[PATCH v4 2/5] powerpc/bpf: implement bpf_arch_text_invalidate for bpf_prog_pack

[Hari Bathini <hbathini@linux.ibm.com>]

Implement bpf_arch_text_invalidate and use it to fill unused part of
the bpf_prog_pack with trap instructions when a BPF program is freed.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---
 arch/powerpc/net/bpf_jit_comp.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 4f896222c579..c0036eb171f0 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -313,3 +313,18 @@ void *bpf_arch_text_copy(void *dst, void *src, size_t len)
 
 	return ret;
 }
+
+int bpf_arch_text_invalidate(void *dst, size_t len)
+{
+	u32 insn = BREAKPOINT_INSTRUCTION;
+	void *ret;
+
+	if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+		return -EINVAL;
+
+	mutex_lock(&text_mutex);
+	ret = bpf_patch_instructions(dst, &insn, len, true);
+	mutex_unlock(&text_mutex);
+
+	return IS_ERR(ret) ? PTR_ERR(ret) : 0;
+}
-- 
2.41.0