powerpc/interrupt: update common interrupt code for

This makes adjustments to 64-bit asm and common C interrupt return
code to be usable by the 64e subarchitecture.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-4-npiggin@gmail.com

arch/powerpc/kernel/entry_64.S

@@ -632,7 +632,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
 	addi	r1,r1,SWITCH_FRAME_SIZE
 	blr
 
-#ifdef CONFIG_PPC_BOOK3S
 	/*
 	 * If MSR EE/RI was never enabled, IRQs not reconciled, NVGPRs not
 	 * touched, no exit work created, then this can be used.
@@ -644,6 +643,7 @@ _ASM_NOKPROBE_SYMBOL(fast_interrupt_return)
 	kuap_check_amr r3, r4
 	ld	r5,_MSR(r1)
 	andi.	r0,r5,MSR_PR
+#ifdef CONFIG_PPC_BOOK3S
 	bne	.Lfast_user_interrupt_return_amr
 	kuap_kernel_restore r3, r4
 	andi.	r0,r5,MSR_RI
@@ -652,6 +652,10 @@ _ASM_NOKPROBE_SYMBOL(fast_interrupt_return)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	unrecoverable_exception
 	b	. /* should not get here */
+#else
+	bne	.Lfast_user_interrupt_return
+	b	.Lfast_kernel_interrupt_return
+#endif
 
 	.balign IFETCH_ALIGN_BYTES
 	.globl interrupt_return
@@ -665,8 +669,10 @@ _ASM_NOKPROBE_SYMBOL(interrupt_return)
 	cmpdi	r3,0
 	bne-	.Lrestore_nvgprs
 
+#ifdef CONFIG_PPC_BOOK3S
 .Lfast_user_interrupt_return_amr:
 	kuap_user_restore r3, r4
+#endif
 .Lfast_user_interrupt_return:
 	ld	r11,_NIP(r1)
 	ld	r12,_MSR(r1)
@@ -775,7 +781,6 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
 
 	RFI_TO_KERNEL
 	b	.	/* prevent speculative execution */
-#endif /* CONFIG_PPC_BOOK3S */
 
 #ifdef CONFIG_PPC_RTAS
 /*

arch/powerpc/kernel/interrupt.c

@@ -235,6 +235,10 @@ 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
@@ -292,7 +296,11 @@ again:
 	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
@@ -349,18 +357,13 @@ again:
 
 	account_cpu_user_exit();
 
-#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not using this */
+	/* Restore user access locks last */
-	/*
-	 * We do this at the end so that we do context switch with KERNEL AMR
-	 */
 	kuap_user_restore(regs);
-#endif
 	kuep_unlock();
 
 	return ret;
 }
 
-#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not yet using this */
 notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr)
 {
 	unsigned long ti_flags;
@@ -372,7 +375,9 @@ 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.
@@ -387,7 +392,11 @@ again:
 	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;
@@ -432,10 +441,9 @@ again:
 
 	account_cpu_user_exit();
 
-	/*
+	/* Restore user access locks last */
-	 * We do this at the end so that we do context switch with KERNEL AMR
-	 */
 	kuap_user_restore(regs);
+
 	return ret;
 }
 
@@ -456,7 +464,7 @@ 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 (TRAP(regs) != 0x700)
+	if (IS_ENABLED(CONFIG_BOOKS) && TRAP(regs) != 0x700)
 		CT_WARN_ON(ct_state() == CONTEXT_USER);
 
 	kuap = kuap_get_and_assert_locked();
@@ -497,12 +505,11 @@ again:
 #endif
 
 	/*
-	 * Don't want to mfspr(SPRN_AMR) here, because this comes after mtmsr,
+	 * 64s does not want to mfspr(SPRN_AMR) here, because this comes after
-	 * which would cause Read-After-Write stalls. Hence, we take the AMR
+	 * mtmsr, which would cause Read-After-Write stalls. Hence, take the
-	 * value from the check above.
+	 * AMR value from the check above.
 	 */
 	kuap_kernel_restore(regs, kuap);
 
 	return ret;
 }
-#endif