From 8f04db78e4e36a5d4858ce841a3e9cc3d69bde36 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Thu, 14 Oct 2021 15:25:51 +0100 Subject: [PATCH 1/3] bpf: Define bpf_jit_alloc_exec_limit for riscv JIT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Expose the maximum amount of useable memory from the riscv JIT. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Acked-by: Luke Nelson Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20211014142554.53120-2-lmb@cloudflare.com --- arch/riscv/net/bpf_jit_core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c index fed86f42dfbe..0fee2cbaaf53 100644 --- a/arch/riscv/net/bpf_jit_core.c +++ b/arch/riscv/net/bpf_jit_core.c @@ -166,6 +166,11 @@ out: return prog; } +u64 bpf_jit_alloc_exec_limit(void) +{ + return BPF_JIT_REGION_SIZE; +} + void *bpf_jit_alloc_exec(unsigned long size) { return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START, From 5d63ae908242f028bd10860cba98450d11c079b8 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Thu, 14 Oct 2021 15:25:52 +0100 Subject: [PATCH 2/3] bpf: Define bpf_jit_alloc_exec_limit for arm64 JIT Expose the maximum amount of useable memory from the arm64 JIT. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211014142554.53120-3-lmb@cloudflare.com --- arch/arm64/net/bpf_jit_comp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 41c23f474ea6..803e7773fa86 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1136,6 +1136,11 @@ out: return prog; } +u64 bpf_jit_alloc_exec_limit(void) +{ + return BPF_JIT_REGION_SIZE; +} + void *bpf_jit_alloc_exec(unsigned long size) { return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START, From fadb7ff1a6c2c565af56b4aacdd086b067eed440 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Thu, 14 Oct 2021 15:25:53 +0100 Subject: [PATCH 3/3] bpf: Prevent increasing bpf_jit_limit above max Restrict bpf_jit_limit to the maximum supported by the arch's JIT. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211014142554.53120-4-lmb@cloudflare.com --- include/linux/filter.h | 1 + kernel/bpf/core.c | 4 +++- net/core/sysctl_net_core.c | 2 +- 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 4a93c12543ee..ef03ff34234d 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1051,6 +1051,7 @@ extern int bpf_jit_enable; extern int bpf_jit_harden; extern int bpf_jit_kallsyms; extern long bpf_jit_limit; +extern long bpf_jit_limit_max; typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d6b7dfdd8066..c1e7eb3f1876 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -524,6 +524,7 @@ int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); int bpf_jit_harden __read_mostly; long bpf_jit_limit __read_mostly; +long bpf_jit_limit_max __read_mostly; static void bpf_prog_ksym_set_addr(struct bpf_prog *prog) @@ -817,7 +818,8 @@ u64 __weak bpf_jit_alloc_exec_limit(void) static int __init bpf_jit_charge_init(void) { /* Only used as heuristic here to derive limit. */ - bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2, + bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); + bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, PAGE_SIZE), LONG_MAX); return 0; } diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index c8496c1142c9..5f88526ad61c 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -419,7 +419,7 @@ static struct ctl_table net_core_table[] = { .mode = 0600, .proc_handler = proc_dolongvec_minmax_bpf_restricted, .extra1 = &long_one, - .extra2 = &long_max, + .extra2 = &bpf_jit_limit_max, }, #endif {