From patchwork Wed Aug 30 06:34:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Shuai X-Patchwork-Id: 13369974 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CA00EC83F01 for ; Wed, 30 Aug 2023 06:35:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=HoCfCaRsxnMIR92OCfnqii0FBxi33wtM7YUXUUVC+I0=; b=V1PueRyvoNxV1e xTxxFKUVJnGb04YqhX7Qcqtd+QjIe5YprHQpCtXz/Caz4CZTTdS1vK7e0ovdH8gEh8oGvGI1/Kj8K dJOoECmH/F1p3plwELLb98oxH6BuikH4C9f29OkH9FzuiZyCvetRAyJqhPZOeZPBWFvPY/4Y9+Pew I8CdWnJ2GhLRgMHZ+7kiZGlY/eVrRpohfIJzwvaNnqN55NsQ6QzS3Ruqrx6RZ15GGEZaBvaQ/p3+O IcG6KlFkU3YAFSgaeYAtLIBJ13bglwhAQmxThKbtbiSgu9t6zIdkaqVcUPGTdMRW4wpm2f9UX64FS hIFXvq+/gRqVFp9azkKQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qbEnU-00CvU9-01; Wed, 30 Aug 2023 06:35:24 +0000 Received: from bg4.exmail.qq.com ([43.154.221.58]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qbEnO-00CvTI-0n for linux-riscv@lists.infradead.org; Wed, 30 Aug 2023 06:35:22 +0000 X-QQ-mid: bizesmtp72t1693377284t20dyyw5 Received: from localhost.localdomain ( [221.226.144.218]) by bizesmtp.qq.com (ESMTP) with id ; Wed, 30 Aug 2023 14:34:42 +0800 (CST) X-QQ-SSF: 01200000000000B0B000000A0000000 X-QQ-FEAT: I8hG9CuxGDLVX4zYenMnZzfme72U6h6VUyCmh7+o/2/nV1SicSheCqLWUS/6f 6UBdxSE+5weyB8T4IXrP/HkOLySS94hUiIsCzTvD5UBUakxSArtJyUcT73pGsZfVR2aAx0u X0NTTXxVE8YaME/T4o2p69r3PUsGs8E+PX+KlZWNJ/aCopGnPy+twcWgkdCRkQpOrGtxObS t92LfKJyicKmsjEyxI21m68yYxHg416+39bO+IFEE4HEKtqI6EJqhBzGEPTuID98pPHXO/1 LQFFbENG8KfWdMSZD/8Yz9zNVHUAzjpcW4PKTXPvbaQx1JrNVtCamJ1z0lr1rby48BJ9pXB L9dc0jYTFpe1jkv8MAvQrXdmPa4760QS2i6adCK X-QQ-GoodBg: 0 X-BIZMAIL-ID: 10736640701935298722 From: Song Shuai To: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, mick@ics.forth.gr, alex@ghiti.fr Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Song Shuai Subject: [PATCH] riscv: kexec: Cleanup riscv_kexec_relocate Date: Wed, 30 Aug 2023 14:34:35 +0800 Message-Id: <20230830063435.1105726-1-songshuaishuai@tinylab.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrsz:qybglogicsvrsz4a-0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230829_233518_631416_A3D150DC X-CRM114-Status: UNSURE ( 9.20 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org For readability and simplicity, cleanup the riscv_kexec_relocate code: - Re-sort the first 4 `mv` instructions against `riscv_kexec_method()` - Eliminate registers for debugging (s9,s10,s11) and storing const-value (s5,s6) - Replace `jalr` with `jr` for no-link jump I tested this on Qemu virt machine and works as it was. Signed-off-by: Song Shuai --- arch/riscv/kernel/kexec_relocate.S | 52 +++++++++++++----------------- 1 file changed, 23 insertions(+), 29 deletions(-) diff --git a/arch/riscv/kernel/kexec_relocate.S b/arch/riscv/kernel/kexec_relocate.S index 059c5e216ae7..de0a4b35d01e 100644 --- a/arch/riscv/kernel/kexec_relocate.S +++ b/arch/riscv/kernel/kexec_relocate.S @@ -17,27 +17,17 @@ SYM_CODE_START(riscv_kexec_relocate) * s1: (const) Phys address to jump to after relocation * s2: (const) Phys address of the FDT image * s3: (const) The hartid of the current hart - * s4: Pointer to the destination address for the relocation - * s5: (const) Number of words per page - * s6: (const) 1, used for subtraction - * s7: (const) kernel_map.va_pa_offset, used when switching MMU off - * s8: (const) Physical address of the main loop - * s9: (debug) indirection page counter - * s10: (debug) entry counter - * s11: (debug) copied words counter + * s4: (const) kernel_map.va_pa_offset, used when switching MMU off + * s5: Pointer to the destination address for the relocation + * s6: (const) Physical address of the main loop */ mv s0, a0 mv s1, a1 mv s2, a2 mv s3, a3 - mv s4, zero - li s5, (PAGE_SIZE / RISCV_SZPTR) - li s6, 1 - mv s7, a4 - mv s8, zero - mv s9, zero - mv s10, zero - mv s11, zero + mv s4, a4 + mv s5, zero + mv s6, zero /* Disable / cleanup interrupts */ csrw CSR_SIE, zero @@ -52,21 +42,27 @@ SYM_CODE_START(riscv_kexec_relocate) * the start of the loop below so that we jump there in * any case. */ - la s8, 1f - sub s8, s8, s7 - csrw CSR_STVEC, s8 + la s6, 1f + sub s6, s6, s4 + csrw CSR_STVEC, s6 + + /* + * With C-extension, here we get 42 Bytes and the next + * .align directive would pad zeros here up to 44 Bytes. + * So manually put a nop here to avoid zeros padding. + */ + nop /* Process entries in a loop */ .align 2 1: - addi s10, s10, 1 REG_L t0, 0(s0) /* t0 = *image->entry */ addi s0, s0, RISCV_SZPTR /* image->entry++ */ /* IND_DESTINATION entry ? -> save destination address */ andi t1, t0, 0x1 beqz t1, 2f - andi s4, t0, ~0x1 + andi s5, t0, ~0x1 j 1b 2: @@ -74,9 +70,8 @@ SYM_CODE_START(riscv_kexec_relocate) andi t1, t0, 0x2 beqz t1, 2f andi s0, t0, ~0x2 - addi s9, s9, 1 csrw CSR_SATP, zero - jalr zero, s8, 0 + jr s6 2: /* IND_DONE entry ? -> jump to done label */ @@ -92,14 +87,13 @@ SYM_CODE_START(riscv_kexec_relocate) andi t1, t0, 0x8 beqz t1, 1b /* Unknown entry type, ignore it */ andi t0, t0, ~0x8 - mv t3, s5 /* i = num words per page */ + li t3, (PAGE_SIZE / RISCV_SZPTR) /* i = num words per page */ 3: /* copy loop */ REG_L t1, (t0) /* t1 = *src_ptr */ - REG_S t1, (s4) /* *dst_ptr = *src_ptr */ + REG_S t1, (s5) /* *dst_ptr = *src_ptr */ addi t0, t0, RISCV_SZPTR /* stc_ptr++ */ - addi s4, s4, RISCV_SZPTR /* dst_ptr++ */ - sub t3, t3, s6 /* i-- */ - addi s11, s11, 1 /* c++ */ + addi s5, s5, RISCV_SZPTR /* dst_ptr++ */ + addi t3, t3, -0x1 /* i-- */ beqz t3, 1b /* copy done ? */ j 3b @@ -146,7 +140,7 @@ SYM_CODE_START(riscv_kexec_relocate) */ fence.i - jalr zero, a2, 0 + jr a2 SYM_CODE_END(riscv_kexec_relocate) riscv_kexec_relocate_end: