Revision be0f272bfc83797f70d44faca86954df62e2bbc0 authored by Ard Biesheuvel on 20 November 2017, 17:41:30 UTC, committed by Will Deacon on 01 December 2017, 13:04:59 UTC
When building the arm64 kernel with both CONFIG_ARM64_MODULE_PLTS and CONFIG_DYNAMIC_FTRACE enabled, the ftrace-mod.o object file is built with the kernel and contains a trampoline that is linked into each module, so that modules can be loaded far away from the kernel and still reach the ftrace entry point in the core kernel with an ordinary relative branch, as is emitted by the compiler instrumentation code dynamic ftrace relies on. In order to be able to build out of tree modules, this object file needs to be included into the linux-headers or linux-devel packages, which is undesirable, as it makes arm64 a special case (although a precedent does exist for 32-bit PPC). Given that the trampoline essentially consists of a PLT entry, let's not bother with a source or object file for it, and simply patch it in whenever the trampoline is being populated, using the existing PLT support routines. Cc: <stable@vger.kernel.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
1 parent 7e8b9c1
cleanpatch
#!/usr/bin/env perl
# SPDX-License-Identifier: GPL-2.0
#
# Clean a patch file -- or directory of patch files -- of stealth whitespace.
# WARNING: this can be a highly destructive operation. Use with caution.
#
use warnings;
use bytes;
use File::Basename;
# Default options
$max_width = 79;
# Clean up space-tab sequences, either by removing spaces or
# replacing them with tabs.
sub clean_space_tabs($)
{
no bytes; # Tab alignment depends on characters
my($li) = @_;
my($lo) = '';
my $pos = 0;
my $nsp = 0;
my($i, $c);
for ($i = 0; $i < length($li); $i++) {
$c = substr($li, $i, 1);
if ($c eq "\t") {
my $npos = ($pos+$nsp+8) & ~7;
my $ntab = ($npos >> 3) - ($pos >> 3);
$lo .= "\t" x $ntab;
$pos = $npos;
$nsp = 0;
} elsif ($c eq "\n" || $c eq "\r") {
$lo .= " " x $nsp;
$pos += $nsp;
$nsp = 0;
$lo .= $c;
$pos = 0;
} elsif ($c eq " ") {
$nsp++;
} else {
$lo .= " " x $nsp;
$pos += $nsp;
$nsp = 0;
$lo .= $c;
$pos++;
}
}
$lo .= " " x $nsp;
return $lo;
}
# Compute the visual width of a string
sub strwidth($) {
no bytes; # Tab alignment depends on characters
my($li) = @_;
my($c, $i);
my $pos = 0;
my $mlen = 0;
for ($i = 0; $i < length($li); $i++) {
$c = substr($li,$i,1);
if ($c eq "\t") {
$pos = ($pos+8) & ~7;
} elsif ($c eq "\n") {
$mlen = $pos if ($pos > $mlen);
$pos = 0;
} else {
$pos++;
}
}
$mlen = $pos if ($pos > $mlen);
return $mlen;
}
$name = basename($0);
@files = ();
while (defined($a = shift(@ARGV))) {
if ($a =~ /^-/) {
if ($a eq '-width' || $a eq '-w') {
$max_width = shift(@ARGV)+0;
} else {
print STDERR "Usage: $name [-width #] files...\n";
exit 1;
}
} else {
push(@files, $a);
}
}
foreach $f ( @files ) {
print STDERR "$name: $f\n";
if (! -f $f) {
print STDERR "$f: not a file\n";
next;
}
if (!open(FILE, '+<', $f)) {
print STDERR "$name: Cannot open file: $f: $!\n";
next;
}
binmode FILE;
# First, verify that it is not a binary file; consider any file
# with a zero byte to be a binary file. Is there any better, or
# additional, heuristic that should be applied?
$is_binary = 0;
while (read(FILE, $data, 65536) > 0) {
if ($data =~ /\0/) {
$is_binary = 1;
last;
}
}
if ($is_binary) {
print STDERR "$name: $f: binary file\n";
next;
}
seek(FILE, 0, 0);
$in_bytes = 0;
$out_bytes = 0;
$lineno = 0;
@lines = ();
$in_hunk = 0;
$err = 0;
while ( defined($line = <FILE>) ) {
$lineno++;
$in_bytes += length($line);
if (!$in_hunk) {
if ($line =~
/^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@/) {
$minus_lines = $2;
$plus_lines = $4;
if ($minus_lines || $plus_lines) {
$in_hunk = 1;
@hunk_lines = ($line);
}
} else {
push(@lines, $line);
$out_bytes += length($line);
}
} else {
# We're in a hunk
if ($line =~ /^\+/) {
$plus_lines--;
$text = substr($line, 1);
$text =~ s/[ \t\r]*$//; # Remove trailing spaces
$text = clean_space_tabs($text);
$l_width = strwidth($text);
if ($max_width && $l_width > $max_width) {
print STDERR
"$f:$lineno: adds line exceeds $max_width ",
"characters ($l_width)\n";
}
push(@hunk_lines, '+'.$text);
} elsif ($line =~ /^\-/) {
$minus_lines--;
push(@hunk_lines, $line);
} elsif ($line =~ /^ /) {
$plus_lines--;
$minus_lines--;
push(@hunk_lines, $line);
} else {
print STDERR "$name: $f: malformed patch\n";
$err = 1;
last;
}
if ($plus_lines < 0 || $minus_lines < 0) {
print STDERR "$name: $f: malformed patch\n";
$err = 1;
last;
} elsif ($plus_lines == 0 && $minus_lines == 0) {
# End of a hunk. Process this hunk.
my $i;
my $l;
my @h = ();
my $adj = 0;
my $done = 0;
for ($i = scalar(@hunk_lines)-1; $i > 0; $i--) {
$l = $hunk_lines[$i];
if (!$done && $l eq "+\n") {
$adj++; # Skip this line
} elsif ($l =~ /^[ +]/) {
$done = 1;
unshift(@h, $l);
} else {
unshift(@h, $l);
}
}
$l = $hunk_lines[0]; # Hunk header
undef @hunk_lines; # Free memory
if ($adj) {
die unless
($l =~ /^\@\@\s+\-([0-9]+),([0-9]+)\s+\+([0-9]+),([0-9]+)\s\@\@(.*)$/);
my $mstart = $1;
my $mlin = $2;
my $pstart = $3;
my $plin = $4;
my $tail = $5; # doesn't include the final newline
$l = sprintf("@@ -%d,%d +%d,%d @@%s\n",
$mstart, $mlin, $pstart, $plin-$adj,
$tail);
}
unshift(@h, $l);
# Transfer to the output array
foreach $l (@h) {
$out_bytes += length($l);
push(@lines, $l);
}
$in_hunk = 0;
}
}
}
if ($in_hunk) {
print STDERR "$name: $f: malformed patch\n";
$err = 1;
}
if (!$err) {
if ($in_bytes != $out_bytes) {
# Only write to the file if changed
seek(FILE, 0, 0);
print FILE @lines;
if ( !defined($where = tell(FILE)) ||
!truncate(FILE, $where) ) {
die "$name: Failed to truncate modified file: $f: $!\n";
}
}
}
close(FILE);
}
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