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Date:   Fri, 13 Nov 2020 18:52:54 +0100
From:   Marco Elver <elver@google.com>
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 11/20] kasan: add and integrate kasan boot parameters
Message-ID: <20201113175254.GA3175464@elver.google.com>
References: <cover.1605046662.git.andreyknvl@google.com>
 <fdf9e3aec8f57ebb2795710195f8aaf79e3b45bd.1605046662.git.andreyknvl@google.com>
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In-Reply-To: <fdf9e3aec8f57ebb2795710195f8aaf79e3b45bd.1605046662.git.andreyknvl@google.com>
User-Agent: Mutt/1.14.6 (2020-07-11)
Precedence: bulk

On Tue, Nov 10, 2020 at 11:20PM +0100, 'Andrey Konovalov' via kasan-dev wrote:
[...]
> +/* kasan.mode=off/prod/full */
> +static int __init early_kasan_mode(char *arg)
> +{
> +	if (!arg)
> +		return -EINVAL;
> +
> +	if (!strcmp(arg, "off"))
> +		kasan_arg_mode = KASAN_ARG_MODE_OFF;
> +	else if (!strcmp(arg, "prod"))
> +		kasan_arg_mode = KASAN_ARG_MODE_PROD;
> +	else if (!strcmp(arg, "full"))
> +		kasan_arg_mode = KASAN_ARG_MODE_FULL;
> +	else
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +early_param("kasan.mode", early_kasan_mode);
> +
> +/* kasan.stack=off/on */
> +static int __init early_kasan_flag_stacktrace(char *arg)
> +{
> +	if (!arg)
> +		return -EINVAL;
> +
> +	if (!strcmp(arg, "off"))
> +		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF;
> +	else if (!strcmp(arg, "on"))
> +		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON;
> +	else
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
> +
> +/* kasan.fault=report/panic */
> +static int __init early_kasan_fault(char *arg)
> +{
> +	if (!arg)
> +		return -EINVAL;
> +
> +	if (!strcmp(arg, "report"))
> +		kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
> +	else if (!strcmp(arg, "panic"))
> +		kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
> +	else
> +		return -EINVAL;
> +
> +	return 0;
> +}
[...]

The above could be simplified, see suggestion below.

Thanks,
-- Marco

------ >8 ------

diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index c91f2c06ecb5..71fc481ad21d 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -64,10 +64,8 @@ static int __init early_kasan_mode(char *arg)
 		kasan_arg_mode = KASAN_ARG_MODE_PROD;
 	else if (!strcmp(arg, "full"))
 		kasan_arg_mode = KASAN_ARG_MODE_FULL;
-	else
-		return -EINVAL;
 
-	return 0;
+	return -EINVAL;
 }
 early_param("kasan.mode", early_kasan_mode);
 
@@ -81,10 +79,8 @@ static int __init early_kasan_flag_stacktrace(char *arg)
 		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF;
 	else if (!strcmp(arg, "on"))
 		kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON;
-	else
-		return -EINVAL;
 
-	return 0;
+	return -EINVAL;
 }
 early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
 
@@ -98,10 +94,8 @@ static int __init early_kasan_fault(char *arg)
 		kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
 	else if (!strcmp(arg, "panic"))
 		kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
-	else
-		return -EINVAL;
 
-	return 0;
+	return -EINVAL;
 }
 early_param("kasan.fault", early_kasan_fault);