powerpc/syscall: Make interrupt.c buildable on PPC32

To allow building interrupt.c on PPC32, ifdef out specific PPC64
code or use helpers which are available on both PP32 and PPC64

Modify Makefile to always build interrupt.o

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ba073ad67bd971a88ce331b65d6655523b54c794.1612796617.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/Makefile

@@ -46,10 +46,10 @@ obj-y				:= cputable.o syscalls.o \
 				   prom.o traps.o setup-common.o \
 				   udbg.o misc.o io.o misc_$(BITS).o \
 				   of_platform.o prom_parse.o firmware.o \
-				   hw_breakpoint_constraints.o
+				   hw_breakpoint_constraints.o interrupt.o
 obj-y				+= ptrace/
 obj-$(CONFIG_PPC64)		+= setup_64.o \
-				   paca.o nvram_64.o note.o interrupt.o
+				   paca.o nvram_64.o note.o
 obj-$(CONFIG_COMPAT)		+= sys_ppc32.o signal_32.o
 obj-$(CONFIG_VDSO32)		+= vdso32/
 obj-$(CONFIG_PPC_WATCHDOG)	+= watchdog.o

arch/powerpc/kernel/interrupt.c

@@ -39,7 +39,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
 		BUG_ON(!(regs->msr & MSR_RI));
 	BUG_ON(!(regs->msr & MSR_PR));
 	BUG_ON(!FULL_REGS(regs));
-	BUG_ON(regs->softe != IRQS_ENABLED);
+	BUG_ON(arch_irq_disabled_regs(regs));
 
 #ifdef CONFIG_PPC_PKEY
 	if (mmu_has_feature(MMU_FTR_PKEY)) {
@@ -65,7 +65,9 @@ notrace long system_call_exception(long r3, long r4, long r5,
 			isync();
 	} else
 #endif
+#ifdef CONFIG_PPC64
 		kuap_check_amr();
+#endif
 
 	account_cpu_user_entry();
 
@@ -77,7 +79,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
 	 * frame, or if the unwinder was taught the first stack frame always
 	 * returns to user with IRQS_ENABLED, this store could be avoided!
 	 */
-	regs->softe = IRQS_ENABLED;
+	irq_soft_mask_regs_set_state(regs, IRQS_ENABLED);
 
 	local_irq_enable();
 
@@ -151,6 +153,7 @@ static notrace inline bool __prep_irq_for_enabled_exit(bool clear_ri)
 		__hard_EE_RI_disable();
 	else
 		__hard_irq_disable();
+#ifdef CONFIG_PPC64
 	if (unlikely(lazy_irq_pending_nocheck())) {
 		/* Took an interrupt, may have more exit work to do. */
 		if (clear_ri)
@@ -162,7 +165,7 @@ static notrace inline bool __prep_irq_for_enabled_exit(bool clear_ri)
 	}
 	local_paca->irq_happened = 0;
 	irq_soft_mask_set(IRQS_ENABLED);
-
+#endif
 	return true;
 }
 
@@ -216,7 +219,9 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 
 	CT_WARN_ON(ct_state() == CONTEXT_USER);
 
+#ifdef CONFIG_PPC64
 	kuap_check_amr();
+#endif
 
 	regs->result = r3;
 
@@ -309,7 +314,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 
 	account_cpu_user_exit();
 
-#ifdef CONFIG_PPC_BOOK3S /* BOOK3E not yet using this */
+#ifdef CONFIG_PPC_BOOK3S_64 /* BOOK3E and ppc32 not using this */
 	/*
 	 * We do this at the end so that we do context switch with KERNEL AMR
 	 */
@@ -318,7 +323,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 	return ret;
 }
 
-#ifdef CONFIG_PPC_BOOK3S /* BOOK3E not yet using this */
+#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not yet using this */
 notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr)
 {
 #ifdef CONFIG_PPC_BOOK3E
@@ -333,14 +338,16 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 		BUG_ON(!(regs->msr & MSR_RI));
 	BUG_ON(!(regs->msr & MSR_PR));
 	BUG_ON(!FULL_REGS(regs));
-	BUG_ON(regs->softe != IRQS_ENABLED);
+	BUG_ON(arch_irq_disabled_regs(regs));
 	CT_WARN_ON(ct_state() == CONTEXT_USER);
 
 	/*
 	 * We don't need to restore AMR on the way back to userspace for KUAP.
 	 * AMR can only have been unlocked if we interrupted the kernel.
 	 */
+#ifdef CONFIG_PPC64
 	kuap_check_amr();
+#endif
 
 	local_irq_save(flags);
 
@@ -407,7 +414,9 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	/*
 	 * We do this at the end so that we do context switch with KERNEL AMR
 	 */
+#ifdef CONFIG_PPC64
 	kuap_user_restore(regs);
+#endif
 	return ret;
 }
 
@@ -419,7 +428,9 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	unsigned long *ti_flagsp = &current_thread_info()->flags;
 	unsigned long flags;
 	unsigned long ret = 0;
+#ifdef CONFIG_PPC64
 	unsigned long amr;
+#endif
 
 	if (IS_ENABLED(CONFIG_PPC_BOOK3S) && unlikely(!(regs->msr & MSR_RI)))
 		unrecoverable_exception(regs);
@@ -432,7 +443,9 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	if (TRAP(regs) != 0x700)
 		CT_WARN_ON(ct_state() == CONTEXT_USER);
 
+#ifdef CONFIG_PPC64
 	amr = kuap_get_and_check_amr();
+#endif
 
 	if (unlikely(*ti_flagsp & _TIF_EMULATE_STACK_STORE)) {
 		clear_bits(_TIF_EMULATE_STACK_STORE, ti_flagsp);
@@ -441,7 +454,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 
 	local_irq_save(flags);
 
-	if (regs->softe == IRQS_ENABLED) {
+	if (!arch_irq_disabled_regs(regs)) {
 		/* Returning to a kernel context with local irqs enabled. */
 		WARN_ON_ONCE(!(regs->msr & MSR_EE));
 again:
@@ -458,8 +471,10 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	} else {
 		/* Returning to a kernel context with local irqs disabled. */
 		__hard_EE_RI_disable();
+#ifdef CONFIG_PPC64
 		if (regs->msr & MSR_EE)
 			local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
+#endif
 	}
 
 
@@ -472,7 +487,9 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	 * which would cause Read-After-Write stalls. Hence, we take the AMR
 	 * value from the check above.
 	 */
+#ifdef CONFIG_PPC64
 	kuap_kernel_restore(regs, amr);
+#endif
 
 	return ret;
 }