From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 0B36CB7079 for ; Thu, 23 Jul 2009 15:59:50 +1000 (EST) To: From: Benjamin Herrenschmidt Date: Thu, 23 Jul 2009 15:59:38 +1000 Subject: [PATCH 2/20] powerpc/of: Remove useless register save/restore when calling OF back Message-Id: <20090723055949.F1844DDD1B@ozlabs.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , enter_prom() used to save and restore registers such as CTR, XER etc.. which are volatile, or SRR0,1... which we don't care about. This removes a bunch of useless code and while at it turns an mtmsrd into an MTMSRD macro which will be useful to Book3E. Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/entry_64.S | 38 ++++++-------------------------------- 1 file changed, 6 insertions(+), 32 deletions(-) --- linux-work.orig/arch/powerpc/kernel/entry_64.S 2009-07-22 15:20:26.000000000 +1000 +++ linux-work/arch/powerpc/kernel/entry_64.S 2009-07-22 15:22:44.000000000 +1000 @@ -823,30 +823,17 @@ _GLOBAL(enter_prom) * of all registers that it saves. We therefore save those registers * PROM might touch to the stack. (r0, r3-r13 are caller saved) */ - SAVE_8GPRS(2, r1) + SAVE_GPR(2, r1) SAVE_GPR(13, r1) SAVE_8GPRS(14, r1) SAVE_10GPRS(22, r1) - mfcr r4 - std r4,_CCR(r1) - mfctr r5 - std r5,_CTR(r1) - mfspr r6,SPRN_XER - std r6,_XER(r1) - mfdar r7 - std r7,_DAR(r1) - mfdsisr r8 - std r8,_DSISR(r1) - mfsrr0 r9 - std r9,_SRR0(r1) - mfsrr1 r10 - std r10,_SRR1(r1) + mfcr r10 mfmsr r11 + std r10,_CCR(r1) std r11,_MSR(r1) /* Get the PROM entrypoint */ - ld r0,GPR4(r1) - mtlr r0 + mtlr r4 /* Switch MSR to 32 bits mode */ @@ -860,8 +847,7 @@ _GLOBAL(enter_prom) mtmsrd r11 isync - /* Restore arguments & enter PROM here... */ - ld r3,GPR3(r1) + /* Enter PROM here... */ blrl /* Just make sure that r1 top 32 bits didn't get @@ -871,7 +857,7 @@ _GLOBAL(enter_prom) /* Restore the MSR (back to 64 bits) */ ld r0,_MSR(r1) - mtmsrd r0 + MTMSRD(r0) isync /* Restore other registers */ @@ -881,18 +867,6 @@ _GLOBAL(enter_prom) REST_10GPRS(22, r1) ld r4,_CCR(r1) mtcr r4 - ld r5,_CTR(r1) - mtctr r5 - ld r6,_XER(r1) - mtspr SPRN_XER,r6 - ld r7,_DAR(r1) - mtdar r7 - ld r8,_DSISR(r1) - mtdsisr r8 - ld r9,_SRR0(r1) - mtsrr0 r9 - ld r10,_SRR1(r1) - mtsrr1 r10 addi r1,r1,PROM_FRAME_SIZE ld r0,16(r1)