extable and module add object is static
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From: Paul E. McKenney on 27 Mar 2010 20:30 On Sat, Mar 27, 2010 at 08:02:34PM -0400, Mathieu Desnoyers wrote: > * Paul E. McKenney (paulmck(a)linux.vnet.ibm.com) wrote: > > On Sat, Mar 27, 2010 at 07:20:24PM -0400, Mathieu Desnoyers wrote: > [...] > > > Something close to "object_is_static()" would be "kernel_text_address()", but it > > > only considers the text section addresses. I'd need something that would be > > > broader than that, containing all core kernel and module bss and data sections. > > > > > > Still looking... > > > > I was actually feeling pretty good about remembering object_is_on_stack() > > and finding it again. ;-) > > > > I am not seeing anything the identifies data or bss, and in any case, > > other situations such as per-CPU, __read_mostly, and who knows what all > > else would also need to be handled. So in the short term, my guess would > > be that it would be best to provide the three functions (possibly renaming > > them as noted above), but to leave the responsibility for figuring out > > which to invoke with the caller. Always happy to be proven wrong, of > > course! > > > > Thanx, Paul > > I think I found a neat way to do object_is_static(), which is all we need here. > Can you have a look at the following patch ? If you think it's right, I'll add > it to the patchset for the next submission. Looks plausible to me! Rusty, any thoughts? Thanx, Paul > extable and module add object is static > > Adds an API to extable.c to check if an object is statically defined. This > permits, along with object_is_on_stack(), to figure out is an object is either > statically defined (object_is_static()) or allocated on the stack > (object_is_on_stack()). > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> > CC: "Paul E. McKenney" <paulmck(a)linux.vnet.ibm.com> > CC: David S. Miller <davem(a)davemloft.net> > CC: akpm(a)linux-foundation.org > CC: mingo(a)elte.hu > CC: laijs(a)cn.fujitsu.com > CC: dipankar(a)in.ibm.com > CC: josh(a)joshtriplett.org > CC: dvhltc(a)us.ibm.com > CC: niv(a)us.ibm.com > CC: tglx(a)linutronix.de > CC: peterz(a)infradead.org > CC: rostedt(a)goodmis.org > CC: Valdis.Kletnieks(a)vt.edu > CC: dhowells(a)redhat.com > CC: eric.dumazet(a)gmail.com > CC: Alexey Dobriyan <adobriyan(a)gmail.com> > --- > include/linux/kernel.h | 2 + > kernel/extable.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 54 insertions(+) > > Index: linux.trees.git/include/linux/kernel.h > =================================================================== > --- linux.trees.git.orig/include/linux/kernel.h 2010-03-27 19:27:02.000000000 -0400 > +++ linux.trees.git/include/linux/kernel.h 2010-03-27 19:28:02.000000000 -0400 > @@ -218,6 +218,8 @@ extern int __kernel_text_address(unsigne > extern int kernel_text_address(unsigned long addr); > extern int func_ptr_is_kernel_text(void *ptr); > > +extern int object_is_static(void *obj); > + > struct pid; > extern struct pid *session_of_pgrp(struct pid *pgrp); > > Index: linux.trees.git/kernel/extable.c > =================================================================== > --- linux.trees.git.orig/kernel/extable.c 2010-03-27 19:28:06.000000000 -0400 > +++ linux.trees.git/kernel/extable.c 2010-03-27 19:54:40.000000000 -0400 > @@ -60,6 +60,14 @@ static inline int init_kernel_text(unsig > return 0; > } > > +static inline int init_kernel_text_or_data(unsigned long addr) > +{ > + if (addr >= (unsigned long)__init_begin && > + addr <= (unsigned long)__init_end) > + return 1; > + return 0; > +} > + > int core_kernel_text(unsigned long addr) > { > if (addr >= (unsigned long)_stext && > @@ -113,3 +121,47 @@ int func_ptr_is_kernel_text(void *ptr) > return 1; > return is_module_text_address(addr); > } > + > +/* > + * Taking the safe approach to refer to each section individually rather than > + * just taking a range between _stext and _end, just in case an architecture > + * would decide to override the standard linker scripts and put a section > + * outside of this range. > + * > + * Should be kept in sync with linux/section.h and asm-generic/vmlinux.lds.h. > + */ > +static int core_object_is_static(void *obj) > +{ > + unsigned long addr = (unsigned long) obj; > + > + if (addr >= (unsigned long)_sdata && > + addr <= (unsigned long)_edata) > + return 1; > + if (addr >= (unsigned long)__bss_start && > + addr <= (unsigned long)__bss_stop) > + return 1; > + if (addr >= (unsigned long)__per_cpu_start && > + addr <= (unsigned long)__per_cpu_end) > + return 1; > + if (addr >= (unsigned long)__start_rodata && > + addr <= (unsigned long)__end_rodata) > + return 1; > + if (system_state == SYSTEM_BOOTING && > + init_kernel_text_or_data(addr)) > + return 1; > + if (core_kernel_text(addr)) > + return 1; > + return 0; > +} > + > +/* > + * object_is_static - returns true is an object is statically defined > + */ > +int object_is_static(void *obj) > +{ > + if (core_object_is_static(obj)) > + return 1; > + if (is_module_address((unsigned long) obj)) > + return 1; > + return 0; > +} > > > -- > Mathieu Desnoyers > Operating System Efficiency R&D Consultant > EfficiOS Inc. > http://www.efficios.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Lai Jiangshan on 28 Mar 2010 21:50 Mathieu Desnoyers wrote: > +static int core_object_is_static(void *obj) > +{ [...] > + if (addr >= (unsigned long)__per_cpu_start && > + addr <= (unsigned long)__per_cpu_end) > + return 1; This may only correct for UP. You may need arch-special codes for SMP. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Mathieu Desnoyers on 28 Mar 2010 23:20 * Lai Jiangshan (laijs(a)cn.fujitsu.com) wrote: > Mathieu Desnoyers wrote: > > +static int core_object_is_static(void *obj) > > +{ > [...] > > + if (addr >= (unsigned long)__per_cpu_start && > > + addr <= (unsigned long)__per_cpu_end) > > + return 1; > > This may only correct for UP. > You may need arch-special codes for SMP. > looking at include/linux/percpu.h: #ifndef PERCPU_ENOUGH_ROOM #define PERCPU_ENOUGH_ROOM \ (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \ PERCPU_MODULE_RESERVE) #endif I was under the impression that most architectures were keeping their per-cpu data within the __per_cpu_start .. __per_cpu_end range. But I see that ia64 is the only one to redefine PERCPU_ENOUGH_ROOM. I'm not sure if it can be a problem. Is that what you had in mind ? (adding Tony and Fenghua in CC so they can confirm) Thanks, Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Peter Zijlstra on 29 Mar 2010 05:20 On Mon, 2010-03-29 at 09:39 +0800, Lai Jiangshan wrote: > Mathieu Desnoyers wrote: > > +static int core_object_is_static(void *obj) > > +{ > [...] > > + if (addr >= (unsigned long)__per_cpu_start && > > + addr <= (unsigned long)__per_cpu_end) > > + return 1; > > This may only correct for UP. > You may need arch-special codes for SMP. > Tejun has patches for this. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Mathieu Desnoyers on 29 Mar 2010 09:20
* Peter Zijlstra (peterz(a)infradead.org) wrote: > On Mon, 2010-03-29 at 09:39 +0800, Lai Jiangshan wrote: > > Mathieu Desnoyers wrote: > > > +static int core_object_is_static(void *obj) > > > +{ > > [...] > > > + if (addr >= (unsigned long)__per_cpu_start && > > > + addr <= (unsigned long)__per_cpu_end) > > > + return 1; > > > > This may only correct for UP. > > You may need arch-special codes for SMP. > > > > Tejun has patches for this. > That's great! Tejun, can you point me out to an update version of these patches ? I am particularly interested in being able to know the range of statically defined per-cpu data. Thanks, Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |