From nobody Thu Dec 18 09:44:08 2025 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9155621D595 for ; Thu, 5 Dec 2024 15:34:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733412844; cv=none; b=EG+EYPHkK4eakQw087oxWp6B7zS1k68hZHz9jFvXz5ld6xuKBSTCklGeLGg40mDEbNrsiWsJZJcaFiIoJnT8lfVvlRba9sB+iQTJTPUpKiS6gsDUDgjrIcIQlBWplLqXkfgXkdF6YWa5vXcNgmKQ6MyNKt+TR/aKz73Xo+DM7I0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733412844; c=relaxed/simple; bh=kUbjanEXjddFgktas16TK/9UQEactJwhG2rx0T5+mxY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lIBl6g1nfKJlxDyrqqp/Qgtb5TZ9khVAmWFtZd5gYVhkVTHp2ttYzpbokY8XSm1DD10nzAQ+EOUoQ1e64jHmrX5y481x443iFxg8wf5fRsK/ZybrEMbKmwKeff/k9lZCVtUEhhJAPE3ryzG+Fte7d1GmhrS/dy+1VxTxu3yrP5I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=br/X6LAo; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="br/X6LAo" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=y4llxN1150m5VJE0hmL7LsJF75dL//a2jb4zHWMLskg=; b=br/X6LAon+bVnEMOZ+v4nxyrPz 7J+UmFFw8U63h+7woD7DsJxDfhd2seCQ/Lq39j9PJdKbD6CLhM7pJLhDsUNkJ+MTDUyHcQwb5+07r T+m8CHjI/1xzdJTAoippv0UZu/LmHhzOgWc49TtT5EKNy31CgyfXX4Ug4PNW9BU/bnt85tmUqgRyd 5HDWqeYVfn/D5Y5hm+teexz57r5l+FXWpRpI+ouqoa6pE0idInaPF3LC8edUXxTrmbjY7gDM8RgLO d5MHjqIWoXbnqxkukNiktNlpLvySiu0UhHgymCjQTary3tUMmxHLktT936BKTwmCe49Hk6UzwLltt dOgjriyQ==; Received: from [2001:8b0:10b:1::ebe] (helo=i7.infradead.org) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tJDrM-0000000DDp6-2JLa; Thu, 05 Dec 2024 15:33:45 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tJDrN-0000000DyLr-2RZ5; Thu, 05 Dec 2024 15:33:45 +0000 From: David Woodhouse To: kexec@lists.infradead.org Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , David Woodhouse , "Kirill A. Shutemov" , Kai Huang , Nikolay Borisov , linux-kernel@vger.kernel.org, Simon Horman , Dave Young , Peter Zijlstra , jpoimboe@kernel.org, bsz@amazon.de Subject: [PATCH v5 10/20] x86/kexec: Drop page_list argument from relocate_kernel() Date: Thu, 5 Dec 2024 15:05:16 +0000 Message-ID: <20241205153343.3275139-11-dwmw2@infradead.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205153343.3275139-1-dwmw2@infradead.org> References: <20241205153343.3275139-1-dwmw2@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Content-Type: text/plain; charset="utf-8" From: David Woodhouse The kernel's virtual mapping of the relocate_kernel page currently needs to be RWX because it is written to before the %cr3 switch. Now that the relocate_kernel page has its own .data section and local variables, it can also have *global* variables. So eliminate the separate page_list argument, and write the same information directly to variables in the relocate_kernel page instead. This way, the relocate_kernel code itself doesn't need to copy it. Signed-off-by: David Woodhouse --- arch/x86/include/asm/kexec.h | 12 ++++------ arch/x86/kernel/machine_kexec_64.c | 18 ++++++-------- arch/x86/kernel/relocate_kernel_64.S | 36 ++++++++++------------------ 3 files changed, 24 insertions(+), 42 deletions(-) diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index ccb8ff37fa9d..48e4f44f794f 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -8,12 +8,6 @@ # define PA_PGD 2 # define PA_SWAP_PAGE 3 # define PAGES_NR 4 -#else -# define PA_CONTROL_PAGE 0 -# define VA_CONTROL_PAGE 1 -# define PA_TABLE_PAGE 2 -# define PA_SWAP_PAGE 3 -# define PAGES_NR 4 #endif =20 # define KEXEC_CONTROL_PAGE_SIZE 4096 @@ -60,6 +54,10 @@ struct kimage; =20 /* The native architecture */ # define KEXEC_ARCH KEXEC_ARCH_X86_64 + +extern unsigned long kexec_va_control_page; +extern unsigned long kexec_pa_table_page; +extern unsigned long kexec_pa_swap_page; #endif =20 /* @@ -122,7 +120,7 @@ relocate_kernel(unsigned long indirection_page, #else unsigned long relocate_kernel(unsigned long indirection_page, - unsigned long page_list, + unsigned long pa_control_page, unsigned long start_address, unsigned int preserve_context, unsigned int host_mem_enc_active); diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_k= exec_64.c index 63dca5c595f6..c9fd60f8f806 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -315,6 +315,11 @@ int machine_kexec_prepare(struct kimage *image) result =3D init_pgtable(image, __pa(control_page)); if (result) return result; + kexec_va_control_page =3D (unsigned long)control_page; + kexec_pa_table_page =3D (unsigned long)__pa(image->arch.pgd); + + if (image->type =3D=3D KEXEC_TYPE_DEFAULT) + kexec_pa_swap_page =3D page_to_pfn(image->swap_page) << PAGE_SHIFT; =20 __memcpy(control_page, __relocate_kernel_start, reloc_end - reloc_start); =20 @@ -339,12 +344,11 @@ void machine_kexec_cleanup(struct kimage *image) void machine_kexec(struct kimage *image) { unsigned long (*relocate_kernel_ptr)(unsigned long indirection_page, - unsigned long page_list, + unsigned long pa_control_page, unsigned long start_address, unsigned int preserve_context, unsigned int host_mem_enc_active); unsigned long reloc_start =3D (unsigned long)__relocate_kernel_start; - unsigned long page_list[PAGES_NR]; unsigned int host_mem_enc_active; int save_ftrace_enabled; void *control_page; @@ -382,14 +386,6 @@ void machine_kexec(struct kimage *image) =20 control_page =3D page_address(image->control_code_page); =20 - page_list[PA_CONTROL_PAGE] =3D virt_to_phys(control_page); - page_list[VA_CONTROL_PAGE] =3D (unsigned long)control_page; - page_list[PA_TABLE_PAGE] =3D (unsigned long)__pa(image->arch.pgd); - - if (image->type =3D=3D KEXEC_TYPE_DEFAULT) - page_list[PA_SWAP_PAGE] =3D (page_to_pfn(image->swap_page) - << PAGE_SHIFT); - /* * Allow for the possibility that relocate_kernel might not be at * the very start of the page. @@ -417,7 +413,7 @@ void machine_kexec(struct kimage *image) =20 /* now call it */ image->start =3D relocate_kernel_ptr((unsigned long)image->head, - (unsigned long)page_list, + virt_to_phys(control_page), image->start, image->preserve_context, host_mem_enc_active); diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocat= e_kernel_64.S index 469af51589ee..16f123527406 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -34,9 +34,9 @@ SYM_DATA_LOCAL(saved_cr0, .quad 0) SYM_DATA_LOCAL(saved_cr3, .quad 0) SYM_DATA_LOCAL(saved_cr4, .quad 0) /* other data */ -SYM_DATA_LOCAL(va_control_page, .quad 0) -SYM_DATA_LOCAL(pa_table_page, .quad 0) -SYM_DATA_LOCAL(pa_swap_page, .quad 0) +SYM_DATA(kexec_va_control_page, .quad 0) +SYM_DATA(kexec_pa_table_page, .quad 0) +SYM_DATA(kexec_pa_swap_page, .quad 0) SYM_DATA_LOCAL(pa_backup_pages_map, .quad 0) =20 .section .text.relocate_kernel,"ax"; @@ -46,7 +46,7 @@ SYM_CODE_START_NOALIGN(relocate_kernel) ANNOTATE_NOENDBR /* * %rdi indirection_page - * %rsi page_list + * %rsi pa_control_page * %rdx start address * %rcx preserve_context * %r8 host_mem_enc_active @@ -79,31 +79,19 @@ SYM_CODE_START_NOALIGN(relocate_kernel) /* Save SME active flag */ movq %r8, %r12 =20 - /* - * get physical and virtual address of control page now - * this is impossible after page table switch - */ - movq PTR(PA_CONTROL_PAGE)(%rsi), %r8 - movq PTR(VA_CONTROL_PAGE)(%rsi), %r11 - - /* get physical address of page table now too */ - movq PTR(PA_TABLE_PAGE)(%rsi), %r9 - - /* get physical address of swap page now */ - movq PTR(PA_SWAP_PAGE)(%rsi), %r10 - - /* save some information for jumping back */ - movq %r9, pa_table_page(%rip) - movq %r10, pa_swap_page(%rip) + /* save indirection list for jumping back */ movq %rdi, pa_backup_pages_map(%rip) - movq %r11, va_control_page(%rip) =20 /* Save the preserve_context to %r11 as swap_pages clobbers %rcx. */ movq %rcx, %r11 =20 /* Switch to the identity mapped page tables */ + movq kexec_pa_table_page(%rip), %r9 movq %r9, %cr3 =20 + /* Physical address of control page */ + movq %rsi, %r8 + /* setup a new stack at the end of the physical control page */ lea PAGE_SIZE(%r8), %rsp =20 @@ -227,13 +215,13 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped) /* get the re-entry point of the peer system */ movq 0(%rsp), %rbp leaq relocate_kernel(%rip), %r8 - movq pa_swap_page(%rip), %r10 + movq kexec_pa_swap_page(%rip), %r10 movq pa_backup_pages_map(%rip), %rdi - movq pa_table_page(%rip), %rax + movq kexec_pa_table_page(%rip), %rax movq %rax, %cr3 lea PAGE_SIZE(%r8), %rsp call swap_pages - movq va_control_page(%rip), %rax + movq kexec_va_control_page(%rip), %rax addq $(virtual_mapped - relocate_kernel), %rax pushq %rax ANNOTATE_UNRET_SAFE --=20 2.47.0