Re: [PATCH v2 1/3] arch/x86: Move UAPI setup structures into setup_data.h

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi Ard

Am 19.12.23 um 11:50 schrieb Ard Biesheuvel:
> Hi Thomas,
> 
> On Fri, 15 Dec 2023 at 13:26, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>
>> The type definition of struct pci_setup_rom in <asm/pci.h> requires
>> struct setup_data from <asm/bootparam.h>. Many drivers include
>> <linux/pci.h>, but do not use boot parameters. Changes to bootparam.h
>> or its included header files could easily trigger a large, unnecessary
>> rebuild of the kernel.
>>
>> Moving struct setup_data and related code into its own own header file
>> avoids including <asm/bootparam.h> in <asm/pci.h>. Instead include the
>> new header <asm/screen_data.h> and remove the include statement for
>> x86_init.h, which is unnecessary but pulls in bootparams.h.
>>
>> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   arch/x86/include/asm/pci.h             |   2 +-
>>   arch/x86/include/uapi/asm/bootparam.h  | 218 +----------------------
>>   arch/x86/include/uapi/asm/setup_data.h | 229 +++++++++++++++++++++++++
>>   3 files changed, 231 insertions(+), 218 deletions(-)
>>   create mode 100644 arch/x86/include/uapi/asm/setup_data.h
>>
> 
> This is an improvement but not quite what I had in mind: setup_data is
> a x86 specific linked list that is only referred to via a u64 in
> setup_header.
> 
> So setup_data and all the specializations belong in setup_data.h.
> OTOH, setup_header, the XLF load flags, efi_info, the e820 related
> definitions etc are not related to setup_data at all but to
> setup_header. Whether or not setup_header could live in its own header
> too (along with those related definitions) is a separate question imo,
> but I don't think they belong in setup_data.h

Thanks for the feedback. I'll send out an update to address this and 
additional changes for PCI and EFI.

So fa, the only reason for a setup_header header file would be 
e820/types.h which includes bootparam.h for E820_MAX_ENTRIES_ZEROPAGE. 
It doesn't make a difference in build time, tough.

Best regards
Thomas

> 
> 
> 
>> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
>> index b40c462b4af3..f6100df3652e 100644
>> --- a/arch/x86/include/asm/pci.h
>> +++ b/arch/x86/include/asm/pci.h
>> @@ -10,7 +10,7 @@
>>   #include <linux/numa.h>
>>   #include <asm/io.h>
>>   #include <asm/memtype.h>
>> -#include <asm/x86_init.h>
>> +#include <asm/setup_data.h>
>>
>>   struct pci_sysdata {
>>          int             domain;         /* PCI domain */
>> diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
>> index 01d19fc22346..f6361eb792fd 100644
>> --- a/arch/x86/include/uapi/asm/bootparam.h
>> +++ b/arch/x86/include/uapi/asm/bootparam.h
>> @@ -2,42 +2,7 @@
>>   #ifndef _ASM_X86_BOOTPARAM_H
>>   #define _ASM_X86_BOOTPARAM_H
>>
>> -/* setup_data/setup_indirect types */
>> -#define SETUP_NONE                     0
>> -#define SETUP_E820_EXT                 1
>> -#define SETUP_DTB                      2
>> -#define SETUP_PCI                      3
>> -#define SETUP_EFI                      4
>> -#define SETUP_APPLE_PROPERTIES         5
>> -#define SETUP_JAILHOUSE                        6
>> -#define SETUP_CC_BLOB                  7
>> -#define SETUP_IMA                      8
>> -#define SETUP_RNG_SEED                 9
>> -#define SETUP_ENUM_MAX                 SETUP_RNG_SEED
>> -
>> -#define SETUP_INDIRECT                 (1<<31)
>> -#define SETUP_TYPE_MAX                 (SETUP_ENUM_MAX | SETUP_INDIRECT)
>> -
>> -/* ram_size flags */
>> -#define RAMDISK_IMAGE_START_MASK       0x07FF
>> -#define RAMDISK_PROMPT_FLAG            0x8000
>> -#define RAMDISK_LOAD_FLAG              0x4000
>> -
>> -/* loadflags */
>> -#define LOADED_HIGH    (1<<0)
>> -#define KASLR_FLAG     (1<<1)
>> -#define QUIET_FLAG     (1<<5)
>> -#define KEEP_SEGMENTS  (1<<6)
>> -#define CAN_USE_HEAP   (1<<7)
>> -
>> -/* xloadflags */
>> -#define XLF_KERNEL_64                  (1<<0)
>> -#define XLF_CAN_BE_LOADED_ABOVE_4G     (1<<1)
>> -#define XLF_EFI_HANDOVER_32            (1<<2)
>> -#define XLF_EFI_HANDOVER_64            (1<<3)
>> -#define XLF_EFI_KEXEC                  (1<<4)
>> -#define XLF_5LEVEL                     (1<<5)
>> -#define XLF_5LEVEL_ENABLED             (1<<6)
>> +#include <asm/setup_data.h>
>>
>>   #ifndef __ASSEMBLY__
>>
>> @@ -48,139 +13,6 @@
>>   #include <asm/ist.h>
>>   #include <video/edid.h>
>>
>> -/* extensible setup data list node */
>> -struct setup_data {
>> -       __u64 next;
>> -       __u32 type;
>> -       __u32 len;
>> -       __u8 data[];
>> -};
>> -
>> -/* extensible setup indirect data node */
>> -struct setup_indirect {
>> -       __u32 type;
>> -       __u32 reserved;  /* Reserved, must be set to zero. */
>> -       __u64 len;
>> -       __u64 addr;
>> -};
>> -
>> -struct setup_header {
>> -       __u8    setup_sects;
>> -       __u16   root_flags;
>> -       __u32   syssize;
>> -       __u16   ram_size;
>> -       __u16   vid_mode;
>> -       __u16   root_dev;
>> -       __u16   boot_flag;
>> -       __u16   jump;
>> -       __u32   header;
>> -       __u16   version;
>> -       __u32   realmode_swtch;
>> -       __u16   start_sys_seg;
>> -       __u16   kernel_version;
>> -       __u8    type_of_loader;
>> -       __u8    loadflags;
>> -       __u16   setup_move_size;
>> -       __u32   code32_start;
>> -       __u32   ramdisk_image;
>> -       __u32   ramdisk_size;
>> -       __u32   bootsect_kludge;
>> -       __u16   heap_end_ptr;
>> -       __u8    ext_loader_ver;
>> -       __u8    ext_loader_type;
>> -       __u32   cmd_line_ptr;
>> -       __u32   initrd_addr_max;
>> -       __u32   kernel_alignment;
>> -       __u8    relocatable_kernel;
>> -       __u8    min_alignment;
>> -       __u16   xloadflags;
>> -       __u32   cmdline_size;
>> -       __u32   hardware_subarch;
>> -       __u64   hardware_subarch_data;
>> -       __u32   payload_offset;
>> -       __u32   payload_length;
>> -       __u64   setup_data;
>> -       __u64   pref_address;
>> -       __u32   init_size;
>> -       __u32   handover_offset;
>> -       __u32   kernel_info_offset;
>> -} __attribute__((packed));
>> -
>> -struct sys_desc_table {
>> -       __u16 length;
>> -       __u8  table[14];
>> -};
>> -
>> -/* Gleaned from OFW's set-parameters in cpu/x86/pc/linux.fth */
>> -struct olpc_ofw_header {
>> -       __u32 ofw_magic;        /* OFW signature */
>> -       __u32 ofw_version;
>> -       __u32 cif_handler;      /* callback into OFW */
>> -       __u32 irq_desc_table;
>> -} __attribute__((packed));
>> -
>> -struct efi_info {
>> -       __u32 efi_loader_signature;
>> -       __u32 efi_systab;
>> -       __u32 efi_memdesc_size;
>> -       __u32 efi_memdesc_version;
>> -       __u32 efi_memmap;
>> -       __u32 efi_memmap_size;
>> -       __u32 efi_systab_hi;
>> -       __u32 efi_memmap_hi;
>> -};
>> -
>> -/*
>> - * This is the maximum number of entries in struct boot_params::e820_table
>> - * (the zeropage), which is part of the x86 boot protocol ABI:
>> - */
>> -#define E820_MAX_ENTRIES_ZEROPAGE 128
>> -
>> -/*
>> - * The E820 memory region entry of the boot protocol ABI:
>> - */
>> -struct boot_e820_entry {
>> -       __u64 addr;
>> -       __u64 size;
>> -       __u32 type;
>> -} __attribute__((packed));
>> -
>> -/*
>> - * Smallest compatible version of jailhouse_setup_data required by this kernel.
>> - */
>> -#define JAILHOUSE_SETUP_REQUIRED_VERSION       1
>> -
>> -/*
>> - * The boot loader is passing platform information via this Jailhouse-specific
>> - * setup data structure.
>> - */
>> -struct jailhouse_setup_data {
>> -       struct {
>> -               __u16   version;
>> -               __u16   compatible_version;
>> -       } __attribute__((packed)) hdr;
>> -       struct {
>> -               __u16   pm_timer_address;
>> -               __u16   num_cpus;
>> -               __u64   pci_mmconfig_base;
>> -               __u32   tsc_khz;
>> -               __u32   apic_khz;
>> -               __u8    standard_ioapic;
>> -               __u8    cpu_ids[255];
>> -       } __attribute__((packed)) v1;
>> -       struct {
>> -               __u32   flags;
>> -       } __attribute__((packed)) v2;
>> -} __attribute__((packed));
>> -
>> -/*
>> - * IMA buffer setup data information from the previous kernel during kexec
>> - */
>> -struct ima_setup_data {
>> -       __u64 addr;
>> -       __u64 size;
>> -} __attribute__((packed));
>> -
>>   /* The so-called "zeropage" */
>>   struct boot_params {
>>          struct screen_info screen_info;                 /* 0x000 */
>> @@ -231,54 +63,6 @@ struct boot_params {
>>          __u8  _pad9[276];                               /* 0xeec */
>>   } __attribute__((packed));
>>
>> -/**
>> - * enum x86_hardware_subarch - x86 hardware subarchitecture
>> - *
>> - * The x86 hardware_subarch and hardware_subarch_data were added as of the x86
>> - * boot protocol 2.07 to help distinguish and support custom x86 boot
>> - * sequences. This enum represents accepted values for the x86
>> - * hardware_subarch.  Custom x86 boot sequences (not X86_SUBARCH_PC) do not
>> - * have or simply *cannot* make use of natural stubs like BIOS or EFI, the
>> - * hardware_subarch can be used on the Linux entry path to revector to a
>> - * subarchitecture stub when needed. This subarchitecture stub can be used to
>> - * set up Linux boot parameters or for special care to account for nonstandard
>> - * handling of page tables.
>> - *
>> - * These enums should only ever be used by x86 code, and the code that uses
>> - * it should be well contained and compartmentalized.
>> - *
>> - * KVM and Xen HVM do not have a subarch as these are expected to follow
>> - * standard x86 boot entries. If there is a genuine need for "hypervisor" type
>> - * that should be considered separately in the future. Future guest types
>> - * should seriously consider working with standard x86 boot stubs such as
>> - * the BIOS or EFI boot stubs.
>> - *
>> - * WARNING: this enum is only used for legacy hacks, for platform features that
>> - *         are not easily enumerated or discoverable. You should not ever use
>> - *         this for new features.
>> - *
>> - * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard
>> - *     PC mechanisms (PCI, ACPI) and doesn't need a special boot flow.
>> - * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest, deprecated
>> - * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path,
>> - *     which start at asm startup_xen() entry point and later jump to the C
>> - *     xen_start_kernel() entry point. Both domU and dom0 type of guests are
>> - *     currently supported through this PV boot path.
>> - * @X86_SUBARCH_INTEL_MID: Used for Intel MID (Mobile Internet Device) platform
>> - *     systems which do not have the PCI legacy interfaces.
>> - * @X86_SUBARCH_CE4100: Used for Intel CE media processor (CE4100) SoC
>> - *     for settop boxes and media devices, the use of a subarch for CE4100
>> - *     is more of a hack...
>> - */
>> -enum x86_hardware_subarch {
>> -       X86_SUBARCH_PC = 0,
>> -       X86_SUBARCH_LGUEST,
>> -       X86_SUBARCH_XEN,
>> -       X86_SUBARCH_INTEL_MID,
>> -       X86_SUBARCH_CE4100,
>> -       X86_NR_SUBARCHS,
>> -};
>> -
>>   #endif /* __ASSEMBLY__ */
>>
>>   #endif /* _ASM_X86_BOOTPARAM_H */
>> diff --git a/arch/x86/include/uapi/asm/setup_data.h b/arch/x86/include/uapi/asm/setup_data.h
>> new file mode 100644
>> index 000000000000..e1396e1bf048
>> --- /dev/null
>> +++ b/arch/x86/include/uapi/asm/setup_data.h
>> @@ -0,0 +1,229 @@
>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
>> +#ifndef _UAPI_ASM_X86_SETUP_DATA_H
>> +#define _UAPI_ASM_X86_SETUP_DATA_H
>> +
>> +/* setup_data/setup_indirect types */
>> +#define SETUP_NONE                     0
>> +#define SETUP_E820_EXT                 1
>> +#define SETUP_DTB                      2
>> +#define SETUP_PCI                      3
>> +#define SETUP_EFI                      4
>> +#define SETUP_APPLE_PROPERTIES         5
>> +#define SETUP_JAILHOUSE                        6
>> +#define SETUP_CC_BLOB                  7
>> +#define SETUP_IMA                      8
>> +#define SETUP_RNG_SEED                 9
>> +#define SETUP_ENUM_MAX                 SETUP_RNG_SEED
>> +
>> +#define SETUP_INDIRECT                 (1<<31)
>> +#define SETUP_TYPE_MAX                 (SETUP_ENUM_MAX | SETUP_INDIRECT)
>> +
>> +/* ram_size flags */
>> +#define RAMDISK_IMAGE_START_MASK       0x07FF
>> +#define RAMDISK_PROMPT_FLAG            0x8000
>> +#define RAMDISK_LOAD_FLAG              0x4000
>> +
>> +/* loadflags */
>> +#define LOADED_HIGH    (1<<0)
>> +#define KASLR_FLAG     (1<<1)
>> +#define QUIET_FLAG     (1<<5)
>> +#define KEEP_SEGMENTS  (1<<6)
>> +#define CAN_USE_HEAP   (1<<7)
>> +
>> +/* xloadflags */
>> +#define XLF_KERNEL_64                  (1<<0)
>> +#define XLF_CAN_BE_LOADED_ABOVE_4G     (1<<1)
>> +#define XLF_EFI_HANDOVER_32            (1<<2)
>> +#define XLF_EFI_HANDOVER_64            (1<<3)
>> +#define XLF_EFI_KEXEC                  (1<<4)
>> +#define XLF_5LEVEL                     (1<<5)
>> +#define XLF_5LEVEL_ENABLED             (1<<6)
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +#include <linux/types.h>
>> +
>> +/* extensible setup data list node */
>> +struct setup_data {
>> +       __u64 next;
>> +       __u32 type;
>> +       __u32 len;
>> +       __u8 data[];
>> +};
>> +
>> +/* extensible setup indirect data node */
>> +struct setup_indirect {
>> +       __u32 type;
>> +       __u32 reserved;  /* Reserved, must be set to zero. */
>> +       __u64 len;
>> +       __u64 addr;
>> +};
>> +
>> +struct setup_header {
>> +       __u8    setup_sects;
>> +       __u16   root_flags;
>> +       __u32   syssize;
>> +       __u16   ram_size;
>> +       __u16   vid_mode;
>> +       __u16   root_dev;
>> +       __u16   boot_flag;
>> +       __u16   jump;
>> +       __u32   header;
>> +       __u16   version;
>> +       __u32   realmode_swtch;
>> +       __u16   start_sys_seg;
>> +       __u16   kernel_version;
>> +       __u8    type_of_loader;
>> +       __u8    loadflags;
>> +       __u16   setup_move_size;
>> +       __u32   code32_start;
>> +       __u32   ramdisk_image;
>> +       __u32   ramdisk_size;
>> +       __u32   bootsect_kludge;
>> +       __u16   heap_end_ptr;
>> +       __u8    ext_loader_ver;
>> +       __u8    ext_loader_type;
>> +       __u32   cmd_line_ptr;
>> +       __u32   initrd_addr_max;
>> +       __u32   kernel_alignment;
>> +       __u8    relocatable_kernel;
>> +       __u8    min_alignment;
>> +       __u16   xloadflags;
>> +       __u32   cmdline_size;
>> +       __u32   hardware_subarch;
>> +       __u64   hardware_subarch_data;
>> +       __u32   payload_offset;
>> +       __u32   payload_length;
>> +       __u64   setup_data;
>> +       __u64   pref_address;
>> +       __u32   init_size;
>> +       __u32   handover_offset;
>> +       __u32   kernel_info_offset;
>> +} __attribute__((packed));
>> +
>> +struct sys_desc_table {
>> +       __u16 length;
>> +       __u8  table[14];
>> +};
>> +
>> +/* Gleaned from OFW's set-parameters in cpu/x86/pc/linux.fth */
>> +struct olpc_ofw_header {
>> +       __u32 ofw_magic;        /* OFW signature */
>> +       __u32 ofw_version;
>> +       __u32 cif_handler;      /* callback into OFW */
>> +       __u32 irq_desc_table;
>> +} __attribute__((packed));
>> +
>> +struct efi_info {
>> +       __u32 efi_loader_signature;
>> +       __u32 efi_systab;
>> +       __u32 efi_memdesc_size;
>> +       __u32 efi_memdesc_version;
>> +       __u32 efi_memmap;
>> +       __u32 efi_memmap_size;
>> +       __u32 efi_systab_hi;
>> +       __u32 efi_memmap_hi;
>> +};
>> +
>> +/*
>> + * This is the maximum number of entries in struct boot_params::e820_table
>> + * (the zeropage), which is part of the x86 boot protocol ABI:
>> + */
>> +#define E820_MAX_ENTRIES_ZEROPAGE 128
>> +
>> +/*
>> + * The E820 memory region entry of the boot protocol ABI:
>> + */
>> +struct boot_e820_entry {
>> +       __u64 addr;
>> +       __u64 size;
>> +       __u32 type;
>> +} __attribute__((packed));
>> +
>> +/*
>> + * Smallest compatible version of jailhouse_setup_data required by this kernel.
>> + */
>> +#define JAILHOUSE_SETUP_REQUIRED_VERSION       1
>> +
>> +/*
>> + * The boot loader is passing platform information via this Jailhouse-specific
>> + * setup data structure.
>> + */
>> +struct jailhouse_setup_data {
>> +       struct {
>> +               __u16   version;
>> +               __u16   compatible_version;
>> +       } __attribute__((packed)) hdr;
>> +       struct {
>> +               __u16   pm_timer_address;
>> +               __u16   num_cpus;
>> +               __u64   pci_mmconfig_base;
>> +               __u32   tsc_khz;
>> +               __u32   apic_khz;
>> +               __u8    standard_ioapic;
>> +               __u8    cpu_ids[255];
>> +       } __attribute__((packed)) v1;
>> +       struct {
>> +               __u32   flags;
>> +       } __attribute__((packed)) v2;
>> +} __attribute__((packed));
>> +
>> +/*
>> + * IMA buffer setup data information from the previous kernel during kexec
>> + */
>> +struct ima_setup_data {
>> +       __u64 addr;
>> +       __u64 size;
>> +} __attribute__((packed));
>> +
>> +/**
>> + * enum x86_hardware_subarch - x86 hardware subarchitecture
>> + *
>> + * The x86 hardware_subarch and hardware_subarch_data were added as of the x86
>> + * boot protocol 2.07 to help distinguish and support custom x86 boot
>> + * sequences. This enum represents accepted values for the x86
>> + * hardware_subarch.  Custom x86 boot sequences (not X86_SUBARCH_PC) do not
>> + * have or simply *cannot* make use of natural stubs like BIOS or EFI, the
>> + * hardware_subarch can be used on the Linux entry path to revector to a
>> + * subarchitecture stub when needed. This subarchitecture stub can be used to
>> + * set up Linux boot parameters or for special care to account for nonstandard
>> + * handling of page tables.
>> + *
>> + * These enums should only ever be used by x86 code, and the code that uses
>> + * it should be well contained and compartmentalized.
>> + *
>> + * KVM and Xen HVM do not have a subarch as these are expected to follow
>> + * standard x86 boot entries. If there is a genuine need for "hypervisor" type
>> + * that should be considered separately in the future. Future guest types
>> + * should seriously consider working with standard x86 boot stubs such as
>> + * the BIOS or EFI boot stubs.
>> + *
>> + * WARNING: this enum is only used for legacy hacks, for platform features that
>> + *         are not easily enumerated or discoverable. You should not ever use
>> + *         this for new features.
>> + *
>> + * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard
>> + *     PC mechanisms (PCI, ACPI) and doesn't need a special boot flow.
>> + * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest, deprecated
>> + * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path,
>> + *     which start at asm startup_xen() entry point and later jump to the C
>> + *     xen_start_kernel() entry point. Both domU and dom0 type of guests are
>> + *     currently supported through this PV boot path.
>> + * @X86_SUBARCH_INTEL_MID: Used for Intel MID (Mobile Internet Device) platform
>> + *     systems which do not have the PCI legacy interfaces.
>> + * @X86_SUBARCH_CE4100: Used for Intel CE media processor (CE4100) SoC
>> + *     for settop boxes and media devices, the use of a subarch for CE4100
>> + *     is more of a hack...
>> + */
>> +enum x86_hardware_subarch {
>> +       X86_SUBARCH_PC = 0,
>> +       X86_SUBARCH_LGUEST,
>> +       X86_SUBARCH_XEN,
>> +       X86_SUBARCH_INTEL_MID,
>> +       X86_SUBARCH_CE4100,
>> +       X86_NR_SUBARCHS,
>> +};
>> +
>> +#endif /* __ASSEMBLY__ */
>> +
>> +#endif /* _UAPI_ASM_X86_SETUP_DATA_H */
>> --
>> 2.43.0
>>
>>

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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