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Subject[PATCH 0/3] syscalls: clean up stub naming convention
Date
Ingo,

as discussed yesterday, here is a mini-series (mostly) implementing your
suggestion on how to tidy up the naming convention for syscall stubs.

For the generic case, we now will have:

t kernel_waitid # common C function (see kernel/exit.c)

i __in_sys_waitid # inlined helper doing the actual work
# (takes parameters as declared)

T __do_sys_waitid # C function calling inlined helper
# (takes parameters of type long; casts
# them to the declared type)

i __in_compat_sys_waitid # inlined helper doing the actual work
(takes parameters as declared)

T __do_compat_sys_waitid # compat C function calling inlined helper
# (takes parameters of type long, casts
# them to unsigned long and then to the
# declared type)

T sys_waitid # alias to __do_sys_waitid() (taking
# parameters as declared), to be included
# in syscall table

T compat_sys_waitid # alias to __do_compat_sys_waitid()
# (taking parameters as declared), to
# be included in syscall table


For 64-bit x86, kernel_waitid, __do_sys_waitid and __in_sys_waitid are the
same. But instead of sys_waitid and compat_sys_waitid, there are:

T __x64_sys_waitid # x86 64-bit-ptregs -> C stub, calls
# __do_sys_waitid(); to be included in
# syscall table

T __ia32_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub,
# calls __do_sys_waitid(); to be included
# in syscall table unless there is a
# compat syscall stub [in that case, it is
# unused]

T __ia32_compat_sys_waitid # IA32_EMULATION 32-bit-ptregs -> C stub,
# calls __do_compat_sys_waitid(); to be
# included in syscall table

T __x32_compat_sys_waitid # x32 64-bit-ptregs -> C stub, calls
# __do_compat_sys_waitid(); to be included
# in syscall table

In short (0xffffffff prefix removed, re-ordered):

810f0af0 t kernel_waitid # common (32/64) kernel helper

<inline> __in_sys_waitid # inlined helper doing actual work
810f0be0 t __do_sys_waitid # C func calling inlined helper

<inline> __in_compat_sys_waitid # inlined helper doing actual work
810f0d80 t __do_compat_sys_waitid # compat C func calling inlined helper

810f2080 T __x64_sys_waitid # x64 64-bit-ptregs -> C stub
810f20b0 T __ia32_sys_waitid # ia32 32-bit-ptregs -> C stub [unused]
810f2470 T __ia32_compat_sys_waitid # ia32 32-bit-ptregs -> compat C stub
810f2490 T __x32_compat_sys_waitid # x32 64-bit-ptregs -> compat C stub

The kbuild test robot barked at an alleged +20038 bytes kernel size regression
for i386-tinyconfig due to the first patch of this series. That seems to be a
false positive, as it likely doesn't take into account the change to
scripts/bloat-o-meter. Moreover, I could not reproduce such a size regression
on local i386 builds.

Thanks,
Dominik

Dominik Brodowski (3):
syscalls: clean up syscall stub naming convention
syscalls: clean up compat syscall stub naming convention
syscalls: rename struct pt_regs-based sys_*() to __x64_sys_*()

Documentation/process/adding-syscalls.rst | 4 +-
arch/x86/entry/syscalls/syscall_32.tbl | 720 +++++++++++-----------
arch/x86/entry/syscalls/syscall_64.tbl | 710 ++++++++++-----------
arch/x86/entry/syscalls/syscalltbl.sh | 14 +-
arch/x86/entry/vsyscall/vsyscall_64.c | 6 +-
arch/x86/include/asm/syscall_wrapper.h | 142 +++--
arch/x86/include/asm/syscalls.h | 2 +-
include/linux/compat.h | 24 +-
include/linux/syscalls.h | 12 +-
scripts/bloat-o-meter | 4 +-
10 files changed, 841 insertions(+), 797 deletions(-)

--
2.17.0

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