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Re: [PATCH 21/23] arm64: ilp32: introduce ilp32-specific handlers for sigframe and ucontext


Hi, Yury


Here is another print issue in this patch:

On 2016/5/24 8:04, Yury Norov wrote:
From: Andrew Pinski <apinski@cavium.com>

ILP32 uses AARCH32 compat structures and syscall handlers for signals.
But ILP32 struct rt_sigframe  and ucontext differs from both LP64 and
AARCH32. So some specific mechanism is needed to take care of it.

[...]
diff --git a/arch/arm64/kernel/signal_ilp32.c b/arch/arm64/kernel/signal_ilp32.c
new file mode 100644
index 0000000..841e8f8
--- /dev/null
+++ b/arch/arm64/kernel/signal_ilp32.c
@@ -0,0 +1,192 @@
+/*
[...]
+asmlinkage long ilp32_sys_rt_sigreturn(struct pt_regs *regs)
+{
+	struct ilp32_rt_sigframe __user *frame;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	/*
+	 * Since we stacked the signal on a 128-bit boundary,
+	 * then 'sp' should be word aligned here.  If it's
+	 * not, then the user is trying to mess with us.
+	 */
+	if (regs->sp & 15)
+		goto badframe;
+
+	frame = (struct ilp32_rt_sigframe __user *)regs->sp;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
+		goto badframe;
+
+	if (restore_ilp32_sigframe(regs, &frame->sig))
+		goto badframe;
+
+	if (compat_restore_altstack(&frame->sig.uc.uc_stack))
+		goto badframe;
+
+	return regs->regs[0];
+
+badframe:
+	if (show_unhandled_signals)
+		pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
+				    current->comm, task_pid_nr(current), __func__,
+				    regs->pc, regs->compat_sp);
It should be sp instead of compat_sp. The latter one is used by aarch32 EE.

Regards

Bamvor
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+


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