bpf: add __weak hook for allocating executable memory
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>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index f93ed66..86817ab 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -623,6 +623,16 @@
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(void *addr)
+{
+ module_memfree(addr);
+}
+
struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
unsigned int alignment,
@@ -640,7 +650,7 @@
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;
@@ -664,7 +674,7 @@
{
u32 pages = hdr->pages;
- module_memfree(hdr);
+ bpf_jit_free_exec(hdr);
bpf_jit_uncharge_modmem(pages);
}
