diff mbox series

[7/7] powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx

Message ID ff7a8bdc9a90a77de2ebc059beb4f644b34186c1.1643015752.git.christophe.leroy@csgroup.eu (mailing list archive)
State New
Headers show
Series Allocate module text and data separately | expand

Commit Message

Christophe Leroy Jan. 24, 2022, 9:22 a.m. UTC 
book3s/32 and 8xx have a separate area for allocating modules,
defined by MODULES_VADDR / MODULES_END.

On book3s/32, it is not possible to protect against execution
on a page basis. A full 256M segment is either Exec or NoExec.
The module area is in an Exec segment while vmalloc area is
in a NoExec segment.

In order to protect module data against execution, select
ARCH_WANTS_MODULES_DATA_IN_VMALLOC.

For the 8xx (and possibly other 32 bits platform in the future),
there is no such constraint on Exec/NoExec protection, however
there is a critical distance between kernel functions and callers
that needs to remain below 32Mbytes in order to avoid costly
trampolines. By allocating data outside of module area, we
increase the chance for module text to remain within acceptable
distance from kernel core text.

So select ARCH_WANTS_MODULES_DATA_IN_VMALLOC for 8xx as well.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/Kconfig | 1 +
 1 file changed, 1 insertion(+)

Comments

kernel test robot Jan. 24, 2022, 12:27 p.m. UTC | #1 
Hi Christophe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mcgrof/modules-next]
[also build test WARNING on powerpc/next linus/master jeyu/modules-next v5.17-rc1 next-20220124]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/Allocate-module-text-and-data-separately/20220124-172517
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git modules-next
config: powerpc-allmodconfig (https://download.01.org/0day-ci/archive/20220124/202201242036.OjeEPlOb-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/2a5f7a254dd5c1efcfb852f5747632c85582016d
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christophe-Leroy/Allocate-module-text-and-data-separately/20220124-172517
        git checkout 2a5f7a254dd5c1efcfb852f5747632c85582016d
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=powerpc SHELL=/bin/bash kernel/debug/kdb/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   kernel/debug/kdb/kdb_main.c: In function 'kdb_lsmod':
>> kernel/debug/kdb/kdb_main.c:2027:38: warning: format '%p' expects a matching 'void *' argument [-Wformat=]
    2027 |                 kdb_printf("/%8u  0x%px ", mod->data_layout.size);
         |                                     ~^
         |                                      |
         |                                      void *


vim +2027 kernel/debug/kdb/kdb_main.c

5d5314d6795f3c1 Jason Wessel     2010-05-20  2006  
5d5314d6795f3c1 Jason Wessel     2010-05-20  2007  #if defined(CONFIG_MODULES)
5d5314d6795f3c1 Jason Wessel     2010-05-20  2008  /*
5d5314d6795f3c1 Jason Wessel     2010-05-20  2009   * kdb_lsmod - This function implements the 'lsmod' command.  Lists
5d5314d6795f3c1 Jason Wessel     2010-05-20  2010   *	currently loaded kernel modules.
5d5314d6795f3c1 Jason Wessel     2010-05-20  2011   *	Mostly taken from userland lsmod.
5d5314d6795f3c1 Jason Wessel     2010-05-20  2012   */
5d5314d6795f3c1 Jason Wessel     2010-05-20  2013  static int kdb_lsmod(int argc, const char **argv)
5d5314d6795f3c1 Jason Wessel     2010-05-20  2014  {
5d5314d6795f3c1 Jason Wessel     2010-05-20  2015  	struct module *mod;
5d5314d6795f3c1 Jason Wessel     2010-05-20  2016  
5d5314d6795f3c1 Jason Wessel     2010-05-20  2017  	if (argc != 0)
5d5314d6795f3c1 Jason Wessel     2010-05-20  2018  		return KDB_ARGCOUNT;
5d5314d6795f3c1 Jason Wessel     2010-05-20  2019  
5d5314d6795f3c1 Jason Wessel     2010-05-20  2020  	kdb_printf("Module                  Size  modstruct     Used by\n");
5d5314d6795f3c1 Jason Wessel     2010-05-20  2021  	list_for_each_entry(mod, kdb_modules, list) {
0d21b0e3477395e Rusty Russell    2013-01-12  2022  		if (mod->state == MODULE_STATE_UNFORMED)
0d21b0e3477395e Rusty Russell    2013-01-12  2023  			continue;
5d5314d6795f3c1 Jason Wessel     2010-05-20  2024  
299a20e0bead4b7 Christophe Leroy 2022-01-24  2025  		kdb_printf("%-20s%8u", mod->name, mod->core_layout.size);
299a20e0bead4b7 Christophe Leroy 2022-01-24  2026  #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
299a20e0bead4b7 Christophe Leroy 2022-01-24 @2027  		kdb_printf("/%8u  0x%px ", mod->data_layout.size);
299a20e0bead4b7 Christophe Leroy 2022-01-24  2028  #endif
299a20e0bead4b7 Christophe Leroy 2022-01-24  2029  		kdb_printf("  0x%px ", (void *)mod);
5d5314d6795f3c1 Jason Wessel     2010-05-20  2030  #ifdef CONFIG_MODULE_UNLOAD
d5db139ab376464 Rusty Russell    2015-01-22  2031  		kdb_printf("%4d ", module_refcount(mod));
5d5314d6795f3c1 Jason Wessel     2010-05-20  2032  #endif
5d5314d6795f3c1 Jason Wessel     2010-05-20  2033  		if (mod->state == MODULE_STATE_GOING)
5d5314d6795f3c1 Jason Wessel     2010-05-20  2034  			kdb_printf(" (Unloading)");
5d5314d6795f3c1 Jason Wessel     2010-05-20  2035  		else if (mod->state == MODULE_STATE_COMING)
5d5314d6795f3c1 Jason Wessel     2010-05-20  2036  			kdb_printf(" (Loading)");
5d5314d6795f3c1 Jason Wessel     2010-05-20  2037  		else
5d5314d6795f3c1 Jason Wessel     2010-05-20  2038  			kdb_printf(" (Live)");
568fb6f42ac6851 Christophe Leroy 2018-09-27  2039  		kdb_printf(" 0x%px", mod->core_layout.base);
299a20e0bead4b7 Christophe Leroy 2022-01-24  2040  #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
299a20e0bead4b7 Christophe Leroy 2022-01-24  2041  		kdb_printf("/0x%px", mod->data_layout.base);
299a20e0bead4b7 Christophe Leroy 2022-01-24  2042  #endif
5d5314d6795f3c1 Jason Wessel     2010-05-20  2043  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 0631c9241af3..0360d6438359 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -161,6 +161,7 @@  config PPC
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
 	select ARCH_WANT_LD_ORPHAN_WARN
+	select ARCH_WANTS_MODULES_DATA_IN_VMALLOC	if PPC_BOOK3S_32 || PPC_8xx
 	select ARCH_WEAK_RELEASE_ACQUIRE
 	select BINFMT_ELF
 	select BUILDTIME_TABLE_SORT