powerpc/bpf: use bpf_jit_binary_pack_[alloc|finalize|free]

Use bpf_jit_binary_pack_alloc in powerpc jit. The jit engine first
writes the program to the rw buffer. When the jit is done, the program
is copied to the final location with bpf_jit_binary_pack_finalize.
With multiple jit_subprogs, bpf_jit_free is called on some subprograms
that haven't got bpf_jit_binary_pack_finalize() yet. Implement custom
bpf_jit_free() like in commit 1d5f82d9dd47 ("bpf, x86: fix freeing of
not-finalized bpf_prog_pack") to call bpf_jit_binary_pack_finalize(),
if necessary. As bpf_flush_icache() is not needed anymore, remove it.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231020141358.643575-6-hbathini@linux.ibm.com

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index 72b7bb34fadea9e608664b235d996a4eb49ae6c3..cdea5dccaefe7333ab3d5a1f46b12ce3c019dd8a 100644 (file)
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -36,9 +36,6 @@
                EMIT(PPC_RAW_BRANCH(offset));                                 \
        } while (0)
 
-/* bl (unconditional 'branch' with link) */
-#define PPC_BL(dest)   EMIT(PPC_RAW_BL((dest) - (unsigned long)(image + ctx->idx)))
-
 /* "cond" here covers BO:BI fields. */
 #define PPC_BCC_SHORT(cond, dest)                                            \
        do {                                                                  \
@@ -147,12 +144,6 @@ struct codegen_context {
 #define BPF_FIXUP_LEN  2 /* Two instructions => 8 bytes */
 #endif
 
-static inline void bpf_flush_icache(void *start, void *end)
-{
-       smp_wmb();      /* smp write barrier */
-       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 - i));
@@ -169,16 +160,17 @@ static inline void bpf_clear_seen_register(struct codegen_context *ctx, int i)
 }
 
 void bpf_jit_init_reg_mapping(struct codegen_context *ctx);
-int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func);
-int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
+int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func);
+int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
                       u32 *addrs, int pass, bool extra_pass);
 void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx);
 void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx);
 void bpf_jit_realloc_regs(struct codegen_context *ctx);
 int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr);
 
-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);
 
 #endif
 

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 7a01bbc2513a5fddf35113802b3c3451fb1c98b5..0f9a2178332961ed70d699efd6447c33f4ca941c 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -44,9 +44,12 @@ int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg,
 }
 
 struct powerpc_jit_data {
-       struct bpf_binary_header *header;
+       /* 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;
 };
@@ -67,11 +70,14 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
        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;
 
@@ -101,9 +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;
@@ -123,7 +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;
@@ -138,7 +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;
                }
@@ -160,17 +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++) {
@@ -178,8 +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;
                }
@@ -199,17 +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);
@@ -219,8 +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:
@@ -234,12 +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 */
@@ -250,9 +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);
 
@@ -263,17 +291,17 @@ 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;
@@ -307,3 +335,27 @@ int bpf_arch_text_invalidate(void *dst, size_t len)
 
        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);
+}

diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index bc7f92ec7f2d701652e4da9d2312865fd158dbc5..2f39c50ca729e1c6c408fd6a07e2801ec2ef71d2 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -200,12 +200,13 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
        EMIT(PPC_RAW_BLR());
 }
 
-int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
+/* Relative offset needs to be calculated based on final image location */
+int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func)
 {
-       s32 rel = (s32)func - (s32)(image + ctx->idx);
+       s32 rel = (s32)func - (s32)(fimage + ctx->idx);
 
        if (image && rel < 0x2000000 && rel >= -0x2000000) {
-               PPC_BL(func);
+               EMIT(PPC_RAW_BL(rel));
        } else {
                /* Load function address into r0 */
                EMIT(PPC_RAW_LIS(_R0, IMM_H(func)));
@@ -278,7 +279,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o
 }
 
 /* Assemble the body code between the prologue & epilogue */
-int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
+int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
                       u32 *addrs, int pass, bool extra_pass)
 {
        const struct bpf_insn *insn = fp->insnsi;
@@ -997,7 +998,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
                                        jmp_off += 4;
                                }
 
-                               ret = bpf_add_extable_entry(fp, image, pass, ctx, insn_idx,
+                               ret = bpf_add_extable_entry(fp, image, fimage, pass, ctx, insn_idx,
                                                            jmp_off, dst_reg);
                                if (ret)
                                        return ret;
@@ -1053,7 +1054,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
                                EMIT(PPC_RAW_STW(bpf_to_ppc(BPF_REG_5), _R1, 12));
                        }
 
-                       ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
+                       ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr);
                        if (ret)
                                return ret;
 

diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 0f8048f6dad630b1547cfa9662d569a8a903c693..79f23974a32045b3e32d44d16107ce01e5de0325 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -240,7 +240,7 @@ static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u
        return 0;
 }
 
-int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
+int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func)
 {
        unsigned int i, ctx_idx = ctx->idx;
 
@@ -361,7 +361,7 @@ asm (
 );
 
 /* Assemble the body code between the prologue & epilogue */
-int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
+int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
                       u32 *addrs, int pass, bool extra_pass)
 {
        enum stf_barrier_type stf_barrier = stf_barrier_type_get();
@@ -940,8 +940,8 @@ emit_clear:
                                addrs[++i] = ctx->idx * 4;
 
                        if (BPF_MODE(code) == BPF_PROBE_MEM) {
-                               ret = bpf_add_extable_entry(fp, image, pass, ctx, ctx->idx - 1,
-                                                           4, dst_reg);
+                               ret = bpf_add_extable_entry(fp, image, fimage, pass, ctx,
+                                                           ctx->idx - 1, 4, dst_reg);
                                if (ret)
                                        return ret;
                        }
@@ -995,7 +995,7 @@ emit_clear:
                        if (func_addr_fixed)
                                ret = bpf_jit_emit_func_call_hlp(image, ctx, func_addr);
                        else
-                               ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
+                               ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr);
 
                        if (ret)
                                return ret;