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Add SYSCALL_ULONG_ARG_[12] to pass long to syscall [BZ #25810]

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X32 has 32-bit long and pointer with 64-bit off_t.  Since x32 psABI
requires that pointers passed in registers must be zero-extended to
64bit, x32 can share many syscall interfaces with LP64.  When a LP64
syscall with long and unsigned long int arguments is used for x32, these
arguments must be properly extended to 64-bit.  Otherwise if the upper
32 bits of the register have undefined value, such a syscall will be
rejected by kernel.

For syscalls implemented in assembly codes, 'U' is added to syscall
signature key letters for unsigned long, which is zero-extended to
64-bit types.  SYSCALL_ULONG_ARG_1 and SYSCALL_ULONG_ARG_2 are passed
to syscall-template.S for the first and the second unsigned long int
arguments if PSEUDOS_HAVE_ULONG_INDICES is defined.  They are used by
x32 to zero-extend 32-bit arguments to 64 bits.

Tested on i386, x86-64 and x32 as well as with build-many-glibcs.py.
This commit is contained in:
H.J. Lu
2020-04-29 05:35:34 -07:00
parent 9207e30d3f
commit 2ad5d0845d
6 changed files with 159 additions and 30 deletions
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24
sysdeps/unix/make-syscalls.sh
View File

@@ -30,6 +30,7 @@
# P: optionally-NULL pointer to typed object (e.g., 3rd argument to sigaction)
# s: non-NULL string (e.g., 1st arg to open)
# S: optionally-NULL string (e.g., 1st arg to acct)
# U: unsigned long int (32-bit types are zero-extended to 64-bit types)
# v: vararg scalar (e.g., optional 3rd arg to open)
# V: byte-per-page vector (3rd arg to mincore)
# W: wait status, optionally-NULL pointer to int (e.g., 2nd arg of wait4)
@@ -184,6 +185,27 @@ while read file srcfile caller syscall args strong weak; do
?:?????????) nargs=9;;
esac
# Derive the unsigned long int arguments from the argument signature
ulong_arg_1=0
ulong_arg_2=0
ulong_count=0
for U in $(echo $args | sed -e "s/.*:/:/" | grep -ob U)
do
ulong_count=$(expr $ulong_count + 1)
ulong_arg=$(echo $U | sed -e "s/:U//")
case $ulong_count in
1)
ulong_arg_1=$ulong_arg
;;
2)
ulong_arg_2=$ulong_arg
;;
*)
echo >&2 "$0: Too many unsigned long int arguments for syscall ($strong $weak)"
exit 2
esac
done
# Make sure only the first syscall rule is used, if multiple dirs
# define the same syscall.
echo ''
@@ -245,6 +267,8 @@ while read file srcfile caller syscall args strong weak; do
\$(make-target-directory)
(echo '#define SYSCALL_NAME $syscall'; \\
echo '#define SYSCALL_NARGS $nargs'; \\
echo '#define SYSCALL_ULONG_ARG_1 $ulong_arg_1'; \\
echo '#define SYSCALL_ULONG_ARG_2 $ulong_arg_2'; \\
echo '#define SYSCALL_SYMBOL $strong'; \\
echo '#define SYSCALL_NOERRNO $noerrno'; \\
echo '#define SYSCALL_ERRVAL $errval'; \\