Subject: [RFC PATCH 1/3] powerpc/32: Implement HAVE_CONTEXT_TRACKING_USER support

From: Nicholas Piggin <[email-masked]>
Date: Tue, 4 Oct 2022 16:33:04 +1000

Context tracking involves tracking user, kernel, guest switches. This
enables existing context tracking code for interrupt entry on 32-bit.
KVM and interrupt exit already has context tracking calls.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/Kconfig                 |  2 +-
 arch/powerpc/include/asm/interrupt.h | 21 ++++++---------------
 2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 81c9f895d690..f667279ec74c 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -204,7 +204,7 @@ config PPC
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ASM_MODVERSIONS
-	select HAVE_CONTEXT_TRACKING_USER		if PPC64
+	select HAVE_CONTEXT_TRACKING_USER
 	select HAVE_C_RECORDMCOUNT
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DEBUG_STACKOVERFLOW
diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 4745bb9998bd..8860a246d51a 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -85,6 +85,8 @@ do {									\
 	    (user_mode(regs) || (TRAP(regs) != INTERRUPT_PROGRAM)))	\
 		BUG_ON(cond);						\
 } while (0)
+#else
+#define INT_SOFT_MASK_BUG_ON(regs, cond)
 #endif
 
 #ifdef CONFIG_PPC_BOOK3S_64
@@ -152,19 +154,8 @@ static inline void booke_restore_dbcr0(void)
 static inline void interrupt_enter_prepare(struct pt_regs *regs)
 {
 #ifdef CONFIG_PPC32
-	if (!arch_irq_disabled_regs(regs))
-		trace_hardirqs_off();
-
-	if (user_mode(regs))
-		kuap_lock();
-	else
-		kuap_save_and_lock(regs);
-
-	if (user_mode(regs))
-		account_cpu_user_entry();
-#endif
-
-#ifdef CONFIG_PPC64
+	bool trace_enable = !arch_irq_disabled_regs(regs);
+#else
 	bool trace_enable = false;
 
 	if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS)) {
@@ -188,8 +179,9 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs)
 	} else {
 		__hard_RI_enable();
 	}
+	/* Only call trace_hardirqs_off when RI=1, it can cause SLB faults */
+#endif
 
-	/* Do this when RI=1 because it can cause SLB faults */
 	if (trace_enable)
 		trace_hardirqs_off();
 
@@ -215,7 +207,6 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs)
 	}
 	INT_SOFT_MASK_BUG_ON(regs, !arch_irq_disabled_regs(regs) &&
 				   !(regs->msr & MSR_EE));
-#endif
 
 	booke_restore_dbcr0();
 }
-- 
2.37.2