacy' (UV1) mode, because the hardware
always uses UV2 mode for selective broadcast.

But the BIOS uses general broadcast and legacy mode, and the hardware
pays attention to the legacy mode bit for general broadcast.
So the kernel must not clear that mode bit.

Signed-off-by: Cliff Wickman <cpw@....com>
---
 arch/x86/include/asm/uv/uv_bau.h |    1 -
 arch/x86/platform/uv/tlb_uv.c    |    1 -
 2 files changed, 2 deletions(-)

Index: linus.current/arch/x86/include/asm/uv/uv_bau.h
===================================================================
--- linus.current.orig/arch/x86/include/asm/uv/uv_bau.h
+++ linus.current/arch/x86/include/asm/uv/uv_bau.h
@@ -149,7 +149,6 @@
 /* 4 bits of software ack period */
 #define UV2_ACK_MASK			0x7UL
 #define UV2_ACK_UNITS_SHFT		3
-#define UV2_LEG_SHFT UV2H_LB_BAU_MISC_CONTROL_USE_LEGACY_DESCRIPTOR_FORMATS_SHFT
 #define UV2_EXT_SHFT UV2H_LB_BAU_MISC_CONTROL_ENABLE_EXTENDED_SB_STATUS_SHFT
 
 /*
Index: linus.current/arch/x86/platform/uv/tlb_uv.c
===================================================================
--- linus.current.orig/arch/x86/platform/uv/tlb_uv.c
+++ linus.current/arch/x86/platform/uv/tlb_uv.c
@@ -1295,7 +1295,6 @@ static void __init enable_timeouts(void)
 		 */
 		mmr_image |= (1L << SOFTACK_MSHIFT);
 		if (is_uv2_hub()) {
-			mmr_image &= ~(1L << UV2_LEG_SHFT);
 			mmr_image |= (1L << UV2_EXT_SHFT);
 		}
 		write_mmr_misc_control(pnode, mmr_image);
--
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