a14a07b801
IA64 dynamic ftrace support. The original _mcount stub for each function is like: alloc r40=ar.pfs,12,8,0 mov r43=r0;; mov r42=b0 mov r41=r1 nop.i 0x0 br.call.sptk.many b0 = _mcount;; The patch convert it to below for nop: [MII] nop.m 0x0 mov r3=ip nop.i 0x0 [MLX] nop.m 0x0 nop.x 0x0;; This isn't completely nop, as there is one instuction 'mov r3=ip', but it should be light and harmless for code follow it. And below is for call [MII] nop.m 0x0 mov r3=ip nop.i 0x0 [MLX] nop.m 0x0 brl.many .;; In this way, only one instruction is changed to convert code between nop and call. This should meet dyn-ftrace's requirement. But this requires CPU support brl instruction, so dyn-ftrace isn't supported for old Itanium system. Assume there are quite few such old system running. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
29 lines
734 B
C
29 lines
734 B
C
#ifndef _ASM_IA64_FTRACE_H
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#define _ASM_IA64_FTRACE_H
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#ifdef CONFIG_FUNCTION_TRACER
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#define MCOUNT_INSN_SIZE 32 /* sizeof mcount call */
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#ifndef __ASSEMBLY__
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extern void _mcount(unsigned long pfs, unsigned long r1, unsigned long b0, unsigned long r0);
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#define mcount _mcount
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#include <asm/kprobes.h>
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/* In IA64, MCOUNT_ADDR is set in link time, so it's not a constant at compile time */
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#define MCOUNT_ADDR (((struct fnptr *)mcount)->ip)
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#define FTRACE_ADDR (((struct fnptr *)ftrace_caller)->ip)
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static inline unsigned long ftrace_call_adjust(unsigned long addr)
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{
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/* second bundle, insn 2 */
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return addr - 0x12;
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}
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struct dyn_arch_ftrace {
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};
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#endif
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#endif /* CONFIG_FUNCTION_TRACER */
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#endif /* _ASM_IA64_FTRACE_H */
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