From nobody Mon Oct 6 13:41:18 2025 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AE8EC1798F for ; Mon, 21 Jul 2025 09:12:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753089177; cv=none; b=CABo+P6sIN4Dd0I0bIyJam8Ss2kAopzQcy6SMcRz7YPN833JIFnxIBACaAMZ3tLdeWsANYXQz//cDMHDnx7z3lPMvPeTH2f/hNhegHaN3dPq/uDdnveTlj3G1MFYHtSS32AnIDhYpMNfheqQcHPfIRYGD2myQd1mdJzlqyxovrc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753089177; c=relaxed/simple; bh=X5IuqxopbgrZ/xk/4Rm96XqTv5uL59yd4KWknf5JCvY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=qx9x7lgmblHbzPSevy7DasBkHFQ5kqrMa8bqDpWsdxWuCUDgjeLxwb7tyJd8tVf1L03/+DQTYAusHsZwDJ7ITzXKw6WTr560NXQitGJWkqbeot7ogLcJ2Zj2iYCv+MLgd4IYWpXlzFDq5KgP4SEpa7Ur8SjJYoFMmhgCzYWsLvE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8CxaWqSBH5oWrQuAQ--.33438S3; Mon, 21 Jul 2025 17:12:50 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by front1 (Coremail) with SMTP id qMiowJBxzsGRBH5oOfofAA--.9767S2; Mon, 21 Jul 2025 17:12:49 +0800 (CST) From: Bibo Mao To: Huacai Chen Cc: WANG Xuerui , Xi Ruoyao , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v2] LoongArch: Implement physical address with ELF program header Date: Mon, 21 Jul 2025 17:12:48 +0800 Message-Id: <20250721091248.3896152-1-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 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 X-CM-TRANSID: qMiowJBxzsGRBH5oOfofAA--.9767S2 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7 ZEXasCq-sGcSsGvfJ3UbIjqfuFe4nvWSU5nxnvy29KBjDU0xBIdaVrnUUvcSsGvfC2Kfnx nUUI43ZEXa7xR_UUUUUUUUU== Content-Type: text/plain; charset="utf-8" With structure elf64_phdr, field p_paddr is physical address of the segment. And it is convenient for qemu to calculate the physical address when directly boot ELF kernel image. Otherwise QEMU needs convert virtual address p_vaddr into physical address, the conversion logic assumes that DMW method is used where 48 bit physical address is supported. However with direct MMU mapping method with start address from 0xFFFF800000000000, only 47 bit physical address is supported. QEMU cannot assume the kernel behavior at kernel loading stage. Here add physical address indication in ELF program header, it is convenient to get physical kernel loading address. Here is output with command readelf -l vmlinux with patch: Elf file type is EXEC (Executable file) Entry point 0x90000000015f5000 There are 2 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000010000 0x9000000000200000 0x0000000000200000 0x000000000293b000 0x0000000002a79b98 RWE 0x10000 And output with command readelf -l vmlinux without the patch: Elf file type is EXEC (Executable file) Entry point 0x90000000015f5000 There are 2 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000010000 0x9000000000200000 0x9000000000200000 0x000000000293b000 0x0000000002a79b98 RWE 0x10000 Signed-off-by: Bibo Mao --- v1 ... v2: 1. Set LOAD_OFFSET with PAGE_OFFSET rather than CACHE_BASE, since it is generic with PAGE_OFFSET. 2. Add AT information with missing edata_padding section.=20 --- arch/loongarch/kernel/vmlinux.lds.S | 36 +++++++++++++++++++---------- 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vm= linux.lds.S index 08ea921cdec1..8ce6b0d948f4 100644 --- a/arch/loongarch/kernel/vmlinux.lds.S +++ b/arch/loongarch/kernel/vmlinux.lds.S @@ -3,10 +3,12 @@ #include #include #include +#include =20 #define PAGE_SIZE _PAGE_SIZE #define RO_EXCEPTION_TABLE_ALIGN 4 #define PHYSADDR_MASK 0xffffffffffff /* 48-bit */ +#define LOAD_OFFSET PAGE_OFFSET =20 /* * Put .bss..swapper_pg_dir as the first thing in .bss. This will @@ -42,7 +44,7 @@ SECTIONS =20 . =3D ALIGN(PECOFF_SEGMENT_ALIGN); _stext =3D .; - .text : { + .text : AT(ADDR(.text) - LOAD_OFFSET) { TEXT_TEXT SCHED_TEXT LOCK_TEXT @@ -60,7 +62,7 @@ SECTIONS __inittext_begin =3D .; =20 INIT_TEXT_SECTION(PAGE_SIZE) - .exit.text : { + .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { EXIT_TEXT } =20 @@ -82,7 +84,7 @@ SECTIONS } =20 INIT_DATA_SECTION(16) - .exit.data : { + .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { EXIT_DATA } =20 @@ -90,7 +92,7 @@ SECTIONS PERCPU_SECTION(1 << CONFIG_L1_CACHE_SHIFT) #endif =20 - .init.bss : { + .init.bss : AT(ADDR(.init.bss) - LOAD_OFFSET) { *(.init.bss) } . =3D ALIGN(PECOFF_SEGMENT_ALIGN); @@ -101,27 +103,34 @@ SECTIONS _sdata =3D .; RO_DATA(4096) =20 - .got : ALIGN(16) { *(.got) } - .plt : ALIGN(16) { *(.plt) } - .got.plt : ALIGN(16) { *(.got.plt) } + . =3D ALIGN(16); + .got : AT(ADDR(.got) - LOAD_OFFSET) { *(.got) } + . =3D ALIGN(16); + .plt : AT(ADDR(.plt) - LOAD_OFFSET) { *(.plt) } + . =3D ALIGN(16); + .got.plt : AT(ADDR(.got.plt) - LOAD_OFFSET) { *(.got.plt) } =20 RW_DATA(1 << CONFIG_L1_CACHE_SHIFT, PAGE_SIZE, THREAD_SIZE) =20 - .rela.dyn : ALIGN(8) { + . =3D ALIGN(8); + .rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET) { __rela_dyn_begin =3D .; *(.rela.dyn) *(.rela*) __rela_dyn_end =3D .; } =20 #ifdef CONFIG_RELR - .relr.dyn : ALIGN(8) { + . =3D ALIGN(8); + .relr.dyn : AT(ADDR(.relr.dyn) - LOAD_OFFSET) { __relr_dyn_begin =3D .; *(.relr.dyn) __relr_dyn_end =3D .; } #endif =20 - .data.rel : { *(.data.rel*) } + .data.rel : AT(ADDR(.data.rel) - LOAD_OFFSET) { + *(.data.rel*) + } =20 #ifdef CONFIG_RELOCATABLE . =3D ALIGN(8); @@ -134,10 +143,13 @@ SECTIONS =20 ORC_UNWIND_TABLE =20 - .sdata : { + .sdata : AT(ADDR(.sdata) - LOAD_OFFSET) { *(.sdata) } - .edata_padding : { BYTE(0); . =3D ALIGN(PECOFF_FILE_ALIGN); } + .edata_padding : AT(ADDR(.edata_padding) - LOAD_OFFSET) { + BYTE(0); + . =3D ALIGN(PECOFF_FILE_ALIGN); + } _edata =3D .; =20 BSS_SECTION(0, SZ_64K, 8) base-commit: 89be9a83ccf1f88522317ce02f854f30d6115c41 --=20 2.39.3