On 12/05/2018 02:24 PM, Will Deacon wrote:

On Wed, Dec 05, 2018 at 01:24:17PM +0100, Daniel Borkmann wrote:

quoted

On 12/04/2018 04:45 PM, Ard Biesheuvel wrote:

quoted

On Mon, 3 Dec 2018 at 13:49, Will Deacon [off-list ref] wrote:

quoted

On Fri, Nov 30, 2018 at 08:20:06PM +0100, Ard Biesheuvel wrote:

quoted

On Fri, 30 Nov 2018 at 19:26, Will Deacon [off-list ref] wrote:

quoted

On Fri, Nov 23, 2018 at 11:18:04PM +0100, Ard Biesheuvel wrote:

quoted

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index a6fdaea07c63..76c2ab40c02d 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c

@@ -940,3 +940,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
                                         tmp : orig_prog);
      return prog;
 }
+
+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,
+                                 __builtin_return_address(0));

I guess we'll want VM_IMMEDIATE_UNMAP here if Rich gets that merged.

I think akpm already queued up that patch.

quoted

In the
meantime, I wonder if it's worth zeroing the region in bpf_jit_free_exec()?
(although we'd need the size information...).

Not sure. What exactly would that achieve?

I think the zero encoding is guaranteed to be undefined, so it would limit
the usefulness of any stale, executable TLB entries. However, we'd also need
cache maintenance to make that stuff visible to the I side, so it's probably
not worth it, especially if akpm has queued the stuff from Rich.

Maybe just add an:

/* FIXME: Remove this when VM_IMMEDIATE_UNMAP is supported */
#ifndef VM_IMMEDIATE_UNMAP
#define VM_IMMEDIATE_UNMAP      0
#endif

so we remember to come back and sort this out? Up to you.

I'll just make a note to send out that patch once the definition lands via -akpm

Could I get an ACK from you for this patch, then I'd take the series into bpf-next.

Gah, thanks for the ping: I thought I acked this initially, but turns out I
didn't.

Acked-by: Will Deacon <redacted>

Applied, thanks everyone!