Messages in this thread Patch in this message | | | Date | Fri, 06 Jun 2008 10:08:08 -0400 | From | Masami Hiramatsu <> | Subject | [PATCH -mm 1/2] kprobes: indirectly call kprobe_target |
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Call kprobe_target indirectly. This prevents gcc to unroll a noinline function in caller function.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> CC: Ananth N Mavinakayanahalli <ananth@in.ibm.com> CC: Jim Keniston <jkenisto@us.ibm.com> CC: David Miller <davem@davemloft.net> --- I ported patches which had been discussed on http://sources.redhat.com/bugzilla/show_bug.cgi?id=3542
tests/test_kprobes.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-)
Index: 2.6.26-rc2-mm1/tests/test_kprobes.c =================================================================== --- 2.6.26-rc2-mm1.orig/tests/test_kprobes.c +++ 2.6.26-rc2-mm1/tests/test_kprobes.c @@ -22,21 +22,10 @@
static u32 rand1, preh_val, posth_val, jph_val; static int errors, handler_errors, num_tests; +static u32 (*target)(u32 value);
static noinline u32 kprobe_target(u32 value) { - /* - * gcc ignores noinline on some architectures unless we stuff - * sufficient lard into the function. The get_kprobe() here is - * just for that. - * - * NOTE: We aren't concerned about the correctness of get_kprobe() - * here; hence, this call is neither under !preempt nor with the - * kprobe_mutex held. This is fine(tm) - */ - if (get_kprobe((void *)0xdeadbeef)) - printk(KERN_INFO "Kprobe smoke test: probe on 0xdeadbeef!\n"); - return (value / div_factor); }
@@ -74,7 +63,7 @@ static int test_kprobe(void) return ret; }
- ret = kprobe_target(rand1); + ret = target(rand1); unregister_kprobe(&kp);
if (preh_val == 0) { @@ -121,7 +110,7 @@ static int test_jprobe(void) return ret; }
- ret = kprobe_target(rand1); + ret = target(rand1); unregister_jprobe(&jp); if (jph_val == 0) { printk(KERN_ERR "Kprobe smoke test failed: " @@ -177,7 +166,7 @@ static int test_kretprobe(void) return ret; }
- ret = kprobe_target(rand1); + ret = target(rand1); unregister_kretprobe(&rp); if (krph_val != rand1) { printk(KERN_ERR "Kprobe smoke test failed: " @@ -193,6 +182,8 @@ int init_test_probes(void) { int ret;
+ target = kprobe_target; + do { rand1 = random32(); } while (rand1 <= div_factor); -- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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