um: pass siginfo to guest process

UML guest processes now get correct siginfo_t for SIGTRAP, SIGFPE,
SIGILL and SIGBUS. Specifically, si_addr and si_code are now correct
where previously they were si_addr = NULL and si_code = 128.

Signed-off-by: Martin Pärtel <martin.partel@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

3 files changed, 34 insertions, 9 deletions

diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 00506c3..9883026 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -30,7 +30,7 @@ static struct irq_fd **last_irq_ptr = &active_fds;
 
 extern void free_irqs(void);
 
-void sigio_handler(int sig, struct uml_pt_regs *regs)
+void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	struct irq_fd *irq_fd;
 	int n;
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index d1a23fb..5f76d4b 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -13,7 +13,7 @@
 #include "kern_util.h"
 #include "os.h"
 
-void timer_handler(int sig, struct uml_pt_regs *regs)
+void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	unsigned long flags;
 
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 3be6076..0353b98 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -172,7 +172,7 @@ void fatal_sigsegv(void)
 	os_dump_core();
 }
 
-void segv_handler(int sig, struct uml_pt_regs *regs)
+void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	struct faultinfo * fi = UPT_FAULTINFO(regs);
 
@@ -258,8 +258,11 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 	return 0;
 }
 
-void relay_signal(int sig, struct uml_pt_regs *regs)
+void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
 {
+	struct faultinfo *fi;
+	struct siginfo clean_si;
+
 	if (!UPT_IS_USER(regs)) {
 		if (sig == SIGBUS)
 			printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
@@ -269,18 +272,40 @@ void relay_signal(int sig, struct uml_pt_regs *regs)
 
 	arch_examine_signal(sig, regs);
 
-	current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
-	force_sig(sig, current);
+	memset(&clean_si, 0, sizeof(clean_si));
+	clean_si.si_signo = si->si_signo;
+	clean_si.si_errno = si->si_errno;
+	clean_si.si_code = si->si_code;
+	switch (sig) {
+	case SIGILL:
+	case SIGFPE:
+	case SIGSEGV:
+	case SIGBUS:
+	case SIGTRAP:
+		fi = UPT_FAULTINFO(regs);
+		clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi);
+		current->thread.arch.faultinfo = *fi;
+#ifdef __ARCH_SI_TRAPNO
+		clean_si.si_trapno = si->si_trapno;
+#endif
+		break;
+	default:
+		printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
+			sig, si->si_code);
+	}
+
+	force_sig_info(sig, &clean_si, current);
 }
 
-void bus_handler(int sig, struct uml_pt_regs *regs)
+void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs)
 {
 	if (current->thread.fault_catcher != NULL)
 		UML_LONGJMP(current->thread.fault_catcher, 1);
-	else relay_signal(sig, regs);
+	else
+		relay_signal(sig, si, regs);
 }
 
-void winch(int sig, struct uml_pt_regs *regs)
+void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	do_IRQ(WINCH_IRQ, regs);
 }