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path: root/arch/arm64/net/bpf_jit_comp.c
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Diffstat (limited to 'arch/arm64/net/bpf_jit_comp.c')
-rw-r--r--arch/arm64/net/bpf_jit_comp.c180
1 files changed, 69 insertions, 111 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index a93350451e8e..a6fdaea07c63 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -21,7 +21,6 @@
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/printk.h>
-#include <linux/skbuff.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
@@ -80,23 +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)
{
@@ -111,26 +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)
{
@@ -163,7 +185,7 @@ static inline int epilogue_offset(const struct jit_ctx *ctx)
/* Tail call offset to jump into */
#define PROLOGUE_OFFSET 7
-static int build_prologue(struct jit_ctx *ctx)
+static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf)
{
const struct bpf_prog *prog = ctx->prog;
const u8 r6 = bpf2a64[BPF_REG_6];
@@ -188,7 +210,7 @@ static int build_prologue(struct jit_ctx *ctx)
* | ... | BPF prog stack
* | |
* +-----+ <= (BPF_FP - prog->aux->stack_depth)
- * |RSVD | JIT scratchpad
+ * |RSVD | padding
* current A64_SP => +-----+ <= (BPF_FP - ctx->stack_size)
* | |
* | ... | Function call stack
@@ -210,19 +232,19 @@ static int build_prologue(struct jit_ctx *ctx)
/* Set up BPF prog stack base register */
emit(A64_MOV(1, fp, A64_SP), ctx);
- /* Initialize tail_call_cnt */
- emit(A64_MOVZ(1, tcc, 0, 0), ctx);
+ if (!ebpf_from_cbpf) {
+ /* Initialize tail_call_cnt */
+ emit(A64_MOVZ(1, tcc, 0, 0), ctx);
- cur_offset = ctx->idx - idx0;
- if (cur_offset != PROLOGUE_OFFSET) {
- pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
- cur_offset, PROLOGUE_OFFSET);
- return -1;
+ cur_offset = ctx->idx - idx0;
+ if (cur_offset != PROLOGUE_OFFSET) {
+ pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
+ cur_offset, PROLOGUE_OFFSET);
+ return -1;
+ }
}
- /* 4 byte extra for skb_copy_bits buffer */
- ctx->stack_size = prog->aux->stack_depth + 4;
- ctx->stack_size = STACK_ALIGN(ctx->stack_size);
+ ctx->stack_size = STACK_ALIGN(prog->aux->stack_depth);
/* Set up function call stack */
emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
@@ -723,71 +745,6 @@ emit_cond_jmp:
emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
break;
- /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */
- case BPF_LD | BPF_ABS | BPF_W:
- case BPF_LD | BPF_ABS | BPF_H:
- case BPF_LD | BPF_ABS | BPF_B:
- /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */
- case BPF_LD | BPF_IND | BPF_W:
- case BPF_LD | BPF_IND | BPF_H:
- case BPF_LD | BPF_IND | BPF_B:
- {
- const u8 r0 = bpf2a64[BPF_REG_0]; /* r0 = return value */
- const u8 r6 = bpf2a64[BPF_REG_6]; /* r6 = pointer to sk_buff */
- const u8 fp = bpf2a64[BPF_REG_FP];
- const u8 r1 = bpf2a64[BPF_REG_1]; /* r1: struct sk_buff *skb */
- const u8 r2 = bpf2a64[BPF_REG_2]; /* r2: int k */
- const u8 r3 = bpf2a64[BPF_REG_3]; /* r3: unsigned int size */
- const u8 r4 = bpf2a64[BPF_REG_4]; /* r4: void *buffer */
- const u8 r5 = bpf2a64[BPF_REG_5]; /* r5: void *(*func)(...) */
- int size;
-
- emit(A64_MOV(1, r1, r6), ctx);
- emit_a64_mov_i(0, r2, imm, ctx);
- if (BPF_MODE(code) == BPF_IND)
- emit(A64_ADD(0, r2, r2, src), ctx);
- switch (BPF_SIZE(code)) {
- case BPF_W:
- size = 4;
- break;
- case BPF_H:
- size = 2;
- break;
- case BPF_B:
- size = 1;
- break;
- default:
- return -EINVAL;
- }
- emit_a64_mov_i64(r3, size, ctx);
- emit(A64_SUB_I(1, r4, fp, ctx->stack_size), ctx);
- emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
- emit(A64_BLR(r5), ctx);
- emit(A64_MOV(1, r0, A64_R(0)), ctx);
-
- jmp_offset = epilogue_offset(ctx);
- check_imm19(jmp_offset);
- emit(A64_CBZ(1, r0, jmp_offset), ctx);
- emit(A64_MOV(1, r5, r0), ctx);
- switch (BPF_SIZE(code)) {
- case BPF_W:
- emit(A64_LDR32(r0, r5, A64_ZR), ctx);
-#ifndef CONFIG_CPU_BIG_ENDIAN
- emit(A64_REV32(0, r0, r0), ctx);
-#endif
- break;
- case BPF_H:
- emit(A64_LDRH(r0, r5, A64_ZR), ctx);
-#ifndef CONFIG_CPU_BIG_ENDIAN
- emit(A64_REV16(0, r0, r0), ctx);
-#endif
- break;
- case BPF_B:
- emit(A64_LDRB(r0, r5, A64_ZR), ctx);
- break;
- }
- break;
- }
default:
pr_err_once("unknown opcode %02x\n", code);
return -EINVAL;
@@ -851,6 +808,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
struct bpf_prog *tmp, *orig_prog = prog;
struct bpf_binary_header *header;
struct arm64_jit_data *jit_data;
+ bool was_classic = bpf_prog_was_classic(prog);
bool tmp_blinded = false;
bool extra_pass = false;
struct jit_ctx ctx;
@@ -905,7 +863,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
goto out_off;
}
- if (build_prologue(&ctx)) {
+ if (build_prologue(&ctx, was_classic)) {
prog = orig_prog;
goto out_off;
}
@@ -928,7 +886,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
skip_init_ctx:
ctx.idx = 0;
- build_prologue(&ctx);
+ build_prologue(&ctx, was_classic);
if (build_body(&ctx)) {
bpf_jit_binary_free(header);
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