Re: [PATCH 06/15] binfmt_flat: remove the uapi <linux/flat.h> header

[Vladimir Murzin <vladimir.murzin@arm.com>]

On 6/10/19 10:20 PM, Christoph Hellwig wrote:
> The split between the two flat.h files is completely arbitrary, and the
> uapi version even contains CONFIG_ ifdefs that can't work in userspace.
> The only userspace program known to use the header is elf2flt, and it
> ships with its own version of the combined header.
> 
> Use the chance to move the <asm/flat.h> inclusion out of this file, as it
> is in no way needed for the format defintion, but just for the binfmt
> implementation.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/binfmt_flat.c          |  1 +
>  include/linux/flat.h      | 45 ++++++++++++++++++++++++++---
>  include/uapi/linux/flat.h | 59 ---------------------------------------
>  3 files changed, 42 insertions(+), 63 deletions(-)
>  delete mode 100644 include/uapi/linux/flat.h

FWIW:

Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>

> 
> diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
> index c09651087eda..6ae0f9af3fc9 100644
> --- a/fs/binfmt_flat.c
> +++ b/fs/binfmt_flat.c
> @@ -42,6 +42,7 @@
>  #include <asm/unaligned.h>
>  #include <asm/cacheflush.h>
>  #include <asm/page.h>
> +#include <asm/flat.h>
>  
>  #ifndef flat_get_relocate_addr
>  #define flat_get_relocate_addr(rel)	(rel)
> diff --git a/include/linux/flat.h b/include/linux/flat.h
> index 569b67d64d5c..21d901ba191b 100644
> --- a/include/linux/flat.h
> +++ b/include/linux/flat.h
> @@ -10,8 +10,47 @@
>  #ifndef _LINUX_FLAT_H
>  #define _LINUX_FLAT_H
>  
> -#include <uapi/linux/flat.h>
> -#include <asm/flat.h>
> +#define	FLAT_VERSION			0x00000004L
> +
> +#ifdef CONFIG_BINFMT_SHARED_FLAT
> +#define	MAX_SHARED_LIBS			(4)
> +#else
> +#define	MAX_SHARED_LIBS			(1)
> +#endif
> +
> +/*
> + * To make everything easier to port and manage cross platform
> + * development,  all fields are in network byte order.
> + */
> +
> +struct flat_hdr {
> +	char magic[4];
> +	unsigned long rev;          /* version (as above) */
> +	unsigned long entry;        /* Offset of first executable instruction
> +	                               with text segment from beginning of file */
> +	unsigned long data_start;   /* Offset of data segment from beginning of
> +	                               file */
> +	unsigned long data_end;     /* Offset of end of data segment
> +	                               from beginning of file */
> +	unsigned long bss_end;      /* Offset of end of bss segment from beginning
> +	                               of file */
> +
> +	/* (It is assumed that data_end through bss_end forms the bss segment.) */
> +
> +	unsigned long stack_size;   /* Size of stack, in bytes */
> +	unsigned long reloc_start;  /* Offset of relocation records from
> +	                               beginning of file */
> +	unsigned long reloc_count;  /* Number of relocation records */
> +	unsigned long flags;
> +	unsigned long build_date;   /* When the program/library was built */
> +	unsigned long filler[5];    /* Reservered, set to zero */
> +};
> +
> +#define FLAT_FLAG_RAM    0x0001 /* load program entirely into RAM */
> +#define FLAT_FLAG_GOTPIC 0x0002 /* program is PIC with GOT */
> +#define FLAT_FLAG_GZIP   0x0004 /* all but the header is compressed */
> +#define FLAT_FLAG_GZDATA 0x0008 /* only data/relocs are compressed (for XIP) */
> +#define FLAT_FLAG_KTRACE 0x0010 /* output useful kernel trace for debugging */
>  
>  /*
>   * While it would be nice to keep this header clean,  users of older
> @@ -22,8 +61,6 @@
>   *        with the format above,  except to fix bugs with old format support.
>   */
>  
> -#include <asm/byteorder.h>
> -
>  #define	OLD_FLAT_VERSION			0x00000002L
>  #define OLD_FLAT_RELOC_TYPE_TEXT	0
>  #define OLD_FLAT_RELOC_TYPE_DATA	1
> diff --git a/include/uapi/linux/flat.h b/include/uapi/linux/flat.h
> deleted file mode 100644
> index 27e595e44fb7..000000000000
> --- a/include/uapi/linux/flat.h
> +++ /dev/null
> @@ -1,59 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> -/*
> - * Copyright (C) 2002-2003  David McCullough <davidm@snapgear.com>
> - * Copyright (C) 1998       Kenneth Albanowski <kjahds@kjahds.com>
> - *                          The Silver Hammer Group, Ltd.
> - *
> - * This file provides the definitions and structures needed to
> - * support uClinux flat-format executables.
> - */
> -
> -#ifndef _UAPI_LINUX_FLAT_H
> -#define _UAPI_LINUX_FLAT_H
> -
> -
> -#define	FLAT_VERSION			0x00000004L
> -
> -#ifdef CONFIG_BINFMT_SHARED_FLAT
> -#define	MAX_SHARED_LIBS			(4)
> -#else
> -#define	MAX_SHARED_LIBS			(1)
> -#endif
> -
> -/*
> - * To make everything easier to port and manage cross platform
> - * development,  all fields are in network byte order.
> - */
> -
> -struct flat_hdr {
> -	char magic[4];
> -	unsigned long rev;          /* version (as above) */
> -	unsigned long entry;        /* Offset of first executable instruction
> -	                               with text segment from beginning of file */
> -	unsigned long data_start;   /* Offset of data segment from beginning of
> -	                               file */
> -	unsigned long data_end;     /* Offset of end of data segment
> -	                               from beginning of file */
> -	unsigned long bss_end;      /* Offset of end of bss segment from beginning
> -	                               of file */
> -
> -	/* (It is assumed that data_end through bss_end forms the bss segment.) */
> -
> -	unsigned long stack_size;   /* Size of stack, in bytes */
> -	unsigned long reloc_start;  /* Offset of relocation records from
> -	                               beginning of file */
> -	unsigned long reloc_count;  /* Number of relocation records */
> -	unsigned long flags;       
> -	unsigned long build_date;   /* When the program/library was built */
> -	unsigned long filler[5];    /* Reservered, set to zero */
> -};
> -
> -#define FLAT_FLAG_RAM    0x0001 /* load program entirely into RAM */
> -#define FLAT_FLAG_GOTPIC 0x0002 /* program is PIC with GOT */
> -#define FLAT_FLAG_GZIP   0x0004 /* all but the header is compressed */
> -#define FLAT_FLAG_GZDATA 0x0008 /* only data/relocs are compressed (for XIP) */
> -#define FLAT_FLAG_KTRACE 0x0010 /* output useful kernel trace for debugging */
> -
> -
> -
> -#endif /* _UAPI_LINUX_FLAT_H */
>