diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index a4aa1e4c9f1c..85457bcb2040 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -638,15 +638,10 @@ static int invoke_bpf_mod_ret(u32 *image, u32 *ro_image, struct codegen_context * for the traced function (BPF subprog/callee) to fetch it. */ static void bpf_trampoline_setup_tail_call_info(u32 *image, struct codegen_context *ctx, - int func_frame_offset, - int bpf_dummy_frame_size, int r4_off) + int bpf_frame_size, int r4_off) { if (IS_ENABLED(CONFIG_PPC64)) { - /* - * func_frame_offset = ...(1) - * bpf_dummy_frame_size + trampoline_frame_size - */ - EMIT(PPC_RAW_LD(_R4, _R1, func_frame_offset)); + EMIT(PPC_RAW_LD(_R4, _R1, bpf_frame_size)); /* Refer to trampoline's Generated stack layout */ EMIT(PPC_RAW_LD(_R3, _R4, -BPF_PPC_TAILCALL)); @@ -657,21 +652,13 @@ static void bpf_trampoline_setup_tail_call_info(u32 *image, struct codegen_conte EMIT(PPC_RAW_CMPLWI(_R3, MAX_TAIL_CALL_CNT)); PPC_BCC_CONST_SHORT(COND_GT, 8); EMIT(PPC_RAW_ADDI(_R3, _R4, -BPF_PPC_TAILCALL)); + /* - * From ...(1) above: - * trampoline_frame_bottom = ...(2) - * func_frame_offset - bpf_dummy_frame_size - * - * Using ...(2) derived above: - * trampoline_tail_call_info_offset = ...(3) - * trampoline_frame_bottom - BPF_PPC_TAILCALL - * - * From ...(3): - * Use trampoline_tail_call_info_offset to write reference of main's - * tail_call_info in trampoline frame. + * Trampoline's tail_call_info is at the same offset, as that of + * any bpf program, with reference to previous frame. Update the + * address of main's tail_call_info in trampoline frame. */ - EMIT(PPC_RAW_STL(_R3, _R1, (func_frame_offset - bpf_dummy_frame_size) - - BPF_PPC_TAILCALL)); + EMIT(PPC_RAW_STL(_R3, _R1, bpf_frame_size - BPF_PPC_TAILCALL)); } else { /* See bpf_jit_stack_offsetof() and BPF_PPC_TC */ EMIT(PPC_RAW_LL(_R4, _R1, r4_off)); @@ -679,7 +666,7 @@ static void bpf_trampoline_setup_tail_call_info(u32 *image, struct codegen_conte } static void bpf_trampoline_restore_tail_call_cnt(u32 *image, struct codegen_context *ctx, - int func_frame_offset, int r4_off) + int bpf_frame_size, int r4_off) { if (IS_ENABLED(CONFIG_PPC32)) { /* @@ -690,12 +677,12 @@ static void bpf_trampoline_restore_tail_call_cnt(u32 *image, struct codegen_cont } } -static void bpf_trampoline_save_args(u32 *image, struct codegen_context *ctx, int func_frame_offset, - int nr_regs, int regs_off) +static void bpf_trampoline_save_args(u32 *image, struct codegen_context *ctx, + int bpf_frame_size, int nr_regs, int regs_off) { int param_save_area_offset; - param_save_area_offset = func_frame_offset; /* the two frames we alloted */ + param_save_area_offset = bpf_frame_size; param_save_area_offset += STACK_FRAME_MIN_SIZE; /* param save area is past frame header */ for (int i = 0; i < nr_regs; i++) { @@ -718,11 +705,11 @@ static void bpf_trampoline_restore_args_regs(u32 *image, struct codegen_context /* Used when we call into the traced function. Replicate parameter save area */ static void bpf_trampoline_restore_args_stack(u32 *image, struct codegen_context *ctx, - int func_frame_offset, int nr_regs, int regs_off) + int bpf_frame_size, int nr_regs, int regs_off) { int param_save_area_offset; - param_save_area_offset = func_frame_offset; /* the two frames we alloted */ + param_save_area_offset = bpf_frame_size; param_save_area_offset += STACK_FRAME_MIN_SIZE; /* param save area is past frame header */ for (int i = 8; i < nr_regs; i++) { @@ -739,10 +726,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im void *func_addr) { int regs_off, nregs_off, ip_off, run_ctx_off, retval_off, nvr_off, alt_lr_off, r4_off = 0; - int i, ret, nr_regs, bpf_frame_size = 0, bpf_dummy_frame_size = 0, func_frame_offset; struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; + int i, ret, nr_regs, retaddr_off, bpf_frame_size = 0; struct codegen_context codegen_ctx, *ctx; u32 *image = (u32 *)rw_image; ppc_inst_t branch_insn; @@ -768,16 +755,11 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im * Generated stack layout: * * func prev back chain [ back chain ] - * [ ] - * bpf prog redzone/tailcallcnt [ ... ] 64 bytes (64-bit powerpc) - * [ ] -- - * LR save area [ r0 save (64-bit) ] | header - * [ r0 save (32-bit) ] | - * dummy frame for unwind [ back chain 1 ] -- * [ tail_call_info ] optional - 64-bit powerpc * [ padding ] align stack frame * r4_off [ r4 (tailcallcnt) ] optional - 32-bit powerpc * alt_lr_off [ real lr (ool stub)] optional - actual lr + * retaddr_off [ return address ] * [ r26 ] * nvr_off [ r25 ] nvr save area * retval_off [ return value ] @@ -841,6 +823,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im nvr_off = bpf_frame_size; bpf_frame_size += 2 * SZL; + /* Save area for return address */ + retaddr_off = bpf_frame_size; + bpf_frame_size += SZL; + /* Optional save area for actual LR in case of ool ftrace */ if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { alt_lr_off = bpf_frame_size; @@ -867,16 +853,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im /* Padding to align stack frame, if any */ bpf_frame_size = round_up(bpf_frame_size, SZL * 2); - /* Dummy frame size for proper unwind - includes 64-bytes red zone for 64-bit powerpc */ - bpf_dummy_frame_size = STACK_FRAME_MIN_SIZE + 64; - - /* Offset to the traced function's stack frame */ - func_frame_offset = bpf_dummy_frame_size + bpf_frame_size; - - /* Create dummy frame for unwind, store original return value */ + /* Store original return value */ EMIT(PPC_RAW_STL(_R0, _R1, PPC_LR_STKOFF)); - /* Protect red zone where tail call count goes */ - EMIT(PPC_RAW_STLU(_R1, _R1, -bpf_dummy_frame_size)); /* Create our stack frame */ EMIT(PPC_RAW_STLU(_R1, _R1, -bpf_frame_size)); @@ -891,14 +869,14 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im if (IS_ENABLED(CONFIG_PPC32) && nr_regs < 2) EMIT(PPC_RAW_STL(_R4, _R1, r4_off)); - bpf_trampoline_save_args(image, ctx, func_frame_offset, nr_regs, regs_off); + bpf_trampoline_save_args(image, ctx, bpf_frame_size, nr_regs, regs_off); /* Save our LR/return address */ EMIT(PPC_RAW_MFLR(_R3)); if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) EMIT(PPC_RAW_STL(_R3, _R1, alt_lr_off)); else - EMIT(PPC_RAW_STL(_R3, _R1, bpf_frame_size + PPC_LR_STKOFF)); + EMIT(PPC_RAW_STL(_R3, _R1, retaddr_off)); /* * Derive IP address of the traced function. @@ -925,9 +903,9 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im EMIT(PPC_RAW_STL(_R3, _R1, ip_off)); if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { - /* Fake our LR for unwind */ + /* Fake our LR for BPF_TRAMP_F_CALL_ORIG case */ EMIT(PPC_RAW_ADDI(_R3, _R3, 4)); - EMIT(PPC_RAW_STL(_R3, _R1, bpf_frame_size + PPC_LR_STKOFF)); + EMIT(PPC_RAW_STL(_R3, _R1, retaddr_off)); } /* Save function arg count -- see bpf_get_func_arg_cnt() */ @@ -966,20 +944,19 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im /* Call the traced function */ if (flags & BPF_TRAMP_F_CALL_ORIG) { /* - * The address in LR save area points to the correct point in the original function + * retaddr on trampoline stack points to the correct point in the original function * with both PPC_FTRACE_OUT_OF_LINE as well as with traditional ftrace instruction * sequence */ - EMIT(PPC_RAW_LL(_R3, _R1, bpf_frame_size + PPC_LR_STKOFF)); + EMIT(PPC_RAW_LL(_R3, _R1, retaddr_off)); EMIT(PPC_RAW_MTCTR(_R3)); /* Replicate tail_call_cnt before calling the original BPF prog */ if (flags & BPF_TRAMP_F_TAIL_CALL_CTX) - bpf_trampoline_setup_tail_call_info(image, ctx, func_frame_offset, - bpf_dummy_frame_size, r4_off); + bpf_trampoline_setup_tail_call_info(image, ctx, bpf_frame_size, r4_off); /* Restore args */ - bpf_trampoline_restore_args_stack(image, ctx, func_frame_offset, nr_regs, regs_off); + bpf_trampoline_restore_args_stack(image, ctx, bpf_frame_size, nr_regs, regs_off); /* Restore TOC for 64-bit */ if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) @@ -993,7 +970,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im /* Restore updated tail_call_cnt */ if (flags & BPF_TRAMP_F_TAIL_CALL_CTX) - bpf_trampoline_restore_tail_call_cnt(image, ctx, func_frame_offset, r4_off); + bpf_trampoline_restore_tail_call_cnt(image, ctx, bpf_frame_size, r4_off); /* Reserve space to patch branch instruction to skip fexit progs */ if (ro_image) /* image is NULL for dummy pass */ @@ -1045,7 +1022,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im EMIT(PPC_RAW_LD(_R2, _R1, 24)); if (flags & BPF_TRAMP_F_SKIP_FRAME) { /* Skip the traced function and return to parent */ - EMIT(PPC_RAW_ADDI(_R1, _R1, func_frame_offset)); + EMIT(PPC_RAW_ADDI(_R1, _R1, bpf_frame_size)); EMIT(PPC_RAW_LL(_R0, _R1, PPC_LR_STKOFF)); EMIT(PPC_RAW_MTLR(_R0)); EMIT(PPC_RAW_BLR()); @@ -1053,13 +1030,13 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im if (IS_ENABLED(CONFIG_PPC_FTRACE_OUT_OF_LINE)) { EMIT(PPC_RAW_LL(_R0, _R1, alt_lr_off)); EMIT(PPC_RAW_MTLR(_R0)); - EMIT(PPC_RAW_ADDI(_R1, _R1, func_frame_offset)); + EMIT(PPC_RAW_ADDI(_R1, _R1, bpf_frame_size)); EMIT(PPC_RAW_LL(_R0, _R1, PPC_LR_STKOFF)); EMIT(PPC_RAW_BLR()); } else { - EMIT(PPC_RAW_LL(_R0, _R1, bpf_frame_size + PPC_LR_STKOFF)); + EMIT(PPC_RAW_LL(_R0, _R1, retaddr_off)); EMIT(PPC_RAW_MTCTR(_R0)); - EMIT(PPC_RAW_ADDI(_R1, _R1, func_frame_offset)); + EMIT(PPC_RAW_ADDI(_R1, _R1, bpf_frame_size)); EMIT(PPC_RAW_LL(_R0, _R1, PPC_LR_STKOFF)); EMIT(PPC_RAW_MTLR(_R0)); EMIT(PPC_RAW_BCTR());