bpf_arch_text_copy is used to dump JITed binary to RX page, allowing
multiple BPF programs to share the same page. Use the newly introduced
patch_instructions() to implement it. Around 5X improvement in speed
of execution observed, using the new patch_instructions() function
over patch_instruction(), while running the tests from test_bpf.ko.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---
 arch/powerpc/net/bpf_jit_comp.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index e93aefcfb83f..0a70319116d1 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c

@@ -13,9 +13,12 @@
 #include <linux/netdevice.h>
 #include <linux/filter.h>
 #include <linux/if_vlan.h>
-#include <asm/kprobes.h>
+#include <linux/memory.h>
 #include <linux/bpf.h>

+#include <asm/kprobes.h>
+#include <asm/code-patching.h>
+
 #include "bpf_jit.h"

 static void bpf_jit_fill_ill_insns(void *area, unsigned int size)

@@ -272,3 +275,21 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct code
        ctx->exentry_idx++;
        return 0;
 }
+
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+       void *ret = ERR_PTR(-EINVAL);
+       int err;
+
+       if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+               return ret;
+
+       ret = dst;
+       mutex_lock(&text_mutex);
+       err = patch_instructions(dst, src, false, len);
+       if (err)
+               ret = ERR_PTR(err);
+       mutex_unlock(&text_mutex);
+
+       return ret;
+}