From: Xu Kuohai <xukuohai@huawei.com>
To: <bpf@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Will Deacon <will@kernel.org>, KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Zi Shen Lim <zlim.lnx@gmail.com>, Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
David Ahern <dsahern@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>,
"H . Peter Anvin" <hpa@zytor.com>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Russell King <rmk+kernel@armlinux.org.uk>,
James Morse <james.morse@arm.com>, Hou Tao <houtao1@huawei.com>,
Jason Wang <wangborong@cdjrlc.com>
Subject: [PATCH bpf-next v8 2/4] arm64: Add LDR (literal) instruction
Date: Mon, 11 Jul 2022 10:47:20 -0400 [thread overview]
Message-ID: <20220711144722.2100039-3-xukuohai@huawei.com> (raw)
In-Reply-To: <20220711144722.2100039-1-xukuohai@huawei.com>
Add LDR (literal) instruction to load data from address relative to PC.
This instruction will be used to implement long jump from bpf prog to
bpf trampoline in the follow-up patch.
The instruction encoding:
3 2 2 2 0 0
0 7 6 4 5 0
+-----+-------+---+-----+-------------------------------------+--------+
| 0 x | 0 1 1 | 0 | 0 0 | imm19 | Rt |
+-----+-------+---+-----+-------------------------------------+--------+
for 32-bit, variant x == 0; for 64-bit, x == 1.
branch_imm_common() is used to check the distance between pc and target
address, since it's reused by this patch and LDR (literal) is not a branch
instruction, rename it to label_imm_common().
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
arch/arm64/include/asm/insn.h | 3 +++
arch/arm64/lib/insn.c | 30 ++++++++++++++++++++++++++----
2 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 6aa2dc836db1..834bff720582 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -510,6 +510,9 @@ u32 aarch64_insn_gen_load_store_imm(enum aarch64_insn_register reg,
unsigned int imm,
enum aarch64_insn_size_type size,
enum aarch64_insn_ldst_type type);
+u32 aarch64_insn_gen_load_literal(unsigned long pc, unsigned long addr,
+ enum aarch64_insn_register reg,
+ bool is64bit);
u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
enum aarch64_insn_register reg2,
enum aarch64_insn_register base,
diff --git a/arch/arm64/lib/insn.c b/arch/arm64/lib/insn.c
index 695d7368fadc..49e972beeac7 100644
--- a/arch/arm64/lib/insn.c
+++ b/arch/arm64/lib/insn.c
@@ -323,7 +323,7 @@ static u32 aarch64_insn_encode_ldst_size(enum aarch64_insn_size_type type,
return insn;
}
-static inline long branch_imm_common(unsigned long pc, unsigned long addr,
+static inline long label_imm_common(unsigned long pc, unsigned long addr,
long range)
{
long offset;
@@ -354,7 +354,7 @@ u32 __kprobes aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr,
* ARM64 virtual address arrangement guarantees all kernel and module
* texts are within +/-128M.
*/
- offset = branch_imm_common(pc, addr, SZ_128M);
+ offset = label_imm_common(pc, addr, SZ_128M);
if (offset >= SZ_128M)
return AARCH64_BREAK_FAULT;
@@ -382,7 +382,7 @@ u32 aarch64_insn_gen_comp_branch_imm(unsigned long pc, unsigned long addr,
u32 insn;
long offset;
- offset = branch_imm_common(pc, addr, SZ_1M);
+ offset = label_imm_common(pc, addr, SZ_1M);
if (offset >= SZ_1M)
return AARCH64_BREAK_FAULT;
@@ -421,7 +421,7 @@ u32 aarch64_insn_gen_cond_branch_imm(unsigned long pc, unsigned long addr,
u32 insn;
long offset;
- offset = branch_imm_common(pc, addr, SZ_1M);
+ offset = label_imm_common(pc, addr, SZ_1M);
insn = aarch64_insn_get_bcond_value();
@@ -543,6 +543,28 @@ u32 aarch64_insn_gen_load_store_imm(enum aarch64_insn_register reg,
return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_12, insn, imm);
}
+u32 aarch64_insn_gen_load_literal(unsigned long pc, unsigned long addr,
+ enum aarch64_insn_register reg,
+ bool is64bit)
+{
+ u32 insn;
+ long offset;
+
+ offset = label_imm_common(pc, addr, SZ_1M);
+ if (offset >= SZ_1M)
+ return AARCH64_BREAK_FAULT;
+
+ insn = aarch64_insn_get_ldr_lit_value();
+
+ if (is64bit)
+ insn |= BIT(30);
+
+ insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn, reg);
+
+ return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_19, insn,
+ offset >> 2);
+}
+
u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
enum aarch64_insn_register reg2,
enum aarch64_insn_register base,
--
2.30.2
next prev parent reply other threads:[~2022-07-11 14:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-11 14:47 [PATCH bpf-next v8 0/4] bpf trampoline for arm64 Xu Kuohai
2022-07-11 14:47 ` [PATCH bpf-next v8 1/4] bpf: Remove is_valid_bpf_tramp_flags() Xu Kuohai
2022-07-11 14:47 ` Xu Kuohai [this message]
2022-07-11 14:47 ` [PATCH bpf-next v8 3/4] bpf, arm64: Implement bpf_arch_text_poke() for arm64 Xu Kuohai
2022-07-11 14:47 ` [PATCH bpf-next v8 4/4] bpf, arm64: bpf trampoline " Xu Kuohai
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