1 files changed, 276 insertions, 0 deletions

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
new file mode 100644
index 000000000..37043dfc1
--- /dev/null
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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
+ */
+#include <linux/moduleloader.h>
+#include <asm/cacheflush.h>
+#include <asm/asm-compat.h>
+#include <linux/netdevice.h>
+#include <linux/filter.h>
+#include <linux/if_vlan.h>
+#include <asm/kprobes.h>
+#include <linux/bpf.h>
+
+#include "bpf_jit.h"
+
+static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
+{
+	memset32(area, BREAKPOINT_INSTRUCTION, size / 4);
+}
+
+int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr)
+{
+	if (!exit_addr || is_offset_in_branch_range(exit_addr - (ctx->idx * 4))) {
+		PPC_JMP(exit_addr);
+	} else if (ctx->alt_exit_addr) {
+		if (WARN_ON(!is_offset_in_branch_range((long)ctx->alt_exit_addr - (ctx->idx * 4))))
+			return -1;
+		PPC_JMP(ctx->alt_exit_addr);
+	} else {
+		ctx->alt_exit_addr = ctx->idx * 4;
+		bpf_jit_build_epilogue(image, ctx);
+	}
+
+	return 0;
+}
+
+struct powerpc64_jit_data {
+	struct bpf_binary_header *header;
+	u32 *addrs;
+	u8 *image;
+	u32 proglen;
+	struct codegen_context ctx;
+};
+
+bool bpf_jit_needs_zext(void)
+{
+	return true;
+}
+
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
+{
+	u32 proglen;
+	u32 alloclen;
+	u8 *image = NULL;
+	u32 *code_base;
+	u32 *addrs;
+	struct powerpc64_jit_data *jit_data;
+	struct codegen_context cgctx;
+	int pass;
+	int flen;
+	struct bpf_binary_header *bpf_hdr;
+	struct bpf_prog *org_fp = fp;
+	struct bpf_prog *tmp_fp;
+	bool bpf_blinded = false;
+	bool extra_pass = false;
+	u32 extable_len;
+	u32 fixup_len;
+
+	if (!fp->jit_requested)
+		return org_fp;
+
+	tmp_fp = bpf_jit_blind_constants(org_fp);
+	if (IS_ERR(tmp_fp))
+		return org_fp;
+
+	if (tmp_fp != org_fp) {
+		bpf_blinded = true;
+		fp = tmp_fp;
+	}
+
+	jit_data = fp->aux->jit_data;
+	if (!jit_data) {
+		jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
+		if (!jit_data) {
+			fp = org_fp;
+			goto out;
+		}
+		fp->aux->jit_data = jit_data;
+	}
+
+	flen = fp->len;
+	addrs = jit_data->addrs;
+	if (addrs) {
+		cgctx = jit_data->ctx;
+		image = jit_data->image;
+		bpf_hdr = jit_data->header;
+		proglen = jit_data->proglen;
+		extra_pass = true;
+		/* During extra pass, ensure index is reset before repopulating extable entries */
+		cgctx.exentry_idx = 0;
+		goto skip_init_ctx;
+	}
+
+	addrs = kcalloc(flen + 1, sizeof(*addrs), GFP_KERNEL);
+	if (addrs == NULL) {
+		fp = org_fp;
+		goto out_addrs;
+	}
+
+	memset(&cgctx, 0, sizeof(struct codegen_context));
+	bpf_jit_init_reg_mapping(&cgctx);
+
+	/* Make sure that the stack is quadword aligned. */
+	cgctx.stack_size = round_up(fp->aux->stack_depth, 16);
+
+	/* Scouting faux-generate pass 0 */
+	if (bpf_jit_build_body(fp, 0, &cgctx, addrs, 0, false)) {
+		/* We hit something illegal or unsupported. */
+		fp = org_fp;
+		goto out_addrs;
+	}
+
+	/*
+	 * If we have seen a tail call, we need a second pass.
+	 * This is because bpf_jit_emit_common_epilogue() is called
+	 * from bpf_jit_emit_tail_call() with a not yet stable ctx->seen.
+	 * We also need a second pass if we ended up with too large
+	 * a program so as to ensure BPF_EXIT branches are in range.
+	 */
+	if (cgctx.seen & SEEN_TAILCALL || !is_offset_in_branch_range((long)cgctx.idx * 4)) {
+		cgctx.idx = 0;
+		if (bpf_jit_build_body(fp, 0, &cgctx, addrs, 0, false)) {
+			fp = org_fp;
+			goto out_addrs;
+		}
+	}
+
+	bpf_jit_realloc_regs(&cgctx);
+	/*
+	 * 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);
+	addrs[fp->len] = cgctx.idx * 4;
+	bpf_jit_build_epilogue(0, &cgctx);
+
+	fixup_len = fp->aux->num_exentries * BPF_FIXUP_LEN * 4;
+	extable_len = fp->aux->num_exentries * sizeof(struct exception_table_entry);
+
+	proglen = cgctx.idx * 4;
+	alloclen = proglen + FUNCTION_DESCR_SIZE + fixup_len + extable_len;
+
+	bpf_hdr = bpf_jit_binary_alloc(alloclen, &image, 4, bpf_jit_fill_ill_insns);
+	if (!bpf_hdr) {
+		fp = org_fp;
+		goto out_addrs;
+	}
+
+	if (extable_len)
+		fp->aux->extable = (void *)image + FUNCTION_DESCR_SIZE + proglen + fixup_len;
+
+skip_init_ctx:
+	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;
+		cgctx.alt_exit_addr = 0;
+		bpf_jit_build_prologue(code_base, &cgctx);
+		if (bpf_jit_build_body(fp, code_base, &cgctx, addrs, pass, extra_pass)) {
+			bpf_jit_binary_free(bpf_hdr);
+			fp = org_fp;
+			goto out_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);
+
+#ifdef CONFIG_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;
+	fp->jited_len = proglen + FUNCTION_DESCR_SIZE;
+
+	bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + bpf_hdr->size);
+	if (!fp->is_func || extra_pass) {
+		bpf_jit_binary_lock_ro(bpf_hdr);
+		bpf_prog_fill_jited_linfo(fp, addrs);
+out_addrs:
+		kfree(addrs);
+		kfree(jit_data);
+		fp->aux->jit_data = NULL;
+	} else {
+		jit_data->addrs = addrs;
+		jit_data->ctx = cgctx;
+		jit_data->proglen = proglen;
+		jit_data->image = image;
+		jit_data->header = bpf_hdr;
+	}
+
+out:
+	if (bpf_blinded)
+		bpf_jit_prog_release_other(fp, fp == org_fp ? tmp_fp : org_fp);
+
+	return fp;
+}
+
+/*
+ * The caller should check for (BPF_MODE(code) == BPF_PROBE_MEM) before calling
+ * this function, as this only applies to BPF_PROBE_MEM, for now.
+ */
+int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct codegen_context *ctx,
+			  int insn_idx, int jmp_off, int dst_reg)
+{
+	off_t offset;
+	unsigned long pc;
+	struct exception_table_entry *ex;
+	u32 *fixup;
+
+	/* Populate extable entries only in the last pass */
+	if (pass != 2)
+		return 0;
+
+	if (!fp->aux->extable ||
+	    WARN_ON_ONCE(ctx->exentry_idx >= fp->aux->num_exentries))
+		return -EINVAL;
+
+	pc = (unsigned long)&image[insn_idx];
+
+	fixup = (void *)fp->aux->extable -
+		(fp->aux->num_exentries * BPF_FIXUP_LEN * 4) +
+		(ctx->exentry_idx * BPF_FIXUP_LEN * 4);
+
+	fixup[0] = PPC_RAW_LI(dst_reg, 0);
+	if (IS_ENABLED(CONFIG_PPC32))
+		fixup[1] = PPC_RAW_LI(dst_reg - 1, 0); /* clear higher 32-bit register too */
+
+	fixup[BPF_FIXUP_LEN - 1] =
+		PPC_RAW_BRANCH((long)(pc + jmp_off) - (long)&fixup[BPF_FIXUP_LEN - 1]);
+
+	ex = &fp->aux->extable[ctx->exentry_idx];
+
+	offset = pc - (long)&ex->insn;
+	if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+		return -ERANGE;
+	ex->insn = offset;
+
+	offset = (long)fixup - (long)&ex->fixup;
+	if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+		return -ERANGE;
+	ex->fixup = offset;
+
+	ctx->exentry_idx++;
+	return 0;
+}