Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755045AbaGHAHo (ORCPT ); Mon, 7 Jul 2014 20:07:44 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56485 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754885AbaGHADa (ORCPT ); Mon, 7 Jul 2014 20:03:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Mackerras , Benjamin Herrenschmidt , Ben Hutchings , Yijing Wang Subject: [PATCH 3.4 37/44] powerpc: Fix emulation of illegal instructions on PowerNV platform Date: Mon, 7 Jul 2014 17:07:27 -0700 Message-Id: <20140707235859.750052364@linuxfoundation.org> X-Mailer: git-send-email 2.0.0.254.g50f84e3 In-Reply-To: <20140707235858.652771077@linuxfoundation.org> References: <20140707235858.652771077@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Mackerras commit bf593907f7236e95698a76b7c7a2bbf8b1165327 upstream. Normally, the kernel emulates a few instructions that are unimplemented on some processors (e.g. the old dcba instruction), or privileged (e.g. mfpvr). The emulation of unimplemented instructions is currently not working on the PowerNV platform. The reason is that on these machines, unimplemented and illegal instructions cause a hypervisor emulation assist interrupt, rather than a program interrupt as on older CPUs. Our vector for the emulation assist interrupt just calls program_check_exception() directly, without setting the bit in SRR1 that indicates an illegal instruction interrupt. This fixes it by making the emulation assist interrupt set that bit before calling program_check_interrupt(). With this, old programs that use no-longer implemented instructions such as dcba now work again. Signed-off-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/exceptions-64s.S | 2 +- arch/powerpc/kernel/traps.c | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -491,7 +491,7 @@ machine_check_common: STD_EXCEPTION_COMMON(0xb00, trap_0b, .unknown_exception) STD_EXCEPTION_COMMON(0xd00, single_step, .single_step_exception) STD_EXCEPTION_COMMON(0xe00, trap_0e, .unknown_exception) - STD_EXCEPTION_COMMON(0xe40, emulation_assist, .program_check_exception) + STD_EXCEPTION_COMMON(0xe40, emulation_assist, .emulation_assist_interrupt) STD_EXCEPTION_COMMON(0xe60, hmi_exception, .unknown_exception) STD_EXCEPTION_COMMON_ASYNC(0xf00, performance_monitor, .performance_monitor_exception) STD_EXCEPTION_COMMON(0x1300, instruction_breakpoint, .instruction_breakpoint_exception) --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1074,6 +1074,16 @@ void __kprobes program_check_exception(s _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); } +/* + * This occurs when running in hypervisor mode on POWER6 or later + * and an illegal instruction is encountered. + */ +void __kprobes emulation_assist_interrupt(struct pt_regs *regs) +{ + regs->msr |= REASON_ILLEGAL; + program_check_exception(regs); +} + void alignment_exception(struct pt_regs *regs) { int sig, code, fixed = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/