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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/powerpc/net/bpf_jit_comp.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/powerpc/net/bpf_jit_comp.c')
-rw-r--r--arch/powerpc/net/bpf_jit_comp.c359
1 files changed, 359 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..43e634126
--- /dev/null
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -0,0 +1,359 @@
+// 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);
+}
+
+/* Fix updated addresses (for subprog calls, ldimm64, et al) during extra pass */
+static int bpf_jit_fixup_addresses(struct bpf_prog *fp, u32 *image,
+ struct codegen_context *ctx, u32 *addrs)
+{
+ const struct bpf_insn *insn = fp->insnsi;
+ bool func_addr_fixed;
+ u64 func_addr;
+ u32 tmp_idx;
+ int i, j, ret;
+
+ for (i = 0; i < fp->len; i++) {
+ /*
+ * During the extra pass, only the branch target addresses for
+ * the subprog calls need to be fixed. All other instructions
+ * can left untouched.
+ *
+ * The JITed image length does not change because we already
+ * ensure that the JITed instruction sequence for these calls
+ * are of fixed length by padding them with NOPs.
+ */
+ if (insn[i].code == (BPF_JMP | BPF_CALL) &&
+ insn[i].src_reg == BPF_PSEUDO_CALL) {
+ ret = bpf_jit_get_func_addr(fp, &insn[i], true,
+ &func_addr,
+ &func_addr_fixed);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Save ctx->idx as this would currently point to the
+ * end of the JITed image and set it to the offset of
+ * the instruction sequence corresponding to the
+ * subprog call temporarily.
+ */
+ tmp_idx = ctx->idx;
+ ctx->idx = addrs[i] / 4;
+ ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
+ if (ret)
+ return ret;
+
+ /*
+ * Restore ctx->idx here. This is safe as the length
+ * of the JITed sequence remains unchanged.
+ */
+ ctx->idx = tmp_idx;
+ } else if (insn[i].code == (BPF_LD | BPF_IMM | BPF_DW)) {
+ tmp_idx = ctx->idx;
+ ctx->idx = addrs[i] / 4;
+#ifdef CONFIG_PPC32
+ PPC_LI32(bpf_to_ppc(insn[i].dst_reg) - 1, (u32)insn[i + 1].imm);
+ PPC_LI32(bpf_to_ppc(insn[i].dst_reg), (u32)insn[i].imm);
+ for (j = ctx->idx - addrs[i] / 4; j < 4; j++)
+ EMIT(PPC_RAW_NOP());
+#else
+ func_addr = ((u64)(u32)insn[i].imm) | (((u64)(u32)insn[i + 1].imm) << 32);
+ PPC_LI64(bpf_to_ppc(insn[i].dst_reg), func_addr);
+ /* overwrite rest with nops */
+ for (j = ctx->idx - addrs[i] / 4; j < 5; j++)
+ EMIT(PPC_RAW_NOP());
+#endif
+ ctx->idx = tmp_idx;
+ i++;
+ }
+ }
+
+ return 0;
+}
+
+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;
+ 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)) {
+ /* 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)) {
+ 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);
+
+ if (extra_pass) {
+ /*
+ * Do not touch the prologue and epilogue as they will remain
+ * unchanged. Only fix the branch target address for subprog
+ * calls in the body, and ldimm64 instructions.
+ *
+ * This does not change the offsets and lengths of the subprog
+ * call instruction sequences and hence, the size of the JITed
+ * image as well.
+ */
+ bpf_jit_fixup_addresses(fp, code_base, &cgctx, addrs);
+
+ /* There is no need to perform the usual passes. */
+ goto skip_codegen_passes;
+ }
+
+ /* 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)) {
+ 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);
+ }
+
+skip_codegen_passes:
+ 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;
+}