From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@kernel.org>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
Jessica Yu <jeyu@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH v2 1/2] bpf: add __weak hook for allocating executable memory
Date: Wed, 21 Nov 2018 14:17:32 +0100 [thread overview]
Message-ID: <20181121131733.14910-2-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20181121131733.14910-1-ard.biesheuvel@linaro.org>
By default, BPF uses module_alloc() to allocate executable memory,
but this is not necessary on all arches and potentially undesirable
on some of them.
So break out the module_alloc() and module_memfree() calls into __weak
functions to allow them to be overridden in arch code.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
kernel/bpf/core.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 1a796e0799ec..f28d8a5eb6b8 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -609,6 +609,16 @@ static void bpf_jit_uncharge_modmem(u32 pages)
atomic_long_sub(pages, &bpf_jit_current);
}
+void *__weak bpf_jit_alloc_exec(unsigned long size)
+{
+ return module_alloc(size);
+}
+
+void __weak bpf_jit_free_exec(const void *addr)
+{
+ return module_memfree(size);
+}
+
struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
unsigned int alignment,
@@ -626,7 +636,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
if (bpf_jit_charge_modmem(pages))
return NULL;
- hdr = module_alloc(size);
+ hdr = bpf_jit_alloc_exec(size);
if (!hdr) {
bpf_jit_uncharge_modmem(pages);
return NULL;
@@ -650,7 +660,7 @@ void bpf_jit_binary_free(struct bpf_binary_header *hdr)
{
u32 pages = hdr->pages;
- module_memfree(hdr);
+ bpf_jit_free_exec(hdr);
bpf_jit_uncharge_modmem(pages);
}
--
2.17.1
next prev parent reply other threads:[~2018-11-21 13:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-21 13:17 [PATCH v2 0/2] bpf: permit JIT allocations to be served outside the module region Ard Biesheuvel
2018-11-21 13:17 ` Ard Biesheuvel [this message]
2018-11-22 20:01 ` [PATCH v2 1/2] bpf: add __weak hook for allocating executable memory kbuild test robot
2018-11-22 21:08 ` Ard Biesheuvel
2018-11-21 13:17 ` [PATCH v2 2/2] arm64/bpf: don't allocate BPF JIT programs in module memory Ard Biesheuvel
2018-11-21 23:20 ` Daniel Borkmann
2018-11-22 8:02 ` Ard Biesheuvel
2018-11-22 22:49 ` Daniel Borkmann
2018-11-24 2:57 ` kbuild test robot
2018-11-21 19:48 ` [PATCH v2 0/2] bpf: permit JIT allocations to be served outside the module region Edgecombe, Rick P
2018-11-21 20:36 ` Ard Biesheuvel
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