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Diffstat (limited to 'arch/arm64/net/bpf_jit_comp.c')
-rw-r--r--arch/arm64/net/bpf_jit_comp.c85
1 files changed, 54 insertions, 31 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 85113cab2046..c8a2620312c0 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -79,23 +79,66 @@ static inline void emit(const u32 insn, struct jit_ctx *ctx)
ctx->idx++;
}
+static inline void emit_a64_mov_i(const int is64, const int reg,
+ const s32 val, struct jit_ctx *ctx)
+{
+ u16 hi = val >> 16;
+ u16 lo = val & 0xffff;
+
+ if (hi & 0x8000) {
+ if (hi == 0xffff) {
+ emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx);
+ } else {
+ emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx);
+ if (lo != 0xffff)
+ emit(A64_MOVK(is64, reg, lo, 0), ctx);
+ }
+ } else {
+ emit(A64_MOVZ(is64, reg, lo, 0), ctx);
+ if (hi)
+ emit(A64_MOVK(is64, reg, hi, 16), ctx);
+ }
+}
+
+static int i64_i16_blocks(const u64 val, bool inverse)
+{
+ return (((val >> 0) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+ (((val >> 16) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+ (((val >> 32) & 0xffff) != (inverse ? 0xffff : 0x0000)) +
+ (((val >> 48) & 0xffff) != (inverse ? 0xffff : 0x0000));
+}
+
static inline void emit_a64_mov_i64(const int reg, const u64 val,
struct jit_ctx *ctx)
{
- u64 tmp = val;
- int shift = 0;
-
- emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx);
- tmp >>= 16;
- shift += 16;
- while (tmp) {
- if (tmp & 0xffff)
- emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
- tmp >>= 16;
- shift += 16;
+ u64 nrm_tmp = val, rev_tmp = ~val;
+ bool inverse;
+ int shift;
+
+ if (!(nrm_tmp >> 32))
+ return emit_a64_mov_i(0, reg, (u32)val, ctx);
+
+ inverse = i64_i16_blocks(nrm_tmp, true) < i64_i16_blocks(nrm_tmp, false);
+ shift = max(round_down((inverse ? (fls64(rev_tmp) - 1) :
+ (fls64(nrm_tmp) - 1)), 16), 0);
+ if (inverse)
+ emit(A64_MOVN(1, reg, (rev_tmp >> shift) & 0xffff, shift), ctx);
+ else
+ emit(A64_MOVZ(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx);
+ shift -= 16;
+ while (shift >= 0) {
+ if (((nrm_tmp >> shift) & 0xffff) != (inverse ? 0xffff : 0x0000))
+ emit(A64_MOVK(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx);
+ shift -= 16;
}
}
+/*
+ * This is an unoptimized 64 immediate emission used for BPF to BPF call
+ * addresses. It will always do a full 64 bit decomposition as otherwise
+ * more complexity in the last extra pass is required since we previously
+ * reserved 4 instructions for the address.
+ */
static inline void emit_addr_mov_i64(const int reg, const u64 val,
struct jit_ctx *ctx)
{
@@ -110,26 +153,6 @@ static inline void emit_addr_mov_i64(const int reg, const u64 val,
}
}
-static inline void emit_a64_mov_i(const int is64, const int reg,
- const s32 val, struct jit_ctx *ctx)
-{
- u16 hi = val >> 16;
- u16 lo = val & 0xffff;
-
- if (hi & 0x8000) {
- if (hi == 0xffff) {
- emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx);
- } else {
- emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx);
- emit(A64_MOVK(is64, reg, lo, 0), ctx);
- }
- } else {
- emit(A64_MOVZ(is64, reg, lo, 0), ctx);
- if (hi)
- emit(A64_MOVK(is64, reg, hi, 16), ctx);
- }
-}
-
static inline int bpf2a64_offset(int bpf_to, int bpf_from,
const struct jit_ctx *ctx)
{