On Sun, Oct 06, 2013 at 11:47:38PM -0700, Victor Kamensky wrote:
__flush_tlb_mm function need to use intermediate 'int' type 'asid' variable int tlb_op macro call. Direct use of ASID macro produces 64 bit unsigned long long type passed to inline assembler statement as 'r' operand (32bit), and resulting behavior is not well specified. It works in little endian case, but is broken in big endian case. In big endian case gcc generate such code that 0 is passed to 'mcr 15, 0, r4, cr8, cr3, {2}' operation.
Note other functions like __local_flush_tlb_mm, and local_flush_tlb_mm already use intermediate 'asid' variable in similar code.
A much better solution would be to ensure that ASID() only returns the 'unsigned' type, not a long long type.
#define ASID(mm) ((unsigned)(mm)->context.id.counter & ~ASID_MASK)