With those patches it becomes possible to tell the kernel in which mode current task is. I need it for compatibility process C/R: restorer is native x86_64 process, that maps vmas, restore task parameters, does clone to add threads and so on. To restore 32-bit application, that runs on x86_64 (in compatibility mode), I need to set proper CS selector for USER32_CS and tell the kernel, that the process is now in compat mode. Switching selector isn't a hard task (and it's done in other selftests with long jump/lret). This patch makes possible to tell Linux kernel in which mode you are. I also did vdso/vvar blob remapping on compat <-> native switch. This part isn't really needed by CRIU, as on restore stage we already have dumped vdso/vvar vma images. So, this part is for other processes that may need to switch their mode. (I will drop this part if no one else needs this possibility). I add a selftest and I did CRIU branch that uses this to C/R 32-bit processes: https://github.com/0x7f454c46/criu/tree/compat-2 There are dozens of patches there and I will prepare them for CRIU master branch after mainstreaming this switching patch. Dmitry Safonov (2): x86/arch_prctl: add ARCH_SET_{COMPAT,NATIVE} to change compatible mode x86/tools/testing: add test for ARCH_SET_COMPAT arch/x86/entry/vdso/vma.c | 76 ++++-- arch/x86/include/asm/vdso.h | 5 + arch/x86/include/uapi/asm/prctl.h | 6 + arch/x86/kernel/process_64.c | 87 ++++++ tools/testing/selftests/x86/Makefile | 1 + .../testing/selftests/x86/arch_prctl_set_compat.c | 295 +++++++++++++++++++++ 6 files changed, 453 insertions(+), 17 deletions(-) create mode 100644 tools/testing/selftests/x86/arch_prctl_set_compat.c -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
