From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
Johan Almbladh <johan.almbladh@anyfinetworks.com>,
Heiko Carstens <hca@linux.ibm.com>,
Ilya Leoshkevich <iii@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>
Subject: [PATCH 4.4 01/23] s390/bpf: Fix optimizing out zero-extensions
Date: Fri, 24 Sep 2021 14:43:42 +0200 [thread overview]
Message-ID: <20210924124327.869013869@linuxfoundation.org> (raw)
In-Reply-To: <20210924124327.816210800@linuxfoundation.org>
From: Ilya Leoshkevich <iii@linux.ibm.com>
commit db7bee653859ef7179be933e7d1384644f795f26 upstream.
Currently the JIT completely removes things like `reg32 += 0`,
however, the BPF_ALU semantics requires the target register to be
zero-extended in such cases.
Fix by optimizing out only the arithmetic operation, but not the
subsequent zero-extension.
Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/s390/net/bpf_jit_comp.c | 50 ++++++++++++++++++++++---------------------
1 file changed, 26 insertions(+), 24 deletions(-)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -596,10 +596,10 @@ static noinline int bpf_jit_insn(struct
EMIT4(0xb9080000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */
- if (!imm)
- break;
- /* alfi %dst,imm */
- EMIT6_IMM(0xc20b0000, dst_reg, imm);
+ if (imm != 0) {
+ /* alfi %dst,imm */
+ EMIT6_IMM(0xc20b0000, dst_reg, imm);
+ }
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */
@@ -621,10 +621,10 @@ static noinline int bpf_jit_insn(struct
EMIT4(0xb9090000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */
- if (!imm)
- break;
- /* alfi %dst,-imm */
- EMIT6_IMM(0xc20b0000, dst_reg, -imm);
+ if (imm != 0) {
+ /* alfi %dst,-imm */
+ EMIT6_IMM(0xc20b0000, dst_reg, -imm);
+ }
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
@@ -651,10 +651,10 @@ static noinline int bpf_jit_insn(struct
EMIT4(0xb90c0000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */
- if (imm == 1)
- break;
- /* msfi %r5,imm */
- EMIT6_IMM(0xc2010000, dst_reg, imm);
+ if (imm != 1) {
+ /* msfi %r5,imm */
+ EMIT6_IMM(0xc2010000, dst_reg, imm);
+ }
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */
@@ -715,6 +715,8 @@ static noinline int bpf_jit_insn(struct
if (BPF_OP(insn->code) == BPF_MOD)
/* lhgi %dst,0 */
EMIT4_IMM(0xa7090000, dst_reg, 0);
+ else
+ EMIT_ZERO(dst_reg);
break;
}
/* lhi %w0,0 */
@@ -807,10 +809,10 @@ static noinline int bpf_jit_insn(struct
EMIT4(0xb9820000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */
- if (!imm)
- break;
- /* xilf %dst,imm */
- EMIT6_IMM(0xc0070000, dst_reg, imm);
+ if (imm != 0) {
+ /* xilf %dst,imm */
+ EMIT6_IMM(0xc0070000, dst_reg, imm);
+ }
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
@@ -831,10 +833,10 @@ static noinline int bpf_jit_insn(struct
EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */
- if (imm == 0)
- break;
- /* sll %dst,imm(%r0) */
- EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
+ if (imm != 0) {
+ /* sll %dst,imm(%r0) */
+ EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
+ }
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */
@@ -856,10 +858,10 @@ static noinline int bpf_jit_insn(struct
EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */
- if (imm == 0)
- break;
- /* srl %dst,imm(%r0) */
- EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
+ if (imm != 0) {
+ /* srl %dst,imm(%r0) */
+ EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
+ }
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */
next prev parent reply other threads:[~2021-09-24 12:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 12:43 [PATCH 4.4 00/23] 4.4.285-rc1 review Greg Kroah-Hartman
2021-09-24 12:43 ` Greg Kroah-Hartman [this message]
2021-09-24 12:43 ` [PATCH 4.4 02/23] PM / wakeirq: Fix unbalanced IRQ enable for wakeirq Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 03/23] sctp: validate chunk size in __rcv_asconf_lookup Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 04/23] sctp: add param size validation for SCTP_PARAM_SET_PRIMARY Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 05/23] thermal/drivers/exynos: Fix an error code in exynos_tmu_probe() Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 06/23] 9p/trans_virtio: Remove sysfs file on probe failure Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 07/23] prctl: allow to setup brk for et_dyn executables Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 08/23] profiling: fix shift-out-of-bounds bugs Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 09/23] pwm: mxs: Dont modify HW state in .probe() after the PWM chip was registered Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 10/23] dmaengine: acpi-dma: check for 64-bit MMIO address Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 11/23] dmaengine: acpi: Avoid comparison GSI with Linux vIRQ Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 12/23] parisc: Move pci_dev_is_behind_card_dino to where it is used Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 13/23] dmaengine: ioat: depends on !UML Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 14/23] ceph: lockdep annotations for try_nonblocking_invalidate Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 15/23] nilfs2: fix memory leak in nilfs_sysfs_create_device_group Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 16/23] nilfs2: fix NULL pointer in nilfs_##name##_attr_release Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 17/23] nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.4 18/23] nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 19/23] nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 20/23] nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 21/23] blk-throttle: fix UAF by deleteing timer in blk_throtl_exit() Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 22/23] drm/nouveau/nvkm: Replace -ENOSYS with -ENODEV Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.4 23/23] sctp: validate from_addr_param return Greg Kroah-Hartman
2021-09-24 13:50 ` [PATCH 4.4 00/23] 4.4.285-rc1 review Daniel Díaz
2021-09-25 11:45 ` Greg Kroah-Hartman
2021-09-24 17:50 ` Jon Hunter
2021-09-24 21:50 ` Pavel Machek
2021-09-24 21:55 ` Shuah Khan
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