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Re: [MULTIBOOT2 DOC PATCH v2 05/11] multiboot2: Add description of suppo
From: |
Andrei Borzenkov |
Subject: |
Re: [MULTIBOOT2 DOC PATCH v2 05/11] multiboot2: Add description of support for EFI boot services |
Date: |
Mon, 28 Nov 2016 20:53:51 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
24.11.2016 23:40, Daniel Kiper пишет:
> Signed-off-by: Daniel Kiper <address@hidden>
> ---
> v2 - suggestions/fixes:
> - clarify physical address meaning for EFI amd64
> mode with boot services enabled
> (suggested by Andrew Cooper).
> ---
> doc/multiboot.texi | 115
> +++++++++++++++++++++++++++++++++++++++++++++++++++-
> doc/multiboot2.h | 2 +
> 2 files changed, 115 insertions(+), 2 deletions(-)
>
> diff --git a/doc/multiboot.texi b/doc/multiboot.texi
> index f0f167e..cc1edab 100644
> --- a/doc/multiboot.texi
> +++ b/doc/multiboot.texi
> @@ -534,6 +534,66 @@ The physical address to which the boot loader should
> jump in order to
> start running the operating system.
> @end table
>
> address@hidden EFI i386 entry address tag of Multiboot2 header
> +
> address@hidden
> address@hidden
> + +-------------------+
> +u16 | type = 8 |
> +u16 | flags |
> +u32 | size |
> +u_virt | entry_addr |
> + +-------------------+
> address@hidden group
> address@hidden example
> +
> +All of the address fields in this tag are physical addresses.
Should not entry_addr be u_phys then? Otherwise what is exact difference
between u_phys and u_virt? Also for type == 3?
> +The meaning of each is as follows:
> +
> address@hidden @code
> +
> address@hidden entry_addr
> +The physical address to which the boot loader should jump in order to
> +start running EFI i386 compatible operating system code.
> address@hidden table
> +
> +This tag is taken into account only on EFI i386 platforms
> +when Multiboot2 image header contains EFI boot services tag.
> +Then entry point specified in ELF header and the entry address
> +tag of Multiboot2 header are ignored.
> +
> address@hidden EFI amd64 entry address tag of Multiboot2 header
> +
> address@hidden
> address@hidden
> + +-------------------+
> +u16 | type = 9 |
> +u16 | flags |
> +u32 | size |
> +u_virt | entry_addr |
> + +-------------------+
> address@hidden group
> address@hidden example
> +
> +All of the address fields in this tag are physical addresses (paging
> +mode is enabled and any memory space defined by the UEFI memory map
> +is identity mapped, hence, virtual address equals physical address;
Same here; it is confusing marking field as u_virt and describing it
immediately as "physical address".
> +Unified Extensible Firmware Interface Specification, Version 2.6,
> +section 2.3.4, x64 Platforms, boot services). The meaning of each
> +is as follows:
> +
> address@hidden @code
> +
> address@hidden entry_addr
> +The physical address to which the boot loader should jump in order to
> +start running EFI amd64 compatible operating system code.
> address@hidden table
> +
> +This tag is taken into account only on EFI amd64 platforms
> +when Multiboot2 image header contains EFI boot services tag.
> +Then entry point specified in ELF header and the entry address
> +tag of Multiboot2 header are ignored.
> +
Why do we have two different tags for what is effectively the same
purpose? Is it possible for the same image to have both of them? Just
for my understanding.
- [MULTIBOOT2 DOC PATCH v2 02/11] multiboot2: Replace redundant if with the, (continued)
- [MULTIBOOT2 DOC PATCH v2 02/11] multiboot2: Replace redundant if with the, Daniel Kiper, 2016/11/24
- [MULTIBOOT2 DOC PATCH v2 01/11] multiboot2: Rename Multiboot to Multiboot2, Daniel Kiper, 2016/11/24
- [MULTIBOOT2 DOC PATCH v2 03/11] multiboot2: Clarify meaning of information request header tag, Daniel Kiper, 2016/11/24
- [MULTIBOOT2 DOC PATCH v2 04/11] multiboot2: Fix description of EFI boot services tag, Daniel Kiper, 2016/11/24
- [MULTIBOOT2 DOC PATCH v2 05/11] multiboot2: Add description of support for EFI boot services, Daniel Kiper, 2016/11/24
- Re: [MULTIBOOT2 DOC PATCH v2 05/11] multiboot2: Add description of support for EFI boot services,
Andrei Borzenkov <=
[MULTIBOOT2 DOC PATCH v2 06/11] multiboot2: Add description of EFI image handle tags, Daniel Kiper, 2016/11/24
[MULTIBOOT2 DOC PATCH v2 07/11] multiboot2: Add description of support for relocatable images, Daniel Kiper, 2016/11/24
[MULTIBOOT2 DOC PATCH v2 08/11] multiboot2: Say that memory maps may not be available on EFI platforms, Daniel Kiper, 2016/11/24
[MULTIBOOT2 DOC PATCH v2 09/11] multiboot2: Add C structure members alignment and padding consideration section, Daniel Kiper, 2016/11/24