Before this change, CONFIG_X86_X32=y fastpath behaviour was different from slowpath:
$ gcc -xc -Wall -O2 - <<'EOF' #include <unistd.h> #include <asm/unistd.h> int main(void) { unsigned long nr = ~0xffffffffUL | __NR_exit; return !!syscall(nr, 42, 1, 2, 3, 4, 5); } EOF $ ./a.out; echo \$?=$? $?=42 $ strace -enone ./a.out syscall_18446744069414584380(0x2a, 0x1, 0x2, 0x3, 0x4, 0x5) = -1 (errno 38) +++ exited with 1 +++ This change syncs CONFIG_X86_X32=y fastpath behaviour with the case when CONFIG_X86_X32 is not enabled. Fixes: fca460f95e92 ("x32: Handle the x32 system call flag") Cc: sta...@vger.kernel.org Signed-off-by: Dmitry V. Levin <l...@altlinux.org> --- arch/x86/entry/entry_64.S | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 4916725..3bab6af 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -185,12 +185,10 @@ entry_SYSCALL_64_fastpath: */ TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) -#if __SYSCALL_MASK == ~0 - cmpq $__NR_syscall_max, %rax -#else - andl $__SYSCALL_MASK, %eax - cmpl $__NR_syscall_max, %eax +#if __SYSCALL_MASK != ~0 + andq $__SYSCALL_MASK, %rax #endif + cmpq $__NR_syscall_max, %rax ja 1f /* return -ENOSYS (already in pt_regs->ax) */ movq %r10, %rcx -- ldv