From: Jisheng Zhang <jszhang@kernel.org>
Date: Mon, 29 Mar 2021 18:25:21 +0000 (+0800)
Subject: riscv: bpf: Avoid breaking W^X
X-Git-Tag: accepted/tizen/unified/20230118.172025~7277^2~19
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fc8504765ec5e812135b8ccafca7101069a0c6d8;p=platform%2Fkernel%2Flinux-rpi.git

riscv: bpf: Avoid breaking W^X

We allocate Non-executable pages, then call bpf_jit_binary_lock_ro()
to enable executable permission after mapping them read-only. This is
to prepare for STRICT_MODULE_RWX in following patch.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---

diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
index d8da819..fed86f4 100644
--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -152,6 +152,7 @@ skip_init_ctx:
 	bpf_flush_icache(jit_data->header, ctx->insns + ctx->ninsns);
 
 	if (!prog->is_func || extra_pass) {
+		bpf_jit_binary_lock_ro(jit_data->header);
 out_offset:
 		kfree(ctx->offset);
 		kfree(jit_data);
@@ -169,7 +170,7 @@ 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,
+				    PAGE_KERNEL, 0, NUMA_NO_NODE,
 				    __builtin_return_address(0));
 }