linux-kernel - Re: [REVIEW][PATCH 19/20] signal/x86: Pass pkey by value

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Message-ID: <alpine.DEB.2.21.1809182251590.1468@nanos.tec.linutronix.de>
Date:   Tue, 18 Sep 2018 22:52:13 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     "Eric W. Biederman" <ebiederm@...ssion.com>
cc:     LKML <linux-kernel@...r.kernel.org>, linux-arch@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [REVIEW][PATCH 19/20] signal/x86: Pass pkey by value

On Tue, 18 Sep 2018, Eric W. Biederman wrote:

> Now that si_code == SEGV_PKUERR is the flag indicating that a pkey
> is present there is no longer a need to pass a pointer to a local
> pkey value, instead pkey can be passed more efficiently by value.
> 
> Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>

Reviewed-by: Thomas Gleixner <tglx@...utronix.de>

> ---
>  arch/x86/mm/fault.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index 548396aa03e1..c09a0c2fa614 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -769,7 +769,7 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code,
>  
>  static void
>  __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
> -		       unsigned long address, u32 *pkey, int si_code)
> +		       unsigned long address, u32 pkey, int si_code)
>  {
>  	struct task_struct *tsk = current;
>  
> @@ -818,7 +818,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
>  		tsk->thread.trap_nr	= X86_TRAP_PF;
>  
>  		if (si_code == SEGV_PKUERR)
> -			force_sig_pkuerr((void __user *)address, *pkey);
> +			force_sig_pkuerr((void __user *)address, pkey);
>  
>  		force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk);
>  
> @@ -835,12 +835,12 @@ static noinline void
>  bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
>  		     unsigned long address)
>  {
> -	__bad_area_nosemaphore(regs, error_code, address, NULL, SEGV_MAPERR);
> +	__bad_area_nosemaphore(regs, error_code, address, 0, SEGV_MAPERR);
>  }
>  
>  static void
>  __bad_area(struct pt_regs *regs, unsigned long error_code,
> -	   unsigned long address, u32 *pkey, int si_code)
> +	   unsigned long address, u32 pkey, int si_code)
>  {
>  	struct mm_struct *mm = current->mm;
>  	/*
> @@ -855,7 +855,7 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
>  static noinline void
>  bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
>  {
> -	__bad_area(regs, error_code, address, NULL, SEGV_MAPERR);
> +	__bad_area(regs, error_code, address, 0, SEGV_MAPERR);
>  }
>  
>  static inline bool bad_area_access_from_pkeys(unsigned long error_code,
> @@ -906,10 +906,10 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
>  		 *	     faulted on a pte with its pkey=4.
>  		 */
>  		u32 pkey = vma_pkey(vma);
> -		__bad_area(regs, error_code, address, &pkey, SEGV_PKUERR);
> +		__bad_area(regs, error_code, address, pkey, SEGV_PKUERR);
>  	}
>  	else
> -		__bad_area(regs, error_code, address, NULL, SEGV_ACCERR);
> +		__bad_area(regs, error_code, address, 0, SEGV_ACCERR);
>  }
>  
>  static void
> -- 
> 2.17.1
> 
>