riscv, bpf: Provide RISC-V specific JIT image alloc/free (7f3631e8) · Commits · 戴 / test

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> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191216091343.23260-7-bjorn.topel@gmail.com

arch/riscv/include/asm/pgtable.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -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

arch/riscv/net/bpf_jit_comp.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -1656,3 +1656,16 @@ out:
		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);
		}

Admin message