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authorPuranjay Mohan <puranjay@kernel.org>2026-04-13 22:11:08 +0300
committerAlexei Starovoitov <ast@kernel.org>2026-04-15 22:09:46 +0300
commit42f18ae53011826cfd3c84d041817e7f07bc645b (patch)
treeb706942b2270804e47d902b7d7853dc32f0f68d6
parent4fddde2a732de60bb97e3307d4eb69ac5f1d2b74 (diff)
downloadlinux-42f18ae53011826cfd3c84d041817e7f07bc645b.tar.xz
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>
-rw-r--r--arch/arm64/net/bpf_jit_comp.c12
1 files changed, 0 insertions, 12 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 4aad9483f8a5..524b67c0867e 100644
--- 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;