Message-ID: <1414800201.13647.9.camel@perches.com>
Subject: Re: [PATCH v2] x86, boot: add hex output for debugging
From: Joe Perches <joe@perches.com>
To: Josh Triplett <josh@joshtriplett.org>
Cc: Yinghai Lu <yinghai@kernel.org>, Kees Cook <keescook@chromium.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        the arch/x86 maintainers <x86@kernel.org>,
        Vivek Goyal <vgoyal@redhat.com>, Junjie Mao <eternal.n08@gmail.com>,
        Andi Kleen <ak@linux.intel.com>
Date: Fri, 31 Oct 2014 17:03:21 -0700
In-Reply-To: <20141031234531.GA12082@thin>
References: <20141031205819.GA13262@www.outflux.net>
	 <CAE9FiQVYBwTifYXACeJRBOEtrN6o5kBpA6v0xLqUYS379pH-Mw@mail.gmail.com>
	 <20141031234531.GA12082@thin>
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On Fri, 2014-10-31 at 16:45 -0700, Josh Triplett wrote:
> I don't think we need the full generality of printf in the decompression
> stub.  I prefer Kees' patch, though I'd still like to see __puthex made
> conditional.

Maybe use a statement expression macro instead?
Something like this could emit the right number of bits for any type

#define __puthex(val)							\
({									\
	typeof(val) value = val;					\
	char alpha[2] = {};						\
	int bits;							\
									\
	__putstr("0x");							\
	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {	\
		int digit = (value >> bits) & 0xf;			\
									\
		if (digit < 10)						\
			alpha[0] = '0' + digit;				\
		else							\
			alpha[0] = 'a' + (digit - 10);			\
									\
		__putstr(alpha);					\
	}								\
})


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