diff options
Diffstat (limited to 'arch/powerpc/net/bpf_jit_comp64.c')
| -rw-r--r-- | arch/powerpc/net/bpf_jit_comp64.c | 89 |
1 files changed, 72 insertions, 17 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 79f23974a320..7703dcf48be8 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -202,29 +202,47 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) EMIT(PPC_RAW_BLR()); } -static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u64 func) +static int +bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) { unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0; long reladdr; - if (WARN_ON_ONCE(!core_kernel_text(func_addr))) + if (WARN_ON_ONCE(!kernel_text_address(func_addr))) return -EINVAL; - if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { - reladdr = func_addr - CTX_NIA(ctx); - - if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) { - pr_err("eBPF: address of %ps out of range of pcrel address.\n", - (void *)func); - return -ERANGE; - } - /* pla r12,addr */ - EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(1) | IMM_H18(reladdr)); - EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | IMM_L(reladdr)); - EMIT(PPC_RAW_MTCTR(_R12)); - EMIT(PPC_RAW_BCTR()); +#ifdef CONFIG_PPC_KERNEL_PCREL + reladdr = func_addr - local_paca->kernelbase; + if (reladdr < (long)SZ_8G && reladdr >= -(long)SZ_8G) { + EMIT(PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase))); + /* Align for subsequent prefix instruction */ + if (!IS_ALIGNED((unsigned long)fimage + CTX_NIA(ctx), 8)) + EMIT(PPC_RAW_NOP()); + /* paddi r12,r12,addr */ + EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(0) | IMM_H18(reladdr)); + EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12) | IMM_L(reladdr)); } else { + unsigned long pc = (unsigned long)fimage + CTX_NIA(ctx); + bool alignment_needed = !IS_ALIGNED(pc, 8); + + reladdr = func_addr - (alignment_needed ? pc + 4 : pc); + + if (reladdr < (long)SZ_8G && reladdr >= -(long)SZ_8G) { + if (alignment_needed) + EMIT(PPC_RAW_NOP()); + /* pla r12,addr */ + EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(1) | IMM_H18(reladdr)); + EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | IMM_L(reladdr)); + } else { + /* We can clobber r12 */ + PPC_LI64(_R12, func); + } + } + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_BCTRL()); +#else + if (core_kernel_text(func_addr)) { reladdr = func_addr - kernel_toc_addr(); if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { pr_err("eBPF: address of %ps out of range of kernel_toc.\n", (void *)func); @@ -235,7 +253,32 @@ static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u EMIT(PPC_RAW_ADDI(_R12, _R12, PPC_LO(reladdr))); EMIT(PPC_RAW_MTCTR(_R12)); EMIT(PPC_RAW_BCTRL()); + } else { + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1)) { + /* func points to the function descriptor */ + PPC_LI64(bpf_to_ppc(TMP_REG_2), func); + /* Load actual entry point from function descriptor */ + EMIT(PPC_RAW_LD(bpf_to_ppc(TMP_REG_1), bpf_to_ppc(TMP_REG_2), 0)); + /* ... and move it to CTR */ + EMIT(PPC_RAW_MTCTR(bpf_to_ppc(TMP_REG_1))); + /* + * Load TOC from function descriptor at offset 8. + * We can clobber r2 since we get called through a + * function pointer (so caller will save/restore r2). + */ + EMIT(PPC_RAW_LD(_R2, bpf_to_ppc(TMP_REG_2), 8)); + } else { + PPC_LI64(_R12, func); + EMIT(PPC_RAW_MTCTR(_R12)); + } + EMIT(PPC_RAW_BCTRL()); + /* + * Load r2 with kernel TOC as kernel TOC is used if function address falls + * within core kernel text. + */ + EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc))); } +#endif return 0; } @@ -285,7 +328,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o int b2p_index = bpf_to_ppc(BPF_REG_3); int bpf_tailcall_prologue_size = 8; - if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) + if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL) && IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) bpf_tailcall_prologue_size += 4; /* skip past the toc load */ /* @@ -803,6 +846,15 @@ emit_clear: /* Get offset into TMP_REG_1 */ EMIT(PPC_RAW_LI(tmp1_reg, off)); + /* + * Enforce full ordering for operations with BPF_FETCH by emitting a 'sync' + * before and after the operation. + * + * This is a requirement in the Linux Kernel Memory Model. + * See __cmpxchg_u64() in asm/cmpxchg.h as an example. + */ + if ((imm & BPF_FETCH) && IS_ENABLED(CONFIG_SMP)) + EMIT(PPC_RAW_SYNC()); tmp_idx = ctx->idx * 4; /* load value from memory into TMP_REG_2 */ if (size == BPF_DW) @@ -865,6 +917,9 @@ emit_clear: PPC_BCC_SHORT(COND_NE, tmp_idx); if (imm & BPF_FETCH) { + /* Emit 'sync' to enforce full ordering */ + if (IS_ENABLED(CONFIG_SMP)) + EMIT(PPC_RAW_SYNC()); EMIT(PPC_RAW_MR(ret_reg, _R0)); /* * Skip unnecessary zero-extension for 32-bit cmpxchg. @@ -993,7 +1048,7 @@ emit_clear: return ret; if (func_addr_fixed) - ret = bpf_jit_emit_func_call_hlp(image, ctx, func_addr); + ret = bpf_jit_emit_func_call_hlp(image, fimage, ctx, func_addr); else ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr); |