kernel/git/stable/linux.git/arch/arm/net, branch linux-5.7.y

arm, bpf: Fix offset overflow for BPF_MEM BPF_DW

2020-04-14T19:27:54+00:00

This patch fixes an incorrect check in how immediate memory offsets are computed for BPF_DW on arm. For BPF_LDX/ST/STX + BPF_DW, the 32-bit arm JIT breaks down an 8-byte access into two separate 4-byte accesses using off+0 and off+4. If off fits in imm12, the JIT emits a ldr/str instruction with the immediate and avoids the use of a temporary register. While the current check off <= 0xfff ensures that the first immediate off+0 doesn't overflow imm12, it's not sufficient for the second immediate off+4, which may cause the second access of BPF_DW to read/write the wrong address. This patch fixes the problem by changing the check to off <= 0xfff - 4 for BPF_DW, ensuring off+4 will never overflow. A side effect of simplifying the check is that it now allows using negative immediate offsets in ldr/str. This means that small negative offsets can also avoid the use of a temporary register. This patch introduces no new failures in test_verifier or test_bpf.c. Fixes: c5eae692571d6 ("ARM: net: bpf: improve 64-bit store implementation") Fixes: ec19e02b343db ("ARM: net: bpf: fix LDX instructions") Co-developed-by: Xi Wang Signed-off-by: Xi Wang Signed-off-by: Luke Nelson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200409221752.28448-1-luke.r.nels@gmail.com

arm, bpf: Fix bugs with ALU64 {RSH, ARSH} BPF_K shift by 0

2020-04-08T23:05:53+00:00

The current arm BPF JIT does not correctly compile RSH or ARSH when the immediate shift amount is 0. This causes the "rsh64 by 0 imm" and "arsh64 by 0 imm" BPF selftests to hang the kernel by reaching an instruction the verifier determines to be unreachable. The root cause is in how immediate right shifts are encoded on arm. For LSR and ASR (logical and arithmetic right shift), a bit-pattern of 00000 in the immediate encodes a shift amount of 32. When the BPF immediate is 0, the generated code shifts by 32 instead of the expected behavior (a no-op). This patch fixes the bugs by adding an additional check if the BPF immediate is 0. After the change, the above mentioned BPF selftests pass. Fixes: 39c13c204bb11 ("arm: eBPF JIT compiler") Co-developed-by: Xi Wang Signed-off-by: Xi Wang Signed-off-by: Luke Nelson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200408181229.10909-1-luke.r.nels@gmail.com

ARM: net: bpf: Improve prologue code sequence

2019-12-11T13:34:26+00:00

Improve the prologue code sequence to be able to take advantage of 64-bit stores, changing the code from: push {r4, r5, r6, r7, r8, r9, fp, lr} mov fp, sp sub ip, sp, #80 ; 0x50 sub sp, sp, #600 ; 0x258 str ip, [fp, #-100] ; 0xffffff9c mov r6, #0 str r6, [fp, #-96] ; 0xffffffa0 mov r4, #0 mov r3, r4 mov r2, r0 str r4, [fp, #-104] ; 0xffffff98 str r4, [fp, #-108] ; 0xffffff94 to the tighter: push {r4, r5, r6, r7, r8, r9, fp, lr} mov fp, sp mov r3, #0 sub r2, sp, #80 ; 0x50 sub sp, sp, #600 ; 0x258 strd r2, [fp, #-100] ; 0xffffff9c mov r2, #0 strd r2, [fp, #-108] ; 0xffffff94 mov r2, r0 resulting in a saving of three instructions. Signed-off-by: Russell King Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/E1ieH2g-0004ih-Rb@rmk-PC.armlinux.org.uk

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2019-06-18T03:20:36+00:00

Honestly all the conflicts were simple overlapping changes, nothing really interesting to report. Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

2019-06-05T15:37:17+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Armijn Hemel Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman

arm: bpf: eliminate zero extension code-gen

2019-05-25T01:58:37+00:00

Cc: Shubham Bansal Signed-off-by: Jiong Wang Signed-off-by: Alexei Starovoitov

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

arm: bpf: implement jitting of JMP32

2019-01-26T21:33:02+00:00

This patch implements code-gen for new JMP32 instructions on arm. For JSET, "ands" (AND with flags updated) is used, so corresponding encoding helper is added. Cc: Shubham Bansal Signed-off-by: Jiong Wang Signed-off-by: Alexei Starovoitov

ARM: net: bpf: improve 64-bit ALU implementation

2018-07-13T13:26:42+00:00

Improbe the 64-bit ALU implementation from: movw r8, #65532 movt r8, #65535 movw r9, #65535 movt r9, #65535 ldr r7, [fp, #-44] adds r7, r7, r8 str r7, [fp, #-44] ldr r7, [fp, #-40] adc r7, r7, r9 str r7, [fp, #-40] to: movw r8, #65532 movt r8, #65535 movw r9, #65535 movt r9, #65535 ldrd r6, [fp, #-44] adds r6, r6, r8 adc r7, r7, r9 strd r6, [fp, #-44] Signed-off-by: Russell King Signed-off-by: Daniel Borkmann

ARM: net: bpf: improve 64-bit store implementation

2018-07-13T13:26:42+00:00

Improve the 64-bit store implementation from: ldr r6, [fp, #-8] str r8, [r6] ldr r6, [fp, #-8] mov r7, #4 add r7, r6, r7 str r9, [r7] to: ldr r6, [fp, #-8] str r8, [r6] str r9, [r6, #4] We leave the store as two separate STR instructions rather than using STRD as the store may not be aligned, and STR can handle misalignment. Signed-off-by: Russell King Signed-off-by: Daniel Borkmann