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5a33fcb8d9
Before, the code to do RDTSC looked like: rdtsc shl $0x20, %rdx mov %eax, %eax or %rdx, %rax The "mov %eax, %eax" is required to clear the high 32 bits of RAX. By declaring low and high as 64-bit variables, the code is simplified to: rdtsc shl $0x20,%rdx or %rdx,%rax Yes, it's a 2-byte instruction that's not on a critical path, but there are principles to be upheld. Every user of EAX_EDX_RET has been checked. I tried to check users of EAX_EDX_ARGS, but there weren't any, so I deleted it to be safe. ( There's no benefit to making "high" 64 bits, but it was the simplest way to proceed. ) Signed-off-by: George Spelvin <linux@horizon.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jacob.jun.pan@linux.intel.com Link: http://lkml.kernel.org/r/20150618075906.4615.qmail@ns.horizon.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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boot | ||
configs | ||
crypto | ||
entry | ||
ia32 | ||
include | ||
kernel | ||
kvm | ||
lguest | ||
lib | ||
math-emu | ||
mm | ||
net | ||
oprofile | ||
pci | ||
platform | ||
power | ||
purgatory | ||
realmode | ||
tools | ||
um | ||
video | ||
xen | ||
.gitignore | ||
Kbuild | ||
Kconfig | ||
Kconfig.cpu | ||
Kconfig.debug | ||
Makefile | ||
Makefile_32.cpu | ||
Makefile.um |