linux-kernel - Re: [PATCH 1/5] tools: Add err.h with ERR_PTR PTR

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 8 Sep 2015 16:22:39 -0400
From:	Raphaël Beamonte <raphael.beamonte@...il.com>
To:	Jiri Olsa <jolsa@...nel.org>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	David Ahern <dsahern@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Matt Fleming <matt@...eblueprint.co.uk>
Subject: Re: [PATCH 1/5] tools: Add err.h with ERR_PTR PTR_ERR interface

2015-09-07 4:38 GMT-04:00 Jiri Olsa <jolsa@...nel.org>:
> Adding part of the kernel's <linux/err.h> interface:
>   inline void * __must_check ERR_PTR(long error);
>   inline long   __must_check PTR_ERR(__force const void *ptr);
>   inline bool   __must_check IS_ERR(__force const void *ptr);
>
> it will be used to propagate error through pointers
> in following patches.
>
> Link: http://lkml.kernel.org/n/tip-ufgnyf683uab69anmmrabgdf@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/include/linux/err.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 tools/include/linux/err.h
>
> diff --git a/tools/include/linux/err.h b/tools/include/linux/err.h
> new file mode 100644
> index 000000000000..c9ada48f5156
> --- /dev/null
> +++ b/tools/include/linux/err.h
> @@ -0,0 +1,49 @@
> +#ifndef __TOOLS_LINUX_ERR_H
> +#define __TOOLS_LINUX_ERR_H
> +
> +#include <linux/compiler.h>
> +#include <linux/types.h>
> +
> +#include <asm/errno.h>
> +
> +/*
> + * Original kernel header comment:
> + *
> + * Kernel pointers have redundant information, so we can use a
> + * scheme where we can return either an error code or a normal
> + * pointer with the same return value.
> + *
> + * This should be a per-architecture thing, to allow different
> + * error and pointer decisions.
> + *
> + * Userspace note:
> + * The same principle works for userspace, because 'error' pointers
> + * fall down to the unused hole far from user space, as described
> + * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
> + *
> + * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
> + * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
> + *
> + * It should be the same case for other architectures, because
> + * this code is used in generic kernel code.
> + */
> +#define MAX_ERRNO      4095
> +
> +#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
> +
> +static inline void * __must_check ERR_PTR(long error)
> +{
> +       return (void *) error;
> +}
> +
> +static inline long __must_check PTR_ERR(__force const void *ptr)
> +{
> +       return (long) ptr;
> +}
> +
> +static inline bool __must_check IS_ERR(__force const void *ptr)
> +{
> +       return IS_ERR_VALUE((unsigned long)ptr);
> +}
> +
> +#endif /* _LINUX_ERR_H */
> --
> 2.4.3

Perhaps a dumb question, but it seems the code is exactly the same as
in linux/err.h besides the part of the comment you added. Why not
using that file directly in the other patches then?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/