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-rw-r--r--arch/arm64/net/bpf_jit_comp.c48
1 files changed, 41 insertions, 7 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index cf3c7d4a1b58..d6a53ef2350b 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -50,7 +50,7 @@ static const int bpf2a64[] = {
[BPF_REG_8] = A64_R(21),
[BPF_REG_9] = A64_R(22),
/* read-only frame pointer to access stack */
- [BPF_REG_FP] = A64_FP,
+ [BPF_REG_FP] = A64_R(25),
/* temporary register for internal BPF JIT */
[TMP_REG_1] = A64_R(23),
[TMP_REG_2] = A64_R(24),
@@ -155,18 +155,49 @@ static void build_prologue(struct jit_ctx *ctx)
stack_size += 4; /* extra for skb_copy_bits buffer */
stack_size = STACK_ALIGN(stack_size);
+ /*
+ * BPF prog stack layout
+ *
+ * high
+ * original A64_SP => 0:+-----+ BPF prologue
+ * |FP/LR|
+ * current A64_FP => -16:+-----+
+ * | ... | callee saved registers
+ * +-----+
+ * | | x25/x26
+ * BPF fp register => -80:+-----+
+ * | |
+ * | ... | BPF prog stack
+ * | |
+ * | |
+ * current A64_SP => +-----+
+ * | |
+ * | ... | Function call stack
+ * | |
+ * +-----+
+ * low
+ *
+ */
+
+ /* Save FP and LR registers to stay align with ARM64 AAPCS */
+ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
+ emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+
/* Save callee-saved register */
emit(A64_PUSH(r6, r7, A64_SP), ctx);
emit(A64_PUSH(r8, r9, A64_SP), ctx);
if (ctx->tmp_used)
emit(A64_PUSH(tmp1, tmp2, A64_SP), ctx);
- /* Set up BPF stack */
- emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx);
+ /* Save fp (x25) and x26. SP requires 16 bytes alignment */
+ emit(A64_PUSH(fp, A64_R(26), A64_SP), ctx);
- /* Set up frame pointer */
+ /* Set up BPF prog stack base register (x25) */
emit(A64_MOV(1, fp, A64_SP), ctx);
+ /* Set up function call stack */
+ emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx);
+
/* Clear registers A and X */
emit_a64_mov_i64(ra, 0, ctx);
emit_a64_mov_i64(rx, 0, ctx);
@@ -190,14 +221,17 @@ static void build_epilogue(struct jit_ctx *ctx)
/* We're done with BPF stack */
emit(A64_ADD_I(1, A64_SP, A64_SP, stack_size), ctx);
+ /* Restore fs (x25) and x26 */
+ emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
+
/* Restore callee-saved register */
if (ctx->tmp_used)
emit(A64_POP(tmp1, tmp2, A64_SP), ctx);
emit(A64_POP(r8, r9, A64_SP), ctx);
emit(A64_POP(r6, r7, A64_SP), ctx);
- /* Restore frame pointer */
- emit(A64_MOV(1, fp, A64_SP), ctx);
+ /* Restore FP/LR registers */
+ emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
/* Set return value */
emit(A64_MOV(1, A64_R(0), r0), ctx);
@@ -758,7 +792,7 @@ void bpf_int_jit_compile(struct bpf_prog *prog)
if (bpf_jit_enable > 1)
bpf_jit_dump(prog->len, image_size, 2, ctx.image);
- bpf_flush_icache(ctx.image, ctx.image + ctx.idx);
+ bpf_flush_icache(header, ctx.image + ctx.idx);
set_memory_ro((unsigned long)header, header->pages);
prog->bpf_func = (void *)ctx.image;