From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- scripts/check-sysctl-docs | 174 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100755 scripts/check-sysctl-docs (limited to 'scripts/check-sysctl-docs') diff --git a/scripts/check-sysctl-docs b/scripts/check-sysctl-docs new file mode 100755 index 000000000..910fd8a9a --- /dev/null +++ b/scripts/check-sysctl-docs @@ -0,0 +1,174 @@ +#!/usr/bin/env -S gawk -f +# SPDX-License-Identifier: GPL-2.0 + +# Script to check sysctl documentation against source files +# +# Copyright (c) 2020 Stephen Kitt + +# Example invocation: +# scripts/check-sysctl-docs -vtable="kernel" \ +# Documentation/admin-guide/sysctl/kernel.rst \ +# $(git grep -l register_sysctl) +# +# Specify -vdebug=1 to see debugging information + +BEGIN { + if (!table) { + print "Please specify the table to look for using the table variable" > "/dev/stderr" + exit 1 + } + + # Documentation title skiplist + skiplist[0] = "^Documentation for" + skiplist[1] = "Network core options$" + skiplist[2] = "POSIX message queues filesystem$" + skiplist[3] = "Configuration options" + skiplist[4] = ". /proc/sys/fs" + skiplist[5] = "^Introduction$" + skiplist[6] = "^seccomp$" + skiplist[7] = "^pty$" + skiplist[8] = "^firmware_config$" + skiplist[9] = "^random$" +} + +# The following globals are used: +# documented: maps documented entries (each key is an entry) +# entries: maps ctl_table names and procnames to counts (so +# enumerating the subkeys for a given ctl_table lists its +# procnames) +# curtable: the name of the current ctl_table struct +# curentry: the name of the current proc entry (procname when parsing +# a ctl_table, constructed path when parsing a ctl_path) + + +# Remove punctuation from the given value +function trimpunct(value) { + while (value ~ /^["&]/) { + value = substr(value, 2) + } + while (value ~ /[]["&,}]$/) { + value = substr(value, 1, length(value) - 1) + } + return value +} + +# Print the information for the given entry +function printentry(entry) { + seen[entry]++ + printf "* %s from %s", entry, file[entry] + if (documented[entry]) { + printf " (documented)" + } + print "" +} + + +# Stage 1: build the list of documented entries +FNR == NR && /^=+$/ { + for (i in skiplist) { + if (prevline ~ skiplist[i]) { + next + } + } + + # The previous line is a section title, parse it + $0 = prevline + if (debug) print "Parsing " $0 + inbrackets = 0 + for (i = 1; i <= NF; i++) { + if (length($i) == 0) { + continue + } + if (!inbrackets && substr($i, 1, 1) == "(") { + inbrackets = 1 + } + if (!inbrackets) { + token = trimpunct($i) + if (length(token) > 0 && token != "and") { + if (debug) print trimpunct($i) + documented[trimpunct($i)]++ + } + } + if (inbrackets && substr($i, length($i), 1) == ")") { + inbrackets = 0 + } + } +} + +FNR == NR { + prevline = $0 + next +} + + +# Stage 2: process each file and find all sysctl tables +BEGINFILE { + delete entries + curtable = "" + curentry = "" + delete vars + if (debug) print "Processing file " FILENAME +} + +/^static( const)? struct ctl_table/ { + match($0, /static( const)? struct ctl_table ([^][]+)/, tables) + curtable = tables[2] + if (debug) print "Processing table " curtable +} + +/^};$/ { + curtable = "" + curentry = "" + delete vars +} + +curtable && /\.procname[\t ]*=[\t ]*".+"/ { + match($0, /.procname[\t ]*=[\t ]*"([^"]+)"/, names) + curentry = names[1] + if (debug) print "Adding entry " curentry " to table " curtable + entries[curtable][curentry]++ + file[curentry] = FILENAME +} + +curtable && /UCOUNT_ENTRY.*/ { + match($0, /UCOUNT_ENTRY\("([^"]+)"\)/, names) + curentry = names[1] + if (debug) print "Adding entry " curentry " to table " curtable + entries[curtable][curentry]++ + file[curentry] = FILENAME +} + +/register_sysctl.*/ { + match($0, /register_sysctl(|_init|_sz)\("([^"]+)" *, *([^,)]+)/, tables) + if (debug) print "Registering table " tables[3] " at " tables[2] + if (tables[2] == table) { + for (entry in entries[tables[3]]) { + printentry(entry) + } + } +} + +/kmemdup.*/ { + match($0, /([^ \t]+) *= *kmemdup\(([^,]+) *,/, names) + if (debug) print "Found variable " names[1] " for table " names[2] + if (names[2] in entries) { + vars[names[1]] = names[2] + } +} + +/__register_sysctl_table.*/ { + match($0, /__register_sysctl_table\([^,]+, *"([^"]+)" *, *([^,]+)/, tables) + if (debug) print "Registering variable table " tables[2] " at " tables[1] + if (tables[1] == table && tables[2] in vars) { + for (entry in entries[vars[tables[2]]]) { + printentry(entry) + } + } +} + +END { + for (entry in documented) { + if (!seen[entry]) + print "No implementation for " entry + } +} -- cgit v1.3.1