[PATCH 5/7] powerpc/entry: add irqentry_state and generic entry support

[Luming Yu]

generic irq entry support via generic irqentry is added for powerpc.
There may be duplciate calls and missing callbacks requires further
work.

Signed-off-by: Luming Yu <luming.yu@xxxxxxxxxxxx>
---
 arch/powerpc/include/asm/entry-common.h | 32 ++++++++++++++++
 arch/powerpc/kernel/interrupt.c         | 51 +++++--------------------
 arch/powerpc/kernel/signal.c            |  7 ++++
 arch/powerpc/kernel/syscall.c           |  2 -
 4 files changed, 49 insertions(+), 43 deletions(-)

diff --git a/arch/powerpc/include/asm/entry-common.h b/arch/powerpc/include/asm/entry-common.h
index 51f1eb767696..faa829e15b5d 100644
--- a/arch/powerpc/include/asm/entry-common.h
+++ b/arch/powerpc/include/asm/entry-common.h
@@ -3,6 +3,7 @@
 #define ARCH_POWERPC_ENTRY_COMMON_H
 
 #include <linux/user-return-notifier.h>
+#include <asm/switch_to.h>
 
 static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
 						  unsigned long ti_work)
@@ -13,4 +14,35 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
 
 #define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare
 
+static inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
+						unsigned long ti_work)
+{
+
+	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) {
+		if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) &&
+				unlikely((ti_work & _TIF_RESTORE_TM))) {
+			restore_tm_state(regs);
+		} else {
+			unsigned long mathflags = MSR_FP;
+
+			if (cpu_has_feature(CPU_FTR_VSX))
+				mathflags |= MSR_VEC | MSR_VSX;
+			else if (cpu_has_feature(CPU_FTR_ALTIVEC))
+				mathflags |= MSR_VEC;
+
+			/*
+			 * If userspace MSR has all available FP bits set,
+			 * then they are live and no need to restore. If not,
+			 * it means the regs were given up and restore_math
+			 * may decide to restore them (to avoid taking an FP
+			 * fault).
+			 */
+			if ((regs->msr & mathflags) != mathflags)
+				restore_math(regs);
+		}
+	}
+}
+
+#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work
+
 #endif
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index 609ba48034de..42af9217136d 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -3,6 +3,7 @@
 #include <linux/context_tracking.h>
 #include <linux/err.h>
 #include <linux/compat.h>
+#include <linux/entry-common.h>
 #include <linux/sched/debug.h> /* for show_regs */
 
 #include <asm/kup.h>
@@ -183,47 +184,11 @@ interrupt_exit_user_prepare_main(unsigned long ret, struct pt_regs *regs)
 
 again:
 	ti_flags = read_thread_flags();
-	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
-		local_irq_enable();
-		if (ti_flags & _TIF_NEED_RESCHED) {
-			schedule();
-		} else {
-			/*
-			 * SIGPENDING must restore signal handler function
-			 * argument GPRs, and some non-volatiles (e.g., r1).
-			 * Restore all for now. This could be made lighter.
-			 */
-			if (ti_flags & _TIF_SIGPENDING)
-				ret |= _TIF_RESTOREALL;
-			do_notify_resume(regs, ti_flags);
-		}
-		local_irq_disable();
-		ti_flags = read_thread_flags();
-	}
 
-	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) {
-		if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) &&
-				unlikely((ti_flags & _TIF_RESTORE_TM))) {
-			restore_tm_state(regs);
-		} else {
-			unsigned long mathflags = MSR_FP;
-
-			if (cpu_has_feature(CPU_FTR_VSX))
-				mathflags |= MSR_VEC | MSR_VSX;
-			else if (cpu_has_feature(CPU_FTR_ALTIVEC))
-				mathflags |= MSR_VEC;
-
-			/*
-			 * If userspace MSR has all available FP bits set,
-			 * then they are live and no need to restore. If not,
-			 * it means the regs were given up and restore_math
-			 * may decide to restore them (to avoid taking an FP
-			 * fault).
-			 */
-			if ((regs->msr & mathflags) != mathflags)
-				restore_math(regs);
-		}
-	}
+	if (ti_flags & _TIF_SIGPENDING)
+		ret |= _TIF_RESTOREALL;
+	if (unlikely(ti_flags & EXIT_TO_USER_MODE_WORK))
+		ti_flags = exit_to_user_mode_loop(regs, ti_flags);
 
 	check_return_regs_valid(regs);
 
@@ -297,11 +262,15 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 	}
 
 	local_irq_disable();
-	ret = interrupt_exit_user_prepare_main(ret, regs);
+	if (ti_flags & _TIF_RESTOREALL)
+		ret |= _TIF_RESTOREALL;
 
+	if (ti_flags & _TIF_SIGPENDING)
+		ret |= _TIF_RESTOREALL;
 #ifdef CONFIG_PPC64
 	regs->exit_result = ret;
 #endif
+	syscall_exit_to_user_mode(regs);
 
 	return ret;
 }
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index aa17e62f3754..da21e7fef46a 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -11,6 +11,7 @@
 #include <linux/uprobes.h>
 #include <linux/key.h>
 #include <linux/context_tracking.h>
+#include <linux/entry-common.h>
 #include <linux/livepatch.h>
 #include <linux/syscalls.h>
 #include <asm/hw_breakpoint.h>
@@ -368,3 +369,9 @@ void signal_fault(struct task_struct *tsk, struct pt_regs *regs,
 		printk_ratelimited(regs->msr & MSR_64BIT ? fm64 : fm32, tsk->comm,
 				   task_pid_nr(tsk), where, ptr, regs->nip, regs->link);
 }
+
+void arch_do_signal_or_restart(struct pt_regs *regs)
+{
+	BUG_ON(regs != current->thread.regs);
+	do_signal(current);
+}
diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
index e0338bd8d383..97f158d13944 100644
--- a/arch/powerpc/kernel/syscall.c
+++ b/arch/powerpc/kernel/syscall.c
@@ -185,8 +185,6 @@ notrace long system_call_exception(struct pt_regs *regs, unsigned long r0)
 	 * So the resulting 6 or 7 bits of entropy is seen in SP[9:4] or SP[9:3].
 	 */
 	choose_random_kstack_offset(mftb());
-	/*common entry*/
-	syscall_exit_to_user_mode(regs);
 
 	return ret;
 }
-- 
2.42.0.windows.2