[dpdk-dev] [PATCH v5] eal_common_cpuflags: Fix %rbx corruption, and simplify the code

H. Peter Anvin hpa at linux.intel.com
Tue Mar 25 21:51:04 CET 2014

On 03/25/2014 12:52 PM, Neil Horman wrote:
> 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>
> Signed-off-by: Neil Horman <nhorman at tuxdriver.com>

Looks good to me.

Reviewed-by: H. Peter Anvin <hpa at linux.intel.com>


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