Messages in this thread | | | Date | Thu, 23 Jul 2015 21:02:14 +0200 | From | Peter Zijlstra <> | Subject | Re: Kernel broken on processors without performance counters |
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On Thu, Jul 23, 2015 at 07:54:36PM +0200, Borislav Petkov wrote: > On Thu, Jul 23, 2015 at 07:08:11PM +0200, Peter Zijlstra wrote: > > That would be bad, how can we force it to emit 5 bytes? > > .byte 0xe9 like we used to do in static_cpu_has_safe().
Like so then?
static __always_inline bool arch_static_branch_jump(struct static_key *key, bool inv) { unsigned long kval = (unsigned long)key + inv;
asm_volatile_goto("1:" ".byte 0xe9\n\t .long %l[l_yes]\n\t" ".pushsection __jump_table, \"aw\" \n\t" _ASM_ALIGN "\n\t" _ASM_PTR "1b, %l[l_yes], %c0 \n\t" ".popsection \n\t" : : "i" (kval) : : l_yes);
return false; l_yes: return true; }
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