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From: Ricardo Neri <>
To: Borislav Petkov <>
Cc: X86 ML <>, LKML <>,
	Kees Cook <>,
	Nick Desaulniers <>
Subject: Re: [PATCH] x86/umip: Fix insn_get_code_seg_params()'s return value
Date: Mon, 27 Nov 2017 19:56:35 -0800	[thread overview]
Message-ID: <20171128035635.GA8145@voyager> (raw)
In-Reply-To: <>

On Thu, Nov 23, 2017 at 10:19:51AM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <>
> In order to save on redundant structs definitions
> insn_get_code_seg_params() was made to return two 4-bit values in a char
> but clang complains:
>   arch/x86/lib/insn-eval.c:780:10: warning: implicit conversion from 'int' to 'char'
> 	  changes value from 132 to -124 [-Wconstant-conversion]
>                   return INSN_CODE_SEG_PARAMS(4, 8);
>                   ~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~
>   ./arch/x86/include/asm/insn-eval.h:16:57: note: expanded from macro 'INSN_CODE_SEG_PARAMS'
>   #define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
> Those two values do get picked apart afterwards the opposite way of how
> they were ORed so wrt to the LSByte, the return value is the same.
> But this function returns -EINVAL in the error case, which is an int. So
> make it return an int which is the native word size anyway and thus fix
> the clang warning.
> Signed-off-by: Borislav Petkov <>
> Reported-by: Kees Cook <>
> Reported-by: Nick Desaulniers <>
> Cc:

Thanks Kees and Nick for finding this bug. Thanks Borislav for the quick fix!
This change looks OK to me.


      parent reply	other threads:[~2017-11-28  3:57 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-23  9:19 Borislav Petkov
2017-11-23 19:25 ` [tip:x86/urgent] " tip-bot for Borislav Petkov
2017-11-28  3:56 ` Ricardo Neri [this message]

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