* Dominik Brodowski <li...@dominikbrodowski.net> wrote: > A few questions remain, from important stuff to bikeshedding: > > 1) Is it acceptable to pass the existing struct pt_regs to the sys_*() > kernel functions in emulate_vsyscall(), or should it use a hand-crafted > struct pt_regs instead?
I think so: we already have task_pt_regs() which gives access to the real return registers on the kernel stack. I think as long as we constify the pointer, we should pass in the real thing. > 2) Is it the right approach to generate the __sys32_ia32_*() names to > include in the syscall table on-the-fly, or should they all be listed > in arch/x86/entry/syscalls/syscall_32.tbl ? I think as a general principle all system call tables should point to the first-hop wrapper symbol name (i.e. __sys32_ia32_*() in this case), not to the generic symbol name - even though we could generate the former from the latter. The more indirection in these tables, the harder to read they become I think. > 3) I have chosen to name the default 64-bit syscall stub sys_*(), same as > the "normal" syscall, and the IA32_EMULATION compat syscall stub > compat_sys_*(), same as the "normal" compat syscall. Though this > might cause some confusion, as the "same" function uses a different > calling convention and different parameters on x86, it has the > advantages that > - the kernel *has* a function sys_*() implementing the syscall, > so those curious in stack traces etc. will find it in plain > sight, > - it is easier to handle in the syscall table generation, and > - error injection works the same. I don't think there should be a symbol space overlap, that will only lead to confusion. The symbols can be _similar_, with a prefix, underscores or so, but they shouldn't match I think. > The whole series is available at > > https://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux.git > syscalls-WIP BTW., I'd like all these bits to go through the x86 tree. What is the expected merge route of the generic preparatory bits? Thanks, Ingo
