[RFC PATCH V3 22/43] rv64ilp32_abi: bpf: Change KERN_ARENA_SZ to 256MiB
From: guoren@kernel.org
Date: 2025-03-25 12:22:02
Also in:
bpf, kvm, kvm-riscv, linux-arch, linux-btrfs, linux-crypto, linux-fsdevel, linux-input, linux-media, linux-mm, linux-nfs, linux-perf-users, linux-riscv, linux-sctp, linux-serial, linux-usb, lkml, netdev, netfilter-devel
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
From: "Guo Ren (Alibaba DAMO Academy)" <guoren@kernel.org> The RV64ILP32 ABI limits the vmalloc range to 512MB, hence the arena kernel range is set to 256MiB instead of 4GiB. Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org> --- kernel/bpf/arena.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c
index 870aeb51d70a..4eb99f83d4a1 100644
--- a/kernel/bpf/arena.c
+++ b/kernel/bpf/arena.c@@ -40,7 +40,14 @@ /* number of bytes addressable by LDX/STX insn with 16-bit 'off' field */ #define GUARD_SZ (1ull << sizeof_field(struct bpf_insn, off) * 8) -#define KERN_VM_SZ (SZ_4G + GUARD_SZ) + +#if BITS_PER_LONG == 64 +#define KERN_ARENA_SZ SZ_4G +#else +#define KERN_ARENA_SZ SZ_256M +#endif + +#define KERN_VM_SZ (KERN_ARENA_SZ + GUARD_SZ) struct bpf_arena { struct bpf_map map;
@@ -115,7 +122,7 @@ static struct bpf_map *arena_map_alloc(union bpf_attr *attr) return ERR_PTR(-EINVAL); vm_range = (u64)attr->max_entries * PAGE_SIZE; - if (vm_range > SZ_4G) + if (vm_range > KERN_ARENA_SZ) return ERR_PTR(-E2BIG); if ((attr->map_extra >> 32) != ((attr->map_extra + vm_range - 1) >> 32))
@@ -321,7 +328,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad if (pgoff) return -EINVAL; - if (len > SZ_4G) + if (len > KERN_ARENA_SZ) return -E2BIG; /* if user_vm_start was specified at arena creation time */
@@ -337,12 +344,14 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad ret = mm_get_unmapped_area(current->mm, filp, addr, len * 2, 0, flags); if (IS_ERR_VALUE(ret)) return ret; +#if BITS_PER_LONG == 64 if ((ret >> 32) == ((ret + len - 1) >> 32)) return ret; +#endif if (WARN_ON_ONCE(arena->user_vm_start)) /* checks at map creation time should prevent this */ return -EFAULT; - return round_up(ret, SZ_4G); + return round_up(ret, KERN_ARENA_SZ); } static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
@@ -366,7 +375,7 @@ static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) return -EBUSY; /* Earlier checks should prevent this */ - if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > SZ_4G || vma->vm_pgoff)) + if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > KERN_ARENA_SZ || vma->vm_pgoff)) return -EFAULT; if (remember_vma(arena, vma))
--
2.40.1