linux-kernel - Re: [PATCH] powerpc/hw_breakpoint: move instruction stepping out of hw_breakpoint

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Message-Id: <57148696-b9a5-d3c1-1e29-82673c558927@linux.ibm.com>
Date:   Wed, 3 Jul 2019 11:50:17 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     Christophe Leroy <christophe.leroy@....fr>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Subject: Re: [PATCH] powerpc/hw_breakpoint: move instruction stepping out of
 hw_breakpoint_handler()



On 6/28/19 9:25 PM, Christophe Leroy wrote:
> On 8xx, breakpoints stop after executing the instruction, so
> stepping/emulation is not needed. Move it into a sub-function and
> remove the #ifdefs.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---

Reviewed-by: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>

Just one neat below...

[...]

> -#ifndef CONFIG_PPC_8xx
> -	/* Do not emulate user-space instructions, instead single-step them */
> -	if (user_mode(regs)) {
> -		current->thread.last_hit_ubp = bp;
> -		regs->msr |= MSR_SE;
> +	if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))

May be split this line. It's 86 chars long and checkpatch.pl is warning
about this:

WARNING: line over 80 characters
#257: FILE: arch/powerpc/kernel/hw_breakpoint.c:282:
+	if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))