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(haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id A79C5604D1; Fri, 19 Aug 2022 13:39:29 +1000 (AEST) From: Rohan McLure To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH v3 15/18] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Date: Fri, 19 Aug 2022 13:38:03 +1000 Message-Id: <20220819033806.162054-16-rmclure@linux.ibm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220819033806.162054-1-rmclure@linux.ibm.com> References: <20220819033806.162054-1-rmclure@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: POOxEpFAo9L41TcRaOPXDG_7Btt5IXgs X-Proofpoint-GUID: POOxEpFAo9L41TcRaOPXDG_7Btt5IXgs X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-19_02,2022-08-18_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 clxscore=1015 phishscore=0 mlxlogscore=909 malwarescore=0 mlxscore=0 impostorscore=0 bulkscore=0 adultscore=0 suspectscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2208190013 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rohan McLure Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Use the convenience macros for saving/clearing/restoring gprs in keeping with syscall calling conventions. The plural variants of these macros can store a range of registers for concision. This works well when the user gpr value we are hoping to save is still live. In the syscall interrupt handlers, user register state is sometimes juggled between registers. Hold-off from issuing the SAVE_GPR macro for applicable neighbouring lines to highlight the delicate register save logic. Signed-off-by: Rohan McLure --- V1 -> V2: Update summary V2 -> V3: Update summary regarding exclusions for the SAVE_GPR marco. Acknowledge new name for ZEROIZE_GPR{,S} macros. --- arch/powerpc/kernel/interrupt_64.S | 51 +++++++--------------------- 1 file changed, 13 insertions(+), 38 deletions(-) diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S index d9625113c7a5..ad302ad93433 100644 --- a/arch/powerpc/kernel/interrupt_64.S +++ b/arch/powerpc/kernel/interrupt_64.S @@ -71,12 +71,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name) mfcr r12 li r11,0 /* Save syscall parameters in r3-r8 */ - std r3,GPR3(r1) - std r4,GPR4(r1) - std r5,GPR5(r1) - std r6,GPR6(r1) - std r7,GPR7(r1) - std r8,GPR8(r1) + SAVE_GPRS(3, 8, r1) /* Zero r9-r12, this should only be required when restoring all GPRs */ std r11,GPR9(r1) std r11,GPR10(r1) @@ -113,8 +108,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) * Zero user registers to prevent influencing speculative execution * state of kernel code. */ - NULLIFY_GPRS(5, 12) - NULLIFY_NVGPRS() + ZEROIZE_GPRS(5, 12) + ZEROIZE_NVGPRS() /* Calling convention has r3 = orig r0, r4 = regs */ mr r3,r0 @@ -157,17 +152,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) /* Could zero these as per ABI, but we may consider a stricter ABI * which preserves these if libc implementations can benefit, so * restore them for now until further measurement is done. */ - ld r0,GPR0(r1) - ld r4,GPR4(r1) - ld r5,GPR5(r1) - ld r6,GPR6(r1) - ld r7,GPR7(r1) - ld r8,GPR8(r1) + REST_GPR(0, r1) + REST_GPRS(4, 8, r1) /* Zero volatile regs that may contain sensitive kernel data */ - li r9,0 - li r10,0 - li r11,0 - li r12,0 + ZEROIZE_GPRS(9, 12) mtspr SPRN_XER,r0 /* @@ -189,7 +177,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) ld r4,_LINK(r1) ld r5,_XER(r1) - ld r0,GPR0(r1) + REST_GPR(0, r1) mtcr r2 mtctr r3 mtlr r4 @@ -257,12 +245,7 @@ END_BTB_FLUSH_SECTION mfcr r12 li r11,0 /* Save syscall parameters in r3-r8 */ - std r3,GPR3(r1) - std r4,GPR4(r1) - std r5,GPR5(r1) - std r6,GPR6(r1) - std r7,GPR7(r1) - std r8,GPR8(r1) + SAVE_GPRS(3, 8, r1) /* Zero r9-r12, this should only be required when restoring all GPRs */ std r11,GPR9(r1) std r11,GPR10(r1) @@ -311,8 +294,8 @@ END_BTB_FLUSH_SECTION * Zero user registers to prevent influencing speculative execution * state of kernel code. */ - NULLIFY_GPRS(5, 12) - NULLIFY_NVGPRS() + ZEROIZE_GPRS(5, 12) + ZEROIZE_NVGPRS() /* Calling convention has r3 = orig r0, r4 = regs */ mr r3,r0 @@ -360,16 +343,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) cmpdi r3,0 bne .Lsyscall_restore_regs /* Zero volatile regs that may contain sensitive kernel data */ - li r0,0 - li r4,0 - li r5,0 - li r6,0 - li r7,0 - li r8,0 - li r9,0 - li r10,0 - li r11,0 - li r12,0 + ZEROIZE_GPR(0) + ZEROIZE_GPRS(4, 12) mtctr r0 mtspr SPRN_XER,r0 .Lsyscall_restore_regs_cont: @@ -394,7 +369,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) ld r4,_XER(r1) mtctr r3 mtspr SPRN_XER,r4 - ld r0,GPR0(r1) + REST_GPR(0, r1) REST_GPRS(4, 12, r1) b .Lsyscall_restore_regs_cont .Lsyscall_rst_end: -- 2.34.1