[xen staging] xen: Fix check-endbr.sh with mawk

[patchbot@xxxxxxx]

commit b2ebe879a44428957e147be52e8bf5227e36e723
Author:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
AuthorDate: Thu Jul 14 15:39:06 2022 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Mon Jul 18 15:31:18 2022 +0100

    xen: Fix check-endbr.sh with mawk
    
    check-endbr.sh works with gawk, but fails with mawk. The produced $ALL
    file is smaller as it is missing 0x$vma_lo on every line.  With mawk,
    int(0x2A) just produces 0, instead of the expected value.
    
    The use of hexadecimal-constant in awk is an optional part of the posix
    spec, and mawk doesn't seems to implemented.
    
    There is a way to convert an hexadecimal to a number be putting it in a
    string, and awk as I understand is supposed to use strtod() to convert
    the string to a number when needed. The expression 'int("0x15") + 21'
    would produce the expected value in `mawk` but now `gawk` won't convert
    the string to a number unless we use the option "--non-decimal-data".
    
    So let's convert the hexadecimal number before using it in the awk
    script. The shell as no issue with dealing with hexadecimal-constant so
    we'll simply use the expression "$(( 0x15 ))" to convert the value
    before using it in awk.
    
    Note: This does introduce a latent portability bug, which fixed in a 
separate
          change to avoid mixing complexity/explanations.
    
    Fixes: 4d037425dc ("x86: Build check for embedded endbr64 instructions")
    Resolves: xen-project/xen#26
    Reported-by: Luca Fancellu <Luca.Fancellu@xxxxxxx>
    Reported-by: Mathieu Tarral <mathieu.tarral@xxxxxxxxxxxxxx>
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/tools/check-endbr.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/xen/tools/check-endbr.sh b/xen/tools/check-endbr.sh
index f633846b0f..b3febd6a4c 100755
--- a/xen/tools/check-endbr.sh
+++ b/xen/tools/check-endbr.sh
@@ -64,6 +64,11 @@ ${OBJDUMP} -j .text $1 -d -w | grep '        endbr64 *$' | 
cut -f 1 -d ':' > $VALID &
 #    split the VMA in half so AWK's numeric addition is only working on 32 bit
 #    numbers, which don't lose precision.
 #
+# 4) MAWK doesn't support plain hex constants (an optional part of the POSIX
+#    spec), and GAWK and MAWK can't agree on how to work with hex constants in
+#    a string.  Use the shell to convert $vma_lo to decimal before passing to
+#    AWK.
+#
 eval $(${OBJDUMP} -j .text $1 -h |
     $AWK '$2 == ".text" {printf "vma_hi=%s\nvma_lo=%s\n", substr($4, 1, 8), 
substr($4, 9, 16)}')
 
@@ -79,7 +84,7 @@ then
 else
     grep -aob -e "$(printf '\363\17\36\372')" -e "$(printf '\363\17\36\373')" \
          -e "$(printf '\146\17\37\1')" $TEXT_BIN
-fi | $AWK -F':' '{printf "%s%x\n", "'$vma_hi'", int(0x'$vma_lo') + $1}' > $ALL
+fi | $AWK -F':' '{printf "%s%x\n", "'$vma_hi'", int('$((0x$vma_lo))') + $1}' > 
$ALL
 
 # Wait for $VALID to become complete
 wait
--
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