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authorDavid S. Miller <davem@davemloft.net>2010-04-12 22:35:24 -0700
committerDavid S. Miller <davem@davemloft.net>2010-04-12 22:35:24 -0700
commit63b754957371c23b7515399a977a2e1d361a036c (patch)
treed1e7cd39f91215970300adfffcdf96b5f7484c43 /arch
parent0c25e9e6cbe7b233bb91d14d0e2c258bf8e6ec83 (diff)
downloadlinux-linaro-63b754957371c23b7515399a977a2e1d361a036c.tar.gz
sparc64: Add HAVE_FUNCTION_TRACE_MCOUNT_TEST and tidy up.
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/sparc/Kconfig1
-rw-r--r--arch/sparc/lib/mcount.S22
2 files changed, 16 insertions, 7 deletions
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 6db51367405..035304c30ab 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -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
diff --git a/arch/sparc/lib/mcount.S b/arch/sparc/lib/mcount.S
index 24b8b12deed..7047997be0e 100644
--- a/arch/sparc/lib/mcount.S
+++ b/arch/sparc/lib/mcount.S
@@ -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