[PATCH] um: remove fault_catcher infrastructure

[Johannes Berg]

From: Johannes Berg <johannes.berg at intel.com>

This was perhaps intended to do _nofault copies, but the
real reason is lost to history. Remove this, it's not
needed, and using longjmp() out of the middle of the
signal handler with all the state it has modified is
not going to be a good idea anyway.

Signed-off-by: Johannes Berg <johannes.berg at intel.com>
---
 arch/um/include/asm/processor-generic.h |  3 ---
 arch/um/include/shared/kern_util.h      |  1 -
 arch/um/kernel/trap.c                   | 16 ----------------
 arch/um/os-Linux/signal.c               |  2 +-
 4 files changed, 1 insertion(+), 21 deletions(-)

diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index bce4595798da..02e759a4a435 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -22,8 +22,6 @@ struct mm_struct;
 struct thread_struct {
 	struct pt_regs regs;
 	struct pt_regs *segv_regs;
-	void *fault_addr;
-	jmp_buf *fault_catcher;
 	struct task_struct *prev_sched;
 	struct arch_thread arch;
 	jmp_buf switch_buf;
@@ -38,7 +36,6 @@ struct thread_struct {
 #define INIT_THREAD \
 { \
 	.regs		   	= EMPTY_REGS,	\
-	.fault_addr		= NULL, \
 	.prev_sched		= NULL, \
 	.arch			= INIT_ARCH_THREAD, \
 	.request		= { } \
diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index d8ffd2db168e..f21dc8517538 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h
@@ -60,7 +60,6 @@ extern unsigned long from_irq_stack(int nested);
 extern int singlestepping(void);
 
 extern void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
-extern void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs);
 extern void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
 extern void fatal_sigsegv(void) __attribute__ ((noreturn));
 
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 97c8df9c4401..cdaee3e94273 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -201,7 +201,6 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 		   struct uml_pt_regs *regs)
 {
-	jmp_buf *catcher;
 	int si_code;
 	int err;
 	int is_write = FAULT_WRITE(fi);
@@ -246,15 +245,8 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 		address = 0;
 	}
 
-	catcher = current->thread.fault_catcher;
 	if (!err)
 		goto out;
-	else if (catcher != NULL) {
-		current->thread.fault_addr = (void *) address;
-		UML_LONGJMP(catcher, 1);
-	}
-	else if (current->thread.fault_addr != NULL)
-		panic("fault_addr set but no fault catcher");
 	else if (!is_user && arch_fixup(ip, regs))
 		goto out;
 
@@ -310,14 +302,6 @@ void relay_signal(int sig, struct siginfo *si, 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, si, regs);
-}
-
 void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	do_IRQ(WINCH_IRQ, regs);
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index b11ed66c8bb0..1978eaa557e9 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -26,7 +26,7 @@ void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
 	[SIGFPE]	= relay_signal,
 	[SIGILL]	= relay_signal,
 	[SIGWINCH]	= winch,
-	[SIGBUS]	= bus_handler,
+	[SIGBUS]	= relay_signal,
 	[SIGSEGV]	= segv_handler,
 	[SIGIO]		= sigio_handler,
 };
-- 
2.47.0