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Date:      Mon, 13 Aug 2012 18:52:52 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r239241 - in head/sys: amd64/amd64 i386/i386
Message-ID:  <201208131852.q7DIqqZW079037@svn.freebsd.org>

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Author: jhb
Date: Mon Aug 13 18:52:51 2012
New Revision: 239241
URL: http://svn.freebsd.org/changeset/base/239241

Log:
  Remove the deassert INIT IPI from the IPI startup sequence for APs.
  It is not listed in the boot sequence in the MP specification (1.4),
  and it is explicitly ignored on modern CPUs.  It was only ever required
  when bootstrapping systems with external APICs (that is, SMP machines
  with 486s), which FreeBSD has never supported (and never will).
  
  While here, tidy some comments and remove some banal ones.

Modified:
  head/sys/amd64/amd64/mp_machdep.c
  head/sys/i386/i386/mp_machdep.c

Modified: head/sys/amd64/amd64/mp_machdep.c
==============================================================================
--- head/sys/amd64/amd64/mp_machdep.c	Mon Aug 13 18:34:04 2012	(r239240)
+++ head/sys/amd64/amd64/mp_machdep.c	Mon Aug 13 18:52:51 2012	(r239241)
@@ -1036,25 +1036,13 @@ ipi_startup(int apic_id, int vector)
 {
 
 	/*
-	 * first we do an INIT/RESET IPI this INIT IPI might be run, reseting
+	 * first we do an INIT IPI: this INIT IPI might be run, resetting
 	 * and running the target CPU. OR this INIT IPI might be latched (P5
 	 * bug), CPU waiting for STARTUP IPI. OR this INIT IPI might be
 	 * ignored.
 	 */
-
-	/* do an INIT IPI: assert RESET */
 	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
 	    APIC_LEVEL_ASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, apic_id);
-
-	/* wait for pending status end */
-	lapic_ipi_wait(-1);
-	DELAY(10000);		/* wait ~10mS */
-
-	/* do an INIT IPI: deassert RESET */
-	lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
-	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
-
-	/* wait for pending status end */
 	lapic_ipi_wait(-1);
 	DELAY(10000);		/* wait ~10mS */
 
@@ -1066,8 +1054,6 @@ ipi_startup(int apic_id, int vector)
 	 * run. OR the previous INIT IPI was ignored. and this STARTUP IPI
 	 * will run.
 	 */
-
-	/* do a STARTUP IPI */
 	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
 	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_STARTUP |
 	    vector, apic_id);
@@ -1080,7 +1066,6 @@ ipi_startup(int apic_id, int vector)
 	 * this STARTUP IPI will be ignored, as only ONE STARTUP IPI is
 	 * recognized after hardware RESET or INIT IPI.
 	 */
-
 	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
 	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_STARTUP |
 	    vector, apic_id);

Modified: head/sys/i386/i386/mp_machdep.c
==============================================================================
--- head/sys/i386/i386/mp_machdep.c	Mon Aug 13 18:34:04 2012	(r239240)
+++ head/sys/i386/i386/mp_machdep.c	Mon Aug 13 18:52:51 2012	(r239241)
@@ -1136,25 +1136,13 @@ ipi_startup(int apic_id, int vector)
 {
 
 	/*
-	 * first we do an INIT/RESET IPI this INIT IPI might be run, reseting
+	 * first we do an INIT IPI: this INIT IPI might be run, resetting
 	 * and running the target CPU. OR this INIT IPI might be latched (P5
 	 * bug), CPU waiting for STARTUP IPI. OR this INIT IPI might be
 	 * ignored.
 	 */
-
-	/* do an INIT IPI: assert RESET */
 	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
 	    APIC_LEVEL_ASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, apic_id);
-
-	/* wait for pending status end */
-	lapic_ipi_wait(-1);
-	DELAY(10000);		/* wait ~10mS */
-
-	/* do an INIT IPI: deassert RESET */
-	lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
-	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
-
-	/* wait for pending status end */
 	lapic_ipi_wait(-1);
 	DELAY(10000);		/* wait ~10mS */
 
@@ -1166,8 +1154,6 @@ ipi_startup(int apic_id, int vector)
 	 * run. OR the previous INIT IPI was ignored. and this STARTUP IPI
 	 * will run.
 	 */
-
-	/* do a STARTUP IPI */
 	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
 	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_STARTUP |
 	    vector, apic_id);
@@ -1180,7 +1166,6 @@ ipi_startup(int apic_id, int vector)
 	 * this STARTUP IPI will be ignored, as only ONE STARTUP IPI is
 	 * recognized after hardware RESET or INIT IPI.
 	 */
-
 	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
 	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_STARTUP |
 	    vector, apic_id);



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