[Adeos-main] [PATCH] x86: Don't instrument vdso functions

[Adeos-main] [PATCH] x86: Don't instrument vdso functions

[Jan Kiszka]

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The mcount instrumentation is currently leaking into vdso functions.
Patch below fixes this (bits taken from 2.6.27).

Jan

---
 arch/x86/vdso/vclock_gettime.c |   15 ++++++++-------
 arch/x86/vdso/vgetcpu.c        |    3 ++-
 2 files changed, 10 insertions(+), 8 deletions(-)

Index: b/arch/x86/vdso/vclock_gettime.c
===================================================================
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -23,7 +23,7 @@
 
 #define gtod vdso_vsyscall_gtod_data
 
-static long vdso_fallback_gettime(long clock, struct timespec *ts)
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
 {
 	long ret;
 	asm("syscall" : "=a" (ret) :
@@ -31,7 +31,7 @@ static long vdso_fallback_gettime(long c
 	return ret;
 }
 
-static inline long vgetns(void)
+notrace static inline long vgetns(void)
 {
 	long v;
 	cycles_t (*vread)(void);
@@ -40,7 +40,7 @@ static inline long vgetns(void)
 	return (v * gtod->clock.mult) >> gtod->clock.shift;
 }
 
-static noinline int do_realtime(struct timespec *ts)
+notrace static noinline int do_realtime(struct timespec *ts)
 {
 	unsigned long seq, ns;
 	do {
@@ -54,7 +54,8 @@ static noinline int do_realtime(struct t
 }
 
 /* Copy of the version in kernel/time.c which we cannot directly access */
-static void vset_normalized_timespec(struct timespec *ts, long sec, long nsec)
+notrace static void
+vset_normalized_timespec(struct timespec *ts, long sec, long nsec)
 {
 	while (nsec >= NSEC_PER_SEC) {
 		nsec -= NSEC_PER_SEC;
@@ -68,7 +69,7 @@ static void vset_normalized_timespec(str
 	ts->tv_nsec = nsec;
 }
 
-static noinline int do_monotonic(struct timespec *ts)
+notrace static noinline int do_monotonic(struct timespec *ts)
 {
 	unsigned long seq, ns, secs;
 	do {
@@ -82,7 +83,7 @@ static noinline int do_monotonic(struct
 	return 0;
 }
 
-int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
+notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
 {
 	if (likely(gtod->sysctl_enabled && gtod->clock.vread))
 		switch (clock) {
@@ -96,7 +97,7 @@ int __vdso_clock_gettime(clockid_t clock
 int clock_gettime(clockid_t, struct timespec *)
 	__attribute__((weak, alias("__vdso_clock_gettime")));
 
-int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
+notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	long ret;
 	if (likely(gtod->sysctl_enabled && gtod->clock.vread)) {
Index: b/arch/x86/vdso/vgetcpu.c
===================================================================
--- a/arch/x86/vdso/vgetcpu.c
+++ b/arch/x86/vdso/vgetcpu.c
@@ -13,7 +13,8 @@
 #include <asm/vgtod.h>
 #include "vextern.h"
 
-long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
+notrace long
+__vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
 {
 	unsigned int p;
 


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Re: [Adeos-main] [PATCH] x86: Don't instrument vdso functions

[Gilles Chanteperdrix]

Jan Kiszka wrote:
> The mcount instrumentation is currently leaking into vdso functions.
> Patch below fixes this (bits taken from 2.6.27).

What are these vdso functions? Functions called from user-space?

-- 
					    Gilles.

Re: [Adeos-main] [PATCH] x86: Don't instrument vdso functions

[Jan Kiszka]

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Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> The mcount instrumentation is currently leaking into vdso functions.
>> Patch below fixes this (bits taken from 2.6.27).
> 
> What are these vdso functions? Functions called from user-space?

They belong to a virtual lib that is automatically mapped into every
process. They provide the same functionality like vsyscalls, but with a
different way to address them (VDSO is more flexible, vsyscalls are legacy).

Jan


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Re: [Adeos-main] [PATCH] x86: Don't instrument vdso functions

[Philippe Gerum]

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> The mcount instrumentation is currently leaking into vdso functions.
>> Patch below fixes this (bits taken from 2.6.27).
> 
> What are these vdso functions? Functions called from user-space?
> 

Yes. Bits of kernel code mapped into user-space to eliminate the need for
reaching them via syscalls.

-- 
Philippe.

Re: [Adeos-main] [PATCH] x86: Don't instrument vdso functions

[Gilles Chanteperdrix]

Philippe Gerum wrote:
> Gilles Chanteperdrix wrote:
>> Jan Kiszka wrote:
>>> The mcount instrumentation is currently leaking into vdso functions.
>>> Patch below fixes this (bits taken from 2.6.27).
>> What are these vdso functions? Functions called from user-space?
>>
> 
> Yes. Bits of kernel code mapped into user-space to eliminate the need for
> reaching them via syscalls.

They have copied it from ARM or Blackfin!

-- 
					    Gilles.