Hi, This is the v7 of syscall user dispatch. This version is a bit different from v6 on the following points, after the modifications requested on that submission. * The interface no longer receives <start>,<end> end parameters, but <start>,<length> as suggested by PeterZ. * Syscall User Dispatch is now done before ptrace, and this means there is some SYSCALL_WORK_EXIT work that needs to be done. No challenges there, but I'd like to draw attention to that region of the code that is new in this submission. * The previous TIF_SYSCALL_USER_DISPATCH is now handled through SYSCALL_WORK flags. * Introduced a new test as patch 6, which benchmarks the fast submission path and test the return in blocked selector state. * Nothing is architecture dependent anymore. No config switches. It only depends on CONFIG_GENERIC_ENTRY. Other smaller changes are documented one each commit. This was tested using the kselftests tests in patch 5 and 6 and compiled tested with !CONFIG_GENERIC_ENTRY. This patchset is based on the core/entry branch of the TIP tree. A working tree with this patchset is available at: https://gitlab.collabora.com/krisman/linux -b syscall-user-dispatch-v7 Previous submissions are archived at: RFC/v1: https://lkml.org/lkml/2020/7/8/96 v2: https://lkml.org/lkml/2020/7/9/17 v3: https://lkml.org/lkml/2020/7/12/4 v4: https://www.spinics.net/lists/linux-kselftest/msg16377.html v5: https://lkml.org/lkml/2020/8/10/1320 v6: https://lkml.org/lkml/2020/9/4/1122 Gabriel Krisman Bertazi (7): x86: vdso: Expose sigreturn address on vdso to the kernel signal: Expose SYS_USER_DISPATCH si_code type kernel: Implement selective syscall userspace redirection entry: Support Syscall User Dispatch on common syscall entry selftests: Add kselftest for syscall user dispatch selftests: Add benchmark for syscall user dispatch docs: Document Syscall User Dispatch .../admin-guide/syscall-user-dispatch.rst | 87 +++++ arch/x86/entry/vdso/vdso2c.c | 2 + arch/x86/entry/vdso/vdso32/sigreturn.S | 2 + arch/x86/entry/vdso/vma.c | 15 + arch/x86/include/asm/elf.h | 2 + arch/x86/include/asm/vdso.h | 2 + arch/x86/kernel/signal_compat.c | 2 +- fs/exec.c | 3 + include/linux/entry-common.h | 2 + include/linux/sched.h | 2 + include/linux/syscall_user_dispatch.h | 40 +++ include/linux/thread_info.h | 2 + include/uapi/asm-generic/siginfo.h | 3 +- include/uapi/linux/prctl.h | 5 + kernel/entry/Makefile | 2 +- kernel/entry/common.c | 17 + kernel/entry/common.h | 16 + kernel/entry/syscall_user_dispatch.c | 102 ++++++ kernel/fork.c | 1 + kernel/sys.c | 5 + tools/testing/selftests/Makefile | 1 + .../syscall_user_dispatch/.gitignore | 3 + .../selftests/syscall_user_dispatch/Makefile | 9 + .../selftests/syscall_user_dispatch/config | 1 + .../syscall_user_dispatch/sud_benchmark.c | 200 +++++++++++ .../syscall_user_dispatch/sud_test.c | 310 ++++++++++++++++++ 26 files changed, 833 insertions(+), 3 deletions(-) create mode 100644 Documentation/admin-guide/syscall-user-dispatch.rst create mode 100644 include/linux/syscall_user_dispatch.h create mode 100644 kernel/entry/common.h create mode 100644 kernel/entry/syscall_user_dispatch.c create mode 100644 tools/testing/selftests/syscall_user_dispatch/.gitignore create mode 100644 tools/testing/selftests/syscall_user_dispatch/Makefile create mode 100644 tools/testing/selftests/syscall_user_dispatch/config create mode 100644 tools/testing/selftests/syscall_user_dispatch/sud_benchmark.c create mode 100644 tools/testing/selftests/syscall_user_dispatch/sud_test.c -- 2.29.2
