powerpc/64e/interrupt: Use new interrupt context tracking scheme

With the new interrupt exit code, context tracking can be managed
more precisely, so remove the last of the 64e workarounds and switch
to the new context tracking code already used by 64s.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-8-npiggin@gmail.com

arch/powerpc/include/asm/interrupt.h

@@ -21,9 +21,6 @@ static inline void nap_adjust_return(struct pt_regs *regs)
 }
 
 struct interrupt_state {
-#ifdef CONFIG_PPC_BOOK3E_64
-	enum ctx_state ctx_state;
-#endif
 };
 
 static inline void booke_restore_dbcr0(void)
@@ -56,9 +53,7 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
 	if (irq_soft_mask_set_return(IRQS_ALL_DISABLED) == IRQS_ENABLED)
 		trace_hardirqs_off();
 	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
-#endif
 
-#ifdef CONFIG_PPC_BOOK3S_64
 	if (user_mode(regs)) {
 		CT_WARN_ON(ct_state() != CONTEXT_USER);
 		user_exit_irqoff();
@@ -75,12 +70,6 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
 	}
 #endif
 
-#ifdef CONFIG_PPC_BOOK3E_64
-	state->ctx_state = exception_enter();
-	if (user_mode(regs))
-		account_cpu_user_entry();
-#endif
-
 	booke_restore_dbcr0();
 }
 
@@ -100,25 +89,8 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
  */
 static inline void interrupt_exit_prepare(struct pt_regs *regs, struct interrupt_state *state)
 {
-#ifdef CONFIG_PPC_BOOK3E_64
-	exception_exit(state->ctx_state);
-#endif
-
 	if (user_mode(regs))
 		kuep_unlock();
-	/*
-	 * Book3S exits to user via interrupt_exit_user_prepare(), which does
-	 * context tracking, which is a cleaner way to handle PREEMPT=y
-	 * and avoid context entry/exit in e.g., preempt_schedule_irq()),
-	 * which is likely to be where the core code wants to end up.
-	 *
-	 * The above comment explains why we can't do the
-	 *
-	 *     if (user_mode(regs))
-	 *         user_exit_irqoff();
-	 *
-	 * sequence here.
-	 */
 }
 
 static inline void interrupt_async_enter_prepare(struct pt_regs *regs, struct interrupt_state *state)

arch/powerpc/kernel/interrupt.c

@@ -235,10 +235,6 @@ static notrace void booke_load_dbcr0(void)
 #endif
 }
 
-/* temporary hack for context tracking, removed in later patch */
-#include <linux/sched/debug.h>
-asmlinkage __visible void __sched schedule_user(void);
-
 /*
  * This should be called after a syscall returns, with r3 the return value
  * from the syscall. If this function returns non-zero, the system call
@@ -296,11 +292,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
 		local_irq_enable();
 		if (ti_flags & _TIF_NEED_RESCHED) {
-#ifdef CONFIG_PPC_BOOK3E_64
-			schedule_user();
-#else
 			schedule();
-#endif
 		} else {
 			/*
 			 * SIGPENDING must restore signal handler function
@@ -375,9 +367,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	BUG_ON(!(regs->msr & MSR_PR));
 	BUG_ON(!FULL_REGS(regs));
 	BUG_ON(arch_irq_disabled_regs(regs));
-#ifdef CONFIG_PPC_BOOK3S_64
 	CT_WARN_ON(ct_state() == CONTEXT_USER);
-#endif
 
 	/*
 	 * We don't need to restore AMR on the way back to userspace for KUAP.
@@ -392,11 +382,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
 		local_irq_enable(); /* returning to user: may enable */
 		if (ti_flags & _TIF_NEED_RESCHED) {
-#ifdef CONFIG_PPC_BOOK3E_64
-			schedule_user();
-#else
 			schedule();
-#endif
 		} else {
 			if (ti_flags & _TIF_SIGPENDING)
 				ret |= _TIF_RESTOREALL;
@@ -464,7 +450,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	 * CT_WARN_ON comes here via program_check_exception,
 	 * so avoid recursion.
 	 */
-	if (IS_ENABLED(CONFIG_BOOKS) && TRAP(regs) != 0x700)
+	if (TRAP(regs) != 0x700)
 		CT_WARN_ON(ct_state() == CONTEXT_USER);
 
 	kuap = kuap_get_and_assert_locked();