Date: Fri, 6 Nov 2009 10:38:33 +0000 (UTC) From: Attilio Rao <attilio@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r198979 - in stable/7/sys: amd64/amd64 i386/i386 Message-ID: <200911061038.nA6AcXgU013645@svn.freebsd.org>
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Author: attilio Date: Fri Nov 6 10:38:33 2009 New Revision: 198979 URL: http://svn.freebsd.org/changeset/base/198979 Log: MFC r198868, r198950: Opteron rev E family of processor expose a bug where acq memory barriers can be broken, resulting in random breakages. Printout a warning message if affected family and model are found. Modified: stable/7/sys/amd64/amd64/identcpu.c stable/7/sys/i386/i386/identcpu.c Directory Properties: stable/7/sys/ (props changed) stable/7/sys/contrib/pf/ (props changed) Modified: stable/7/sys/amd64/amd64/identcpu.c ============================================================================== --- stable/7/sys/amd64/amd64/identcpu.c Fri Nov 6 10:17:08 2009 (r198978) +++ stable/7/sys/amd64/amd64/identcpu.c Fri Nov 6 10:38:33 2009 (r198979) @@ -627,6 +627,21 @@ print_AMD_info(void) printf(", %d lines/tag", (regs[2] >> 8) & 0x0f); print_AMD_l2_assoc((regs[2] >> 12) & 0x0f); } + + /* + * Opteron Rev E shows a bug as in very rare occasions a read memory + * barrier is not performed as expected if it is followed by a + * non-atomic read-modify-write instruction. + * As long as that bug pops up very rarely (intensive machine usage + * on other operating systems generally generates one unexplainable + * crash any 2 months) and as long as a model specific fix would be + * impratical at this stage, print out a warning string if the broken + * model and family are identified. + */ + if (AMD64_CPU_FAMILY(cpu_id) == 0xf && + AMD64_CPU_MODEL(cpu_id) >= 0x20 && AMD64_CPU_MODEL(cpu_id) <= 0x3f) + printf("WARNING: This architecture revision has known SMP " + "hardware bugs which may cause random instability\n"); } static void Modified: stable/7/sys/i386/i386/identcpu.c ============================================================================== --- stable/7/sys/i386/i386/identcpu.c Fri Nov 6 10:17:08 2009 (r198978) +++ stable/7/sys/i386/i386/identcpu.c Fri Nov 6 10:38:33 2009 (r198979) @@ -1320,6 +1320,21 @@ print_AMD_info(void) (amd_whcr & 0x0100) ? "Enable" : "Disable"); } } + + /* + * Opteron Rev E shows a bug as in very rare occasions a read memory + * barrier is not performed as expected if it is followed by a + * non-atomic read-modify-write instruction. + * As long as that bug pops up very rarely (intensive machine usage + * on other operating systems generally generates one unexplainable + * crash any 2 months) and as long as a model specific fix would be + * impratical at this stage, print out a warning string if the broken + * model and family are identified. + */ + if (I386_CPU_FAMILY(cpu_id) == 0xf && I386_CPU_MODEL(cpu_id) >= 0x20 && + I386_CPU_MODEL(cpu_id) <= 0x3f) + printf("WARNING: This architecture revision has known SMP " + "hardware bugs which may cause random instability\n"); } static void
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