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2014-01-30x86, boot: Fix word-size assumptions in has_eflag() inline asmDavid Woodhouse1-5/+20
Commit dd78b97367bd575918204cc89107c1479d3fc1a7 ("x86, boot: Move CPU flags out of cpucheck") introduced ambiguous inline asm in the has_eflag() function. In 16-bit mode want the instruction to be 'pushfl', but we just say 'pushf' and hope the compiler does what we wanted. When building with 'clang -m16', it won't, because clang doesn't use the horrid '.code16gcc' hack that even 'gcc -m16' uses internally. Say what we mean and don't make the compiler make assumptions. [ hpa: ideally we would be able to use the gcc %zN construct here, but that is broken for 64-bit integers in gcc < 4.5. The code with plain "pushf/popf" is fine for 32- or 64-bit mode, but not for 16-bit mode; in 16-bit mode those are 16-bit instructions in .code16 mode, and 32-bit instructions in .code16gcc mode. ] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Link: http://lkml.kernel.org/r/1391079628.26079.82.camel@shinybook.infradead.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-10-13x86, boot: Rename get_flags() and check_flags() to *_cpuflags()H. Peter Anvin1-1/+1
When a function is used in more than one file it may not be possible to immediately tell from context what the intended meaning is. As such, it is more important that the naming be self-evident. Thus, change get_flags() to get_cpuflags(). For consistency, change check_flags() to check_cpuflags() even though it is only used in cpucheck.c. Link: http://lkml.kernel.org/r/1381450698-28710-2-git-send-email-keescook@chromium.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-10-13x86, boot: Move CPU flags out of cpucheckKees Cook1-0/+104
Refactor the CPU flags handling out of the cpucheck routines so that they can be reused by the future ASLR routines (in order to detect CPU features like RDRAND and RDTSC). This reworks has_eflag() and has_fpu() to be used on both 32-bit and 64-bit, and refactors the calls to cpuid to make them PIC-safe on 32-bit. Signed-off-by: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/1381450698-28710-2-git-send-email-keescook@chromium.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>