[dpdk-dev] [PATCH v4] eal_common_cpuflags: Fix %rbx corruption, and simplify the code
Chris Wright
chrisw at redhat.com
Tue Mar 25 18:06:36 CET 2014
* Neil Horman (nhorman at tuxdriver.com) wrote:
(given the format, I'd expect a From hpa here)
> Neil Horman reported that on x86-64 the upper half of %rbx would get
> clobbered when the code was compiled PIC or PIE, because the
> i386-specific code to preserve %ebx was incorrectly compiled.
>
> However, the code is really way more complex than it needs to be. For
> one thing, the CPUID instruction only needs %eax (leaf) and %ecx
> (subleaf) as parameters, and since we are testing for bits, we might
> as well list the bits explicitly. Furthermore, we can use an array
> rather than doing a switch statement inside a structure.
>
> Reported-by: Neil Horman <nhorman at tuxdriver.com>
> Signed-off-by: H. Peter Anvin <hpa at linux.intel.com>
And an S-o-B by you
(sorry for the otherwise content free nitpick)
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