From: Xu Kuohai <xukuohai@huaweicloud.com> To: Puranjay Mohan <puranjay12@gmail.com>, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, bpf@vger.kernel.org, kpsingh@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH bpf-next v5 2/3] arm64: patching: Add aarch64_insn_set() Date: Sat, 9 Sep 2023 17:13:21 +0800 [thread overview] Message-ID: <2095a591-8f3e-318c-a390-a43a653ce6d5@huaweicloud.com> (raw) In-Reply-To: <20230908144320.2474-3-puranjay12@gmail.com> On 9/8/2023 10:43 PM, Puranjay Mohan wrote: > The BPF JIT needs to write invalid instructions to RX regions of memory > to invalidate removed BPF programs. This needs a function like memset() > that can work with RX memory. > > Implement aarch64_insn_set() which is similar to text_poke_set() of x86. > > Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> > --- > arch/arm64/include/asm/patching.h | 1 + > arch/arm64/kernel/patching.c | 40 +++++++++++++++++++++++++++++++ > 2 files changed, 41 insertions(+) > > diff --git a/arch/arm64/include/asm/patching.h b/arch/arm64/include/asm/patching.h > index f78a0409cbdb..551933338739 100644 > --- a/arch/arm64/include/asm/patching.h > +++ b/arch/arm64/include/asm/patching.h > @@ -8,6 +8,7 @@ int aarch64_insn_read(void *addr, u32 *insnp); > int aarch64_insn_write(void *addr, u32 insn); > > int aarch64_insn_write_literal_u64(void *addr, u64 val); > +int aarch64_insn_set(void *dst, const u32 insn, size_t len); > void *aarch64_insn_copy(void *dst, const void *src, size_t len); > > int aarch64_insn_patch_text_nosync(void *addr, u32 insn); > diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c > index 243d6ae8d2d8..63d9e0e77806 100644 > --- a/arch/arm64/kernel/patching.c > +++ b/arch/arm64/kernel/patching.c > @@ -146,6 +146,46 @@ noinstr void *aarch64_insn_copy(void *dst, const void *src, size_t len) > return dst; > } > > +/** > + * aarch64_insn_set - memset for RX memory regions. > + * @dst: address to modify > + * @c: value to set insn > + * @len: length of memory region. > + * > + * Useful for JITs to fill regions of RX memory with illegal instructions. > + */ > +noinstr int aarch64_insn_set(void *dst, const u32 insn, size_t len) const is unnecessary > +{ > + unsigned long flags; > + size_t patched = 0; > + size_t size; > + void *waddr; > + void *ptr; > + > + /* A64 instructions must be word aligned */ > + if ((uintptr_t)dst & 0x3) > + return -EINVAL; > + > + raw_spin_lock_irqsave(&patch_lock, flags); > + > + while (patched < len) { > + ptr = dst + patched; > + size = min_t(size_t, PAGE_SIZE - offset_in_page(ptr), > + len - patched); > + > + waddr = patch_map(ptr, FIX_TEXT_POKE0); > + memset32(waddr, insn, size / 4); > + patch_unmap(FIX_TEXT_POKE0); > + > + patched += size; > + } > + raw_spin_unlock_irqrestore(&patch_lock, flags); > + > + caches_clean_inval_pou((uintptr_t)dst, (uintptr_t)dst + len); > + > + return 0; > +} > + this function shares most of the code with aarch64_insn_copy(), how about extracting the shared code to a separate function? > int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn) > { > u32 *tp = addr;
WARNING: multiple messages have this Message-ID (diff)
From: Xu Kuohai <xukuohai@huaweicloud.com> To: Puranjay Mohan <puranjay12@gmail.com>, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, bpf@vger.kernel.org, kpsingh@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH bpf-next v5 2/3] arm64: patching: Add aarch64_insn_set() Date: Sat, 9 Sep 2023 17:13:21 +0800 [thread overview] Message-ID: <2095a591-8f3e-318c-a390-a43a653ce6d5@huaweicloud.com> (raw) In-Reply-To: <20230908144320.2474-3-puranjay12@gmail.com> On 9/8/2023 10:43 PM, Puranjay Mohan wrote: > The BPF JIT needs to write invalid instructions to RX regions of memory > to invalidate removed BPF programs. This needs a function like memset() > that can work with RX memory. > > Implement aarch64_insn_set() which is similar to text_poke_set() of x86. > > Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> > --- > arch/arm64/include/asm/patching.h | 1 + > arch/arm64/kernel/patching.c | 40 +++++++++++++++++++++++++++++++ > 2 files changed, 41 insertions(+) > > diff --git a/arch/arm64/include/asm/patching.h b/arch/arm64/include/asm/patching.h > index f78a0409cbdb..551933338739 100644 > --- a/arch/arm64/include/asm/patching.h > +++ b/arch/arm64/include/asm/patching.h > @@ -8,6 +8,7 @@ int aarch64_insn_read(void *addr, u32 *insnp); > int aarch64_insn_write(void *addr, u32 insn); > > int aarch64_insn_write_literal_u64(void *addr, u64 val); > +int aarch64_insn_set(void *dst, const u32 insn, size_t len); > void *aarch64_insn_copy(void *dst, const void *src, size_t len); > > int aarch64_insn_patch_text_nosync(void *addr, u32 insn); > diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c > index 243d6ae8d2d8..63d9e0e77806 100644 > --- a/arch/arm64/kernel/patching.c > +++ b/arch/arm64/kernel/patching.c > @@ -146,6 +146,46 @@ noinstr void *aarch64_insn_copy(void *dst, const void *src, size_t len) > return dst; > } > > +/** > + * aarch64_insn_set - memset for RX memory regions. > + * @dst: address to modify > + * @c: value to set insn > + * @len: length of memory region. > + * > + * Useful for JITs to fill regions of RX memory with illegal instructions. > + */ > +noinstr int aarch64_insn_set(void *dst, const u32 insn, size_t len) const is unnecessary > +{ > + unsigned long flags; > + size_t patched = 0; > + size_t size; > + void *waddr; > + void *ptr; > + > + /* A64 instructions must be word aligned */ > + if ((uintptr_t)dst & 0x3) > + return -EINVAL; > + > + raw_spin_lock_irqsave(&patch_lock, flags); > + > + while (patched < len) { > + ptr = dst + patched; > + size = min_t(size_t, PAGE_SIZE - offset_in_page(ptr), > + len - patched); > + > + waddr = patch_map(ptr, FIX_TEXT_POKE0); > + memset32(waddr, insn, size / 4); > + patch_unmap(FIX_TEXT_POKE0); > + > + patched += size; > + } > + raw_spin_unlock_irqrestore(&patch_lock, flags); > + > + caches_clean_inval_pou((uintptr_t)dst, (uintptr_t)dst + len); > + > + return 0; > +} > + this function shares most of the code with aarch64_insn_copy(), how about extracting the shared code to a separate function? > int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn) > { > u32 *tp = addr; _______________________________________________ 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:[~2023-09-09 9:13 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-09-08 14:43 [PATCH bpf-next v5 0/3] bpf, arm64: use BPF prog pack allocator in BPF JIT Puranjay Mohan 2023-09-08 14:43 ` Puranjay Mohan 2023-09-08 14:43 ` [PATCH bpf-next v5 1/3] arm64: patching: Add aarch64_insn_copy() Puranjay Mohan 2023-09-08 14:43 ` Puranjay Mohan 2023-09-09 9:04 ` Xu Kuohai 2023-09-09 9:04 ` Xu Kuohai 2023-09-21 14:33 ` Puranjay Mohan 2023-09-21 14:33 ` Puranjay Mohan 2023-11-02 16:19 ` Mark Rutland 2023-11-02 16:19 ` Mark Rutland 2023-11-02 17:41 ` Alexei Starovoitov 2023-11-02 17:41 ` Alexei Starovoitov 2023-09-08 14:43 ` [PATCH bpf-next v5 2/3] arm64: patching: Add aarch64_insn_set() Puranjay Mohan 2023-09-08 14:43 ` Puranjay Mohan 2023-09-09 9:13 ` Xu Kuohai [this message] 2023-09-09 9:13 ` Xu Kuohai 2023-09-21 14:50 ` Puranjay Mohan 2023-09-21 14:50 ` Puranjay Mohan 2023-09-22 1:25 ` Xu Kuohai 2023-09-22 1:25 ` Xu Kuohai 2023-11-02 16:26 ` Mark Rutland 2023-11-02 16:26 ` Mark Rutland 2023-09-08 14:43 ` [PATCH bpf-next v5 3/3] bpf, arm64: use bpf_jit_binary_pack_alloc Puranjay Mohan 2023-09-08 14:43 ` Puranjay Mohan 2023-09-09 8:59 ` Xu Kuohai 2023-09-09 8:59 ` Xu Kuohai
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