On Thu, Mar 9, 2023 at 10:03 AM Hari Bathini <hbath...@linux.ibm.com> wrote:
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. While here, correct the misnomer powerpc64_jit_data to
powerpc_jit_data as it is meant for both ppc32 and ppc64.
Signed-off-by: Hari Bathini <hbath...@linux.ibm.com>
---
arch/powerpc/net/bpf_jit.h | 7 +-
arch/powerpc/net/bpf_jit_comp.c | 104 +++++++++++++++++++++---------
arch/powerpc/net/bpf_jit_comp32.c | 4 +-
arch/powerpc/net/bpf_jit_comp64.c | 6 +-
4 files changed, 83 insertions(+), 38 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index d767e39d5645..a8b7480c4d43 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -168,15 +168,16 @@ 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_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 d1794d9f0154..ece75c829499 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -42,10 +42,11 @@ 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 {
+ struct bpf_binary_header *hdr;
+ struct bpf_binary_header *fhdr;
u32 *addrs;
- u8 *image;
+ u8 *fimage;
u32 proglen;
struct codegen_context ctx;
};
Some comments about the f- prefix will be helpful. (Yes, I should have done
better job adding comments for the x86 counterpart..)
@@ -62,15 +63,18 @@ 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;
@@ -100,9 +104,11 @@ 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;
+ 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;
goto skip_init_ctx;
}
@@ -120,7 +126,7 @@ 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;
@@ -135,7 +141,7 @@ 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;
}
@@ -157,17 +163,19 @@ 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++) {
@@ -175,8 +183,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
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;
}
@@ -192,21 +201,23 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
* Note that we output the base address of the code_base
* rather than image, since opcodes are in code_base.
*/
Maybe update the comment above with fcode_base to avoid
confusion.
- bpf_jit_dump(flen, proglen, pass, code_base);
+ bpf_jit_dump(flen, proglen, pass, fcode_base);
#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);
@@ -216,8 +227,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
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:
@@ -231,12 +243,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *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)
+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 */
@@ -247,9 +260,16 @@ 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 firt written to image before copying to the
s/firt/first/
+ * 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);
@@ -260,17 +280,17 @@ 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;
@@ -308,3 +328,27 @@ 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);
I just realized x86 is the same. But I think we only need the following
here?
bpf_arch_text_copy(&jit_data->fhdr->size, &jit_data->hdr->size,
sizeof(jit_data->hdr->size));
Right?
