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-rw-r--r--arch/powerpc/net/bpf_jit_comp64.c954
1 files changed, 954 insertions, 0 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
new file mode 100644
index 000000000000..6073b78516f6
--- /dev/null
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -0,0 +1,954 @@
+/*
+ * bpf_jit_comp64.c: eBPF JIT compiler
+ *
+ * Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
+ * IBM Corporation
+ *
+ * Based on the powerpc classic BPF JIT compiler by Matt Evans
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+#include <linux/moduleloader.h>
+#include <asm/cacheflush.h>
+#include <linux/netdevice.h>
+#include <linux/filter.h>
+#include <linux/if_vlan.h>
+#include <asm/kprobes.h>
+
+#include "bpf_jit64.h"
+
+int bpf_jit_enable __read_mostly;
+
+static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
+{
+ int *p = area;
+
+ /* Fill whole space with trap instructions */
+ while (p < (int *)((char *)area + size))
+ *p++ = BREAKPOINT_INSTRUCTION;
+}
+
+static inline void bpf_flush_icache(void *start, void *end)
+{
+ smp_wmb();
+ 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 - b2p[i])));
+}
+
+static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
+{
+ ctx->seen |= (1 << (31 - b2p[i]));
+}
+
+static inline bool bpf_has_stack_frame(struct codegen_context *ctx)
+{
+ /*
+ * We only need a stack frame if:
+ * - we call other functions (kernel helpers), or
+ * - 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);
+}
+
+static void bpf_jit_emit_skb_loads(u32 *image, struct codegen_context *ctx)
+{
+ /*
+ * Load skb->len and skb->data_len
+ * r3 points to skb
+ */
+ PPC_LWZ(b2p[SKB_HLEN_REG], 3, offsetof(struct sk_buff, len));
+ PPC_LWZ(b2p[TMP_REG_1], 3, offsetof(struct sk_buff, data_len));
+ /* header_len = len - data_len */
+ PPC_SUB(b2p[SKB_HLEN_REG], b2p[SKB_HLEN_REG], b2p[TMP_REG_1]);
+
+ /* skb->data pointer */
+ 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)
+{
+#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_build_prologue(u32 *image, struct codegen_context *ctx)
+{
+ int i;
+ bool new_stack_frame = bpf_has_stack_frame(ctx);
+
+ if (new_stack_frame) {
+ /*
+ * We need a stack frame, but we don't necessarily need to
+ * save/restore LR unless we call other functions
+ */
+ if (ctx->seen & SEEN_FUNC) {
+ EMIT(PPC_INST_MFLR | __PPC_RT(R0));
+ PPC_BPF_STL(0, 1, PPC_LR_STKOFF);
+ }
+
+ PPC_BPF_STLU(1, 1, -BPF_PPC_STACKFRAME);
+ }
+
+ /*
+ * Back up non-volatile regs -- BPF registers 6-10
+ * If we haven't created our own stack frame, we save these
+ * 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))
+ PPC_BPF_STL(b2p[i], 1,
+ (new_stack_frame ? BPF_PPC_STACKFRAME : 0) -
+ (8 * (32 - b2p[i])));
+
+ /*
+ * Save additional non-volatile regs if we cache skb
+ * Also, setup skb data
+ */
+ if (ctx->seen & SEEN_SKB) {
+ PPC_BPF_STL(b2p[SKB_HLEN_REG], 1,
+ BPF_PPC_STACKFRAME - (8 * (32 - b2p[SKB_HLEN_REG])));
+ PPC_BPF_STL(b2p[SKB_DATA_REG], 1,
+ BPF_PPC_STACKFRAME - (8 * (32 - b2p[SKB_DATA_REG])));
+ bpf_jit_emit_skb_loads(image, ctx);
+ }
+
+ /* Setup frame pointer to point to the bpf stack area */
+ if (bpf_is_seen_register(ctx, BPF_REG_FP))
+ PPC_ADDI(b2p[BPF_REG_FP], 1,
+ BPF_PPC_STACKFRAME - BPF_PPC_STACK_SAVE);
+}
+
+static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
+{
+ int i;
+ bool new_stack_frame = bpf_has_stack_frame(ctx);
+
+ /* 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))
+ PPC_BPF_LL(b2p[i], 1,
+ (new_stack_frame ? BPF_PPC_STACKFRAME : 0) -
+ (8 * (32 - b2p[i])));
+
+ /* Restore non-volatile registers used for skb cache */
+ if (ctx->seen & SEEN_SKB) {
+ PPC_BPF_LL(b2p[SKB_HLEN_REG], 1,
+ BPF_PPC_STACKFRAME - (8 * (32 - b2p[SKB_HLEN_REG])));
+ PPC_BPF_LL(b2p[SKB_DATA_REG], 1,
+ BPF_PPC_STACKFRAME - (8 * (32 - b2p[SKB_DATA_REG])));
+ }
+
+ /* Tear down our stack frame */
+ if (new_stack_frame) {
+ PPC_ADDI(1, 1, BPF_PPC_STACKFRAME);
+ if (ctx->seen & SEEN_FUNC) {
+ PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
+ PPC_MTLR(0);
+ }
+ }
+
+ PPC_BLR();
+}
+
+/* Assemble the body code between the prologue & epilogue */
+static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
+ struct codegen_context *ctx,
+ u32 *addrs)
+{
+ const struct bpf_insn *insn = fp->insnsi;
+ int flen = fp->len;
+ int i;
+
+ /* Start of epilogue code - will only be valid 2nd pass onwards */
+ u32 exit_addr = addrs[flen];
+
+ for (i = 0; i < flen; i++) {
+ u32 code = insn[i].code;
+ u32 dst_reg = b2p[insn[i].dst_reg];
+ u32 src_reg = b2p[insn[i].src_reg];
+ s16 off = insn[i].off;
+ s32 imm = insn[i].imm;
+ u64 imm64;
+ u8 *func;
+ u32 true_cond;
+ int stack_local_off;
+
+ /*
+ * addrs[] maps a BPF bytecode address into a real offset from
+ * the start of the body code.
+ */
+ addrs[i] = ctx->idx * 4;
+
+ /*
+ * As an optimization, we note down which non-volatile registers
+ * are used so that we can only save/restore those in our
+ * prologue and epilogue. We do this here regardless of whether
+ * the actual BPF instruction uses src/dst registers or not
+ * (for instance, BPF_CALL does not use them). The expectation
+ * is that those instructions will have src_reg/dst_reg set to
+ * 0. Even otherwise, we just lose some prologue/epilogue
+ * optimization but everything else should work without
+ * any issues.
+ */
+ if (dst_reg >= 24 && dst_reg <= 31)
+ bpf_set_seen_register(ctx, insn[i].dst_reg);
+ if (src_reg >= 24 && src_reg <= 31)
+ bpf_set_seen_register(ctx, insn[i].src_reg);
+
+ switch (code) {
+ /*
+ * Arithmetic operations: ADD/SUB/MUL/DIV/MOD/NEG
+ */
+ case BPF_ALU | BPF_ADD | BPF_X: /* (u32) dst += (u32) src */
+ case BPF_ALU64 | BPF_ADD | BPF_X: /* dst += src */
+ PPC_ADD(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_SUB | BPF_X: /* (u32) dst -= (u32) src */
+ case BPF_ALU64 | BPF_SUB | BPF_X: /* dst -= src */
+ PPC_SUB(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */
+ case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
+ case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */
+ case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */
+ if (BPF_OP(code) == BPF_SUB)
+ imm = -imm;
+ if (imm) {
+ if (imm >= -32768 && imm < 32768)
+ PPC_ADDI(dst_reg, dst_reg, IMM_L(imm));
+ else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]);
+ }
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */
+ case BPF_ALU64 | BPF_MUL | BPF_X: /* dst *= src */
+ if (BPF_CLASS(code) == BPF_ALU)
+ PPC_MULW(dst_reg, dst_reg, src_reg);
+ else
+ PPC_MULD(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_MUL | BPF_K: /* (u32) dst *= (u32) imm */
+ case BPF_ALU64 | BPF_MUL | BPF_K: /* dst *= imm */
+ if (imm >= -32768 && imm < 32768)
+ PPC_MULI(dst_reg, dst_reg, IMM_L(imm));
+ else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ if (BPF_CLASS(code) == BPF_ALU)
+ PPC_MULW(dst_reg, dst_reg,
+ b2p[TMP_REG_1]);
+ else
+ PPC_MULD(dst_reg, dst_reg,
+ b2p[TMP_REG_1]);
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_DIV | BPF_X: /* (u32) dst /= (u32) src */
+ case BPF_ALU | BPF_MOD | BPF_X: /* (u32) dst %= (u32) src */
+ PPC_CMPWI(src_reg, 0);
+ PPC_BCC_SHORT(COND_NE, (ctx->idx * 4) + 12);
+ PPC_LI(b2p[BPF_REG_0], 0);
+ PPC_JMP(exit_addr);
+ if (BPF_OP(code) == BPF_MOD) {
+ PPC_DIVWU(b2p[TMP_REG_1], dst_reg, src_reg);
+ PPC_MULW(b2p[TMP_REG_1], src_reg,
+ b2p[TMP_REG_1]);
+ PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]);
+ } else
+ PPC_DIVWU(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
+ case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
+ PPC_CMPDI(src_reg, 0);
+ PPC_BCC_SHORT(COND_NE, (ctx->idx * 4) + 12);
+ PPC_LI(b2p[BPF_REG_0], 0);
+ PPC_JMP(exit_addr);
+ if (BPF_OP(code) == BPF_MOD) {
+ PPC_DIVD(b2p[TMP_REG_1], dst_reg, src_reg);
+ PPC_MULD(b2p[TMP_REG_1], src_reg,
+ b2p[TMP_REG_1]);
+ PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]);
+ } else
+ PPC_DIVD(dst_reg, dst_reg, src_reg);
+ break;
+ case BPF_ALU | BPF_MOD | BPF_K: /* (u32) dst %= (u32) imm */
+ case BPF_ALU | BPF_DIV | BPF_K: /* (u32) dst /= (u32) imm */
+ case BPF_ALU64 | BPF_MOD | BPF_K: /* dst %= imm */
+ case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */
+ if (imm == 0)
+ return -EINVAL;
+ else if (imm == 1)
+ goto bpf_alu32_trunc;
+
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ switch (BPF_CLASS(code)) {
+ case BPF_ALU:
+ if (BPF_OP(code) == BPF_MOD) {
+ PPC_DIVWU(b2p[TMP_REG_2], dst_reg,
+ b2p[TMP_REG_1]);
+ PPC_MULW(b2p[TMP_REG_1],
+ b2p[TMP_REG_1],
+ b2p[TMP_REG_2]);
+ PPC_SUB(dst_reg, dst_reg,
+ b2p[TMP_REG_1]);
+ } else
+ PPC_DIVWU(dst_reg, dst_reg,
+ b2p[TMP_REG_1]);
+ break;
+ case BPF_ALU64:
+ if (BPF_OP(code) == BPF_MOD) {
+ PPC_DIVD(b2p[TMP_REG_2], dst_reg,
+ b2p[TMP_REG_1]);
+ PPC_MULD(b2p[TMP_REG_1],
+ b2p[TMP_REG_1],
+ b2p[TMP_REG_2]);
+ PPC_SUB(dst_reg, dst_reg,
+ b2p[TMP_REG_1]);
+ } else
+ PPC_DIVD(dst_reg, dst_reg,
+ b2p[TMP_REG_1]);
+ break;
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_NEG: /* (u32) dst = -dst */
+ case BPF_ALU64 | BPF_NEG: /* dst = -dst */
+ PPC_NEG(dst_reg, dst_reg);
+ goto bpf_alu32_trunc;
+
+ /*
+ * Logical operations: AND/OR/XOR/[A]LSH/[A]RSH
+ */
+ case BPF_ALU | BPF_AND | BPF_X: /* (u32) dst = dst & src */
+ case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
+ PPC_AND(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_AND | BPF_K: /* (u32) dst = dst & imm */
+ case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
+ if (!IMM_H(imm))
+ PPC_ANDI(dst_reg, dst_reg, IMM_L(imm));
+ else {
+ /* Sign-extended */
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_AND(dst_reg, dst_reg, b2p[TMP_REG_1]);
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
+ case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
+ PPC_OR(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_OR | BPF_K:/* dst = (u32) dst | (u32) imm */
+ case BPF_ALU64 | BPF_OR | BPF_K:/* dst = dst | imm */
+ if (imm < 0 && BPF_CLASS(code) == BPF_ALU64) {
+ /* Sign-extended */
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_OR(dst_reg, dst_reg, b2p[TMP_REG_1]);
+ } else {
+ if (IMM_L(imm))
+ PPC_ORI(dst_reg, dst_reg, IMM_L(imm));
+ if (IMM_H(imm))
+ PPC_ORIS(dst_reg, dst_reg, IMM_H(imm));
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_XOR | BPF_X: /* (u32) dst ^= src */
+ case BPF_ALU64 | BPF_XOR | BPF_X: /* dst ^= src */
+ PPC_XOR(dst_reg, dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_XOR | BPF_K: /* (u32) dst ^= (u32) imm */
+ case BPF_ALU64 | BPF_XOR | BPF_K: /* dst ^= imm */
+ if (imm < 0 && BPF_CLASS(code) == BPF_ALU64) {
+ /* Sign-extended */
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_XOR(dst_reg, dst_reg, b2p[TMP_REG_1]);
+ } else {
+ if (IMM_L(imm))
+ PPC_XORI(dst_reg, dst_reg, IMM_L(imm));
+ if (IMM_H(imm))
+ PPC_XORIS(dst_reg, dst_reg, IMM_H(imm));
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_LSH | BPF_X: /* (u32) dst <<= (u32) src */
+ /* slw clears top 32 bits */
+ PPC_SLW(dst_reg, dst_reg, src_reg);
+ break;
+ case BPF_ALU64 | BPF_LSH | BPF_X: /* dst <<= src; */
+ PPC_SLD(dst_reg, dst_reg, src_reg);
+ break;
+ case BPF_ALU | BPF_LSH | BPF_K: /* (u32) dst <<== (u32) imm */
+ /* with imm 0, we still need to clear top 32 bits */
+ PPC_SLWI(dst_reg, dst_reg, imm);
+ break;
+ case BPF_ALU64 | BPF_LSH | BPF_K: /* dst <<== imm */
+ if (imm != 0)
+ PPC_SLDI(dst_reg, dst_reg, imm);
+ break;
+ case BPF_ALU | BPF_RSH | BPF_X: /* (u32) dst >>= (u32) src */
+ PPC_SRW(dst_reg, dst_reg, src_reg);
+ break;
+ case BPF_ALU64 | BPF_RSH | BPF_X: /* dst >>= src */
+ PPC_SRD(dst_reg, dst_reg, src_reg);
+ break;
+ case BPF_ALU | BPF_RSH | BPF_K: /* (u32) dst >>= (u32) imm */
+ PPC_SRWI(dst_reg, dst_reg, imm);
+ break;
+ case BPF_ALU64 | BPF_RSH | BPF_K: /* dst >>= imm */
+ if (imm != 0)
+ PPC_SRDI(dst_reg, dst_reg, imm);
+ break;
+ case BPF_ALU64 | BPF_ARSH | BPF_X: /* (s64) dst >>= src */
+ PPC_SRAD(dst_reg, dst_reg, src_reg);
+ break;
+ case BPF_ALU64 | BPF_ARSH | BPF_K: /* (s64) dst >>= imm */
+ if (imm != 0)
+ PPC_SRADI(dst_reg, dst_reg, imm);
+ break;
+
+ /*
+ * MOV
+ */
+ case BPF_ALU | BPF_MOV | BPF_X: /* (u32) dst = src */
+ case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
+ PPC_MR(dst_reg, src_reg);
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_MOV | BPF_K: /* (u32) dst = imm */
+ case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = (s64) imm */
+ PPC_LI32(dst_reg, imm);
+ if (imm < 0)
+ goto bpf_alu32_trunc;
+ break;
+
+bpf_alu32_trunc:
+ /* Truncate to 32-bits */
+ if (BPF_CLASS(code) == BPF_ALU)
+ PPC_RLWINM(dst_reg, dst_reg, 0, 0, 31);
+ break;
+
+ /*
+ * BPF_FROM_BE/LE
+ */
+ case BPF_ALU | BPF_END | BPF_FROM_LE:
+ case BPF_ALU | BPF_END | BPF_FROM_BE:
+#ifdef __BIG_ENDIAN__
+ if (BPF_SRC(code) == BPF_FROM_BE)
+ goto emit_clear;
+#else /* !__BIG_ENDIAN__ */
+ if (BPF_SRC(code) == BPF_FROM_LE)
+ goto emit_clear;
+#endif
+ switch (imm) {
+ case 16:
+ /* Rotate 8 bits left & mask with 0x0000ff00 */
+ PPC_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 16, 23);
+ /* Rotate 8 bits right & insert LSB to reg */
+ PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 24, 31);
+ /* Move result back to dst_reg */
+ PPC_MR(dst_reg, b2p[TMP_REG_1]);
+ break;
+ case 32:
+ /*
+ * Rotate word left by 8 bits:
+ * 2 bytes are already in their final position
+ * -- byte 2 and 4 (of bytes 1, 2, 3 and 4)
+ */
+ PPC_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 0, 31);
+ /* Rotate 24 bits and insert byte 1 */
+ PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 0, 7);
+ /* Rotate 24 bits and insert byte 3 */
+ PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 16, 23);
+ PPC_MR(dst_reg, b2p[TMP_REG_1]);
+ break;
+ case 64:
+ /*
+ * Way easier and faster(?) to store the value
+ * into stack and then use ldbrx
+ *
+ * First, determine where in stack we can store
+ * this:
+ * - if we have allotted a stack frame, then we
+ * will utilize the area set aside by
+ * BPF_PPC_STACK_LOCALS
+ * - else, we use the area beneath the NV GPR
+ * save area
+ *
+ * ctx->seen will be reliable in pass2, but
+ * the instructions generated will remain the
+ * same across all passes
+ */
+ if (bpf_has_stack_frame(ctx))
+ stack_local_off = STACK_FRAME_MIN_SIZE;
+ else
+ stack_local_off = -(BPF_PPC_STACK_SAVE + 8);
+
+ PPC_STD(dst_reg, 1, stack_local_off);
+ PPC_ADDI(b2p[TMP_REG_1], 1, stack_local_off);
+ PPC_LDBRX(dst_reg, 0, b2p[TMP_REG_1]);
+ break;
+ }
+ break;
+
+emit_clear:
+ switch (imm) {
+ case 16:
+ /* zero-extend 16 bits into 64 bits */
+ PPC_RLDICL(dst_reg, dst_reg, 0, 48);
+ break;
+ case 32:
+ /* zero-extend 32 bits into 64 bits */
+ PPC_RLDICL(dst_reg, dst_reg, 0, 32);
+ break;
+ case 64:
+ /* nop */
+ break;
+ }
+ break;
+
+ /*
+ * BPF_ST(X)
+ */
+ case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src */
+ case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
+ if (BPF_CLASS(code) == BPF_ST) {
+ PPC_LI(b2p[TMP_REG_1], imm);
+ src_reg = b2p[TMP_REG_1];
+ }
+ PPC_STB(src_reg, dst_reg, off);
+ break;
+ case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
+ case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
+ if (BPF_CLASS(code) == BPF_ST) {
+ PPC_LI(b2p[TMP_REG_1], imm);
+ src_reg = b2p[TMP_REG_1];
+ }
+ PPC_STH(src_reg, dst_reg, off);
+ break;
+ case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
+ case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
+ if (BPF_CLASS(code) == BPF_ST) {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ src_reg = b2p[TMP_REG_1];
+ }
+ PPC_STW(src_reg, dst_reg, off);
+ break;
+ case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
+ case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
+ if (BPF_CLASS(code) == BPF_ST) {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ src_reg = b2p[TMP_REG_1];
+ }
+ PPC_STD(src_reg, dst_reg, off);
+ break;
+
+ /*
+ * BPF_STX XADD (atomic_add)
+ */
+ /* *(u32 *)(dst + off) += src */
+ case BPF_STX | BPF_XADD | BPF_W:
+ /* Get EA into TMP_REG_1 */
+ PPC_ADDI(b2p[TMP_REG_1], dst_reg, off);
+ /* error if EA is not word-aligned */
+ PPC_ANDI(b2p[TMP_REG_2], b2p[TMP_REG_1], 0x03);
+ PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + 12);
+ PPC_LI(b2p[BPF_REG_0], 0);
+ PPC_JMP(exit_addr);
+ /* load value from memory into TMP_REG_2 */
+ PPC_BPF_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
+ /* add value from src_reg into this */
+ PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
+ /* store result back */
+ PPC_BPF_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
+ /* we're done if this succeeded */
+ PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + (7*4));
+ /* otherwise, let's try once more */
+ PPC_BPF_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
+ PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
+ PPC_BPF_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
+ /* exit if the store was not successful */
+ PPC_LI(b2p[BPF_REG_0], 0);
+ PPC_BCC(COND_NE, exit_addr);
+ break;
+ /* *(u64 *)(dst + off) += src */
+ case BPF_STX | BPF_XADD | BPF_DW:
+ PPC_ADDI(b2p[TMP_REG_1], dst_reg, off);
+ /* error if EA is not doubleword-aligned */
+ PPC_ANDI(b2p[TMP_REG_2], b2p[TMP_REG_1], 0x07);
+ PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + (3*4));
+ PPC_LI(b2p[BPF_REG_0], 0);
+ PPC_JMP(exit_addr);
+ PPC_BPF_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
+ PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
+ PPC_BPF_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
+ PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + (7*4));
+ PPC_BPF_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
+ PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
+ PPC_BPF_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
+ PPC_LI(b2p[BPF_REG_0], 0);
+ PPC_BCC(COND_NE, exit_addr);
+ break;
+
+ /*
+ * BPF_LDX
+ */
+ /* dst = *(u8 *)(ul) (src + off) */
+ case BPF_LDX | BPF_MEM | BPF_B:
+ PPC_LBZ(dst_reg, src_reg, off);
+ break;
+ /* dst = *(u16 *)(ul) (src + off) */
+ case BPF_LDX | BPF_MEM | BPF_H:
+ PPC_LHZ(dst_reg, src_reg, off);
+ break;
+ /* dst = *(u32 *)(ul) (src + off) */
+ case BPF_LDX | BPF_MEM | BPF_W:
+ PPC_LWZ(dst_reg, src_reg, off);
+ break;
+ /* dst = *(u64 *)(ul) (src + off) */
+ case BPF_LDX | BPF_MEM | BPF_DW:
+ PPC_LD(dst_reg, src_reg, off);
+ break;
+
+ /*
+ * Doubleword load
+ * 16 byte instruction that uses two 'struct bpf_insn'
+ */
+ case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
+ imm64 = ((u64)(u32) insn[i].imm) |
+ (((u64)(u32) insn[i+1].imm) << 32);
+ /* Adjust for two bpf instructions */
+ addrs[++i] = ctx->idx * 4;
+ PPC_LI64(dst_reg, imm64);
+ break;
+
+ /*
+ * Return/Exit
+ */
+ case BPF_JMP | BPF_EXIT:
+ /*
+ * If this isn't the very last instruction, branch to
+ * the epilogue. If we _are_ the last instruction,
+ * we'll just fall through to the epilogue.
+ */
+ if (i != flen - 1)
+ PPC_JMP(exit_addr);
+ /* else fall through to the epilogue */
+ break;
+
+ /*
+ * Call kernel helper
+ */
+ case BPF_JMP | BPF_CALL:
+ ctx->seen |= SEEN_FUNC;
+ func = (u8 *) __bpf_call_base + imm;
+
+ /* Save skb pointer if we need to re-cache skb data */
+ if (bpf_helper_changes_skb_data(func))
+ PPC_BPF_STL(3, 1, STACK_FRAME_MIN_SIZE);
+
+ bpf_jit_emit_func_call(image, ctx, (u64)func);
+
+ /* move return value from r3 to BPF_REG_0 */
+ PPC_MR(b2p[BPF_REG_0], 3);
+
+ /* refresh skb cache */
+ if (bpf_helper_changes_skb_data(func)) {
+ /* reload skb pointer to r3 */
+ PPC_BPF_LL(3, 1, STACK_FRAME_MIN_SIZE);
+ bpf_jit_emit_skb_loads(image, ctx);
+ }
+ break;
+
+ /*
+ * Jumps and branches
+ */
+ case BPF_JMP | BPF_JA:
+ PPC_JMP(addrs[i + 1 + off]);
+ break;
+
+ case BPF_JMP | BPF_JGT | BPF_K:
+ case BPF_JMP | BPF_JGT | BPF_X:
+ case BPF_JMP | BPF_JSGT | BPF_K:
+ case BPF_JMP | BPF_JSGT | BPF_X:
+ true_cond = COND_GT;
+ goto cond_branch;
+ case BPF_JMP | BPF_JGE | BPF_K:
+ case BPF_JMP | BPF_JGE | BPF_X:
+ case BPF_JMP | BPF_JSGE | BPF_K:
+ case BPF_JMP | BPF_JSGE | BPF_X:
+ true_cond = COND_GE;
+ goto cond_branch;
+ case BPF_JMP | BPF_JEQ | BPF_K:
+ case BPF_JMP | BPF_JEQ | BPF_X:
+ true_cond = COND_EQ;
+ goto cond_branch;
+ case BPF_JMP | BPF_JNE | BPF_K:
+ case BPF_JMP | BPF_JNE | BPF_X:
+ true_cond = COND_NE;
+ goto cond_branch;
+ case BPF_JMP | BPF_JSET | BPF_K:
+ case BPF_JMP | BPF_JSET | BPF_X:
+ true_cond = COND_NE;
+ /* Fall through */
+
+cond_branch:
+ switch (code) {
+ case BPF_JMP | BPF_JGT | BPF_X:
+ case BPF_JMP | BPF_JGE | BPF_X:
+ case BPF_JMP | BPF_JEQ | BPF_X:
+ case BPF_JMP | BPF_JNE | BPF_X:
+ /* unsigned comparison */
+ PPC_CMPLD(dst_reg, src_reg);
+ break;
+ case BPF_JMP | BPF_JSGT | BPF_X:
+ case BPF_JMP | BPF_JSGE | BPF_X:
+ /* signed comparison */
+ PPC_CMPD(dst_reg, src_reg);
+ break;
+ case BPF_JMP | BPF_JSET | BPF_X:
+ PPC_AND_DOT(b2p[TMP_REG_1], dst_reg, src_reg);
+ break;
+ case BPF_JMP | BPF_JNE | BPF_K:
+ case BPF_JMP | BPF_JEQ | BPF_K:
+ case BPF_JMP | BPF_JGT | BPF_K:
+ case BPF_JMP | BPF_JGE | BPF_K:
+ /*
+ * Need sign-extended load, so only positive
+ * values can be used as imm in cmpldi
+ */
+ if (imm >= 0 && imm < 32768)
+ PPC_CMPLDI(dst_reg, imm);
+ else {
+ /* sign-extending load */
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ /* ... but unsigned comparison */
+ PPC_CMPLD(dst_reg, b2p[TMP_REG_1]);
+ }
+ break;
+ case BPF_JMP | BPF_JSGT | BPF_K:
+ case BPF_JMP | BPF_JSGE | BPF_K:
+ /*
+ * signed comparison, so any 16-bit value
+ * can be used in cmpdi
+ */
+ if (imm >= -32768 && imm < 32768)
+ PPC_CMPDI(dst_reg, imm);
+ else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_CMPD(dst_reg, b2p[TMP_REG_1]);
+ }
+ break;
+ case BPF_JMP | BPF_JSET | BPF_K:
+ /* andi does not sign-extend the immediate */
+ if (imm >= 0 && imm < 32768)
+ /* PPC_ANDI is _only/always_ dot-form */
+ PPC_ANDI(b2p[TMP_REG_1], dst_reg, imm);
+ else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_AND_DOT(b2p[TMP_REG_1], dst_reg,
+ b2p[TMP_REG_1]);
+ }
+ break;
+ }
+ PPC_BCC(true_cond, addrs[i + 1 + off]);
+ break;
+
+ /*
+ * Loads from packet header/data
+ * Assume 32-bit input value in imm and X (src_reg)
+ */
+
+ /* Absolute loads */
+ case BPF_LD | BPF_W | BPF_ABS:
+ func = (u8 *)CHOOSE_LOAD_FUNC(imm, sk_load_word);
+ goto common_load_abs;
+ case BPF_LD | BPF_H | BPF_ABS:
+ func = (u8 *)CHOOSE_LOAD_FUNC(imm, sk_load_half);
+ goto common_load_abs;
+ case BPF_LD | BPF_B | BPF_ABS:
+ func = (u8 *)CHOOSE_LOAD_FUNC(imm, sk_load_byte);
+common_load_abs:
+ /*
+ * Load from [imm]
+ * Load into r4, which can just be passed onto
+ * skb load helpers as the second parameter
+ */
+ PPC_LI32(4, imm);
+ goto common_load;
+
+ /* Indirect loads */
+ case BPF_LD | BPF_W | BPF_IND:
+ func = (u8 *)sk_load_word;
+ goto common_load_ind;
+ case BPF_LD | BPF_H | BPF_IND:
+ func = (u8 *)sk_load_half;
+ goto common_load_ind;
+ case BPF_LD | BPF_B | BPF_IND:
+ func = (u8 *)sk_load_byte;
+common_load_ind:
+ /*
+ * Load from [src_reg + imm]
+ * Treat src_reg as a 32-bit value
+ */
+ PPC_EXTSW(4, src_reg);
+ if (imm) {
+ if (imm >= -32768 && imm < 32768)
+ PPC_ADDI(4, 4, IMM_L(imm));
+ else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ PPC_ADD(4, 4, b2p[TMP_REG_1]);
+ }
+ }
+
+common_load:
+ ctx->seen |= SEEN_SKB;
+ ctx->seen |= SEEN_FUNC;
+ bpf_jit_emit_func_call(image, ctx, (u64)func);
+
+ /*
+ * Helper returns 'lt' condition on error, and an
+ * appropriate return value in BPF_REG_0
+ */
+ PPC_BCC(COND_LT, exit_addr);
+ break;
+
+ /*
+ * TODO: Tail call
+ */
+ case BPF_JMP | BPF_CALL | BPF_X:
+
+ default:
+ /*
+ * The filter contains something cruel & unusual.
+ * We don't handle it, but also there shouldn't be
+ * anything missing from our list.
+ */
+ pr_err_ratelimited("eBPF filter opcode %04x (@%d) unsupported\n",
+ code, i);
+ return -ENOTSUPP;
+ }
+ }
+
+ /* Set end-of-body-code address for exit. */
+ addrs[i] = ctx->idx * 4;
+
+ return 0;
+}
+
+void bpf_jit_compile(struct bpf_prog *fp) { }
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
+{
+ u32 proglen;
+ u32 alloclen;
+ u8 *image = NULL;
+ u32 *code_base;
+ u32 *addrs;
+ struct codegen_context cgctx;
+ int pass;
+ int flen;
+ struct bpf_binary_header *bpf_hdr;
+
+ if (!bpf_jit_enable)
+ return fp;
+
+ flen = fp->len;
+ addrs = kzalloc((flen+1) * sizeof(*addrs), GFP_KERNEL);
+ if (addrs == NULL)
+ return fp;
+
+ cgctx.idx = 0;
+ cgctx.seen = 0;
+ /* Scouting faux-generate pass 0 */
+ if (bpf_jit_build_body(fp, 0, &cgctx, addrs))
+ /* We hit something illegal or unsupported. */
+ goto out;
+
+ /*
+ * Pretend to build prologue, given the features we've seen. This will
+ * update ctgtx.idx as it pretends to output instructions, then we can
+ * calculate total size from idx.
+ */
+ bpf_jit_build_prologue(0, &cgctx);
+ bpf_jit_build_epilogue(0, &cgctx);
+
+ proglen = cgctx.idx * 4;
+ alloclen = proglen + FUNCTION_DESCR_SIZE;
+
+ bpf_hdr = bpf_jit_binary_alloc(alloclen, &image, 4,
+ bpf_jit_fill_ill_insns);
+ if (!bpf_hdr)
+ goto out;
+
+ code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);
+
+ /* Code generation passes 1-2 */
+ for (pass = 1; pass < 3; pass++) {
+ /* Now build the prologue, body code & epilogue for real. */
+ cgctx.idx = 0;
+ bpf_jit_build_prologue(code_base, &cgctx);
+ bpf_jit_build_body(fp, code_base, &cgctx, addrs);
+ bpf_jit_build_epilogue(code_base, &cgctx);
+
+ if (bpf_jit_enable > 1)
+ pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass,
+ proglen - (cgctx.idx * 4), cgctx.seen);
+ }
+
+ if (bpf_jit_enable > 1)
+ /*
+ * Note that we output the base address of the code_base
+ * rather than image, since opcodes are in code_base.
+ */
+ bpf_jit_dump(flen, proglen, pass, code_base);
+
+ if (image) {
+ bpf_flush_icache(bpf_hdr, image + alloclen);
+#ifdef PPC64_ELF_ABI_v1
+ /* Function descriptor nastiness: Address + TOC */
+ ((u64 *)image)[0] = (u64)code_base;
+ ((u64 *)image)[1] = local_paca->kernel_toc;
+#endif
+ fp->bpf_func = (void *)image;
+ fp->jited = 1;
+ }
+
+out:
+ kfree(addrs);
+ return fp;
+}
+
+void bpf_jit_free(struct bpf_prog *fp)
+{
+ unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
+ struct bpf_binary_header *bpf_hdr = (void *)addr;
+
+ if (fp->jited)
+ bpf_jit_binary_free(bpf_hdr);
+
+ bpf_prog_unlock_free(fp);
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.