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kprobes: indirectly call kprobe_target

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Call kprobe_target indirectly.  This prevents gcc to unroll a noinline
function in caller function.

I ported patches which had been discussed on
http://sources.redhat.com/bugzilla/show_bug.cgi?id=3542

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Masami Hiramatsu 2009-01-06 14:41:47 -08:00 committed by Linus Torvalds
parent bc2f70151f
commit 8e1144050e
1 changed files with 6 additions and 15 deletions
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21
kernel/test_kprobes.c
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@ -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);