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 00506c3d5d6e..9883026f0730 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 d1a23fb3190d..5f76d4ba151c 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 3be60765c0e2..0353b98ae35a 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);
 }