powerpc/bpf: Move common helpers into bpf_jit.h

Move functions bpf_flush_icache(), bpf_is_seen_register() and
bpf_set_seen_register() in order to reuse them in future
bpf_jit_comp32.c

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/28e8d5a75e64807d7e9d39a4b52658755e259f8c.1616430991.git.christophe.leroy@csgroup.eu

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index d0a67a1bbaf1..b8fa6908fc5e 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -108,6 +108,41 @@ static inline bool is_nearbranch(int offset)
 #define COND_LT		(CR0_LT | COND_CMP_TRUE)
 #define COND_LE		(CR0_GT | COND_CMP_FALSE)
 
+#define SEEN_FUNC	0x1000 /* might call external helpers */
+#define SEEN_STACK	0x2000 /* uses BPF stack */
+#define SEEN_TAILCALL	0x4000 /* uses tail calls */
+
+struct codegen_context {
+	/*
+	 * This is used to track register usage as well
+	 * as calls to external helpers.
+	 * - register usage is tracked with corresponding
+	 *   bits (r3-r10 and r27-r31)
+	 * - rest of the bits can be used to track other
+	 *   things -- for now, we use bits 16 to 23
+	 *   encoded in SEEN_* macros above
+	 */
+	unsigned int seen;
+	unsigned int idx;
+	unsigned int stack_size;
+};
+
+static inline void bpf_flush_icache(void *start, void *end)
+{
+	smp_wmb();	/* smp write barrier */
+	flush_icache_range((unsigned long)start, (unsigned long)end);
+}
+
+static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
+{
+	return ctx->seen & (1 << (31 - i));
+}
+
+static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
+{
+	ctx->seen |= 1 << (31 - i);
+}
+
 #endif
 
 #endif