RISC-V Fixes and Cleanups for 4.19-rc2

This tag contains a handful of patches that filtered their way in during
 the merge window but just didn't make the deadline.  It includes:
 
 * Additional documentation in the riscv,cpu-intc device tree binding
   that resulted from some feedback I missed in the original patch set.
 * A build fix that provides the definition of tlb_flush() before
   including tlb.h, which fixes a RISC-V build regression introduced
   during this merge window.
 * A cosmetic cleanup to sys_riscv_flush_icache().
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Merge tag 'riscv-for-linus-4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux

Pull RISC-V fixes from Palmer Dabbelt:
 "RISC-V Fixes and Cleanups for 4.19-rc2

  This contains a handful of patches that filtered their way in during
  the merge window but just didn't make the deadline. It includes:

   - Additional documentation in the riscv,cpu-intc device tree binding
     that resulted from some feedback I missed in the original patch
     set.

   - A build fix that provides the definition of tlb_flush() before
     including tlb.h, which fixes a RISC-V build regression introduced
     during this merge window.

   - A cosmetic cleanup to sys_riscv_flush_icache()"

* tag 'riscv-for-linus-4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
  RISC-V: Use a less ugly workaround for unused variable warnings
  riscv: tlb: Provide definition of tlb_flush() before including tlb.h
  dt-bindings: riscv,cpu-intc: Cleanups from a missed review

Documentation/devicetree/bindings/interrupt-controller/riscv,cpu-intc.txt

@@ -11,7 +11,7 @@ The RISC-V supervisor ISA manual specifies three interrupt sources that are
 attached to every HLIC: software interrupts, the timer interrupt, and external
 interrupts.  Software interrupts are used to send IPIs between cores.  The
 timer interrupt comes from an architecturally mandated real-time timer that is
-controller via Supervisor Binary Interface (SBI) calls and CSR reads.  External
+controlled via Supervisor Binary Interface (SBI) calls and CSR reads.  External
 interrupts connect all other device interrupts to the HLIC, which are routed
 via the platform-level interrupt controller (PLIC).
 
@@ -25,7 +25,15 @@ in the system.
 
 Required properties:
 - compatible : "riscv,cpu-intc"
-- #interrupt-cells : should be <1>
+- #interrupt-cells : should be <1>.  The interrupt sources are defined by the
+  RISC-V supervisor ISA manual, with only the following three interrupts being
+  defined for supervisor mode:
+    - Source 1 is the supervisor software interrupt, which can be sent by an SBI
+      call and is reserved for use by software.
+    - Source 5 is the supervisor timer interrupt, which can be configured by
+      SBI calls and implements a one-shot timer.
+    - Source 9 is the supervisor external interrupt, which chains to all other
+      device interrupts.
 - interrupt-controller : Identifies the node as an interrupt controller
 
 Furthermore, this interrupt-controller MUST be embedded inside the cpu
@@ -38,7 +46,7 @@ An example device tree entry for a HLIC is show below.
 		...
 		cpu1-intc: interrupt-controller {
 			#interrupt-cells = <1>;
-			compatible = "riscv,cpu-intc", "sifive,fu540-c000-cpu-intc";
+			compatible = "sifive,fu540-c000-cpu-intc", "riscv,cpu-intc";
 			interrupt-controller;
 		};
 	};

arch/riscv/include/asm/tlb.h

@@ -14,6 +14,10 @@
 #ifndef _ASM_RISCV_TLB_H
 #define _ASM_RISCV_TLB_H
 
+struct mmu_gather;
+
+static void tlb_flush(struct mmu_gather *tlb);
+
 #include <asm-generic/tlb.h>
 
 static inline void tlb_flush(struct mmu_gather *tlb)

arch/riscv/kernel/sys_riscv.c

@@ -65,24 +65,11 @@ SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
 	uintptr_t, flags)
 {
-#ifdef CONFIG_SMP
-	struct mm_struct *mm = current->mm;
-	bool local = (flags & SYS_RISCV_FLUSH_ICACHE_LOCAL) != 0;
-#endif
-
 	/* Check the reserved flags. */
 	if (unlikely(flags & ~SYS_RISCV_FLUSH_ICACHE_ALL))
 		return -EINVAL;
 
-	/*
-	 * Without CONFIG_SMP flush_icache_mm is a just a flush_icache_all(),
-	 * which generates unused variable warnings all over this function.
-	 */
-#ifdef CONFIG_SMP
-	flush_icache_mm(mm, local);
-#else
-	flush_icache_all();
-#endif
+	flush_icache_mm(current->mm, flags & SYS_RISCV_FLUSH_ICACHE_LOCAL);
 
 	return 0;
 }