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sparc64: Add HAVE_FUNCTION_TRACE_MCOUNT_TEST and tidy up.

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Check function_trace_stop at ftrace_caller

Toss mcount_call and dummy call of ftrace_stub, unnecessary.

Document problems we'll have if the final kernel image link
ever turns on relaxation.

Properly size 'ftrace_call' so it looks right when inspecting
instructions under gdb et al.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2010-04-12 22:35:24 -07:00
parent 0c25e9e6cb
commit 63b7549573
2 changed files with 16 additions and 7 deletions
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1
arch/sparc/Kconfig
View File

@ -37,6 +37,7 @@ config SPARC64
def_bool 64BIT
select ARCH_SUPPORTS_MSI
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_TRACE_MCOUNT_TEST
select HAVE_KRETPROBES
select HAVE_KPROBES
select HAVE_LMB

22
arch/sparc/lib/mcount.S
View File

@ -96,13 +96,12 @@ mcount:
#endif
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
mov %o7, %o0
.globl mcount_call
mcount_call:
call ftrace_stub
mov %o0, %o7
/* Do nothing, the retl/nop below is all we need. */
#else
sethi %hi(ftrace_trace_function), %g1
sethi %hi(function_trace_stop), %g1
lduw [%g1 + %lo(function_trace_stop)], %g2
brnz,pn %g2, 1f
sethi %hi(ftrace_trace_function), %g1
sethi %hi(ftrace_stub), %g2
ldx [%g1 + %lo(ftrace_trace_function)], %g1
or %g2, %lo(ftrace_stub), %g2
@ -131,14 +130,23 @@ ftrace_stub:
.globl ftrace_caller
.type ftrace_caller,#function
ftrace_caller:
sethi %hi(function_trace_stop), %g1
mov %i7, %o1
mov %o7, %o0
lduw [%g1 + %lo(function_trace_stop)], %g2
brnz,pn %g2, ftrace_stub
mov %o7, %o0
.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
.size ftrace_call,.-ftrace_call
.size ftrace_caller,.-ftrace_caller
#endif
#endif