Subject: Re: [PATCH v7 16/28] powerpc: Define and use __get_user_instr{, inatomic}()

From: Alistair Popple <[email-masked]>
Date: Tue, 05 May 2020 11:46:53 +1000

Doesn't change any behaviour from what I can see.

Reviewed-by: Alistair Popple <[email-masked]>

On Friday, 1 May 2020 1:42:08 PM AEST Jordan Niethe wrote:
> Define specific __get_user_instr() and __get_user_instr_inatomic()
> macros for reading instructions from user space.
> 
> Signed-off-by: Jordan Niethe <[email-masked]>
> ---
>  arch/powerpc/include/asm/uaccess.h  | 5 +++++
>  arch/powerpc/kernel/align.c         | 2 +-
>  arch/powerpc/kernel/hw_breakpoint.c | 2 +-
>  arch/powerpc/kernel/vecemu.c        | 2 +-
>  4 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/uaccess.h
> b/arch/powerpc/include/asm/uaccess.h index 2f500debae21..c0a35e4586a5
> 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -105,6 +105,11 @@ static inline int __access_ok(unsigned long addr,
> unsigned long size, #define __put_user_inatomic(x, ptr) \
>  	__put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
> 
> +#define __get_user_instr(x, ptr) \
> +	__get_user_nocheck((x).val, (u32 *)(ptr), sizeof(u32), true)
> +
> +#define __get_user_instr_inatomic(x, ptr) \
> +	__get_user_nosleep((x).val, (u32 *)(ptr), sizeof(u32))
>  extern long __put_user_bad(void);
> 
>  /*
> diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
> index 9e66e6c62354..b8f56052c6fe 100644
> --- a/arch/powerpc/kernel/align.c
> +++ b/arch/powerpc/kernel/align.c
> @@ -304,7 +304,7 @@ int fix_alignment(struct pt_regs *regs)
>  	 */
>  	CHECK_FULL_REGS(regs);
> 
> -	if (unlikely(__get_user(instr.val, (unsigned int __user *)regs->nip)))
> +	if (unlikely(__get_user_instr(instr, (void __user *)regs->nip)))
>  		return -EFAULT;
>  	if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
>  		/* We don't handle PPC little-endian any more... */
> diff --git a/arch/powerpc/kernel/hw_breakpoint.c
> b/arch/powerpc/kernel/hw_breakpoint.c index 2db9a7ac7bcb..423603c92c0f
> 100644
> --- a/arch/powerpc/kernel/hw_breakpoint.c
> +++ b/arch/powerpc/kernel/hw_breakpoint.c
> @@ -249,7 +249,7 @@ static bool stepping_handler(struct pt_regs *regs,
> struct perf_event *bp, struct instruction_op op;
>  	unsigned long addr = info->address;
> 
> -	if (__get_user_inatomic(instr.val, (unsigned int *)regs->nip))
> +	if (__get_user_instr_inatomic(instr, (void __user *)regs->nip))
>  		goto fail;
> 
>  	ret = analyse_instr(&op, regs, instr);
> diff --git a/arch/powerpc/kernel/vecemu.c b/arch/powerpc/kernel/vecemu.c
> index bb262707fb5c..adcdba6d534e 100644
> --- a/arch/powerpc/kernel/vecemu.c
> +++ b/arch/powerpc/kernel/vecemu.c
> @@ -266,7 +266,7 @@ int emulate_altivec(struct pt_regs *regs)
>  	unsigned int va, vb, vc, vd;
>  	vector128 *vrs;
> 
> -	if (get_user(instr.val, (unsigned int __user *) regs->nip))
> +	if (__get_user_instr(instr, (void __user *) regs->nip))
>  		return -EFAULT;
> 
>  	word = ppc_inst_val(instr);