[PATCH 3/3] riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT

[guoren]

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

Lockdep is needed by proving the spinlocks and rwlocks. To suupport
it, we need fixup TRACE_IRQFLAGS_SUPPORT in kernel/entry.S. This
patch follow Documentation/irqflags-tracing.txt.

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
---
 arch/riscv/Kconfig        |  3 +++
 arch/riscv/kernel/entry.S | 41 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a31e1a4..550e0ec 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -170,6 +170,9 @@ config PGTABLE_LEVELS
 	default 3 if 64BIT
 	default 2
 
+config LOCKDEP_SUPPORT
+	def_bool y
+
 source "arch/riscv/Kconfig.socs"
 
 menu "Platform type"
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 56d071b..02c5b8e 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -97,17 +97,25 @@ _save_context:
 	la gp, __global_pointer$
 .option pop
 
-	la ra, ret_from_exception
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_off
+#endif
 	/*
 	 * MSB of cause differentiates between
 	 * interrupts and exceptions
 	 */
 	bge s4, zero, 1f
 
+	la ra, ret_from_exception
+
 	/* Handle interrupts */
 	move a0, sp /* pt_regs */
 	tail do_IRQ
 1:
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_on
+	REG_L s1, PT_STATUS(sp)
+#endif
 	/*
 	 * Exceptions run with interrupts enabled or disabled depending on the
 	 * state of SR_PIE in m/sstatus.
@@ -117,8 +125,23 @@ _save_context:
 	csrs CSR_STATUS, SR_IE
 
 1:
+#ifdef CONFIG_TRACE_IRQFLAGS
+	REG_L a0, PT_A0(sp)
+	REG_L a1, PT_A1(sp)
+	REG_L a2, PT_A2(sp)
+	REG_L a3, PT_A3(sp)
+	REG_L a4, PT_A4(sp)
+	REG_L a5, PT_A5(sp)
+	REG_L a6, PT_A6(sp)
+	REG_L a7, PT_A7(sp)
+#endif
+	la ra, ret_from_exception
 	/* Handle syscalls */
 	li t0, EXC_SYSCALL
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+	REG_L s4, PT_CAUSE(sp)
+#endif
 	beq s4, t0, handle_syscall
 
 	/* Handle other exceptions */
@@ -141,6 +164,9 @@ handle_syscall:
 	 * Advance SEPC to avoid executing the original
 	 * scall instruction on sret
 	 */
+#ifdef CONFIG_TRACE_IRQFLAGS
+	REG_L s2, PT_EPC(sp)
+#endif
 	addi s2, s2, 0x4
 	REG_S s2, PT_EPC(sp)
 	/* Trace syscalls, but only if requested by the user. */
@@ -188,6 +214,9 @@ ret_from_syscall_rejected:
 ret_from_exception:
 	REG_L s0, PT_STATUS(sp)
 	csrc CSR_STATUS, SR_IE
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_off
+#endif
 #ifdef CONFIG_RISCV_M_MODE
 	/* the MPP value is too large to be used as an immediate arg for addi */
 	li t0, SR_MPP
@@ -214,6 +243,16 @@ resume_userspace:
 	csrw CSR_SCRATCH, tp
 
 restore_all:
+#ifdef CONFIG_TRACE_IRQFLAGS
+	REG_L s1, PT_STATUS(sp)
+	andi t0, s1, SR_PIE
+	beqz t0, 1f
+	call trace_hardirqs_on
+	j 2f
+1:
+	call trace_hardirqs_off
+2:
+#endif
 	REG_L a0, PT_STATUS(sp)
 	/*
 	 * The current load reservation is effectively part of the processor's
-- 
2.7.4