Merge tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Comprehensive interface overhaul:
   =================================

   Objtool's interface has some issues:

     - Several features are done unconditionally, without any way to
       turn them off. Some of them might be surprising. This makes
       objtool tricky to use, and prevents porting individual features
       to other arches.

     - The config dependencies are too coarse-grained. Objtool
       enablement is tied to CONFIG_STACK_VALIDATION, but it has several
       other features independent of that.

     - The objtool subcmds ("check" and "orc") are clumsy: "check" is
       really a subset of "orc", so it has all the same options.

       The subcmd model has never really worked for objtool, as it only
       has a single purpose: "do some combination of things on an object
       file".

     - The '--lto' and '--vmlinux' options are nonsensical and have
       surprising behavior.

   Overhaul the interface:

      - get rid of subcmds

      - make all features individually selectable

      - remove and/or clarify confusing/obsolete options

      - update the documentation

      - fix some bugs found along the way

 - Fix x32 regression

 - Fix Kbuild cleanup bugs

 - Add scripts/objdump-func helper script to disassemble a single
   function from an object file.

 - Rewrite scripts/faddr2line to be section-aware, by basing it on
   'readelf', moving it away from 'nm', which doesn't handle multiple
   sections well, which can result in decoding failure.

 - Rewrite & fix symbol handling - which had a number of bugs wrt.
   object files that don't have global symbols - which is rare but
   possible. Also fix a bunch of symbol handling bugs found along the
   way.

* tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  objtool: Fix objtool regression on x32 systems
  objtool: Fix symbol creation
  scripts/faddr2line: Fix overlapping text section failures
  scripts: Create objdump-func helper script
  objtool: Remove libsubcmd.a when make clean
  objtool: Remove inat-tables.c when make clean
  objtool: Update documentation
  objtool: Remove --lto and --vmlinux in favor of --link
  objtool: Add HAVE_NOINSTR_VALIDATION
  objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION"
  objtool: Make noinstr hacks optional
  objtool: Make jump label hack optional
  objtool: Make static call annotation optional
  objtool: Make stack validation frame-pointer-specific
  objtool: Add CONFIG_OBJTOOL
  objtool: Extricate sls from stack validation
  objtool: Rework ibt and extricate from stack validation
  objtool: Make stack validation optional
  objtool: Add option to print section addresses
  objtool: Don't print parentheses in function addresses
  ...

1 files changed, 97 insertions, 53 deletions

diff --git a/scripts/faddr2line b/scripts/faddr2line
index 6c6439f69a72..0e6268d59883 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -44,17 +44,6 @@
 set -o errexit
 set -o nounset
 
-READELF="${CROSS_COMPILE:-}readelf"
-ADDR2LINE="${CROSS_COMPILE:-}addr2line"
-SIZE="${CROSS_COMPILE:-}size"
-NM="${CROSS_COMPILE:-}nm"
-
-command -v awk >/dev/null 2>&1 || die "awk isn't installed"
-command -v ${READELF} >/dev/null 2>&1 || die "readelf isn't installed"
-command -v ${ADDR2LINE} >/dev/null 2>&1 || die "addr2line isn't installed"
-command -v ${SIZE} >/dev/null 2>&1 || die "size isn't installed"
-command -v ${NM} >/dev/null 2>&1 || die "nm isn't installed"
-
 usage() {
 	echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2
 	exit 1
@@ -69,6 +58,14 @@ die() {
 	exit 1
 }
 
+READELF="${CROSS_COMPILE:-}readelf"
+ADDR2LINE="${CROSS_COMPILE:-}addr2line"
+AWK="awk"
+
+command -v ${AWK} >/dev/null 2>&1 || die "${AWK} isn't installed"
+command -v ${READELF} >/dev/null 2>&1 || die "${READELF} isn't installed"
+command -v ${ADDR2LINE} >/dev/null 2>&1 || die "${ADDR2LINE} isn't installed"
+
 # Try to figure out the source directory prefix so we can remove it from the
 # addr2line output.  HACK ALERT: This assumes that start_kernel() is in
 # init/main.c!  This only works for vmlinux.  Otherwise it falls back to
@@ -76,7 +73,7 @@ die() {
 find_dir_prefix() {
 	local objfile=$1
 
-	local start_kernel_addr=$(${READELF} -sW $objfile | awk '$8 == "start_kernel" {printf "0x%s", $2}')
+	local start_kernel_addr=$(${READELF} --symbols --wide $objfile | ${AWK} '$8 == "start_kernel" {printf "0x%s", $2}')
 	[[ -z $start_kernel_addr ]] && return
 
 	local file_line=$(${ADDR2LINE} -e $objfile $start_kernel_addr)
@@ -97,86 +94,133 @@ __faddr2line() {
 	local dir_prefix=$3
 	local print_warnings=$4
 
-	local func=${func_addr%+*}
+	local sym_name=${func_addr%+*}
 	local offset=${func_addr#*+}
 	offset=${offset%/*}
-	local size=
-	[[ $func_addr =~ "/" ]] && size=${func_addr#*/}
+	local user_size=
+	[[ $func_addr =~ "/" ]] && user_size=${func_addr#*/}
 
-	if [[ -z $func ]] || [[ -z $offset ]] || [[ $func = $func_addr ]]; then
+	if [[ -z $sym_name ]] || [[ -z $offset ]] || [[ $sym_name = $func_addr ]]; then
 		warn "bad func+offset $func_addr"
 		DONE=1
 		return
 	fi
 
 	# Go through each of the object's symbols which match the func name.
-	# In rare cases there might be duplicates.
-	file_end=$(${SIZE} -Ax $objfile | awk '$1 == ".text" {print $2}')
-	while read symbol; do
-		local fields=($symbol)
-		local sym_base=0x${fields[0]}
-		local sym_type=${fields[1]}
-		local sym_end=${fields[3]}
-
-		# calculate the size
-		local sym_size=$(($sym_end - $sym_base))
+	# In rare cases there might be duplicates, in which case we print all
+	# matches.
+	while read line; do
+		local fields=($line)
+		local sym_addr=0x${fields[1]}
+		local sym_elf_size=${fields[2]}
+		local sym_sec=${fields[6]}
+
+		# Get the section size:
+		local sec_size=$(${READELF} --section-headers --wide $objfile |
+			sed 's/\[ /\[/' |
+			${AWK} -v sec=$sym_sec '$1 == "[" sec "]" { print "0x" $6; exit }')
+
+		if [[ -z $sec_size ]]; then
+			warn "bad section size: section: $sym_sec"
+			DONE=1
+			return
+		fi
+
+		# Calculate the symbol size.
+		#
+		# Unfortunately we can't use the ELF size, because kallsyms
+		# also includes the padding bytes in its size calculation.  For
+		# kallsyms, the size calculation is the distance between the
+		# symbol and the next symbol in a sorted list.
+		local sym_size
+		local cur_sym_addr
+		local found=0
+		while read line; do
+			local fields=($line)
+			cur_sym_addr=0x${fields[1]}
+			local cur_sym_elf_size=${fields[2]}
+			local cur_sym_name=${fields[7]:-}
+
+			if [[ $cur_sym_addr = $sym_addr ]] &&
+			   [[ $cur_sym_elf_size = $sym_elf_size ]] &&
+			   [[ $cur_sym_name = $sym_name ]]; then
+				found=1
+				continue
+			fi
+
+			if [[ $found = 1 ]]; then
+				sym_size=$(($cur_sym_addr - $sym_addr))
+				[[ $sym_size -lt $sym_elf_size ]] && continue;
+				found=2
+				break
+			fi
+		done < <(${READELF} --symbols --wide $objfile | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)
+
+		if [[ $found = 0 ]]; then
+			warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
+			DONE=1
+			return
+		fi
+
+		# If nothing was found after the symbol, assume it's the last
+		# symbol in the section.
+		[[ $found = 1 ]] && sym_size=$(($sec_size - $sym_addr))
+
 		if [[ -z $sym_size ]] || [[ $sym_size -le 0 ]]; then
-			warn "bad symbol size: base: $sym_base end: $sym_end"
+			warn "bad symbol size: sym_addr: $sym_addr cur_sym_addr: $cur_sym_addr"
 			DONE=1
 			return
 		fi
+
 		sym_size=0x$(printf %x $sym_size)
 
-		# calculate the address
-		local addr=$(($sym_base + $offset))
+		# Calculate the section address from user-supplied offset:
+		local addr=$(($sym_addr + $offset))
 		if [[ -z $addr ]] || [[ $addr = 0 ]]; then
-			warn "bad address: $sym_base + $offset"
+			warn "bad address: $sym_addr + $offset"
 			DONE=1
 			return
 		fi
 		addr=0x$(printf %x $addr)
 
-		# weed out non-function symbols
-		if [[ $sym_type != t ]] && [[ $sym_type != T ]]; then
-			[[ $print_warnings = 1 ]] &&
-				echo "skipping $func address at $addr due to non-function symbol of type '$sym_type'"
-			continue
-		fi
-
-		# if the user provided a size, make sure it matches the symbol's size
-		if [[ -n $size ]] && [[ $size -ne $sym_size ]]; then
+		# If the user provided a size, make sure it matches the symbol's size:
+		if [[ -n $user_size ]] && [[ $user_size -ne $sym_size ]]; then
 			[[ $print_warnings = 1 ]] &&
-				echo "skipping $func address at $addr due to size mismatch ($size != $sym_size)"
+				echo "skipping $sym_name address at $addr due to size mismatch ($user_size != $sym_size)"
 			continue;
 		fi
 
-		# make sure the provided offset is within the symbol's range
+		# Make sure the provided offset is within the symbol's range:
 		if [[ $offset -gt $sym_size ]]; then
 			[[ $print_warnings = 1 ]] &&
-				echo "skipping $func address at $addr due to size mismatch ($offset > $sym_size)"
+				echo "skipping $sym_name address at $addr due to size mismatch ($offset > $sym_size)"
 			continue
 		fi
 
-		# separate multiple entries with a blank line
+		# In case of duplicates or multiple addresses specified on the
+		# cmdline, separate multiple entries with a blank line:
 		[[ $FIRST = 0 ]] && echo
 		FIRST=0
 
-		# pass real address to addr2line
-		echo "$func+$offset/$sym_size:"
-		local file_lines=$(${ADDR2LINE} -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;")
-		[[ -z $file_lines ]] && return
+		echo "$sym_name+$offset/$sym_size:"
 
+		# Pass section address to addr2line and strip absolute paths
+		# from the output:
+		local output=$(${ADDR2LINE} -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;")
+		[[ -z $output ]] && continue
+
+		# Default output (non --list):
 		if [[ $LIST = 0 ]]; then
-			echo "$file_lines" | while read -r line
+			echo "$output" | while read -r line
 			do
 				echo $line
 			done
 			DONE=1;
-			return
+			continue
 		fi
 
-		# show each line with context
-		echo "$file_lines" | while read -r line
+		# For --list, show each line with its corresponding source code:
+		echo "$output" | while read -r line
 		do
 			echo
 			echo $line
@@ -184,12 +228,12 @@ __faddr2line() {
 			n1=$[$n-5]
 			n2=$[$n+5]
 			f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')
-			awk 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
+			${AWK} 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
 		done
 
 		DONE=1
 
-	done < <(${NM} -n $objfile | awk -v fn=$func -v end=$file_end '$3 == fn { found=1; line=$0; start=$1; next } found == 1 { found=0; print line, "0x"$1 } END {if (found == 1) print line, end; }')
+	done < <(${READELF} --symbols --wide $objfile | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')
 }
 
 [[ $# -lt 2 ]] && usage