From patchwork Thu Jul 27 13:38:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Oleksii K." 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([94.75.70.14]) by smtp.gmail.com with ESMTPSA id l3-20020a2e7003000000b002b6bb68c7eesm341955ljc.110.2023.07.27.06.38.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Jul 2023 06:38:04 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d112e3db-2c82-11ee-b248-6b7b168915f2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690465085; x=1691069885; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=VVrY+IwKxbHDcjyK2IpdTfw6/z7cxU09eme1nE/toW4=; b=qhiHRzyKb+DM4KVt4S08A6E16pb6Ox+6N+AovsfGeRC6koDzQvy8u31gZzbsI0QdZF wq7Zeb1RzrPBHZvdnKJqD+WleAU6SfQFGC/nVOgGGMu0ze4DSqjy+9CoHAhf2EaQTHGB awQzsk5U368dHpLj699dc/zwtFxXvQVt5aqdTYfaoOIE4dPhQ2GClj/x2A4wqlIJ1zT4 ku3HuTuh+tfLf9U4B0rgyH70D+N+mLwCCDMFAYF5omxV5haH0JVLAM4OrixOaeP8Dlzw HODEKMVNG7hz37YGaG42hY3934JdOyVmSDNizFK749mRRptHaWXYUeXIm5hKs0mWzobi 3ndQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690465085; x=1691069885; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=VVrY+IwKxbHDcjyK2IpdTfw6/z7cxU09eme1nE/toW4=; b=Zt9T/NcePq2r5PIbaVCCQyEAOyqMO0m7rT+JQnPn3SUJ/tLDgIILyoW6P3nE+LgEO9 JUZ50/id1bUTkiVSf5Dtkn6j4Bp1E0YQM7Yn034z7N7OwZgCtwmXlGedR0+nCky8yYhQ HKYghcGVItqOpmhZT88Mf059CYCgk4Eg8Z/z+fIFlGCirO8d/tzjH5gvMTD3yCpKWGtj kfGgk7lI1Iwb9Ba1lS9MLT+TZy1vleYY33w2eMDEBnTMwXZAhf2r2OPLs+Wo3ylK+eS4 GxAyNTOmmQRFcU/hlSSRA6f+q43gIaO9H8pUL8y6/gzBtMeP4bwyyLxF9Lsuh4ACfILD +8FA== X-Gm-Message-State: ABy/qLamFqEdAlR8o2vVdg5UluS1E+dlNGnNmortzZZNzBN4EjkT5gQU gn/k9Ov+1DPmS9vBvmTPRP6FQQ4qxiU= X-Google-Smtp-Source: APBJJlGkVc0AaTUa3EEv91hubQZIzwgfwVIYP+JmrTV3JnqWEFxkbjjFMx3IXch8O8BWq0UTWhkBAQ== X-Received: by 2002:a2e:9316:0:b0:2b7:764:3caf with SMTP id e22-20020a2e9316000000b002b707643cafmr1768721ljh.10.1690465085098; Thu, 27 Jul 2023 06:38:05 -0700 (PDT) From: Oleksii Kurochko To: xen-devel@lists.xenproject.org Cc: Jan Beulich , Andrew Cooper , Oleksii Kurochko , Bob Eshleman , Alistair Francis , Connor Davis Subject: [PATCH v5 1/2] xen/riscv: introduce function for physical offset calculation Date: Thu, 27 Jul 2023 16:38:00 +0300 Message-ID: <8013798bc397e5afb27d3aa3b263e06f68590b12.1690464789.git.oleksii.kurochko@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 The function was introduced to calculate and save physical offset before MMU is enabled because access to start() is PC-relative and in case of linker_addr != load_addr it will result in incorrect value in phys_offset. Signed-off-by: Oleksii Kurochko --- Changes in V5: - update prototype of calc_phys_offset(). now it returns phys_offset. - declare phys_offset as static. - save returned value of calc_phys_offset to register s2. --- Changes in V4: - update the comment messages in head.S related to save/restore of a0/a1 regs. --- Changes in V3: - save/restore of a0/a1 registers before C first function call. --- Changes in V2: - add __ro_after_init for phys_offset variable. - remove double blank lines. - add __init for calc_phys_offset(). - update the commit message. - declaring variable phys_off as non static as it will be used in head.S. --- xen/arch/riscv/include/asm/mm.h | 2 ++ xen/arch/riscv/mm.c | 19 ++++++++++++++++--- xen/arch/riscv/riscv64/head.S | 14 ++++++++++++++ 3 files changed, 32 insertions(+), 3 deletions(-) diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h index 5e3ac5cde3..7b94cbadd7 100644 --- a/xen/arch/riscv/include/asm/mm.h +++ b/xen/arch/riscv/include/asm/mm.h @@ -15,4 +15,6 @@ void setup_initial_pagetables(void); void enable_mmu(void); void cont_after_mmu_is_enabled(void); +unsigned long calc_phys_offset(void); + #endif /* _ASM_RISCV_MM_H */ diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c index fddb3cd0bd..1df39ddf1b 100644 --- a/xen/arch/riscv/mm.c +++ b/xen/arch/riscv/mm.c @@ -1,5 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0-only */ +#include #include #include #include @@ -19,9 +20,10 @@ struct mmu_desc { pte_t *pgtbl_base; }; -#define PHYS_OFFSET ((unsigned long)_start - XEN_VIRT_START) -#define LOAD_TO_LINK(addr) ((addr) - PHYS_OFFSET) -#define LINK_TO_LOAD(addr) ((addr) + PHYS_OFFSET) +static unsigned long __ro_after_init phys_offset; + +#define LOAD_TO_LINK(addr) ((unsigned long)(addr) - phys_offset) +#define LINK_TO_LOAD(addr) ((unsigned long)(addr) + phys_offset) /* * It is expected that Xen won't be more then 2 MB. @@ -273,3 +275,14 @@ void __init noreturn noinline enable_mmu() switch_stack_and_jump((unsigned long)cpu0_boot_stack + STACK_SIZE, cont_after_mmu_is_enabled); } + +/* + * calc_phys_offset() should be used before MMU is enabled because access to + * start() is PC-relative and in case when load_addr != linker_addr phys_offset + * will have an incorrect value + */ +unsigned long __init calc_phys_offset(void) +{ + phys_offset = (unsigned long)start - XEN_VIRT_START; + return phys_offset; +} diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S index 2c0304646a..ae194bb099 100644 --- a/xen/arch/riscv/riscv64/head.S +++ b/xen/arch/riscv/riscv64/head.S @@ -29,6 +29,20 @@ ENTRY(start) jal reset_stack + /* + * save hart_id ( bootcpu_id ) and dtb_base as a0 and a1 register can + * be used by C code + */ + mv s0, a0 + mv s1, a1 + + jal calc_phys_offset + mv s2, a0 + + /* restore hart_id ( bootcpu_id ) and dtb address */ + mv a0, s0 + mv a1, s1 + tail start_xen .section .text, "ax", %progbits