[PATCH] x86/insn-eval: Mark expected switch fall-through

[PATCH] x86/insn-eval: Mark expected switch fall-through

[Gustavo A. R. Silva]

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

arch/x86/lib/insn-eval.c: In function ‘resolve_default_seg’:
arch/x86/lib/insn-eval.c:179:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (insn->addr_bytes == 2)
      ^
arch/x86/lib/insn-eval.c:182:2: note: here
  case -EDOM:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enabling
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 arch/x86/lib/insn-eval.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 9119d8e41f1f..8f1b2d8db4e2 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -178,6 +178,7 @@ static int resolve_default_seg(struct insn *insn, struct pt_regs *regs, int off)
 		/* Need insn to verify address size. */
 		if (insn->addr_bytes == 2)
 			return -EINVAL;
+		/* fall through */
 
 	case -EDOM:
 	case offsetof(struct pt_regs, bx):
-- 
2.20.1

Re: [PATCH] x86/insn-eval: Mark expected switch fall-through

[Borislav Petkov]

On Fri, Jan 25, 2019 at 02:55:20PM -0600, Gustavo A. R. Silva wrote:
> In preparation to enabling -Wimplicit-fallthrough, mark switch
> cases where we are expecting to fall through.
> 
> This patch fixes the following warning:
> 
> arch/x86/lib/insn-eval.c: In function ‘resolve_default_seg’:
> arch/x86/lib/insn-eval.c:179:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
>    if (insn->addr_bytes == 2)
>       ^
> arch/x86/lib/insn-eval.c:182:2: note: here
>   case -EDOM:
>   ^~~~
> 
> Warning level 3 was used: -Wimplicit-fallthrough=3
> 
> This patch is part of the ongoing efforts to enabling

For the future:

Avoid having "This patch" or "This commit" in the commit message. It is
tautologically useless.

Also, do

$ git grep 'This patch' Documentation/process

for more details.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

[tip:x86/cleanups] x86/insn-eval: Mark expected switch-case fall-through

[tip-bot for Gustavo A. R. Silva]

Commit-ID:  89da3446294a8b811b28a4807e74e7ee7044d49f
Gitweb:     https://git.kernel.org/tip/89da3446294a8b811b28a4807e74e7ee7044d49f
Author:     Gustavo A. R. Silva <gustavo@embeddedor.com>
AuthorDate: Fri, 25 Jan 2019 14:55:20 -0600
Committer:  Borislav Petkov <bp@suse.de>
CommitDate: Sat, 26 Jan 2019 10:46:42 +0100

x86/insn-eval: Mark expected switch-case fall-through

In preparation to enable -Wimplicit-fallthrough by default, mark
switch-case statements where fall-through is intentional, explicitly.

Thus fix the following warning:

  arch/x86/lib/insn-eval.c: In function ‘resolve_default_seg’:
  arch/x86/lib/insn-eval.c:179:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
     if (insn->addr_bytes == 2)
        ^
  arch/x86/lib/insn-eval.c:182:2: note: here
    case -EDOM:
    ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This is part of the ongoing efforts to enable -Wimplicit-fallthrough by
default.

 [ bp: Massage commit message. ]

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190125205520.GA9602@embeddedor
---
 arch/x86/lib/insn-eval.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 9119d8e41f1f..cf00ab6c6621 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -179,6 +179,8 @@ static int resolve_default_seg(struct insn *insn, struct pt_regs *regs, int off)
 		if (insn->addr_bytes == 2)
 			return -EINVAL;
 
+		/* fall through */
+
 	case -EDOM:
 	case offsetof(struct pt_regs, bx):
 	case offsetof(struct pt_regs, si):

Re: [PATCH] x86/insn-eval: Mark expected switch fall-through

[Gustavo A. R. Silva]

Boris,

On 1/26/19 3:47 AM, Borislav Petkov wrote:
> On Fri, Jan 25, 2019 at 02:55:20PM -0600, Gustavo A. R. Silva wrote:
>> In preparation to enabling -Wimplicit-fallthrough, mark switch
>> cases where we are expecting to fall through.
>>
>> This patch fixes the following warning:
>>
>> arch/x86/lib/insn-eval.c: In function ‘resolve_default_seg’:
>> arch/x86/lib/insn-eval.c:179:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
>>    if (insn->addr_bytes == 2)
>>       ^
>> arch/x86/lib/insn-eval.c:182:2: note: here
>>   case -EDOM:
>>   ^~~~
>>
>> Warning level 3 was used: -Wimplicit-fallthrough=3
>>
>> This patch is part of the ongoing efforts to enabling
> 
> For the future:
> 
> Avoid having "This patch" or "This commit" in the commit message. It is
> tautologically useless.
> 
> Also, do
> 
> $ git grep 'This patch' Documentation/process
> 
> for more details.
> 

I've got it.

Thanks for the feedback.

--
Gustavo