On 04/18/2017 08:58 PM, David Miller wrote:
This is an eBPF JIT for sparc64. All major features are supported
except for tail calls.
test_bpf passes with no failures and all tests are JIT'd, both with
and without hardening enabled.
Signed-off-by: David S. Miller <da...@davemloft.net>
[...]
While going over the code again, I noticed two minor
things that could still be changed before applying:
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
+{
+ struct bpf_prog *tmp, *orig_prog = prog;
+ struct bpf_binary_header *header;
+ bool tmp_blinded = false;
+ struct jit_ctx ctx;
+ u32 image_size;
+ u8 *image_ptr;
+ int pass;
+
+ if (!bpf_jit_enable)
+ return orig_prog;
+
+ if (!prog || !prog->len)
+ return orig_prog;
This condition can be removed, see also 93a73d442d37
("bpf, x86/arm64: remove useless checks on prog"), since
there's no way we could land here under such circumstance.
+ tmp = bpf_jit_blind_constants(prog);
+ /* If blinding was requested and we failed during blinding,
+ * we must fall back to the interpreter.
+ */
+ if (IS_ERR(tmp))
+ return orig_prog;
+ if (tmp != prog) {
+ tmp_blinded = true;
+ prog = tmp;
+ }
+
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.prog = prog;
+
+ ctx.offset = kcalloc(prog->len, sizeof(unsigned int), GFP_KERNEL);
+ if (ctx.offset == NULL) {
+ prog = orig_prog;
+ goto out;
+ }
+
+ /* Fake pass to detect features used, and get an accurate assessment
+ * of what the final image size will be.
+ */
+ if (build_body(&ctx)) {
+ prog = orig_prog;
+ goto out_off;
+ }
+ build_prologue(&ctx);
+ build_epilogue(&ctx);
+
+ /* Now we know the actual image size. */
+ image_size = sizeof(u32) * ctx.idx;
+ header = bpf_jit_binary_alloc(image_size, &image_ptr,
+ sizeof(u32), jit_fill_hole);
+ if (header == NULL) {
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ ctx.image = (u32 *)image_ptr;
+
+ for (pass = 1; pass < 3; pass++) {
+ ctx.idx = 0;
+
+ build_prologue(&ctx);
+
+ if (build_body(&ctx)) {
+ bpf_jit_binary_free(header);
+ prog = orig_prog;
+ goto out_off;
+ }
+
+ build_epilogue(&ctx);
+
+ if (bpf_jit_enable > 1)
+ pr_info("Pass %d: shrink = %d, seen = [%c%c%c%c%c]\n",
pass,
+ image_size - (ctx.idx * 4),
+ ctx.tmp_1_used ? '1' : ' ',
+ ctx.tmp_2_used ? '2' : ' ',
+ ctx.tmp_3_used ? '3' : ' ',
+ ctx.saw_ld_abs_ind ? 'L' : ' ',
+ ctx.saw_frame_pointer ? 'F' : ' ');
+ }
+
+ if (bpf_jit_enable > 1)
+ bpf_jit_dump(prog->len, image_size, pass, ctx.image);
+ bpf_flush_icache(ctx.image, ctx.image + image_size);
Since remaining parts were filled through jit_fill_hole(),
it would be better / more correct to flush the whole buffer,
see also the recent ppc64 commit 10528b9c45cf ("powerpc/bpf:
Flush the entire JIT buffer") that fixed it for their jit.
+ bpf_jit_binary_lock_ro(header);
+
+ prog->bpf_func = (void *)ctx.image;
+ prog->jited = 1;
+
+out_off:
+ kfree(ctx.offset);
Thanks a lot,
Daniel
