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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id i14sm96530950pfk.0.2019.07.29.09.34.22 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 29 Jul 2019 09:34:23 -0700 (PDT) Date: Mon, 29 Jul 2019 09:34:21 -0700 From: Kees Cook To: "Gustavo A. R. Silva" Cc: Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Stephen Rothwell Subject: Re: [PATCH] ARM: alignment: Mark expected switch fall-throughs Message-ID: <201907290934.7C7C914@keescook> References: <20190728231920.GA22247@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190728231920.GA22247@embeddedor> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 28, 2019 at 06:19:20PM -0500, Gustavo A. R. Silva wrote: > Mark switch cases where we are expecting to fall through. > > This patch fixes the following warnings: > > arch/arm/mm/alignment.c: In function 'thumb2arm': > arch/arm/mm/alignment.c:688:6: warning: this statement may fall through [-Wimplicit-fallthrough=] > if ((tinstr & (3 << 9)) == 0x0400) { > ^ > arch/arm/mm/alignment.c:700:2: note: here > default: > ^~~~~~~ > arch/arm/mm/alignment.c: In function 'do_alignment_t32_to_handler': > arch/arm/mm/alignment.c:753:15: warning: this statement may fall through [-Wimplicit-fallthrough=] > poffset->un = (tinst2 & 0xff) << 2; > ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~ > arch/arm/mm/alignment.c:754:2: note: here > case 0xe940: > ^~~~ > > Reported-by: Stephen Rothwell > Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook -Kees > --- > arch/arm/mm/alignment.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c > index 8cdb78642e93..04b36436cbc0 100644 > --- a/arch/arm/mm/alignment.c > +++ b/arch/arm/mm/alignment.c > @@ -695,7 +695,7 @@ thumb2arm(u16 tinstr) > return subset[(L<<1) | ((tinstr & (1<<8)) >> 8)] | > (tinstr & 255); /* register_list */ > } > - /* Else fall through for illegal instruction case */ > + /* Else, fall through - for illegal instruction case */ > > default: > return BAD_INSTR; > @@ -751,6 +751,8 @@ do_alignment_t32_to_handler(unsigned long *pinstr, struct pt_regs *regs, > case 0xe8e0: > case 0xe9e0: > poffset->un = (tinst2 & 0xff) << 2; > + /* Fall through */ > + > case 0xe940: > case 0xe9c0: > return do_alignment_ldrdstrd; > -- > 2.22.0 > -- Kees Cook