linux-kernel - Re: [tip:x86/asm] x86, processor-flags: Fix the datatypes and add bit number defines

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Date:	Wed, 26 Jun 2013 01:07:27 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	mingo@...nel.org, hpa@...or.com, linux-kernel@...r.kernel.org,
	torvalds@...ux-foundation.org, tglx@...utronix.de,
	hpa@...ux.intel.com
Cc:	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/asm] x86, processor-flags: Fix the datatypes and add
 bit number defines

On Tue, Jun 25, 2013 at 03:54:56PM -0700, tip-bot for H. Peter Anvin wrote:
> Commit-ID:  5d378644340de4c43dd3a50ed3a03e916c840d17
> Gitweb:     http://git.kernel.org/tip/5d378644340de4c43dd3a50ed3a03e916c840d17
> Author:     H. Peter Anvin <hpa@...ux.intel.com>
> AuthorDate: Sat, 27 Apr 2013 16:11:17 -0700
> Committer:  H. Peter Anvin <hpa@...ux.intel.com>
> CommitDate: Tue, 25 Jun 2013 15:50:05 -0700
> 
> x86, processor-flags: Fix the datatypes and add bit number defines
> 
> The control registers are unsigned long (32 bits on i386, 64 bits on
> x86-64), and so make that manifest in the data type for the various
> constants.  Add defines with a _BIT suffix which defines the bit
> number, as opposed to the bit mask.
> 
> This should resolve some issues with ~bitmask that Linus discovered.
> 
> Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
> Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
> Link: http://lkml.kernel.org/n/tip-cwckhbrib2aux1qbteaebij0@git.kernel.org
> ---
>  arch/x86/include/uapi/asm/processor-flags.h | 154 +++++++++++++++++++---------
>  1 file changed, 104 insertions(+), 50 deletions(-)
> 
> diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
> index 1b34df5..180a0c3 100644
> --- a/arch/x86/include/uapi/asm/processor-flags.h
> +++ b/arch/x86/include/uapi/asm/processor-flags.h
> @@ -2,75 +2,129 @@
>  #define _UAPI_ASM_X86_PROCESSOR_FLAGS_H
>  /* Various flags defined: can be included from assembler. */
>  
> +#include <linux/const.h>
> +
>  /*
>   * EFLAGS bits
>   */
> -#define X86_EFLAGS_CF	0x00000001 /* Carry Flag */
> -#define X86_EFLAGS_FIXED 0x00000002 /* Bit 1 - always on */
> -#define X86_EFLAGS_PF	0x00000004 /* Parity Flag */
> -#define X86_EFLAGS_AF	0x00000010 /* Auxiliary carry Flag */
> -#define X86_EFLAGS_ZF	0x00000040 /* Zero Flag */
> -#define X86_EFLAGS_SF	0x00000080 /* Sign Flag */
> -#define X86_EFLAGS_TF	0x00000100 /* Trap Flag */
> -#define X86_EFLAGS_IF	0x00000200 /* Interrupt Flag */
> -#define X86_EFLAGS_DF	0x00000400 /* Direction Flag */
> -#define X86_EFLAGS_OF	0x00000800 /* Overflow Flag */
> -#define X86_EFLAGS_IOPL	0x00003000 /* IOPL mask */
> -#define X86_EFLAGS_NT	0x00004000 /* Nested Task */
> -#define X86_EFLAGS_RF	0x00010000 /* Resume Flag */
> -#define X86_EFLAGS_VM	0x00020000 /* Virtual Mode */
> -#define X86_EFLAGS_AC	0x00040000 /* Alignment Check */
> -#define X86_EFLAGS_VIF	0x00080000 /* Virtual Interrupt Flag */
> -#define X86_EFLAGS_VIP	0x00100000 /* Virtual Interrupt Pending */
> -#define X86_EFLAGS_ID	0x00200000 /* CPUID detection flag */
> +#define X86_EFLAGS_CF_BIT	0 /* Carry Flag */
> +#define X86_EFLAGS_CF		_BITUL(X86_EFLAGS_CF_BIT)

Btw, are you going to need those _BIT defines anywhere else?

Because if no, you could simply do:

#define X86_EFLAGS_CF		_BITUL(0) /* Carry Flag */

and so on, and drop the _BIT defines.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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