Thread (11 messages) 11 messages, 3 authors, 2020-12-18
STALE2040d

[RFC PATCH v1 2/7] powerpc/bpf: Change register numbering for bpf_set/is_seen_register()

From: Christophe Leroy <hidden>
Date: 2020-12-16 10:08:16
Also in: bpf, lkml, netdev
Subsystem: bpf jit for powerpc (32-bit and 64-bit), bpf [general] (safe dynamic programs and tools), linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Hari Bathini, Christophe Leroy, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Madhavan Srinivasan, Michael Ellerman, Linus Torvalds

Instead of using BPF register number as input in functions
bpf_set_seen_register() and bpf_is_seen_register(), use
CPU register number directly.

Signed-off-by: Christophe Leroy <redacted>
---
 arch/powerpc/net/bpf_jit_comp64.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 022103c6a201..26a836a904f5 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -31,12 +31,12 @@ static inline void bpf_flush_icache(void *start, void *end)
 
 static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
 {
-	return (ctx->seen & (1 << (31 - b2p[i])));
+	return ctx->seen & (1 << (31 - i));
 }
 
 static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
 {
-	ctx->seen |= (1 << (31 - b2p[i]));
+	ctx->seen |= 1 << (31 - i);
 }
 
 static inline bool bpf_has_stack_frame(struct codegen_context *ctx)
@@ -47,7 +47,7 @@ static inline bool bpf_has_stack_frame(struct codegen_context *ctx)
 	 * - the bpf program uses its stack area
 	 * The latter condition is deduced from the usage of BPF_REG_FP
 	 */
-	return ctx->seen & SEEN_FUNC || bpf_is_seen_register(ctx, BPF_REG_FP);
+	return ctx->seen & SEEN_FUNC || bpf_is_seen_register(ctx, b2p[BPF_REG_FP]);
 }
 
 /*
@@ -124,11 +124,11 @@ static void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
 	 * in the protected zone below the previous stack frame
 	 */
 	for (i = BPF_REG_6; i <= BPF_REG_10; i++)
-		if (bpf_is_seen_register(ctx, i))
+		if (bpf_is_seen_register(ctx, b2p[i]))
 			PPC_BPF_STL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
 
 	/* Setup frame pointer to point to the bpf stack area */
-	if (bpf_is_seen_register(ctx, BPF_REG_FP))
+	if (bpf_is_seen_register(ctx, b2p[BPF_REG_FP]))
 		EMIT(PPC_RAW_ADDI(b2p[BPF_REG_FP], 1,
 				STACK_FRAME_MIN_SIZE + ctx->stack_size));
 }
@@ -139,7 +139,7 @@ static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx
 
 	/* Restore NVRs */
 	for (i = BPF_REG_6; i <= BPF_REG_10; i++)
-		if (bpf_is_seen_register(ctx, i))
+		if (bpf_is_seen_register(ctx, b2p[i]))
 			PPC_BPF_LL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
 
 	/* Tear down our stack frame */
@@ -330,9 +330,9 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
 		 * any issues.
 		 */
 		if (dst_reg >= BPF_PPC_NVR_MIN && dst_reg < 32)
-			bpf_set_seen_register(ctx, insn[i].dst_reg);
+			bpf_set_seen_register(ctx, dst_reg);
 		if (src_reg >= BPF_PPC_NVR_MIN && src_reg < 32)
-			bpf_set_seen_register(ctx, insn[i].src_reg);
+			bpf_set_seen_register(ctx, src_reg);
 
 		switch (code) {
 		/*
-- 
2.25.0
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