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From: Palmer Dabbelt <palmerdabbelt@google.com>
To: Bjorn Topel <bjorn.topel@gmail.com>
Cc: daniel@iogearbox.net, netdev@vger.kernel.org, ast@kernel.org,
	Bjorn Topel <bjorn.topel@gmail.com>,
	linux-riscv@lists.infradead.org, bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free
Date: Mon, 23 Dec 2019 10:30:38 -0800 (PST)
Message-ID: <mhng-3299fb62-01d1-4e83-90fe-d706d2495bc1@palmerdabbelt-glaptop> (raw)
In-Reply-To: <20191216091343.23260-7-bjorn.topel@gmail.com>

On Mon, 16 Dec 2019 01:13:40 PST (-0800), Bjorn Topel wrote:
> This commit makes sure that the JIT images is kept close to the kernel
> text, so BPF calls can use relative calling with auipc/jalr or jal
> instead of loading the full 64-bit address and jalr.
>
> The BPF JIT image region is 128 MB before the kernel text.
>
> Signed-off-by: Björn Töpel <bjorn.topel@gmail.com>
> ---
>  arch/riscv/include/asm/pgtable.h |  4 ++++
>  arch/riscv/net/bpf_jit_comp.c    | 13 +++++++++++++
>  2 files changed, 17 insertions(+)
>
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 7ff0ed4f292e..cc3f49415620 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -404,6 +404,10 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
>  #define VMALLOC_END      (PAGE_OFFSET - 1)
>  #define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
>
> +#define BPF_JIT_REGION_SIZE	(SZ_128M)
> +#define BPF_JIT_REGION_START	(PAGE_OFFSET - BPF_JIT_REGION_SIZE)
> +#define BPF_JIT_REGION_END	(VMALLOC_END)
> +
>  /*
>   * Roughly size the vmemmap space to be large enough to fit enough
>   * struct pages to map half the virtual address space. Then
> diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c
> index 8aa19c846881..46cff093f526 100644
> --- a/arch/riscv/net/bpf_jit_comp.c
> +++ b/arch/riscv/net/bpf_jit_comp.c
> @@ -1656,3 +1656,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>  					   tmp : orig_prog);
>  	return prog;
>  }
> +
> +void *bpf_jit_alloc_exec(unsigned long size)
> +{
> +	return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START,
> +				    BPF_JIT_REGION_END, GFP_KERNEL,
> +				    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
> +				    __builtin_return_address(0));
> +}
> +
> +void bpf_jit_free_exec(void *addr)
> +{
> +	return vfree(addr);
> +}

Ah, I guess I should have read the whole patch set :)

Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

and feel free to put the same on whatever patch I just asked that question
on, though maybe this one should go before the others as they sort of depend on
it?


  parent reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  9:13 [PATCH bpf-next v2 0/9] riscv: BPF JIT fix, optimizations and far jumps support Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 1/9] riscv, bpf: fix broken BPF tail calls Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 3/9] riscv, bpf: add support for far branching when emitting tail call Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 5/9] riscv, bpf: optimize BPF tail calls Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free Björn Töpel
2019-12-16 15:09   ` Daniel Borkmann
2019-12-18  6:23     ` Björn Töpel
2020-01-04  1:32       ` Paul Walmsley
2020-01-07 10:24         ` Björn Töpel
2020-01-07 10:47           ` Paul Walmsley
2020-02-02 13:37   ` Alex Ghiti
2020-02-03 12:28     ` Björn Töpel
2020-02-03 20:57       ` Alex Ghiti
2019-12-16  9:13 ` [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 8/9] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 9/9] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs Björn Töpel
2019-12-19 15:07 ` [PATCH bpf-next v2 0/9] riscv: BPF JIT fix, optimizations and far jumps support Daniel Borkmann
2019-12-19 22:02 ` [PATCH bpf-next v2 1/9] riscv, bpf: fix broken BPF tail calls Palmer Dabbelt
2019-12-23 18:03 ` [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching Palmer Dabbelt
2020-01-07  8:13   ` Björn Töpel
2020-01-23  2:08   ` Palmer Dabbelt
2019-12-23 18:18 ` [PATCH bpf-next v2 3/9] riscv, bpf: add support for far branching when emitting tail call Palmer Dabbelt
2019-12-23 18:18 ` [PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits Palmer Dabbelt
2019-12-23 18:29 ` [PATCH bpf-next v2 5/9] riscv, bpf: optimize BPF tail calls Palmer Dabbelt
2019-12-23 18:30 ` Palmer Dabbelt [this message]
2019-12-23 18:58 ` [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls Palmer Dabbelt
2020-01-07 10:14   ` Björn Töpel
2020-01-28  2:15   ` Palmer Dabbelt
2020-02-03 12:11     ` Björn Töpel
2019-12-23 18:58 ` [PATCH bpf-next v2 8/9] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs Palmer Dabbelt
2019-12-23 18:58 ` [PATCH bpf-next v2 9/9] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs Palmer Dabbelt

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