From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from na01-by2-obe.outbound.protection.outlook.com (mail-by2on0140.outbound.protection.outlook.com [207.46.100.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 7B4901A0017 for ; Wed, 7 Oct 2015 09:56:09 +1100 (AEDT) From: Scott Wood To: Simon Horman CC: , , "Michael Ellerman" , Scott Wood , "Samuel Mendoza-Jonas" Subject: [PATCH v2 2/3] ppc64: Avoid rfid if no need to clear MSR_LE Date: Tue, 6 Oct 2015 17:55:49 -0500 Message-ID: <1444172150-29493-2-git-send-email-scottwood@freescale.com> In-Reply-To: <1444172150-29493-1-git-send-email-scottwood@freescale.com> References: <1444172150-29493-1-git-send-email-scottwood@freescale.com> MIME-Version: 1.0 Content-Type: text/plain List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Commit a304e2d82a8c3 ("ppc64: purgatory: Reset primary cpu endian to big-endian) changed bctr to rfid. rfid is book3s-only and will cause a fatal exception on book3e. Purgatory is an isolated environment which makes importing information about the subarch awkward, so instead rely on the fact that MSR_LE should never be set on book3e, and the rfid is only needed if MSR_LE is set (and thus needs to be cleared). In theory that MSR bit is reserved on book3e, rather than zero, but in practice I have not seen it set. Signed-off-by: Scott Wood Cc: Samuel Mendoza-Jonas --- v2: new patch purgatory/arch/ppc64/v2wrap.S | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/purgatory/arch/ppc64/v2wrap.S b/purgatory/arch/ppc64/v2wrap.S index 179ade9..3534080 100644 --- a/purgatory/arch/ppc64/v2wrap.S +++ b/purgatory/arch/ppc64/v2wrap.S @@ -116,9 +116,17 @@ master: stw 7,0x5c(4) # and patch it into the kernel mr 3,16 # restore dt address + mfmsr 5 + andi. 10,5,1 # test MSR_LE + bne little_endian + + li 5,0 # r5 will be 0 for kernel + mtctr 4 # prepare branch to + bctr # start kernel + +little_endian: # book3s-only mtsrr0 4 # prepare branch to - mfmsr 5 clrrdi 5,5,1 # clear MSR_LE mtsrr1 5 -- 2.1.4