From ed6067b73d7bdd92b38afa628254600febd44113 Mon Sep 17 00:00:00 2001
From: Hajime Tazaki <thehajime@gmail.com>
Date: Wed, 11 Dec 2024 15:23:06 +0900
Subject: [PATCH] fix sigreturn etc

---
 arch/um/kernel/signal.c               |  3 +++
 arch/x86/um/nommu/entry_64.S          | 12 ++++++++++++
 arch/x86/um/nommu/os-Linux/mcontext.c |  2 ++
 arch/x86/um/nommu/signal.c            |  4 ++++
 4 files changed, 21 insertions(+)

diff --git a/arch/um/kernel/signal.c b/arch/um/kernel/signal.c
index a56b44522766fe..74cb02e76a8468 100644
--- a/arch/um/kernel/signal.c
+++ b/arch/um/kernel/signal.c
@@ -97,6 +97,9 @@ void do_signal(struct pt_regs *regs)
 	struct ksignal ksig;
 	int handled_sig = 0;
 
+	if (regs->regs.gp[15] == 58)
+		return;
+	
 	while (get_signal(&ksig)) {
 		handled_sig = 1;
 		/* Whee!  Actually deliver the signal.  */
diff --git a/arch/x86/um/nommu/entry_64.S b/arch/x86/um/nommu/entry_64.S
index cb0642172e0084..e10df55af3c955 100644
--- a/arch/x86/um/nommu/entry_64.S
+++ b/arch/x86/um/nommu/entry_64.S
@@ -76,6 +76,9 @@ ENTRY(__kernel_vsyscall)
 
 	POP_REGS
 
+	cmpq	$15, (%rsp)
+	je	sigret
+
 	addq	$8, %rsp	/* skip orig_ax */
 	addq	$8, %rsp	/* skip ip */
 	addq	$8, %rsp	/* skip cs */
@@ -83,6 +86,15 @@ ENTRY(__kernel_vsyscall)
 	popq	%rsp
 
 	ret
+sigret:
+	addq	$8, %rsp	/* skip orig_ax */
+	popq	%r11		/* ip */
+	addq	$8, %rsp	/* skip cs */
+	addq	$8, %rsp	/* skip flags */
+	popq	%rsp
+	//jmpq	*%r11
+	pushq	%r11
+	ret
 
 END(__kernel_vsyscall)
 
diff --git a/arch/x86/um/nommu/os-Linux/mcontext.c b/arch/x86/um/nommu/os-Linux/mcontext.c
index 2d5148848f88db..85f4f66ec564c9 100644
--- a/arch/x86/um/nommu/os-Linux/mcontext.c
+++ b/arch/x86/um/nommu/os-Linux/mcontext.c
@@ -6,10 +6,12 @@
 #include <sysdep/mcontext.h>
 #include <sysdep/syscalls.h>
 
+extern void userspace(struct uml_pt_regs *regs);
 static void userspace_sigreturn(void)
 {
 	__asm__ volatile("movq $15, %rax");
 	__asm__ volatile("call *%0" : : "r"(__kernel_vsyscall) :);
+//	__asm__ volatile("call *%0" : : "r"(userspace) :);
 }
 
 void mc_set_regs_ip_relay(mcontext_t *mc)
diff --git a/arch/x86/um/nommu/signal.c b/arch/x86/um/nommu/signal.c
index a94e9b86273afe..b661a5981661a5 100644
--- a/arch/x86/um/nommu/signal.c
+++ b/arch/x86/um/nommu/signal.c
@@ -11,6 +11,10 @@ int arch_setup_signal_stack_si(struct rt_sigframe __user **frame,
 {
 	int err = 0;
 
+	if (sigismember(&ksig->ka.sa.sa_mask, ksig->sig)) {
+		pr_warn("signal masked");
+		return 0;
+	}
 	/*
 	 * we need to push handler address at top of stack, as
 	 * __kernel_vsyscall, called after this returns with ret with