1 files changed, 119 insertions, 31 deletions

diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
index fed86f42dfbe..f6ca5cfa6b2f 100644
--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -8,10 +8,13 @@
 
 #include <linux/bpf.h>
 #include <linux/filter.h>
+#include <linux/memory.h>
+#include <asm/text-patching.h>
+#include <asm/cfi.h>
 #include "bpf_jit.h"
 
 /* Number of iterations to try until offsets converge. */
-#define NR_JIT_ITERATIONS	16
+#define NR_JIT_ITERATIONS	32
 
 static int build_body(struct rv_jit_context *ctx, bool extra_pass, int *offset)
 {
@@ -23,9 +26,8 @@ static int build_body(struct rv_jit_context *ctx, bool extra_pass, int *offset)
 		int ret;
 
 		ret = bpf_jit_emit_insn(insn, ctx, extra_pass);
-		/* BPF_LD | BPF_IMM | BPF_DW: skip the next instruction. */
 		if (ret > 0)
-			i++;
+			i++; /* skip the next instruction */
 		if (offset)
 			offset[i] = ctx->ninsns;
 		if (ret < 0)
@@ -41,12 +43,12 @@ bool bpf_jit_needs_zext(void)
 
 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 {
+	unsigned int prog_size = 0, extable_size = 0;
 	bool tmp_blinded = false, extra_pass = false;
 	struct bpf_prog *tmp, *orig_prog = prog;
 	int pass = 0, prev_ninsns = 0, i;
 	struct rv_jit_data *jit_data;
 	struct rv_jit_context *ctx;
-	unsigned int image_size = 0;
 
 	if (!prog->jit_requested)
 		return orig_prog;
@@ -73,16 +75,24 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 
 	if (ctx->offset) {
 		extra_pass = true;
-		image_size = sizeof(*ctx->insns) * ctx->ninsns;
+		prog_size = sizeof(*ctx->insns) * ctx->ninsns;
 		goto skip_init_ctx;
 	}
 
+	ctx->arena_vm_start = bpf_arena_get_kern_vm_start(prog->aux->arena);
+	ctx->user_vm_start = bpf_arena_get_user_vm_start(prog->aux->arena);
 	ctx->prog = prog;
 	ctx->offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
 	if (!ctx->offset) {
 		prog = orig_prog;
 		goto out_offset;
 	}
+
+	if (build_body(ctx, extra_pass, NULL)) {
+		prog = orig_prog;
+		goto out_offset;
+	}
+
 	for (i = 0; i < prog->len; i++) {
 		prev_ninsns += 32;
 		ctx->offset[i] = prev_ninsns;
@@ -91,29 +101,44 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	for (i = 0; i < NR_JIT_ITERATIONS; i++) {
 		pass++;
 		ctx->ninsns = 0;
+
+		bpf_jit_build_prologue(ctx, bpf_is_subprog(prog));
+		ctx->prologue_len = ctx->ninsns;
+
 		if (build_body(ctx, extra_pass, ctx->offset)) {
 			prog = orig_prog;
 			goto out_offset;
 		}
-		bpf_jit_build_prologue(ctx);
+
 		ctx->epilogue_offset = ctx->ninsns;
 		bpf_jit_build_epilogue(ctx);
 
 		if (ctx->ninsns == prev_ninsns) {
 			if (jit_data->header)
 				break;
+			/* obtain the actual image size */
+			extable_size = prog->aux->num_exentries *
+				sizeof(struct exception_table_entry);
+			prog_size = sizeof(*ctx->insns) * ctx->ninsns;
 
-			image_size = sizeof(*ctx->insns) * ctx->ninsns;
-			jit_data->header =
-				bpf_jit_binary_alloc(image_size,
-						     &jit_data->image,
-						     sizeof(u32),
-						     bpf_fill_ill_insns);
-			if (!jit_data->header) {
+			jit_data->ro_header =
+				bpf_jit_binary_pack_alloc(prog_size + extable_size,
+							  &jit_data->ro_image, sizeof(u32),
+							  &jit_data->header, &jit_data->image,
+							  bpf_fill_ill_insns);
+			if (!jit_data->ro_header) {
 				prog = orig_prog;
 				goto out_offset;
 			}
 
+			/*
+			 * Use the image(RW) for writing the JITed instructions. But also save
+			 * the ro_image(RX) for calculating the offsets in the image. The RW
+			 * image will be later copied to the RX image from where the program
+			 * will run. The bpf_jit_binary_pack_finalize() will do this copy in the
+			 * final step.
+			 */
+			ctx->ro_insns = (u16 *)jit_data->ro_image;
 			ctx->insns = (u16 *)jit_data->image;
 			/*
 			 * Now, when the image is allocated, the image can
@@ -125,34 +150,49 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 
 	if (i == NR_JIT_ITERATIONS) {
 		pr_err("bpf-jit: image did not converge in <%d passes!\n", i);
-		bpf_jit_binary_free(jit_data->header);
 		prog = orig_prog;
-		goto out_offset;
+		goto out_free_hdr;
 	}
 
+	if (extable_size)
+		prog->aux->extable = (void *)ctx->ro_insns + prog_size;
+
 skip_init_ctx:
 	pass++;
 	ctx->ninsns = 0;
+	ctx->nexentries = 0;
 
-	bpf_jit_build_prologue(ctx);
+	bpf_jit_build_prologue(ctx, bpf_is_subprog(prog));
 	if (build_body(ctx, extra_pass, NULL)) {
-		bpf_jit_binary_free(jit_data->header);
 		prog = orig_prog;
-		goto out_offset;
+		goto out_free_hdr;
 	}
 	bpf_jit_build_epilogue(ctx);
 
 	if (bpf_jit_enable > 1)
-		bpf_jit_dump(prog->len, image_size, pass, ctx->insns);
+		bpf_jit_dump(prog->len, prog_size, pass, ctx->insns);
 
-	prog->bpf_func = (void *)ctx->insns;
+	prog->bpf_func = (void *)ctx->ro_insns + cfi_get_offset();
 	prog->jited = 1;
-	prog->jited_len = image_size;
-
-	bpf_flush_icache(jit_data->header, ctx->insns + ctx->ninsns);
+	prog->jited_len = prog_size - cfi_get_offset();
 
 	if (!prog->is_func || extra_pass) {
-		bpf_jit_binary_lock_ro(jit_data->header);
+		if (WARN_ON(bpf_jit_binary_pack_finalize(jit_data->ro_header, jit_data->header))) {
+			/* ro_header has been freed */
+			jit_data->ro_header = NULL;
+			prog = orig_prog;
+			goto out_offset;
+		}
+		/*
+		 * The instructions have now been copied to the ROX region from
+		 * where they will execute.
+		 * Write any modified data cache blocks out to memory and
+		 * invalidate the corresponding blocks in the instruction cache.
+		 */
+		bpf_flush_icache(jit_data->ro_header, ctx->ro_insns + ctx->ninsns);
+		for (i = 0; i < prog->len; i++)
+			ctx->offset[i] = ninsns_rvoff(ctx->offset[i]);
+		bpf_prog_fill_jited_linfo(prog, ctx->offset);
 out_offset:
 		kfree(ctx->offset);
 		kfree(jit_data);
@@ -164,17 +204,65 @@ out:
 		bpf_jit_prog_release_other(prog, prog == orig_prog ?
 					   tmp : orig_prog);
 	return prog;
+
+out_free_hdr:
+	if (jit_data->header) {
+		bpf_arch_text_copy(&jit_data->ro_header->size, &jit_data->header->size,
+				   sizeof(jit_data->header->size));
+		bpf_jit_binary_pack_free(jit_data->ro_header, jit_data->header);
+	}
+	goto out_offset;
 }
 
-void *bpf_jit_alloc_exec(unsigned long size)
+u64 bpf_jit_alloc_exec_limit(void)
 {
-	return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START,
-				    BPF_JIT_REGION_END, GFP_KERNEL,
-				    PAGE_KERNEL, 0, NUMA_NO_NODE,
-				    __builtin_return_address(0));
+	return BPF_JIT_REGION_SIZE;
 }
 
-void bpf_jit_free_exec(void *addr)
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
 {
-	return vfree(addr);
+	int ret;
+
+	mutex_lock(&text_mutex);
+	ret = patch_text_nosync(dst, src, len);
+	mutex_unlock(&text_mutex);
+
+	if (ret)
+		return ERR_PTR(-EINVAL);
+
+	return dst;
+}
+
+int bpf_arch_text_invalidate(void *dst, size_t len)
+{
+	int ret;
+
+	mutex_lock(&text_mutex);
+	ret = patch_text_set_nosync(dst, 0, len);
+	mutex_unlock(&text_mutex);
+
+	return ret;
+}
+
+void bpf_jit_free(struct bpf_prog *prog)
+{
+	if (prog->jited) {
+		struct rv_jit_data *jit_data = prog->aux->jit_data;
+		struct bpf_binary_header *hdr;
+
+		/*
+		 * If we fail the final pass of JIT (from jit_subprogs),
+		 * the program may not be finalized yet. Call finalize here
+		 * before freeing it.
+		 */
+		if (jit_data) {
+			bpf_jit_binary_pack_finalize(jit_data->ro_header, jit_data->header);
+			kfree(jit_data);
+		}
+		hdr = bpf_jit_binary_pack_hdr(prog);
+		bpf_jit_binary_pack_free(hdr, NULL);
+		WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
+	}
+
+	bpf_prog_unlock_free(prog);
 }