diff options
Diffstat (limited to 'arch/powerpc/net/bpf_jit_comp.c')
-rw-r--r-- | arch/powerpc/net/bpf_jit_comp.c | 149 |
1 files changed, 117 insertions, 32 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 37043dfc1a..0f9a217833 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -13,9 +13,13 @@ #include <linux/netdevice.h> #include <linux/filter.h> #include <linux/if_vlan.h> -#include <asm/kprobes.h> +#include <linux/kernel.h> +#include <linux/memory.h> #include <linux/bpf.h> +#include <asm/kprobes.h> +#include <asm/code-patching.h> + #include "bpf_jit.h" static void bpf_jit_fill_ill_insns(void *area, unsigned int size) @@ -39,10 +43,13 @@ int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, return 0; } -struct powerpc64_jit_data { - struct bpf_binary_header *header; +struct powerpc_jit_data { + /* address of rw header */ + struct bpf_binary_header *hdr; + /* address of ro final header */ + struct bpf_binary_header *fhdr; u32 *addrs; - u8 *image; + u8 *fimage; u32 proglen; struct codegen_context ctx; }; @@ -59,15 +66,18 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) u8 *image = NULL; u32 *code_base; u32 *addrs; - struct powerpc64_jit_data *jit_data; + struct powerpc_jit_data *jit_data; struct codegen_context cgctx; int pass; int flen; - struct bpf_binary_header *bpf_hdr; + struct bpf_binary_header *fhdr = NULL; + struct bpf_binary_header *hdr = NULL; struct bpf_prog *org_fp = fp; struct bpf_prog *tmp_fp; bool bpf_blinded = false; bool extra_pass = false; + u8 *fimage = NULL; + u32 *fcode_base; u32 extable_len; u32 fixup_len; @@ -97,9 +107,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) addrs = jit_data->addrs; if (addrs) { cgctx = jit_data->ctx; - image = jit_data->image; - bpf_hdr = jit_data->header; + /* + * JIT compiled to a writable location (image/code_base) first. + * It is then moved to the readonly final location (fimage/fcode_base) + * using instruction patching. + */ + fimage = jit_data->fimage; + fhdr = jit_data->fhdr; proglen = jit_data->proglen; + hdr = jit_data->hdr; + image = (void *)hdr + ((void *)fimage - (void *)fhdr); extra_pass = true; /* During extra pass, ensure index is reset before repopulating extable entries */ cgctx.exentry_idx = 0; @@ -119,7 +136,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 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)) { + if (bpf_jit_build_body(fp, NULL, NULL, &cgctx, addrs, 0, false)) { /* We hit something illegal or unsupported. */ fp = org_fp; goto out_addrs; @@ -134,7 +151,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) */ 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)) { + if (bpf_jit_build_body(fp, NULL, NULL, &cgctx, addrs, 0, false)) { fp = org_fp; goto out_addrs; } @@ -146,9 +163,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) * 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_prologue(NULL, &cgctx); addrs[fp->len] = cgctx.idx * 4; - bpf_jit_build_epilogue(0, &cgctx); + bpf_jit_build_epilogue(NULL, &cgctx); fixup_len = fp->aux->num_exentries * BPF_FIXUP_LEN * 4; extable_len = fp->aux->num_exentries * sizeof(struct exception_table_entry); @@ -156,17 +173,19 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 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) { + fhdr = bpf_jit_binary_pack_alloc(alloclen, &fimage, 4, &hdr, &image, + bpf_jit_fill_ill_insns); + if (!fhdr) { fp = org_fp; goto out_addrs; } if (extable_len) - fp->aux->extable = (void *)image + FUNCTION_DESCR_SIZE + proglen + fixup_len; + fp->aux->extable = (void *)fimage + FUNCTION_DESCR_SIZE + proglen + fixup_len; skip_init_ctx: code_base = (u32 *)(image + FUNCTION_DESCR_SIZE); + fcode_base = (u32 *)(fimage + FUNCTION_DESCR_SIZE); /* Code generation passes 1-2 */ for (pass = 1; pass < 3; pass++) { @@ -174,8 +193,10 @@ skip_init_ctx: 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); + if (bpf_jit_build_body(fp, code_base, fcode_base, &cgctx, addrs, pass, + extra_pass)) { + bpf_arch_text_copy(&fhdr->size, &hdr->size, sizeof(hdr->size)); + bpf_jit_binary_pack_free(fhdr, hdr); fp = org_fp; goto out_addrs; } @@ -195,17 +216,19 @@ skip_init_ctx: #ifdef CONFIG_PPC64_ELF_ABI_V1 /* Function descriptor nastiness: Address + TOC */ - ((u64 *)image)[0] = (u64)code_base; + ((u64 *)image)[0] = (u64)fcode_base; ((u64 *)image)[1] = local_paca->kernel_toc; #endif - fp->bpf_func = (void *)image; + fp->bpf_func = (void *)fimage; 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); + if (bpf_jit_binary_pack_finalize(fp, fhdr, hdr)) { + fp = org_fp; + goto out_addrs; + } bpf_prog_fill_jited_linfo(fp, addrs); out_addrs: kfree(addrs); @@ -215,8 +238,9 @@ out_addrs: jit_data->addrs = addrs; jit_data->ctx = cgctx; jit_data->proglen = proglen; - jit_data->image = image; - jit_data->header = bpf_hdr; + jit_data->fimage = fimage; + jit_data->fhdr = fhdr; + jit_data->hdr = hdr; } out: @@ -230,12 +254,13 @@ out: * 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) +int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, 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; + struct exception_table_entry *ex, *ex_entry; u32 *fixup; /* Populate extable entries only in the last pass */ @@ -246,9 +271,16 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct code WARN_ON_ONCE(ctx->exentry_idx >= fp->aux->num_exentries)) return -EINVAL; + /* + * Program is first written to image before copying to the + * final location (fimage). Accordingly, update in the image first. + * As all offsets used are relative, copying as is to the + * final location should be alright. + */ pc = (unsigned long)&image[insn_idx]; + ex = (void *)fp->aux->extable - (void *)fimage + (void *)image; - fixup = (void *)fp->aux->extable - + fixup = (void *)ex - (fp->aux->num_exentries * BPF_FIXUP_LEN * 4) + (ctx->exentry_idx * BPF_FIXUP_LEN * 4); @@ -259,18 +291,71 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct code 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]; + ex_entry = &ex[ctx->exentry_idx]; - offset = pc - (long)&ex->insn; + offset = pc - (long)&ex_entry->insn; if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN)) return -ERANGE; - ex->insn = offset; + ex_entry->insn = offset; - offset = (long)fixup - (long)&ex->fixup; + offset = (long)fixup - (long)&ex_entry->fixup; if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN)) return -ERANGE; - ex->fixup = offset; + ex_entry->fixup = offset; ctx->exentry_idx++; return 0; } + +void *bpf_arch_text_copy(void *dst, void *src, size_t len) +{ + int err; + + if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst))) + return ERR_PTR(-EINVAL); + + mutex_lock(&text_mutex); + err = patch_instructions(dst, src, len, false); + mutex_unlock(&text_mutex); + + return err ? ERR_PTR(err) : dst; +} + +int bpf_arch_text_invalidate(void *dst, size_t len) +{ + u32 insn = BREAKPOINT_INSTRUCTION; + int ret; + + if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst))) + return -EINVAL; + + mutex_lock(&text_mutex); + ret = patch_instructions(dst, &insn, len, true); + mutex_unlock(&text_mutex); + + return ret; +} + +void bpf_jit_free(struct bpf_prog *fp) +{ + if (fp->jited) { + struct powerpc_jit_data *jit_data = fp->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(fp, jit_data->fhdr, jit_data->hdr); + kvfree(jit_data->addrs); + kfree(jit_data); + } + hdr = bpf_jit_binary_pack_hdr(fp); + bpf_jit_binary_pack_free(hdr, NULL); + WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); + } + + bpf_prog_unlock_free(fp); +} |