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SubjectRe: [uml-devel] [PATCH 3/8] UML - Fix missing x86_64 register definitions
Date
On Monday 25 September 2006 20:34, Jeff Dike wrote:
> The UML/x86_64 headers were missing ptrace support for some segment
> registers. The underlying problem was that the x86_64 kernel uses
> user_regs_struct rather than the ptrace register definitions in ptrace.
> This patch switches UML/x86_64 to using user_regs_struct for its
> definitions of the host's registers.

> Signed-off-by: Jeff Dike <jdike@addtoit.com>
> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
> Signed-off-by: Andrew Morton <akpm@osdl.org>
> ---
>
> arch/um/include/sysdep-x86_64/ptrace.h | 43 +++++++++++++++++++++--
> arch/um/include/sysdep-x86_64/sc.h | 2 -
> include/asm-um/ptrace-x86_64.h | 3 +
> 3 files changed, 44 insertions(+), 4 deletions(-)
>
> diff -puN
> arch/um/include/sysdep-x86_64/ptrace.h~uml-fix-missing-x86_64-register-defi
>nitions arch/um/include/sysdep-x86_64/ptrace.h ---
> a/arch/um/include/sysdep-x86_64/ptrace.h~uml-fix-missing-x86_64-register-de
>finitions +++ a/arch/um/include/sysdep-x86_64/ptrace.h
> @@ -50,6 +50,21 @@
> #define HOST_FS 25
> #define HOST_GS 26
>
> +/* Also defined in asm/ptrace-x86_64.h, but not in libc headers. So,
> these + * are already defined for kernel code, but not for userspace code.
> + */
> +#ifndef FS_BASE
> +/* These aren't defined in ptrace.h, but exist in struct user_regs_struct,
> + * which is what x86_64 ptrace actually uses.
> + */
> +#define FS_BASE (HOST_FS_BASE * sizeof(long))
> +#define GS_BASE (HOST_GS_BASE * sizeof(long))
> +#define DS (HOST_DS * sizeof(long))
> +#define ES (HOST_ES * sizeof(long))
> +#define FS (HOST_FS * sizeof(long))
> +#define GS (HOST_GS * sizeof(long))
> +#endif
> +
> #define REGS_FS_BASE(r) ((r)[HOST_FS_BASE])
> #define REGS_GS_BASE(r) ((r)[HOST_GS_BASE])
> #define REGS_DS(r) ((r)[HOST_DS])

> diff -puN
> include/asm-um/ptrace-x86_64.h~uml-fix-missing-x86_64-register-definitions
> include/asm-um/ptrace-x86_64.h ---
> a/include/asm-um/ptrace-x86_64.h~uml-fix-missing-x86_64-register-definition
>s +++ a/include/asm-um/ptrace-x86_64.h
> @@ -16,12 +16,15 @@
>
> #define HOST_AUDIT_ARCH AUDIT_ARCH_X86_64
>
> +/* Also defined in sysdep/ptrace.h, so may already be defined. */
> +#ifndef FS_BASE
> #define FS_BASE (21 * sizeof(unsigned long))
> #define GS_BASE (22 * sizeof(unsigned long))
> #define DS (23 * sizeof(unsigned long))
> #define ES (24 * sizeof(unsigned long))
> #define FS (25 * sizeof(unsigned long))
> #define GS (26 * sizeof(unsigned long))
> +#endif
>
> #define PT_REGS_RBX(r) UPT_RBX(&(r)->regs)
> #define PT_REGS_RCX(r) UPT_RCX(&(r)->regs)

The patch is ok for me, but frankly, this hunk could be further cleaned up -
there is an awful hardcoded duplication of code which could be removed (the
definition could be split away from <sysdep/ptrace.h> if inclusion order hell
starts).
--
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade
http://www.user-mode-linux.org/~blaisorblade
Chiacchiera con i tuoi amici in tempo reale!
http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com

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