Commit 532826f3 authored by Michael Weiser's avatar Michael Weiser Committed by Will Deacon

arm64: Mirror arm for unimplemented compat syscalls

Mirror arm behaviour for unimplemented syscalls: Below 2048 return
-ENOSYS, above 2048 raise SIGILL.
Signed-off-by: default avatarMichael Weiser <michael.weiser@gmx.de>
[will: Tweak die string to identify as compat syscall]
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 4a3928c6
......@@ -27,6 +27,7 @@
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/system_misc.h>
#include <asm/unistd.h>
static long
......@@ -67,6 +68,7 @@ do_compat_cache_op(unsigned long start, unsigned long end, int flags)
*/
long compat_arm_syscall(struct pt_regs *regs)
{
siginfo_t info;
unsigned int no = regs->regs[7];
switch (no) {
......@@ -99,6 +101,23 @@ long compat_arm_syscall(struct pt_regs *regs)
return 0;
default:
return -ENOSYS;
/*
* Calls 9f00xx..9f07ff are defined to return -ENOSYS
* if not implemented, rather than raising SIGILL. This
* way the calling program can gracefully determine whether
* a feature is supported.
*/
if ((no & 0xffff) <= 0x7ff)
return -ENOSYS;
break;
}
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLTRP;
info.si_addr = (void __user *)instruction_pointer(regs) -
(compat_thumb_mode(regs) ? 2 : 4);
arm64_notify_die("Oops - bad compat syscall(2)", regs, &info, no);
return 0;
}
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