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[34.85.216.189]) by smtp.gmail.com with ESMTPSA id l195sm1528731qke.98.2021.09.30.07.31.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Sep 2021 07:31:27 -0700 (PDT) From: Pasha Tatashin To: pasha.tatashin@soleen.com, sashal@kernel.org, ebiederm@xmission.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, maz@kernel.org, james.morse@arm.com, vladimir.murzin@arm.com, matthias.bgg@gmail.com, linux-mm@kvack.org, mark.rutland@arm.com, steve.capper@arm.com, rfontana@redhat.com, tglx@linutronix.de, selindag@gmail.com, kernelfans@gmail.com, akpm@linux-foundation.org Subject: [PATCH v18 12/15] arm64: kexec: keep MMU enabled during kexec relocation Date: Thu, 30 Sep 2021 14:31:10 +0000 Message-Id: <20210930143113.1502553-13-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.33.0.800.g4c38ced690-goog In-Reply-To: <20210930143113.1502553-1-pasha.tatashin@soleen.com> References: <20210930143113.1502553-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210930_073130_017675_7D63FBF3 X-CRM114-Status: GOOD ( 18.00 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Now, that we have linear map page tables configured, keep MMU enabled to allow faster relocation of segments to final destination. Cavium ThunderX2: Kernel Image size: 38M Iniramfs size: 46M Total relocation size: 84M MMU-disabled: relocation 7.489539915s MMU-enabled: relocation 0.03946095s Broadcom Stingray: The performance data: for a moderate size kernel + initramfs: 25M the relocation was taking 0.382s, with enabled MMU it now takes 0.019s only or x20 improvement. The time is proportional to the size of relocation, therefore if initramfs is larger, 100M it could take over a second. Signed-off-by: Pasha Tatashin Tested-by: Pingfan Liu Acked-by: Catalin Marinas --- arch/arm64/include/asm/kexec.h | 3 +++ arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kernel/machine_kexec.c | 16 +++++++++++---- arch/arm64/kernel/relocate_kernel.S | 31 +++++++++++++++++++---------- 4 files changed, 36 insertions(+), 15 deletions(-) diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index d678f0ceb7ee..dca6dedc3b25 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -97,8 +97,11 @@ struct kimage_arch { phys_addr_t dtb_mem; phys_addr_t kern_reloc; phys_addr_t el2_vectors; + phys_addr_t ttbr0; phys_addr_t ttbr1; phys_addr_t zero_page; + unsigned long phys_offset; + unsigned long t0sz; }; #ifdef CONFIG_KEXEC_FILE diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 1f565224dafd..2124357c2075 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -176,6 +176,7 @@ int main(void) DEFINE(KIMAGE_ARCH_DTB_MEM, offsetof(struct kimage, arch.dtb_mem)); DEFINE(KIMAGE_ARCH_EL2_VECTORS, offsetof(struct kimage, arch.el2_vectors)); DEFINE(KIMAGE_ARCH_ZERO_PAGE, offsetof(struct kimage, arch.zero_page)); + DEFINE(KIMAGE_ARCH_PHYS_OFFSET, offsetof(struct kimage, arch.phys_offset)); DEFINE(KIMAGE_ARCH_TTBR1, offsetof(struct kimage, arch.ttbr1)); DEFINE(KIMAGE_HEAD, offsetof(struct kimage, head)); DEFINE(KIMAGE_START, offsetof(struct kimage, start)); diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index fbff545565f1..1e9a2a45e016 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -196,6 +196,11 @@ int machine_kexec_post_load(struct kimage *kimage) reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start; memcpy(reloc_code, __relocate_new_kernel_start, reloc_size); kimage->arch.kern_reloc = __pa(reloc_code); + rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0, + &kimage->arch.t0sz, reloc_code); + if (rc) + return rc; + kimage->arch.phys_offset = virt_to_phys(kimage) - (long)kimage; /* Flush the reloc_code in preparation for its execution. */ dcache_clean_inval_poc((unsigned long)reloc_code, @@ -230,9 +235,9 @@ void machine_kexec(struct kimage *kimage) local_daif_mask(); /* - * Both restart and cpu_soft_restart will shutdown the MMU, disable data + * Both restart and kernel_reloc will shutdown the MMU, disable data * caches. However, restart will start new kernel or purgatory directly, - * cpu_soft_restart will transfer control to arm64_relocate_new_kernel + * kernel_reloc contains the body of arm64_relocate_new_kernel * In kexec case, kimage->start points to purgatory assuming that * kernel entry and dtb address are embedded in purgatory by * userspace (kexec-tools). @@ -246,10 +251,13 @@ void machine_kexec(struct kimage *kimage) restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, 0, 0); } else { + void (*kernel_reloc)(struct kimage *kimage); + if (is_hyp_nvhe()) __hyp_set_vectors(kimage->arch.el2_vectors); - cpu_soft_restart(kimage->arch.kern_reloc, - virt_to_phys(kimage), 0, 0); + cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz); + kernel_reloc = (void *)kimage->arch.kern_reloc; + kernel_reloc(kimage); } BUG(); /* Should never get here. */ diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S index 2b80232246f7..f0a3df9e18a3 100644 --- a/arch/arm64/kernel/relocate_kernel.S +++ b/arch/arm64/kernel/relocate_kernel.S @@ -4,6 +4,8 @@ * * Copyright (C) Linaro. * Copyright (C) Huawei Futurewei Technologies. + * Copyright (C) 2021, Microsoft Corporation. + * Pasha Tatashin */ #include @@ -15,6 +17,13 @@ #include #include +.macro turn_off_mmu tmp1, tmp2 + mov_q \tmp1, INIT_SCTLR_EL1_MMU_OFF + pre_disable_mmu_workaround + msr sctlr_el1, \tmp1 + isb +.endm + .section ".kexec_relocate.text", "ax" /* * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it. @@ -32,22 +41,21 @@ SYM_CODE_START(arm64_relocate_new_kernel) ldr x18, [x0, #KIMAGE_ARCH_ZERO_PAGE] /* x18 = zero page for BBM */ ldr x17, [x0, #KIMAGE_ARCH_TTBR1] /* x17 = linear map copy */ ldr x16, [x0, #KIMAGE_HEAD] /* x16 = kimage_head */ - mov x14, xzr /* x14 = entry ptr */ - mov x13, xzr /* x13 = copy dest */ + ldr x22, [x0, #KIMAGE_ARCH_PHYS_OFFSET] /* x22 phys_offset */ raw_dcache_line_size x15, x1 /* x15 = dcache line size */ break_before_make_ttbr_switch x18, x17, x1, x2 /* set linear map */ .Lloop: and x12, x16, PAGE_MASK /* x12 = addr */ - + sub x12, x12, x22 /* Convert x12 to virt */ /* Test the entry flags. */ .Ltest_source: tbz x16, IND_SOURCE_BIT, .Ltest_indirection /* Invalidate dest page to PoC. */ - mov x2, x13 - add x1, x2, #PAGE_SIZE - dcache_by_myline_op ivac, sy, x2, x1, x15, x20 + mov x19, x13 copy_page x13, x12, x1, x2, x3, x4, x5, x6, x7, x8 + add x1, x19, #PAGE_SIZE + dcache_by_myline_op civac, sy, x19, x1, x15, x20 b .Lnext .Ltest_indirection: tbz x16, IND_INDIRECTION_BIT, .Ltest_destination @@ -64,19 +72,20 @@ SYM_CODE_START(arm64_relocate_new_kernel) ic iallu dsb nsh isb + ldr x4, [x0, #KIMAGE_START] /* relocation start */ + ldr x1, [x0, #KIMAGE_ARCH_EL2_VECTORS] /* relocation start */ + ldr x0, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */ + turn_off_mmu x12, x13 /* Start new image. */ - ldr x1, [x0, #KIMAGE_ARCH_EL2_VECTORS] /* relocation start */ cbz x1, .Lel1 - ldr x1, [x0, #KIMAGE_START] /* relocation start */ - ldr x2, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */ + mov x1, x4 /* relocation start */ + mov x2, x0 /* dtb address */ mov x3, xzr mov x4, xzr mov x0, #HVC_SOFT_RESTART hvc #0 /* Jumps from el2 */ .Lel1: - ldr x4, [x0, #KIMAGE_START] /* relocation start */ - ldr x0, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */ mov x2, xzr mov x3, xzr br x4 /* Jumps from el1 */