bpf, arm64: Remove redundant bpf_flush_icache() after pack allocator finalize

bpf_flush_icache() calls flush_icache_range() to clean the data cache
and invalidate the instruction cache for the JITed code region. However,
since commit 1dad391daef1 ("bpf, arm64: use bpf_prog_pack for memory
management"), this flush is redundant.

bpf_jit_binary_pack_finalize() copies the JITed instructions to the ROX
region via bpf_arch_text_copy() -> aarch64_insn_copy() -> __text_poke(),
and __text_poke() already calls flush_icache_range() on the written
range. The subsequent bpf_flush_icache() repeats the same cache
maintenance on an overlapping range, including an unnecessary second
synchronous IPI to all CPUs via kick_all_cpus_sync().

Remove the redundant bpf_flush_icache() call and its now-unused
definition.

Fixes: 1dad391daef1 ("bpf, arm64: use bpf_prog_pack for memory management")
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20260413191111.3426023-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 4aad9483f8a501cfecf7a089fada02de04fde189..524b67c0867e758c74af6d4b36d52c8bdb03c97c 100644 (file)
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -18,7 +18,6 @@
 
 #include <asm/asm-extable.h>
 #include <asm/byteorder.h>
-#include <asm/cacheflush.h>
 #include <asm/cpufeature.h>
 #include <asm/debug-monitors.h>
 #include <asm/insn.h>
@@ -1961,11 +1960,6 @@ static int validate_ctx(struct jit_ctx *ctx)
        return 0;
 }
 
-static inline void bpf_flush_icache(void *start, void *end)
-{
-       flush_icache_range((unsigned long)start, (unsigned long)end);
-}
-
 static void priv_stack_init_guard(void __percpu *priv_stack_ptr, int alloc_size)
 {
        int cpu, underflow_idx = (alloc_size - PRIV_STACK_GUARD_SZ) >> 3;
@@ -2204,12 +2198,6 @@ skip_init_ctx:
                        prog = orig_prog;
                        goto out_off;
                }
-               /*
-                * The instructions have now been copied to the ROX region from
-                * where they will execute. Now the data cache has to be cleaned to
-                * the PoU and the I-cache has to be invalidated for the VAs.
-                */
-               bpf_flush_icache(ro_header, ctx.ro_image + ctx.idx);
        } else {
                jit_data->ctx = ctx;
                jit_data->ro_image = ro_image_ptr;