From: Hou Tao <houtao1@huawei.com> To: Xu Kuohai <xukuohai@huawei.com>, <bpf@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>, <linux-kselftest@vger.kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>, Daniel Borkmann <daniel@iogearbox.net>, Alexei Starovoitov <ast@kernel.org>, Zi Shen Lim <zlim.lnx@gmail.com>, Andrii Nakryiko <andrii@kernel.org>, Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>, John Fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@kernel.org>, "David S . Miller" <davem@davemloft.net>, Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>, David Ahern <dsahern@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>, <hpa@zytor.com>, Shuah Khan <shuah@kernel.org>, Mark Rutland <mark.rutland@arm.com>, Ard Biesheuvel <ardb@kernel.org>, Pasha Tatashin <pasha.tatashin@soleen.com>, Peter Collingbourne <pcc@google.com>, Daniel Kiss <daniel.kiss@arm.com>, Sudeep Holla <sudeep.holla@arm.com>, Steven Price <steven.price@arm.com>, Marc Zyngier <maz@kernel.org>, Mark Brown <broonie@kernel.org>, Kumar Kartikeya Dwivedi <memxor@gmail.com>, Delyan Kratunov <delyank@fb.com> Subject: Re: [PATCH bpf-next v2 4/6] bpf, arm64: Impelment bpf_arch_text_poke() for arm64 Date: Fri, 15 Apr 2022 10:34:47 +0800 [thread overview] Message-ID: <ba838451-1a96-2c83-9188-a994f45d7523@huawei.com> (raw) In-Reply-To: <20220414162220.1985095-5-xukuohai@huawei.com> Hi, On 4/15/2022 12:22 AM, Xu Kuohai wrote: > Impelment bpf_arch_text_poke() for arm64, so bpf trampoline code can use > it to replace nop with jump, or replace jump with nop. > > Signed-off-by: Xu Kuohai <xukuohai@huawei.com> > Acked-by: Song Liu <songliubraving@fb.com> > --- > arch/arm64/net/bpf_jit_comp.c | 52 +++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c > index 8ab4035dea27..1a1c3ea75ee2 100644 > --- a/arch/arm64/net/bpf_jit_comp.c > +++ b/arch/arm64/net/bpf_jit_comp.c > @@ -9,6 +9,7 @@ > > #include <linux/bitfield.h> > #include <linux/bpf.h> > +#include <linux/memory.h> > #include <linux/filter.h> > #include <linux/printk.h> > #include <linux/slab.h> > @@ -18,6 +19,7 @@ > #include <asm/cacheflush.h> > #include <asm/debug-monitors.h> > #include <asm/insn.h> > +#include <asm/patching.h> > #include <asm/set_memory.h> > > #include "bpf_jit.h" > @@ -1529,3 +1531,53 @@ void bpf_jit_free_exec(void *addr) > { > return vfree(addr); > } > + > +static int gen_branch_or_nop(enum aarch64_insn_branch_type type, void *ip, > + void *addr, u32 *insn) > +{ > + if (!addr) > + *insn = aarch64_insn_gen_nop(); > + else > + *insn = aarch64_insn_gen_branch_imm((unsigned long)ip, > + (unsigned long)addr, > + type); > + > + return *insn != AARCH64_BREAK_FAULT ? 0 : -EFAULT; > +} > + > +int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, > + void *old_addr, void *new_addr) > +{ > + int ret; > + u32 old_insn; > + u32 new_insn; > + u32 replaced; > + enum aarch64_insn_branch_type branch_type; > + In bpf_arch_text_poke() of x86, it disables the poking of kernel module, can you explain why it is OK to do so in arm64 ? Because there is no test cases for fentry on linux kernel module, could you please add some tests for it ? > + if (poke_type == BPF_MOD_CALL) > + branch_type = AARCH64_INSN_BRANCH_LINK; > + else > + branch_type = AARCH64_INSN_BRANCH_NOLINK; > + > + if (gen_branch_or_nop(branch_type, ip, old_addr, &old_insn) < 0) > + return -EFAULT; > + > + if (gen_branch_or_nop(branch_type, ip, new_addr, &new_insn) < 0) > + return -EFAULT; > + > + mutex_lock(&text_mutex); > + if (aarch64_insn_read(ip, &replaced)) { > + ret = -EFAULT; > + goto out; > + } > + > + if (replaced != old_insn) { > + ret = -EFAULT; > + goto out; > + } > + > + ret = aarch64_insn_patch_text_nosync((void *)ip, new_insn); > +out: > + mutex_unlock(&text_mutex); > + return ret; > +}
WARNING: multiple messages have this Message-ID (diff)
From: Hou Tao <houtao1@huawei.com> To: Xu Kuohai <xukuohai@huawei.com>, <bpf@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>, <linux-kselftest@vger.kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>, Daniel Borkmann <daniel@iogearbox.net>, Alexei Starovoitov <ast@kernel.org>, Zi Shen Lim <zlim.lnx@gmail.com>, Andrii Nakryiko <andrii@kernel.org>, Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>, John Fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@kernel.org>, "David S . Miller" <davem@davemloft.net>, Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>, David Ahern <dsahern@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>, <hpa@zytor.com>, Shuah Khan <shuah@kernel.org>, Mark Rutland <mark.rutland@arm.com>, Ard Biesheuvel <ardb@kernel.org>, Pasha Tatashin <pasha.tatashin@soleen.com>, Peter Collingbourne <pcc@google.com>, Daniel Kiss <daniel.kiss@arm.com>, Sudeep Holla <sudeep.holla@arm.com>, Steven Price <steven.price@arm.com>, Marc Zyngier <maz@kernel.org>, Mark Brown <broonie@kernel.org>, Kumar Kartikeya Dwivedi <memxor@gmail.com>, Delyan Kratunov <delyank@fb.com> Subject: Re: [PATCH bpf-next v2 4/6] bpf, arm64: Impelment bpf_arch_text_poke() for arm64 Date: Fri, 15 Apr 2022 10:34:47 +0800 [thread overview] Message-ID: <ba838451-1a96-2c83-9188-a994f45d7523@huawei.com> (raw) In-Reply-To: <20220414162220.1985095-5-xukuohai@huawei.com> Hi, On 4/15/2022 12:22 AM, Xu Kuohai wrote: > Impelment bpf_arch_text_poke() for arm64, so bpf trampoline code can use > it to replace nop with jump, or replace jump with nop. > > Signed-off-by: Xu Kuohai <xukuohai@huawei.com> > Acked-by: Song Liu <songliubraving@fb.com> > --- > arch/arm64/net/bpf_jit_comp.c | 52 +++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c > index 8ab4035dea27..1a1c3ea75ee2 100644 > --- a/arch/arm64/net/bpf_jit_comp.c > +++ b/arch/arm64/net/bpf_jit_comp.c > @@ -9,6 +9,7 @@ > > #include <linux/bitfield.h> > #include <linux/bpf.h> > +#include <linux/memory.h> > #include <linux/filter.h> > #include <linux/printk.h> > #include <linux/slab.h> > @@ -18,6 +19,7 @@ > #include <asm/cacheflush.h> > #include <asm/debug-monitors.h> > #include <asm/insn.h> > +#include <asm/patching.h> > #include <asm/set_memory.h> > > #include "bpf_jit.h" > @@ -1529,3 +1531,53 @@ void bpf_jit_free_exec(void *addr) > { > return vfree(addr); > } > + > +static int gen_branch_or_nop(enum aarch64_insn_branch_type type, void *ip, > + void *addr, u32 *insn) > +{ > + if (!addr) > + *insn = aarch64_insn_gen_nop(); > + else > + *insn = aarch64_insn_gen_branch_imm((unsigned long)ip, > + (unsigned long)addr, > + type); > + > + return *insn != AARCH64_BREAK_FAULT ? 0 : -EFAULT; > +} > + > +int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, > + void *old_addr, void *new_addr) > +{ > + int ret; > + u32 old_insn; > + u32 new_insn; > + u32 replaced; > + enum aarch64_insn_branch_type branch_type; > + In bpf_arch_text_poke() of x86, it disables the poking of kernel module, can you explain why it is OK to do so in arm64 ? Because there is no test cases for fentry on linux kernel module, could you please add some tests for it ? > + if (poke_type == BPF_MOD_CALL) > + branch_type = AARCH64_INSN_BRANCH_LINK; > + else > + branch_type = AARCH64_INSN_BRANCH_NOLINK; > + > + if (gen_branch_or_nop(branch_type, ip, old_addr, &old_insn) < 0) > + return -EFAULT; > + > + if (gen_branch_or_nop(branch_type, ip, new_addr, &new_insn) < 0) > + return -EFAULT; > + > + mutex_lock(&text_mutex); > + if (aarch64_insn_read(ip, &replaced)) { > + ret = -EFAULT; > + goto out; > + } > + > + if (replaced != old_insn) { > + ret = -EFAULT; > + goto out; > + } > + > + ret = aarch64_insn_patch_text_nosync((void *)ip, new_insn); > +out: > + mutex_unlock(&text_mutex); > + return ret; > +} _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-04-15 2:34 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-14 16:22 [PATCH bpf-next v2 0/6] bpf trampoline for arm64 Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-14 16:22 ` [PATCH bpf-next v2 1/6] arm64: ftrace: Add ftrace direct call support Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-14 16:22 ` [PATCH bpf-next v2 2/6] ftrace: Fix deadloop caused by direct call in ftrace selftest Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-20 23:24 ` Steven Rostedt 2022-04-20 23:24 ` Steven Rostedt 2022-04-21 3:01 ` Xu Kuohai 2022-04-21 3:01 ` Xu Kuohai 2022-04-14 16:22 ` [PATCH bpf-next v2 3/6] bpf: Move is_valid_bpf_tramp_flags() to the public trampoline code Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-14 16:22 ` [PATCH bpf-next v2 4/6] bpf, arm64: Impelment bpf_arch_text_poke() for arm64 Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-15 2:34 ` Hou Tao [this message] 2022-04-15 2:34 ` Hou Tao 2022-04-15 3:39 ` Xu Kuohai 2022-04-15 3:39 ` Xu Kuohai 2022-04-22 10:54 ` Jakub Sitnicki 2022-04-22 10:54 ` Jakub Sitnicki 2022-04-24 5:05 ` Xu Kuohai 2022-04-24 5:05 ` Xu Kuohai 2022-04-25 14:26 ` Jakub Sitnicki 2022-04-25 14:26 ` Jakub Sitnicki 2022-04-26 4:01 ` Xu Kuohai 2022-04-26 4:01 ` Xu Kuohai 2022-04-14 16:22 ` [PATCH bpf-next v2 5/6] bpf, arm64: bpf trampoline " Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-15 17:12 ` Andrii Nakryiko 2022-04-15 17:12 ` Andrii Nakryiko 2022-04-16 1:57 ` Xu Kuohai 2022-04-16 1:57 ` Xu Kuohai 2022-04-20 7:43 ` Xu Kuohai 2022-04-20 7:43 ` Xu Kuohai 2022-04-20 11:42 ` KP Singh 2022-04-20 11:42 ` KP Singh 2022-04-14 16:22 ` [PATCH bpf-next v2 6/6] selftests/bpf: Fix trivial typo in fentry_fexit.c Xu Kuohai 2022-04-14 16:22 ` Xu Kuohai 2022-04-15 2:37 ` [PATCH bpf-next v2 0/6] bpf trampoline for arm64 Hou Tao 2022-04-15 2:37 ` Hou Tao 2022-04-15 3:47 ` Xu Kuohai 2022-04-15 3:47 ` Xu Kuohai
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