linux-kernel - Re: [PATCH 01/10] selftests/x86: In syscall

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Message-ID: <20160302125952.GG16954@pd.tnic>
Date:	Wed, 2 Mar 2016 13:59:52 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Andy Lutomirski <luto@...nel.org>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Oleg Nesterov <oleg@...hat.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	Brian Gerst <brgerst@...il.com>
Subject: Re: [PATCH 01/10] selftests/x86: In syscall_nt, test NT|TF as well

On Sun, Feb 28, 2016 at 09:28:46PM -0800, Andy Lutomirski wrote:
> Setting TF prevents fastpath returns in most cases, which causes the
> test to fail on 32-bit kernels because 32-bit kernels do not, in
> fact, handle NT correctly on SYSENTER entries.
> 
> The next patch will fix 32-bit kernels.
> 
> Signed-off-by: Andy Lutomirski <luto@...nel.org>
> ---
>  tools/testing/selftests/x86/syscall_nt.c | 57 +++++++++++++++++++++++++++-----
>  1 file changed, 49 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/testing/selftests/x86/syscall_nt.c b/tools/testing/selftests/x86/syscall_nt.c
> index 60c06af4646a..a6ceff86c199 100644
> --- a/tools/testing/selftests/x86/syscall_nt.c
> +++ b/tools/testing/selftests/x86/syscall_nt.c

...

> +static void do_it(unsigned long extraflags)
> +{
> +	unsigned long flags;
> +
> +	set_eflags(get_eflags() | extraflags);
>  	syscall(SYS_getpid);
> -	if (get_eflags() & X86_EFLAGS_NT) {
> -		printf("[OK]\tThe syscall worked and NT is still set\n");
> -		return 0;
> +	flags = get_eflags();
> +	if ((flags & extraflags) == extraflags) {
> +		printf("[OK]\tThe syscall worked and flags are still set\n");
>  	} else {
> -		printf("[FAIL]\tThe syscall worked but NT was cleared\n");
> -		return 1;
> +		printf("[FAIL]\tThe syscall worked but flags were cleared (flags = 0x%lx but expected 0x%lx set)\n",
> +		       flags, extraflags);
> +		nerrs++;
>  	}
>  }
> +
> +int main()

ERROR: Bad function definition - int main() should probably be int main(void)

-- 
Regards/Gruss,
    Boris.

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