Re: git: 9ded074e875c - main - Refactor makesyscalls.lua into a library
Date: Thu, 16 Jan 2025 22:43:07 UTC
On Thu, Jan 16, 2025 at 03:52:22PM -0600, Kyle Evans wrote:
> On 10/30/24 16:08, Brooks Davis wrote:
> > The branch main has been updated by brooks:
> >
> > URL: https://cgit.FreeBSD.org/src/commit/?id=9ded074e875c29cb92d5f643801990d7bb23cca4
> >
> > commit 9ded074e875c29cb92d5f643801990d7bb23cca4
> > Author: agge3 <sterspark@gmail.com>
> > AuthorDate: 2024-10-21 21:42:13 +0000
> > Commit: Brooks Davis <brooks@FreeBSD.org>
> > CommitDate: 2024-10-30 21:04:30 +0000
> >
> > Refactor makesyscalls.lua into a library
> > * main.lua replicates the functionality of makesyscalls.lua
> > * Individual files are generated by their associated module
> > * Modules can be called as standalone scripts to generate a specific
> > file
> > * Data and procedures are performed by objects instead of procedual code
> > * Bitmasks are replaced by declarative types
> > * Temporary files are no longer produced, writing is stored in memory
> > * Comments provide explanation to functions and semantics
> > Google Summer of Code 2024 Final Work Product
> > Co-authored-by: Warner Losh <imp@freebsd.org>
> > Co-authored-by: Kyle Evans <kevans@freebsd.org>
> > Co-authored-by: Brooks Davis <brooks@freebsd.org>
> > Sponsored by: Google (GSoC 24)
> > Pull Request: https://github.com/freebsd/freebsd-src/pull/1362
> > Signed-off-by: agge3 <sterspark@gmail.com>
> > ---
> > sys/tools/syscalls/README.md | 49 +++
> > sys/tools/syscalls/config.lua | 312 +++++++++++++++++
> > sys/tools/syscalls/core/freebsd-syscall.lua | 147 ++++++++
> > sys/tools/syscalls/core/scarg.lua | 163 +++++++++
> > sys/tools/syscalls/core/scret.lua | 45 +++
> > sys/tools/syscalls/core/syscall.lua | 497 +++++++++++++++++++++++++++
> > sys/tools/syscalls/main.lua | 64 ++++
> > sys/tools/syscalls/scripts/init_sysent.lua | 193 +++++++++++
> > sys/tools/syscalls/scripts/libsys_h.lua | 111 ++++++
> > sys/tools/syscalls/scripts/syscall_h.lua | 97 ++++++
> > sys/tools/syscalls/scripts/syscall_mk.lua | 90 +++++
> > sys/tools/syscalls/scripts/syscalls.lua | 109 ++++++
> > sys/tools/syscalls/scripts/syscalls_map.lua | 74 ++++
> > sys/tools/syscalls/scripts/sysproto_h.lua | 242 +++++++++++++
> > sys/tools/syscalls/scripts/systrace_args.lua | 268 +++++++++++++++
> > sys/tools/syscalls/tools/generator.lua | 113 ++++++
> > sys/tools/syscalls/tools/util.lua | 194 +++++++++++
> > 17 files changed, 2768 insertions(+)
> >
> > [...]
> > diff --git a/sys/tools/syscalls/core/freebsd-syscall.lua b/sys/tools/syscalls/core/freebsd-syscall.lua
> > new file mode 100644
> > index 000000000000..193b1e43563c
> > --- /dev/null
> > +++ b/sys/tools/syscalls/core/freebsd-syscall.lua
> > @@ -0,0 +1,147 @@
> > [...]
> > +function FreeBSDSyscall:parseSysfile()
> > + local file = self.sysfile
> > + local config = self.config
> > + local commentExpr = "^%s*;.*"
> > +
> > + if file == nil then
> > + return nil, "No file given"
> > + end
> > +
> > + self.syscalls = {}
> > +
> > + local fh, msg = io.open(file)
> > + if fh == nil then
> > + return nil, msg
> > + end
> > +
> > + local incs = ""
> > + local defs = ""
> > + local s
> > + for line in fh:lines() do
> > + line = line:gsub(commentExpr, "") -- Strip any comments.
> > + -- NOTE: Can't use pure pattern matching here because of
> > + -- the 's' test and this is shorter than a generic pattern
> > + -- matching pattern.
> > + if line == nil or line == "" then
> > + goto skip -- Blank line, skip this line.
> > + elseif s ~= nil then
> > + -- If we have a partial system call object s,
> > + -- then feed it one more line.
> > + if s:add(line) then
> > + -- Append to system call list.
> > + for t in s:iter() do
> > + if t:validate(t.num - 1) then
> > + table.insert(self.syscalls, t)
> > + else
> > + util.abort(1,
> > + "Skipped system call " ..
> > + "at number " .. t.num)
> > + end
> > + end
> > + s = nil
> > + end
> > + elseif line:match("^#%s*include") then
> > + incs = incs .. line .. "\n"
> > + elseif line:match("%%ABI_HEADERS%%") then
> > + local h = self.config.abi_headers
> > + if h ~= nil and h ~= "" then
> > + incs = incs .. h .. "\n"
> > + end
> > + elseif line:match("^#%s*define") then
> > + defs = defs .. line.. "\n"
> > + elseif line:match("^#") then
> > + util.abort(1, "Unsupported cpp op " .. line)
>
> This specifically is kind of a huge regression, and I don't really know how to
> cope with it. We've guaranteed for years that we'll copy preprocessor
> directives through to all output files. We don't use that upstream in
> FreeBSD, but we work with downstreams/vendors that make extensive use of it in
> their syscall definitions.
>
> I don't really know what the answer is to this, but we probably shouldn't have
> dropped it without some discussion first. This is going to be a bit of a
> headache...
This response seems rather hyperbolic. This change was up for review
for months and the feature is unused in tree so there was no way to know
it was important.
It would be helpful to work through some examples understand what people
need here and if it really has to be a refactor to pass things through
or if adding some new tags and config values could do the job.
The quickest workaround would probably to revert these commits locally
(I took care to isolate them for exactly this reason):
5212b9500116 sysent: GC sys/tools/makesyscalls.lua
204d065dac81 sysent: switch to refactored makesyscalls.lua
You might also need to revert this commit or implement it in
makesyscalls.lua:
bbc0f33b1317 sysent: add a NOLIB modifer to prevent stub generation
If we need be, I'd even be ok with temporarily restoring makesyscalls.lua
and back porting easy features, but maintaining two is certainly not
viable indefinitely.
-- Brooks