From: Abhishek Dubey <[email protected]> Ensure the dummy trampoline address field present between the OOL stub and the long branch stub is 8-byte aligned, for memory compatibility when content loaded to a register.
Reported-by: Hari Bathini <[email protected]> Fixes: d243b62b7bd3 ("powerpc64/bpf: Add support for bpf trampolines") Cc: [email protected] Signed-off-by: Abhishek Dubey <[email protected]> --- arch/powerpc/net/bpf_jit.h | 4 ++-- arch/powerpc/net/bpf_jit_comp.c | 34 ++++++++++++++++++++++++++----- arch/powerpc/net/bpf_jit_comp64.c | 4 ++-- 3 files changed, 33 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h index 7354e1d72f79..1184ad15d5a4 100644 --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -208,8 +208,8 @@ int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context * 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_build_fentry_stubs(u32 *image, struct codegen_context *ctx); +void bpf_jit_build_epilogue(u32 *image, u32 *fimage, struct codegen_context *ctx); +void bpf_jit_build_fentry_stubs(u32 *image, u32 *fimage, 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); diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index a62a9a92b7b5..c255b30a37b0 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -49,11 +49,34 @@ asm ( " .popsection ;" ); -void bpf_jit_build_fentry_stubs(u32 *image, struct codegen_context *ctx) +void bpf_jit_build_fentry_stubs(u32 *image, u32 *fimage, struct codegen_context *ctx) { int ool_stub_idx, long_branch_stub_idx; /* + * In the final pass, align the mis-aligned dummy_tramp_addr field + * in the fimage. The alignment NOP must appear before OOL stub, + * to make ool_stub_idx & long_branch_stub_idx constant from end. + * + * Need alignment NOP in following conditions: + * + * OOL stub aligned CONFIG_PPC_FTRACE_OUT_OF_LINE Alignment NOP + * Y Y N + * Y N Y + * N Y Y + * N N N + */ +#ifdef CONFIG_PPC64 + if (fimage && image) { + unsigned long pc = (unsigned long)fimage + CTX_NIA(ctx); + + if (IS_ALIGNED(pc, 8) ^ + IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) + EMIT(PPC_RAW_NOP()); + } +#endif + + /* nop // optional, for alignment of dummy_tramp_addr * Out-of-line stub: * mflr r0 * [b|bl] tramp @@ -70,7 +93,7 @@ void bpf_jit_build_fentry_stubs(u32 *image, struct codegen_context *ctx) /* * Long branch stub: - * .long <dummy_tramp_addr> + * .long <dummy_tramp_addr> // 8-byte aligned * mflr r11 * bcl 20,31,$+4 * mflr r12 @@ -81,6 +104,7 @@ void bpf_jit_build_fentry_stubs(u32 *image, struct codegen_context *ctx) */ if (image) *((unsigned long *)&image[ctx->idx]) = (unsigned long)dummy_tramp; + ctx->idx += SZL / 4; long_branch_stub_idx = ctx->idx; EMIT(PPC_RAW_MFLR(_R11)); @@ -107,7 +131,7 @@ int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, PPC_JMP(ctx->alt_exit_addr); } else { ctx->alt_exit_addr = ctx->idx * 4; - bpf_jit_build_epilogue(image, ctx); + bpf_jit_build_epilogue(image, NULL, ctx); } return 0; @@ -240,7 +264,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) */ bpf_jit_build_prologue(NULL, &cgctx); addrs[fp->len] = cgctx.idx * 4; - bpf_jit_build_epilogue(NULL, &cgctx); + bpf_jit_build_epilogue(NULL, NULL, &cgctx); fixup_len = fp->aux->num_exentries * BPF_FIXUP_LEN * 4; extable_len = fp->aux->num_exentries * sizeof(struct exception_table_entry); @@ -275,7 +299,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) fp = org_fp; goto out_addrs; } - bpf_jit_build_epilogue(code_base, &cgctx); + bpf_jit_build_epilogue(code_base, fcode_base, &cgctx); if (bpf_jit_enable > 1) pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass, diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index c5e26d231cd5..d4873979ae9d 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -348,7 +348,7 @@ static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx } } -void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) +void bpf_jit_build_epilogue(u32 *image, u32 *fimage, struct codegen_context *ctx) { bpf_jit_emit_common_epilogue(image, ctx); @@ -357,7 +357,7 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) EMIT(PPC_RAW_BLR()); - bpf_jit_build_fentry_stubs(image, ctx); + bpf_jit_build_fentry_stubs(image, fimage, ctx); } /* -- 2.52.0
