linux-kernel - [PATCH 4/4] arm64: bpf: do not allocate executable memory

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Message-Id: <20190523102256.29168-5-ard.biesheuvel@arm.com>
Date:   Thu, 23 May 2019 11:22:56 +0100
From:   Ard Biesheuvel <ard.biesheuvel@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     marc.zyngier@....com, mark.rutland@....com,
        linux-kernel@...r.kernel.org,
        Ard Biesheuvel <ard.biesheuvel@....com>,
        Nadav Amit <namit@...are.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Will Deacon <will.deacon@....com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        James Morse <james.morse@....com>
Subject: [PATCH 4/4] arm64: bpf: do not allocate executable memory

The BPF code now takes care of mapping the code pages executable
after mapping them read-only, to ensure that no RWX mapped regions
are needed, even transiently. This means we can drop the executable
permissions from the mapping at allocation time.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@....com>
---
 arch/arm64/net/bpf_jit_comp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index df845cee438e..aef4ff467222 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -981,7 +981,7 @@ 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));
 }
 
-- 
2.17.1