riscv: jump_label: Batch icache maintenance

Switch to the batched version of the jump label update functions so
instruction cache maintenance is deferred until the end of the update.

Reviewed-by: Björn Töpel <[email protected]>
Signed-off-by: Samuel Holland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

Author: SiFiveHolland

arch/riscv/include/asm/jump_label.h

@@ -12,6 +12,8 @@
 #include <linux/types.h>
 #include <asm/asm.h>
 
+#define HAVE_JUMP_LABEL_BATCH
+
 #define JUMP_LABEL_NOP_SIZE 4
 
 static __always_inline bool arch_static_branch(struct static_key * const key,

arch/riscv/kernel/jump_label.c

@@ -9,13 +9,14 @@
 #include <linux/memory.h>
 #include <linux/mutex.h>
 #include <asm/bug.h>
+#include <asm/cacheflush.h>
 #include <asm/patch.h>
 
 #define RISCV_INSN_NOP 0x00000013U
 #define RISCV_INSN_JAL 0x0000006fU
 
-void arch_jump_label_transform(struct jump_entry *entry,
-			       enum jump_label_type type)
+bool arch_jump_label_transform_queue(struct jump_entry *entry,
+				     enum jump_label_type type)
 {
 	void *addr = (void *)jump_entry_code(entry);
 	u32 insn;
@@ -24,7 +25,7 @@ void arch_jump_label_transform(struct jump_entry *entry,
 		long offset = jump_entry_target(entry) - jump_entry_code(entry);
 
 		if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
-			return;
+			return true;
 
 		insn = RISCV_INSN_JAL |
 			(((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
@@ -36,6 +37,13 @@ void arch_jump_label_transform(struct jump_entry *entry,
 	}
 
 	mutex_lock(&text_mutex);
-	patch_text_nosync(addr, &insn, sizeof(insn));
+	patch_insn_write(addr, &insn, sizeof(insn));
 	mutex_unlock(&text_mutex);
+
+	return true;
+}
+
+void arch_jump_label_transform_apply(void)
+{
+	flush_icache_all();
 }