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-rw-r--r--arch/powerpc/net/bpf_jit.h2
-rw-r--r--arch/powerpc/net/bpf_jit64.h1
-rw-r--r--arch/powerpc/net/bpf_jit_comp64.c149
3 files changed, 124 insertions, 28 deletions
diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index d5301b6f20d0..89f70073dec8 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -40,6 +40,8 @@
#define PPC_BLR() EMIT(PPC_INST_BLR)
#define PPC_BLRL() EMIT(PPC_INST_BLRL)
#define PPC_MTLR(r) EMIT(PPC_INST_MTLR | ___PPC_RT(r))
+#define PPC_BCTR() EMIT(PPC_INST_BCTR)
+#define PPC_MTCTR(r) EMIT(PPC_INST_MTCTR | ___PPC_RT(r))
#define PPC_ADDI(d, a, i) EMIT(PPC_INST_ADDI | ___PPC_RT(d) | \
___PPC_RA(a) | IMM_L(i))
#define PPC_MR(d, a) PPC_OR(d, a, a)
diff --git a/arch/powerpc/net/bpf_jit64.h b/arch/powerpc/net/bpf_jit64.h
index a1645d7a4033..038e00bf2b77 100644
--- a/arch/powerpc/net/bpf_jit64.h
+++ b/arch/powerpc/net/bpf_jit64.h
@@ -88,6 +88,7 @@ DECLARE_LOAD_FUNC(sk_load_byte);
#define SEEN_FUNC 0x1000 /* might call external helpers */
#define SEEN_STACK 0x2000 /* uses BPF stack */
#define SEEN_SKB 0x4000 /* uses sk_buff */
+#define SEEN_TAILCALL 0x8000 /* uses tail calls */
struct codegen_context {
/*
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 5f8c91fa612e..3ec29d6fba60 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -17,6 +17,7 @@
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <asm/kprobes.h>
+#include <linux/bpf.h>
#include "bpf_jit64.h"
@@ -77,6 +78,11 @@ static int bpf_jit_stack_local(struct codegen_context *ctx)
return -(BPF_PPC_STACK_SAVE + 16);
}
+static int bpf_jit_stack_tailcallcnt(struct codegen_context *ctx)
+{
+ return bpf_jit_stack_local(ctx) + 8;
+}
+
static int bpf_jit_stack_offsetof(struct codegen_context *ctx, int reg)
{
if (reg >= BPF_PPC_NVR_MIN && reg < 32)
@@ -102,33 +108,25 @@ static void bpf_jit_emit_skb_loads(u32 *image, struct codegen_context *ctx)
PPC_BPF_LL(b2p[SKB_DATA_REG], 3, offsetof(struct sk_buff, data));
}
-static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func)
+static void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
{
-#ifdef PPC64_ELF_ABI_v1
- /* func points to the function descriptor */
- PPC_LI64(b2p[TMP_REG_2], func);
- /* Load actual entry point from function descriptor */
- PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
- /* ... and move it to LR */
- PPC_MTLR(b2p[TMP_REG_1]);
+ int i;
+
/*
- * Load TOC from function descriptor at offset 8.
- * We can clobber r2 since we get called through a
- * function pointer (so caller will save/restore r2)
- * and since we don't use a TOC ourself.
+ * Initialize tail_call_cnt if we do tail calls.
+ * Otherwise, put in NOPs so that it can be skipped when we are
+ * invoked through a tail call.
*/
- PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
-#else
- /* We can clobber r12 */
- PPC_FUNC_ADDR(12, func);
- PPC_MTLR(12);
-#endif
- PPC_BLRL();
-}
+ if (ctx->seen & SEEN_TAILCALL) {
+ PPC_LI(b2p[TMP_REG_1], 0);
+ /* this goes in the redzone */
+ PPC_BPF_STL(b2p[TMP_REG_1], 1, -(BPF_PPC_STACK_SAVE + 8));
+ } else {
+ PPC_NOP();
+ PPC_NOP();
+ }
-static void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
-{
- int i;
+#define BPF_TAILCALL_PROLOGUE_SIZE 8
if (bpf_has_stack_frame(ctx)) {
/*
@@ -170,13 +168,10 @@ static void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
STACK_FRAME_MIN_SIZE + MAX_BPF_STACK);
}
-static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
+static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx)
{
int i;
- /* Move result to r3 */
- PPC_MR(3, b2p[BPF_REG_0]);
-
/* Restore NVRs */
for (i = BPF_REG_6; i <= BPF_REG_10; i++)
if (bpf_is_seen_register(ctx, i))
@@ -198,10 +193,105 @@ static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
PPC_MTLR(0);
}
}
+}
+
+static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
+{
+ bpf_jit_emit_common_epilogue(image, ctx);
+
+ /* Move result to r3 */
+ PPC_MR(3, b2p[BPF_REG_0]);
PPC_BLR();
}
+static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func)
+{
+#ifdef PPC64_ELF_ABI_v1
+ /* func points to the function descriptor */
+ PPC_LI64(b2p[TMP_REG_2], func);
+ /* Load actual entry point from function descriptor */
+ PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
+ /* ... and move it to LR */
+ PPC_MTLR(b2p[TMP_REG_1]);
+ /*
+ * Load TOC from function descriptor at offset 8.
+ * We can clobber r2 since we get called through a
+ * function pointer (so caller will save/restore r2)
+ * and since we don't use a TOC ourself.
+ */
+ PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
+#else
+ /* We can clobber r12 */
+ PPC_FUNC_ADDR(12, func);
+ PPC_MTLR(12);
+#endif
+ PPC_BLRL();
+}
+
+static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
+{
+ /*
+ * By now, the eBPF program has already setup parameters in r3, r4 and r5
+ * r3/BPF_REG_1 - pointer to ctx -- passed as is to the next bpf program
+ * r4/BPF_REG_2 - pointer to bpf_array
+ * r5/BPF_REG_3 - index in bpf_array
+ */
+ int b2p_bpf_array = b2p[BPF_REG_2];
+ int b2p_index = b2p[BPF_REG_3];
+
+ /*
+ * if (index >= array->map.max_entries)
+ * goto out;
+ */
+ PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries));
+ PPC_CMPLW(b2p_index, b2p[TMP_REG_1]);
+ PPC_BCC(COND_GE, out);
+
+ /*
+ * if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ */
+ PPC_LD(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
+ PPC_CMPLWI(b2p[TMP_REG_1], MAX_TAIL_CALL_CNT);
+ PPC_BCC(COND_GT, out);
+
+ /*
+ * tail_call_cnt++;
+ */
+ PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], 1);
+ PPC_BPF_STL(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
+
+ /* prog = array->ptrs[index]; */
+ PPC_MULI(b2p[TMP_REG_1], b2p_index, 8);
+ PPC_ADD(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p_bpf_array);
+ PPC_LD(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_array, ptrs));
+
+ /*
+ * if (prog == NULL)
+ * goto out;
+ */
+ PPC_CMPLDI(b2p[TMP_REG_1], 0);
+ PPC_BCC(COND_EQ, out);
+
+ /* goto *(prog->bpf_func + prologue_size); */
+ PPC_LD(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_prog, bpf_func));
+#ifdef PPC64_ELF_ABI_v1
+ /* skip past the function descriptor */
+ PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1],
+ FUNCTION_DESCR_SIZE + BPF_TAILCALL_PROLOGUE_SIZE);
+#else
+ PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], BPF_TAILCALL_PROLOGUE_SIZE);
+#endif
+ PPC_MTCTR(b2p[TMP_REG_1]);
+
+ /* tear down stack, restore NVRs, ... */
+ bpf_jit_emit_common_epilogue(image, ctx);
+
+ PPC_BCTR();
+ /* out: */
+}
+
/* Assemble the body code between the prologue & epilogue */
static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
struct codegen_context *ctx,
@@ -846,9 +936,12 @@ common_load:
break;
/*
- * TODO: Tail call
+ * Tail call
*/
case BPF_JMP | BPF_CALL | BPF_X:
+ ctx->seen |= SEEN_TAILCALL;
+ bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]);
+ break;
default:
/*
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 05:02:47 +0000