sparc64: Give a stack frame to the ftrace call sites.
David Miller
maintainerPATCH 6/7 sparc64: Give a stack frame to the ftrace call sites.
It's the only way we'll be able to implement the function graph tracer properly.
A positive is that we no longer have to worry about the linker over-optimizing the tail call, since we don't use a tail call any more.
Signed-off-by David S. Miller <[email protected]>
--- arch/sparc/lib/mcount.S | 31 ++++++++++++++++--------------- 1 files changed, 16 insertions(+), 15 deletions(-)
arch/sparc/lib/mcount.S +16 -15
@@ -33,9 +33,13 @@ mcount: or %g2, %lo(ftrace_stub), %g2 cmp %g1, %g2 be,pn %icc, 1f - mov %i7, %o1 - jmpl %g1, %g0 - mov %o7, %o0 + mov %i7, %g2 + save %sp, -128, %sp + mov %g2, %o1 + jmpl %g1, %o7 + mov %i7, %o0 + ret + restore /* not reached */ 1: #endif
@@ -57,21 +61,18 @@ ftrace_stub: .type ftrace_caller,#function ftrace_caller: sethi %hi(function_trace_stop), %g1 - mov %i7, %o1 - lduw [%g1 + %lo(function_trace_stop)], %g2 - brnz,pn %g2, ftrace_stub - mov %o7, %o0 + mov %i7, %g2 + lduw [%g1 + %lo(function_trace_stop)], %g3 + brnz,pn %g3, ftrace_stub + nop + save %sp, -128, %sp + mov %g2, %o1 .globl ftrace_call ftrace_call: - /* If the final kernel link ever turns on relaxation, we'll need - * to do something about this tail call. Otherwise the linker - * will rewrite the call into a branch and nop out the move - * instruction. - */ call ftrace_stub - mov %o0, %o7 - retl - nop + mov %i7, %o0 + ret + restore .size ftrace_call,.-ftrace_call .size ftrace_caller,.-ftrace_caller #endif
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1.7.0.4