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 4.14 01/27] s390/bpf: Fix optimizing out zero-extensions
Date: Fri, 24 Sep 2021 14:43:55 +0200 [thread overview]
Message-ID: <20210924124329.226243340@linuxfoundation.org> (raw)
In-Reply-To: <20210924124329.173674820@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
@@ -592,10 +592,10 @@ 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 */
@@ -617,10 +617,10 @@ 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 */
@@ -647,10 +647,10 @@ 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 */
@@ -711,6 +711,8 @@ 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 */
@@ -803,10 +805,10 @@ 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 */
@@ -827,10 +829,10 @@ 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 */
@@ -852,10 +854,10 @@ 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 12:47 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-24 12:43 [PATCH 4.14 00/27] 4.14.248-rc1 review Greg Kroah-Hartman
2021-09-24 12:43 ` Greg Kroah-Hartman [this message]
2021-09-24 12:43 ` [PATCH 4.14 02/27] rcu: Fix missed wakeup of exp_wq waiters Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.14 03/27] apparmor: remove duplicate macro list_entry_is_head() Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.14 04/27] crypto: talitos - fix max key size for sha384 and sha512 Greg Kroah-Hartman
2021-09-24 12:43 ` [PATCH 4.14 05/27] sctp: validate chunk size in __rcv_asconf_lookup Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 06/27] sctp: add param size validation for SCTP_PARAM_SET_PRIMARY Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 07/27] dmaengine: acpi: Avoid comparison GSI with Linux vIRQ Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 08/27] thermal/drivers/exynos: Fix an error code in exynos_tmu_probe() Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 09/27] 9p/trans_virtio: Remove sysfs file on probe failure Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 10/27] prctl: allow to setup brk for et_dyn executables Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 11/27] profiling: fix shift-out-of-bounds bugs Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 12/27] pwm: lpc32xx: Dont modify HW state in .probe() after the PWM chip was registered Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 13/27] pwm: mxs: " Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 14/27] Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 15/27] parisc: Move pci_dev_is_behind_card_dino to where it is used Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 16/27] dmaengine: ioat: depends on !UML Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 17/27] dmaengine: xilinx_dma: Set DMA mask for coherent APIs Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 18/27] ceph: lockdep annotations for try_nonblocking_invalidate Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 19/27] nilfs2: fix memory leak in nilfs_sysfs_create_device_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 20/27] nilfs2: fix NULL pointer in nilfs_##name##_attr_release Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 21/27] nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 22/27] nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 23/27] nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 24/27] nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 25/27] pwm: rockchip: Dont modify HW state in .remove() callback Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 26/27] blk-throttle: fix UAF by deleteing timer in blk_throtl_exit() Greg Kroah-Hartman
2021-09-24 12:44 ` [PATCH 4.14 27/27] drm/nouveau/nvkm: Replace -ENOSYS with -ENODEV Greg Kroah-Hartman
2021-09-24 13:55 ` [PATCH 4.14 00/27] 4.14.248-rc1 review Daniel Díaz
2021-09-24 17:51 ` Jon Hunter
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