Re: [PATCH 17/31] MIPS: Quit exposing Kconfig symbols in uapi headers.

[Paolo Bonzini <pbonzini@redhat.com>]

Il 07/06/2013 19:03, David Daney ha scritto:
> From: David Daney <david.daney@cavium.com>
> 
> The kernel's struct pt_regs has many fields conditional on various
> Kconfig variables, we cannot be exporting this garbage to user-space.
> 
> Move the kernel's definition to asm/ptrace.h, and put a uapi only
> version in uapi/asm/ptrace.h gated by #ifndef __KERNEL__
> 
> Signed-off-by: David Daney <david.daney@cavium.com>
> ---
>  arch/mips/include/asm/ptrace.h      | 32 ++++++++++++++++++++++++++++++++
>  arch/mips/include/uapi/asm/ptrace.h | 17 ++---------------
>  2 files changed, 34 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
> index a3186f2..5e6cd09 100644
> --- a/arch/mips/include/asm/ptrace.h
> +++ b/arch/mips/include/asm/ptrace.h
> @@ -16,6 +16,38 @@
>  #include <asm/isadep.h>
>  #include <uapi/asm/ptrace.h>
>  
> +/*
> + * This struct defines the way the registers are stored on the stack during a
> + * system call/exception. As usual the registers k0/k1 aren't being saved.
> + */
> +struct pt_regs {
> +#ifdef CONFIG_32BIT
> +	/* Pad bytes for argument save space on the stack. */
> +	unsigned long pad0[6];
> +#endif
> +
> +	/* Saved main processor registers. */
> +	unsigned long regs[32];
> +
> +	/* Saved special registers. */
> +	unsigned long cp0_status;
> +	unsigned long hi;
> +	unsigned long lo;
> +#ifdef CONFIG_CPU_HAS_SMARTMIPS
> +	unsigned long acx;
> +#endif
> +	unsigned long cp0_badvaddr;
> +	unsigned long cp0_cause;
> +	unsigned long cp0_epc;
> +#ifdef CONFIG_MIPS_MT_SMTC
> +	unsigned long cp0_tcstatus;
> +#endif /* CONFIG_MIPS_MT_SMTC */
> +#ifdef CONFIG_CPU_CAVIUM_OCTEON
> +	unsigned long long mpl[3];	  /* MTM{0,1,2} */
> +	unsigned long long mtp[3];	  /* MTP{0,1,2} */
> +#endif
> +} __aligned(8);
> +
>  struct task_struct;
>  
>  extern int ptrace_getregs(struct task_struct *child, __s64 __user *data);
> diff --git a/arch/mips/include/uapi/asm/ptrace.h b/arch/mips/include/uapi/asm/ptrace.h
> index 4d58d84..b26f7e3 100644
> --- a/arch/mips/include/uapi/asm/ptrace.h
> +++ b/arch/mips/include/uapi/asm/ptrace.h
> @@ -22,16 +22,12 @@
>  #define DSP_CONTROL	77
>  #define ACX		78
>  
> +#ifndef __KERNEL__
>  /*
>   * This struct defines the way the registers are stored on the stack during a
>   * system call/exception. As usual the registers k0/k1 aren't being saved.
>   */
>  struct pt_regs {
> -#ifdef CONFIG_32BIT
> -	/* Pad bytes for argument save space on the stack. */
> -	unsigned long pad0[6];
> -#endif
> -

Out of curiosity, how has this ever worked (and how will this work) on
32-bit arches? :)  I can see that maybe no one uses pt_regs beyond .lo,
but these are at the beginning.  Maybe for the uapi version you can use
the __mips__ preprocessor symbol?

Paolo

>  	/* Saved main processor registers. */
>  	unsigned long regs[32];
>  
> @@ -39,20 +35,11 @@ struct pt_regs {
>  	unsigned long cp0_status;
>  	unsigned long hi;
>  	unsigned long lo;
> -#ifdef CONFIG_CPU_HAS_SMARTMIPS
> -	unsigned long acx;
> -#endif
>  	unsigned long cp0_badvaddr;
>  	unsigned long cp0_cause;
>  	unsigned long cp0_epc;
> -#ifdef CONFIG_MIPS_MT_SMTC
> -	unsigned long cp0_tcstatus;
> -#endif /* CONFIG_MIPS_MT_SMTC */
> -#ifdef CONFIG_CPU_CAVIUM_OCTEON
> -	unsigned long long mpl[3];	  /* MTM{0,1,2} */
> -	unsigned long long mtp[3];	  /* MTP{0,1,2} */
> -#endif
>  } __attribute__ ((aligned (8)));
> +#endif /* __KERNEL__ */
>  
>  /* Arbitrarily choose the same ptrace numbers as used by the Sparc code. */
>  #define PTRACE_GETREGS		12
>