After the V!=R rework (commit c98d2ecae08f ("s390/mm: Uncouple physical vs virtual address spaces")), all kernel code and related data are allocated within a 4G region, making it possible to use relative addressing in BPF code more extensively. Convert as many indirect calls and jumps to direct calls as possible, namely: * BPF_CALL * __bpf_tramp_enter() * __bpf_tramp_exit() * __bpf_prog_enter() * __bpf_prog_exit() * fentry * fmod_ret * fexit * BPF_TRAMP_F_CALL_ORIG without BPF_TRAMP_F_ORIG_STACK * Trampoline returns without BPF_TRAMP_F_SKIP_FRAME and BPF_TRAMP_F_ORIG_STACK The following indirect calls and jumps remain: * Prog returns * Trampoline returns with BPF_TRAMP_F_SKIP_FRAME or BPF_TRAMP_F_ORIG_STACK * BPF_TAIL_CALL * BPF_TRAMP_F_CALL_ORIG with BPF_TRAMP_F_ORIG_STACK As a result, only one usage of call_r1() remains, so inline it. Signed-off-by: Ilya Leoshkevich --- arch/s390/net/bpf_jit_comp.c | 80 +++++++++++++++--------------------- 1 file changed, 32 insertions(+), 48 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index bb17efe29d65..0d61784abd33 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -674,20 +674,6 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp) _EMIT2(0x07f0 | reg); \ } while (0) -/* - * Call r1 either directly or via __s390_indirect_jump_r1 thunk - */ -static void call_r1(struct bpf_jit *jit) -{ - if (nospec_uses_trampoline()) - /* brasl %r14,__s390_indirect_jump_r1 */ - EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, - __s390_indirect_jump_r1); - else - /* basr %r14,%r1 */ - EMIT2(0x0d00, REG_14, REG_1); -} - /* * Function epilogue */ @@ -1819,10 +1805,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, } } - /* lgrl %w1,func */ - EMIT6_PCREL_RILB(0xc4080000, REG_W1, _EMIT_CONST_U64(func)); - /* %r1() */ - call_r1(jit); + /* brasl %r14,func */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, (void *)func); /* lgr %b0,%r2: load return value into %b0 */ EMIT4(0xb9040000, BPF_REG_0, REG_2); break; @@ -2517,14 +2501,12 @@ static int invoke_bpf_prog(struct bpf_tramp_jit *tjit, * goto skip; */ - /* %r1 = __bpf_prog_enter */ - load_imm64(jit, REG_1, (u64)bpf_trampoline_enter(p)); /* %r2 = p */ load_imm64(jit, REG_2, (u64)p); /* la %r3,run_ctx_off(%r15) */ EMIT4_DISP(0x41000000, REG_3, REG_15, tjit->run_ctx_off); - /* %r1() */ - call_r1(jit); + /* brasl %r14,__bpf_prog_enter */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, bpf_trampoline_enter(p)); /* ltgr %r7,%r2 */ EMIT4(0xb9020000, REG_7, REG_2); /* brcl 8,skip */ @@ -2535,15 +2517,13 @@ static int invoke_bpf_prog(struct bpf_tramp_jit *tjit, * retval = bpf_func(args, p->insnsi); */ - /* %r1 = p->bpf_func */ - load_imm64(jit, REG_1, (u64)p->bpf_func); /* la %r2,bpf_args_off(%r15) */ EMIT4_DISP(0x41000000, REG_2, REG_15, tjit->bpf_args_off); /* %r3 = p->insnsi */ if (!p->jited) load_imm64(jit, REG_3, (u64)p->insnsi); - /* %r1() */ - call_r1(jit); + /* brasl %r14,p->bpf_func */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, p->bpf_func); /* stg %r2,retval_off(%r15) */ if (save_ret) { if (sign_extend(jit, REG_2, m->ret_size, m->ret_flags)) @@ -2560,16 +2540,14 @@ static int invoke_bpf_prog(struct bpf_tramp_jit *tjit, * __bpf_prog_exit(p, start, &run_ctx); */ - /* %r1 = __bpf_prog_exit */ - load_imm64(jit, REG_1, (u64)bpf_trampoline_exit(p)); /* %r2 = p */ load_imm64(jit, REG_2, (u64)p); /* lgr %r3,%r7 */ EMIT4(0xb9040000, REG_3, REG_7); /* la %r4,run_ctx_off(%r15) */ EMIT4_DISP(0x41000000, REG_4, REG_15, tjit->run_ctx_off); - /* %r1() */ - call_r1(jit); + /* brasl %r14,__bpf_prog_exit */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, bpf_trampoline_exit(p)); return 0; } @@ -2729,9 +2707,6 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, /* lgr %r8,%r0 */ EMIT4(0xb9040000, REG_8, REG_0); - } else { - /* %r8 = func_addr + S390X_PATCH_SIZE */ - load_imm64(jit, REG_8, (u64)func_addr + S390X_PATCH_SIZE); } /* @@ -2757,12 +2732,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, * __bpf_tramp_enter(im); */ - /* %r1 = __bpf_tramp_enter */ - load_imm64(jit, REG_1, (u64)__bpf_tramp_enter); /* %r2 = im */ load_imm64(jit, REG_2, (u64)im); - /* %r1() */ - call_r1(jit); + /* brasl %r14,__bpf_tramp_enter */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, __bpf_tramp_enter); } for (i = 0; i < fentry->nr_links; i++) @@ -2815,10 +2788,19 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, /* mvc tail_call_cnt(4,%r15),tccnt_off(%r15) */ _EMIT6(0xd203f000 | offsetof(struct prog_frame, tail_call_cnt), 0xf000 | tjit->tccnt_off); - /* lgr %r1,%r8 */ - EMIT4(0xb9040000, REG_1, REG_8); - /* %r1() */ - call_r1(jit); + if (flags & BPF_TRAMP_F_ORIG_STACK) { + if (nospec_uses_trampoline()) + /* brasl %r14,__s390_indirect_jump_r8 */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, + __s390_indirect_jump_r8); + else + /* basr %r14,%r8 */ + EMIT2(0x0d00, REG_14, REG_8); + } else { + /* brasl %r14,func_addr+S390X_PATCH_SIZE */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, + func_addr + S390X_PATCH_SIZE); + } /* stg %r2,retval_off(%r15) */ EMIT6_DISP_LH(0xe3000000, 0x0024, REG_2, REG_0, REG_15, tjit->retval_off); @@ -2846,12 +2828,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, * __bpf_tramp_exit(im); */ - /* %r1 = __bpf_tramp_exit */ - load_imm64(jit, REG_1, (u64)__bpf_tramp_exit); /* %r2 = im */ load_imm64(jit, REG_2, (u64)im); - /* %r1() */ - call_r1(jit); + /* brasl %r14,__bpf_tramp_exit */ + EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, __bpf_tramp_exit); } /* lmg %r2,%rN,reg_args_off(%r15) */ @@ -2860,7 +2840,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, REG_2 + (nr_reg_args - 1), REG_15, tjit->reg_args_off); /* lgr %r1,%r8 */ - if (!(flags & BPF_TRAMP_F_SKIP_FRAME)) + if (!(flags & BPF_TRAMP_F_SKIP_FRAME) && + (flags & BPF_TRAMP_F_ORIG_STACK)) EMIT4(0xb9040000, REG_1, REG_8); /* lmg %r7,%r8,r7_r8_off(%r15) */ EMIT6_DISP_LH(0xeb000000, 0x0004, REG_7, REG_8, REG_15, @@ -2879,9 +2860,12 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, EMIT4_IMM(0xa70b0000, REG_15, tjit->stack_size); if (flags & BPF_TRAMP_F_SKIP_FRAME) EMIT_JUMP_REG(14); - else + else if (flags & BPF_TRAMP_F_ORIG_STACK) EMIT_JUMP_REG(1); - + else + /* brcl 0xf,func_addr+S390X_PATCH_SIZE */ + EMIT6_PCREL_RILC_PTR(0xc0040000, 0xf, + func_addr + S390X_PATCH_SIZE); return 0; } -- 2.50.1