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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 03/10] xen: add elfnote.h to avoid using numbers instead of constants
On 18/02/16 11:30, Daniel Kiper wrote:
> On Wed, Feb 17, 2016 at 06:19:30PM +0100, Juergen Gross wrote:
>> Various features and parameters of a pv-kernel are specified via
>> elf notes in the kernel image. Those notes are part of the interface
>> between the Xen hypervisor and the kernel.
>>
>> Instead of using num,bers in the code when interpreting the elf notes
>> make use of the header supplied by Xen for that purpose.
>>
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>
> Yummy! Just one nitpick.
>
> Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
>
>> ---
>> grub-core/loader/i386/xen_fileXX.c | 19 +--
>> include/xen/elfnote.h | 281
>> +++++++++++++++++++++++++++++++++++++
>> 2 files changed, 291 insertions(+), 9 deletions(-)
>> create mode 100644 include/xen/elfnote.h
>>
>> diff --git a/grub-core/loader/i386/xen_fileXX.c
>> b/grub-core/loader/i386/xen_fileXX.c
>> index 5475819..1f7f71d 100644
>> --- a/grub-core/loader/i386/xen_fileXX.c
>> +++ b/grub-core/loader/i386/xen_fileXX.c
>> @@ -18,6 +18,7 @@
>>
>> #include <grub/xen_file.h>
>> #include <grub/misc.h>
>> +#include <xen/elfnote.h>
>>
>> static grub_err_t
>> parse_xen_guest (grub_elf_t elf, struct grub_xen_file_info *xi,
>> @@ -201,35 +202,35 @@ parse_note (grub_elf_t elf, struct grub_xen_file_info
>> *xi,
>> xi->has_note = 1;
>> switch (nh->n_type)
>> {
>> - case 1:
>> + case XEN_ELFNOTE_ENTRY:
>> xi->entry_point = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
>> break;
>> - case 2:
>> + case XEN_ELFNOTE_HYPERCALL_PAGE:
>> xi->hypercall_page = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
>> xi->has_hypercall_page = 1;
>> break;
>> - case 3:
>> + case XEN_ELFNOTE_VIRT_BASE:
>> xi->virt_base = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
>> break;
>> - case 4:
>> + case XEN_ELFNOTE_PADDR_OFFSET:
>> xi->paddr_offset = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
>> break;
>> - case 5:
>> + case XEN_ELFNOTE_XEN_VERSION:
>> grub_dprintf ("xen", "xenversion = `%s'\n", (char *) desc);
>> break;
>> - case 6:
>> + case XEN_ELFNOTE_GUEST_OS:
>> grub_dprintf ("xen", "name = `%s'\n", (char *) desc);
>> break;
>> - case 7:
>> + case XEN_ELFNOTE_GUEST_VERSION:
>> grub_dprintf ("xen", "version = `%s'\n", (char *) desc);
>> break;
>> - case 8:
>> + case XEN_ELFNOTE_LOADER:
>> if (descsz < 7
>> || grub_memcmp (desc, "generic", descsz == 7 ? 7 : 8) != 0)
>> return grub_error (GRUB_ERR_BAD_OS, "invalid loader");
>> break;
>> /* PAE */
>> - case 9:
>> + case XEN_ELFNOTE_PAE_MODE:
>> grub_dprintf ("xen", "pae = `%s', %d, %d\n", (char *) desc,
>> xi->arch, descsz);
>> if (xi->arch != GRUB_XEN_FILE_I386
>> diff --git a/include/xen/elfnote.h b/include/xen/elfnote.h
>> new file mode 100644
>> index 0000000..353985f
>> --- /dev/null
>> +++ b/include/xen/elfnote.h
>> @@ -0,0 +1,281 @@
>> +/******************************************************************************
>> + * elfnote.h
>> + *
>> + * Definitions used for the Xen ELF notes.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> copy
>> + * of this software and associated documentation files (the "Software"), to
>> + * deal in the Software without restriction, including without limitation
>> the
>> + * rights to use, copy, modify, merge, publish, distribute, sublicense,
>> and/or
>> + * sell copies of the Software, and to permit persons to whom the Software
>> is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included
>> in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
>> OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> THE
>> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
>> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
>> + * DEALINGS IN THE SOFTWARE.
>> + *
>> + * Copyright (c) 2006, Ian Campbell, XenSource Ltd.
>> + */
>> +
>> +#ifndef __XEN_PUBLIC_ELFNOTE_H__
>> +#define __XEN_PUBLIC_ELFNOTE_H__
>> +
>> +/*
>> + * `incontents 200 elfnotes ELF notes
>> + *
>> + * The notes should live in a PT_NOTE segment and have "Xen" in the
>> + * name field.
>> + *
>> + * Numeric types are either 4 or 8 bytes depending on the content of
>> + * the desc field.
>> + *
>> + * LEGACY indicated the fields in the legacy __xen_guest string which
>> + * this a note type replaces.
>> + *
>> + * String values (for non-legacy) are NULL terminated ASCII, also known
>> + * as ASCIZ type.
>> + */
>> +
>> +/*
>> + * NAME=VALUE pair (string).
>> + */
>> +#define XEN_ELFNOTE_INFO 0
>> +
>> +/*
>> + * The virtual address of the entry point (numeric).
>> + *
>> + * LEGACY: VIRT_ENTRY
>> + */
>> +#define XEN_ELFNOTE_ENTRY 1
>> +
>> +/* The virtual address of the hypercall transfer page (numeric).
>> + *
>> + * LEGACY: HYPERCALL_PAGE. (n.b. legacy value is a physical page
>> + * number not a virtual address)
>> + */
>> +#define XEN_ELFNOTE_HYPERCALL_PAGE 2
>> +
>> +/* The virtual address where the kernel image should be mapped (numeric).
>> + *
>> + * Defaults to 0.
>> + *
>> + * LEGACY: VIRT_BASE
>> + */
>> +#define XEN_ELFNOTE_VIRT_BASE 3
>> +
>> +/*
>> + * The offset of the ELF paddr field from the actual required
>> + * pseudo-physical address (numeric).
>> + *
>> + * This is used to maintain backwards compatibility with older kernels
>> + * which wrote __PAGE_OFFSET into that field. This field defaults to 0
>> + * if not present.
>> + *
>> + * LEGACY: ELF_PADDR_OFFSET. (n.b. legacy default is VIRT_BASE)
>> + */
>> +#define XEN_ELFNOTE_PADDR_OFFSET 4
>> +
>> +/*
>> + * The version of Xen that we work with (string).
>> + *
>> + * LEGACY: XEN_VER
>> + */
>> +#define XEN_ELFNOTE_XEN_VERSION 5
>> +
>> +/*
>> + * The name of the guest operating system (string).
>> + *
>> + * LEGACY: GUEST_OS
>> + */
>> +#define XEN_ELFNOTE_GUEST_OS 6
>> +
>> +/*
>> + * The version of the guest operating system (string).
>> + *
>> + * LEGACY: GUEST_VER
>> + */
>> +#define XEN_ELFNOTE_GUEST_VERSION 7
>> +
>> +/*
>> + * The loader type (string).
>> + *
>> + * LEGACY: LOADER
>> + */
>> +#define XEN_ELFNOTE_LOADER 8
>> +
>> +/*
>> + * The kernel supports PAE (x86/32 only, string = "yes", "no" or
>> + * "bimodal").
>> + *
>> + * For compatibility with Xen 3.0.3 and earlier the "bimodal" setting
>> + * may be given as "yes,bimodal" which will cause older Xen to treat
>> + * this kernel as PAE.
>> + *
>> + * LEGACY: PAE (n.b. The legacy interface included a provision to
>> + * indicate 'extended-cr3' support allowing L3 page tables to be
>> + * placed above 4G. It is assumed that any kernel new enough to use
>> + * these ELF notes will include this and therefore "yes" here is
>> + * equivalent to "yes[entended-cr3]" in the __xen_guest interface.
>> + */
>> +#define XEN_ELFNOTE_PAE_MODE 9
>> +
>> +/*
>> + * The features supported/required by this kernel (string).
>> + *
>> + * The string must consist of a list of feature names (as given in
>> + * features.h, without the "XENFEAT_" prefix) separated by '|'
>> + * characters. If a feature is required for the kernel to function
>> + * then the feature name must be preceded by a '!' character.
>> + *
>> + * LEGACY: FEATURES
>> + */
>> +#define XEN_ELFNOTE_FEATURES 10
>> +
>> +/*
>> + * The kernel requires the symbol table to be loaded (string = "yes" or
>> "no")
>> + * LEGACY: BSD_SYMTAB (n.b. The legacy treated the presence or absence
>> + * of this string as a boolean flag rather than requiring "yes" or
>> + * "no".
>> + */
>> +#define XEN_ELFNOTE_BSD_SYMTAB 11
>> +
>> +/*
>> + * The lowest address the hypervisor hole can begin at (numeric).
>> + *
>> + * This must not be set higher than HYPERVISOR_VIRT_START. Its presence
>> + * also indicates to the hypervisor that the kernel can deal with the
>> + * hole starting at a higher address.
>> + */
>> +#define XEN_ELFNOTE_HV_START_LOW 12
>> +
>> +/*
>> + * List of maddr_t-sized mask/value pairs describing how to recognize
>> + * (non-present) L1 page table entries carrying valid MFNs (numeric).
>> + */
>> +#define XEN_ELFNOTE_L1_MFN_VALID 13
>> +
>> +/*
>> + * Whether or not the guest supports cooperative suspend cancellation.
>> + * This is a numeric value.
>> + *
>> + * Default is 0
>> + */
>> +#define XEN_ELFNOTE_SUSPEND_CANCEL 14
>> +
>> +/*
>> + * The (non-default) location the initial phys-to-machine map should be
>> + * placed at by the hypervisor (Dom0) or the tools (DomU).
>> + * The kernel must be prepared for this mapping to be established using
>> + * large pages, despite such otherwise not being available to guests.
>> + * The kernel must also be able to handle the page table pages used for
>> + * this mapping not being accessible through the initial mapping.
>> + * (Only x86-64 supports this at present.)
>> + */
>> +#define XEN_ELFNOTE_INIT_P2M 15
>> +
>> +/*
>> + * Whether or not the guest can deal with being passed an initrd not
>> + * mapped through its initial page tables.
>> + */
>> +#define XEN_ELFNOTE_MOD_START_PFN 16
>> +
>> +/*
>> + * The features supported by this kernel (numeric).
>> + *
>> + * Other than XEN_ELFNOTE_FEATURES on pre-4.2 Xen, this note allows a
>> + * kernel to specify support for features that older hypervisors don't
>> + * know about. The set of features 4.2 and newer hypervisors will
>> + * consider supported by the kernel is the combination of the sets
>> + * specified through this and the string note.
>> + *
>> + * LEGACY: FEATURES
>> + */
>> +#define XEN_ELFNOTE_SUPPORTED_FEATURES 17
>> +
>> +/*
>> + * Physical entry point into the kernel.
>> + *
>> + * 32bit entry point into the kernel. When requested to launch the
>> + * guest kernel in a HVM container, Xen will use this entry point to
>> + * launch the guest in 32bit protected mode with paging disabled.
>> + * Ignored otherwise.
>> + */
>> +#define XEN_ELFNOTE_PHYS32_ENTRY 18
>> +
>> +/*
>> + * The number of the highest elfnote defined.
>> + */
>> +#define XEN_ELFNOTE_MAX XEN_ELFNOTE_PHYS32_ENTRY
>> +
>> +/*
>> + * System information exported through crash notes.
>> + *
>> + * The kexec / kdump code will create one XEN_ELFNOTE_CRASH_INFO
>> + * note in case of a system crash. This note will contain various
>> + * information about the system, see xen/include/xen/elfcore.h.
>> + */
>> +#define XEN_ELFNOTE_CRASH_INFO 0x1000001
>> +
>> +/*
>> + * System registers exported through crash notes.
>> + *
>> + * The kexec / kdump code will create one XEN_ELFNOTE_CRASH_REGS
>> + * note per cpu in case of a system crash. This note is architecture
>> + * specific and will contain registers not saved in the "CORE" note.
>> + * See xen/include/xen/elfcore.h for more information.
>> + */
>> +#define XEN_ELFNOTE_CRASH_REGS 0x1000002
>> +
>> +
>> +/*
>> + * xen dump-core none note.
>> + * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_NONE
>> + * in its dump file to indicate that the file is xen dump-core
>> + * file. This note doesn't have any other information.
>> + * See tools/libxc/xc_core.h for more information.
>> + */
>> +#define XEN_ELFNOTE_DUMPCORE_NONE 0x2000000
>> +
>> +/*
>> + * xen dump-core header note.
>> + * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_HEADER
>> + * in its dump file.
>> + * See tools/libxc/xc_core.h for more information.
>> + */
>> +#define XEN_ELFNOTE_DUMPCORE_HEADER 0x2000001
>> +
>> +/*
>> + * xen dump-core xen version note.
>> + * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_XEN_VERSION
>> + * in its dump file. It contains the xen version obtained via the
>> + * XENVER hypercall.
>> + * See tools/libxc/xc_core.h for more information.
>> + */
>> +#define XEN_ELFNOTE_DUMPCORE_XEN_VERSION 0x2000002
>> +
>> +/*
>> + * xen dump-core format version note.
>> + * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_FORMAT_VERSION
>> + * in its dump file. It contains a format version identifier.
>> + * See tools/libxc/xc_core.h for more information.
>> + */
>> +#define XEN_ELFNOTE_DUMPCORE_FORMAT_VERSION 0x2000003
>> +
>> +#endif /* __XEN_PUBLIC_ELFNOTE_H__ */
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * tab-width: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>
> I am not sure that Emacs footer should be copied to GRUB2 source.
Other xen include files contain it, too.
Juergen
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