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Mon, 1 Jul 2024 13:34:43 GMT Received: from smtprelay03.fra02v.mail.ibm.com ([9.218.2.224]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 402vktypwt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 01 Jul 2024 13:34:43 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay03.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 461DYcjP57344404 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 1 Jul 2024 13:34:40 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3E8A82004E; Mon, 1 Jul 2024 13:34:38 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B92AB20040; Mon, 1 Jul 2024 13:34:37 +0000 (GMT) Received: from heavy.ibm.com (unknown [9.179.5.21]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 1 Jul 2024 13:34:37 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Ilya Leoshkevich Subject: [PATCH bpf-next v2 06/11] s390/bpf: Support BPF_PROBE_MEM32 Date: Mon, 1 Jul 2024 15:24:44 +0200 Message-ID: <20240701133432.3883-7-iii@linux.ibm.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240701133432.3883-1-iii@linux.ibm.com> References: <20240701133432.3883-1-iii@linux.ibm.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: o1etRcP4QPCi3ZYFHZ-fUUGj1t9oPUX3 X-Proofpoint-GUID: o1etRcP4QPCi3ZYFHZ-fUUGj1t9oPUX3 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-07-01_12,2024-06-28_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 priorityscore=1501 malwarescore=0 mlxlogscore=999 mlxscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 spamscore=0 clxscore=1015 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2406140001 definitions=main-2407010103 X-Patchwork-Delegate: bpf@iogearbox.net BPF_PROBE_MEM32 is a new mode for LDX, ST and STX instructions. The JIT is supposed to add the start address of the kernel arena mapping to the %dst register, and use a probing variant of the respective memory access. Reuse the existing probing infrastructure for that. Put the arena address into the literal pool, load it into %r1 and use that as an index register. Do not clear any registers in ex_handler_bpf() for failing ST and STX instructions. Signed-off-by: Ilya Leoshkevich --- arch/s390/net/bpf_jit_comp.c | 137 ++++++++++++++++++++++++++++------- 1 file changed, 110 insertions(+), 27 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index ecd53f8f0602..4b62b5162dfb 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -53,6 +53,7 @@ struct bpf_jit { int excnt; /* Number of exception table entries */ int prologue_plt_ret; /* Return address for prologue hotpatch PLT */ int prologue_plt; /* Start of prologue hotpatch PLT */ + int kern_arena; /* Pool offset of kernel arena address */ }; #define SEEN_MEM BIT(0) /* use mem[] for temporary storage */ @@ -670,7 +671,8 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth) bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs) { regs->psw.addr = extable_fixup(x); - regs->gprs[x->data] = 0; + if (x->data != -1) + regs->gprs[x->data] = 0; return true; } @@ -681,6 +683,7 @@ struct bpf_jit_probe { int prg; /* JITed instruction offset */ int nop_prg; /* JITed nop offset */ int reg; /* Register to clear on exception */ + int arena_reg; /* Register to use for arena addressing */ }; static void bpf_jit_probe_init(struct bpf_jit_probe *probe) @@ -688,6 +691,7 @@ static void bpf_jit_probe_init(struct bpf_jit_probe *probe) probe->prg = -1; probe->nop_prg = -1; probe->reg = -1; + probe->arena_reg = REG_0; } /* @@ -708,13 +712,31 @@ static void bpf_jit_probe_load_pre(struct bpf_jit *jit, struct bpf_insn *insn, struct bpf_jit_probe *probe) { if (BPF_MODE(insn->code) != BPF_PROBE_MEM && - BPF_MODE(insn->code) != BPF_PROBE_MEMSX) + BPF_MODE(insn->code) != BPF_PROBE_MEMSX && + BPF_MODE(insn->code) != BPF_PROBE_MEM32) return; + if (BPF_MODE(insn->code) == BPF_PROBE_MEM32) { + /* lgrl %r1,kern_arena */ + EMIT6_PCREL_RILB(0xc4080000, REG_W1, jit->kern_arena); + probe->arena_reg = REG_W1; + } probe->prg = jit->prg; probe->reg = reg2hex[insn->dst_reg]; } +static void bpf_jit_probe_store_pre(struct bpf_jit *jit, struct bpf_insn *insn, + struct bpf_jit_probe *probe) +{ + if (BPF_MODE(insn->code) != BPF_PROBE_MEM32) + return; + + /* lgrl %r1,kern_arena */ + EMIT6_PCREL_RILB(0xc4080000, REG_W1, jit->kern_arena); + probe->arena_reg = REG_W1; + probe->prg = jit->prg; +} + static int bpf_jit_probe_post(struct bpf_jit *jit, struct bpf_prog *fp, struct bpf_jit_probe *probe) { @@ -1384,51 +1406,99 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, * BPF_ST(X) */ case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */ - /* stcy %src,off(%dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off); + case BPF_STX | BPF_PROBE_MEM32 | BPF_B: + bpf_jit_probe_store_pre(jit, insn, &probe); + /* stcy %src,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */ - /* sthy %src,off(%dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off); + case BPF_STX | BPF_PROBE_MEM32 | BPF_H: + bpf_jit_probe_store_pre(jit, insn, &probe); + /* sthy %src,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */ - /* sty %src,off(%dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off); + case BPF_STX | BPF_PROBE_MEM32 | BPF_W: + bpf_jit_probe_store_pre(jit, insn, &probe); + /* sty %src,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */ - /* stg %src,off(%dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off); + case BPF_STX | BPF_PROBE_MEM32 | BPF_DW: + bpf_jit_probe_store_pre(jit, insn, &probe); + /* stg %src,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */ + case BPF_ST | BPF_PROBE_MEM32 | BPF_B: /* lhi %w0,imm */ EMIT4_IMM(0xa7080000, REG_W0, (u8) imm); - /* stcy %w0,off(dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off); + bpf_jit_probe_store_pre(jit, insn, &probe); + /* stcy %w0,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */ + case BPF_ST | BPF_PROBE_MEM32 | BPF_H: /* lhi %w0,imm */ EMIT4_IMM(0xa7080000, REG_W0, (u16) imm); - /* sthy %w0,off(dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off); + bpf_jit_probe_store_pre(jit, insn, &probe); + /* sthy %w0,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */ + case BPF_ST | BPF_PROBE_MEM32 | BPF_W: /* llilf %w0,imm */ EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm); - /* sty %w0,off(%dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off); + bpf_jit_probe_store_pre(jit, insn, &probe); + /* sty %w0,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */ + case BPF_ST | BPF_PROBE_MEM32 | BPF_DW: /* lgfi %w0,imm */ EMIT6_IMM(0xc0010000, REG_W0, imm); - /* stg %w0,off(%dst) */ - EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off); + bpf_jit_probe_store_pre(jit, insn, &probe); + /* stg %w0,off(%dst,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, + probe.arena_reg, off); + err = bpf_jit_probe_post(jit, fp, &probe); + if (err < 0) + return err; jit->seen |= SEEN_MEM; break; /* @@ -1506,9 +1576,11 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, */ case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */ case BPF_LDX | BPF_PROBE_MEM | BPF_B: + case BPF_LDX | BPF_PROBE_MEM32 | BPF_B: bpf_jit_probe_load_pre(jit, insn, &probe); - /* llgc %dst,0(off,%src) */ - EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off); + /* llgc %dst,off(%src,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, + probe.arena_reg, off); err = bpf_jit_probe_post(jit, fp, &probe); if (err < 0) return err; @@ -1519,7 +1591,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, case BPF_LDX | BPF_MEMSX | BPF_B: /* dst = *(s8 *)(ul) (src + off) */ case BPF_LDX | BPF_PROBE_MEMSX | BPF_B: bpf_jit_probe_load_pre(jit, insn, &probe); - /* lgb %dst,0(off,%src) */ + /* lgb %dst,off(%src) */ EMIT6_DISP_LH(0xe3000000, 0x0077, dst_reg, src_reg, REG_0, off); err = bpf_jit_probe_post(jit, fp, &probe); if (err < 0) @@ -1528,9 +1600,11 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, break; case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */ case BPF_LDX | BPF_PROBE_MEM | BPF_H: + case BPF_LDX | BPF_PROBE_MEM32 | BPF_H: bpf_jit_probe_load_pre(jit, insn, &probe); - /* llgh %dst,0(off,%src) */ - EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off); + /* llgh %dst,off(%src,%arena) */ + EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, + probe.arena_reg, off); err = bpf_jit_probe_post(jit, fp, &probe); if (err < 0) return err; @@ -1541,7 +1615,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, case BPF_LDX | BPF_MEMSX | BPF_H: /* dst = *(s16 *)(ul) (src + off) */ case BPF_LDX | BPF_PROBE_MEMSX | BPF_H: bpf_jit_probe_load_pre(jit, insn, &probe); - /* lgh %dst,0(off,%src) */ + /* lgh %dst,off(%src) */ EMIT6_DISP_LH(0xe3000000, 0x0015, dst_reg, src_reg, REG_0, off); err = bpf_jit_probe_post(jit, fp, &probe); if (err < 0) @@ -1550,10 +1624,12 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, break; case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */ case BPF_LDX | BPF_PROBE_MEM | BPF_W: + case BPF_LDX | BPF_PROBE_MEM32 | BPF_W: bpf_jit_probe_load_pre(jit, insn, &probe); /* llgf %dst,off(%src) */ jit->seen |= SEEN_MEM; - EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off); + EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, + probe.arena_reg, off); err = bpf_jit_probe_post(jit, fp, &probe); if (err < 0) return err; @@ -1572,10 +1648,12 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, break; case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */ case BPF_LDX | BPF_PROBE_MEM | BPF_DW: + case BPF_LDX | BPF_PROBE_MEM32 | BPF_DW: bpf_jit_probe_load_pre(jit, insn, &probe); - /* lg %dst,0(off,%src) */ + /* lg %dst,off(%src,%arena) */ jit->seen |= SEEN_MEM; - EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off); + EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, + probe.arena_reg, off); err = bpf_jit_probe_post(jit, fp, &probe); if (err < 0) return err; @@ -1988,12 +2066,17 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp, bool extra_pass, u32 stack_depth) { int i, insn_count, lit32_size, lit64_size; + u64 kern_arena; jit->lit32 = jit->lit32_start; jit->lit64 = jit->lit64_start; jit->prg = 0; jit->excnt = 0; + kern_arena = bpf_arena_get_kern_vm_start(fp->aux->arena); + if (kern_arena) + jit->kern_arena = _EMIT_CONST_U64(kern_arena); + bpf_jit_prologue(jit, fp, stack_depth); if (bpf_set_addr(jit, 0) < 0) return -1;