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-rw-r--r--arch/arm/net/bpf_jit_32.c10
-rw-r--r--arch/s390/net/bpf_jit.h10
-rw-r--r--arch/s390/net/bpf_jit_comp.c106
-rw-r--r--arch/x86/net/bpf_jit_comp.c150
4 files changed, 248 insertions, 28 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index e0e23582c8b4..4550d247e308 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -873,6 +873,16 @@ b_epilogue:
off = offsetof(struct sk_buff, queue_mapping);
emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
break;
+ case BPF_LDX | BPF_W | BPF_ABS:
+ /*
+ * load a 32bit word from struct seccomp_data.
+ * seccomp_check_filter() will already have checked
+ * that k is 32bit aligned and lies within the
+ * struct seccomp_data.
+ */
+ ctx->seen |= SEEN_SKB;
+ emit(ARM_LDR_I(r_A, r_skb, k), ctx);
+ break;
default:
return -1;
}
diff --git a/arch/s390/net/bpf_jit.h b/arch/s390/net/bpf_jit.h
index de156ba3bd71..f6498eec9ee1 100644
--- a/arch/s390/net/bpf_jit.h
+++ b/arch/s390/net/bpf_jit.h
@@ -28,6 +28,9 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
* | old backchain | |
* +---------------+ |
* | r15 - r6 | |
+ * +---------------+ |
+ * | 4 byte align | |
+ * | tail_call_cnt | |
* BFP -> +===============+ |
* | | |
* | BPF stack | |
@@ -46,14 +49,17 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
* R15 -> +---------------+ + low
*
* We get 160 bytes stack space from calling function, but only use
- * 11 * 8 byte (old backchain + r15 - r6) for storing registers.
+ * 12 * 8 byte for old backchain, r15..r6, and tail_call_cnt.
*/
#define STK_SPACE (MAX_BPF_STACK + 8 + 4 + 4 + 160)
-#define STK_160_UNUSED (160 - 11 * 8)
+#define STK_160_UNUSED (160 - 12 * 8)
#define STK_OFF (STK_SPACE - STK_160_UNUSED)
#define STK_OFF_TMP 160 /* Offset of tmp buffer on stack */
#define STK_OFF_HLEN 168 /* Offset of SKB header length on stack */
+#define STK_OFF_R6 (160 - 11 * 8) /* Offset of r6 on stack */
+#define STK_OFF_TCCNT (160 - 12 * 8) /* Offset of tail_call_cnt on stack */
+
/* Offset to skip condition code check */
#define OFF_OK 4
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 55423d8be580..d3766dd67e23 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -21,6 +21,7 @@
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/init.h>
+#include <linux/bpf.h>
#include <asm/cacheflush.h>
#include <asm/dis.h>
#include "bpf_jit.h"
@@ -40,6 +41,8 @@ struct bpf_jit {
int base_ip; /* Base address for literal pool */
int ret0_ip; /* Address of return 0 */
int exit_ip; /* Address of exit */
+ int tail_call_start; /* Tail call start offset */
+ int labels[1]; /* Labels for local jumps */
};
#define BPF_SIZE_MAX 4096 /* Max size for program */
@@ -49,6 +52,7 @@ struct bpf_jit {
#define SEEN_RET0 4 /* ret0_ip points to a valid return 0 */
#define SEEN_LITERAL 8 /* code uses literals */
#define SEEN_FUNC 16 /* calls C functions */
+#define SEEN_TAIL_CALL 32 /* code uses tail calls */
#define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB)
/*
@@ -60,6 +64,7 @@ struct bpf_jit {
#define REG_L (__MAX_BPF_REG+3) /* Literal pool register */
#define REG_15 (__MAX_BPF_REG+4) /* Register 15 */
#define REG_0 REG_W0 /* Register 0 */
+#define REG_1 REG_W1 /* Register 1 */
#define REG_2 BPF_REG_1 /* Register 2 */
#define REG_14 BPF_REG_0 /* Register 14 */
@@ -223,6 +228,24 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
REG_SET_SEEN(b3); \
})
+#define EMIT6_PCREL_LABEL(op1, op2, b1, b2, label, mask) \
+({ \
+ int rel = (jit->labels[label] - jit->prg) >> 1; \
+ _EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), \
+ op2 | mask << 12); \
+ REG_SET_SEEN(b1); \
+ REG_SET_SEEN(b2); \
+})
+
+#define EMIT6_PCREL_IMM_LABEL(op1, op2, b1, imm, label, mask) \
+({ \
+ int rel = (jit->labels[label] - jit->prg) >> 1; \
+ _EMIT6(op1 | (reg_high(b1) | mask) << 16 | \
+ (rel & 0xffff), op2 | (imm & 0xff) << 8); \
+ REG_SET_SEEN(b1); \
+ BUILD_BUG_ON(((unsigned long) imm) > 0xff); \
+})
+
#define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \
({ \
/* Branch instruction needs 6 bytes */ \
@@ -286,7 +309,7 @@ static void jit_fill_hole(void *area, unsigned int size)
*/
static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
{
- u32 off = 72 + (rs - 6) * 8;
+ u32 off = STK_OFF_R6 + (rs - 6) * 8;
if (rs == re)
/* stg %rs,off(%r15) */
@@ -301,7 +324,7 @@ static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
*/
static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re)
{
- u32 off = 72 + (rs - 6) * 8;
+ u32 off = STK_OFF_R6 + (rs - 6) * 8;
if (jit->seen & SEEN_STACK)
off += STK_OFF;
@@ -374,6 +397,16 @@ static void save_restore_regs(struct bpf_jit *jit, int op)
*/
static void bpf_jit_prologue(struct bpf_jit *jit)
{
+ if (jit->seen & SEEN_TAIL_CALL) {
+ /* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
+ _EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT);
+ } else {
+ /* j tail_call_start: NOP if no tail calls are used */
+ EMIT4_PCREL(0xa7f40000, 6);
+ _EMIT2(0);
+ }
+ /* Tail calls have to skip above initialization */
+ jit->tail_call_start = jit->prg;
/* Save registers */
save_restore_regs(jit, REGS_SAVE);
/* Setup literal pool */
@@ -951,6 +984,75 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
EMIT4(0xb9040000, BPF_REG_0, REG_2);
break;
}
+ case BPF_JMP | BPF_CALL | BPF_X:
+ /*
+ * Implicit input:
+ * B1: pointer to ctx
+ * B2: pointer to bpf_array
+ * B3: index in bpf_array
+ */
+ jit->seen |= SEEN_TAIL_CALL;
+
+ /*
+ * if (index >= array->map.max_entries)
+ * goto out;
+ */
+
+ /* llgf %w1,map.max_entries(%b2) */
+ EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2,
+ offsetof(struct bpf_array, map.max_entries));
+ /* clgrj %b3,%w1,0xa,label0: if %b3 >= %w1 goto out */
+ EMIT6_PCREL_LABEL(0xec000000, 0x0065, BPF_REG_3,
+ REG_W1, 0, 0xa);
+
+ /*
+ * if (tail_call_cnt++ > MAX_TAIL_CALL_CNT)
+ * goto out;
+ */
+
+ if (jit->seen & SEEN_STACK)
+ off = STK_OFF_TCCNT + STK_OFF;
+ else
+ off = STK_OFF_TCCNT;
+ /* lhi %w0,1 */
+ EMIT4_IMM(0xa7080000, REG_W0, 1);
+ /* laal %w1,%w0,off(%r15) */
+ EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, REG_15, off);
+ /* clij %w1,MAX_TAIL_CALL_CNT,0x2,label0 */
+ EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007f, REG_W1,
+ MAX_TAIL_CALL_CNT, 0, 0x2);
+
+ /*
+ * prog = array->prog[index];
+ * if (prog == NULL)
+ * goto out;
+ */
+
+ /* sllg %r1,%b3,3: %r1 = index * 8 */
+ EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, BPF_REG_3, REG_0, 3);
+ /* lg %r1,prog(%b2,%r1) */
+ EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, BPF_REG_2,
+ REG_1, offsetof(struct bpf_array, prog));
+ /* clgij %r1,0,0x8,label0 */
+ EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007d, REG_1, 0, 0, 0x8);
+
+ /*
+ * Restore registers before calling function
+ */
+ save_restore_regs(jit, REGS_RESTORE);
+
+ /*
+ * goto *(prog->bpf_func + tail_call_start);
+ */
+
+ /* lg %r1,bpf_func(%r1) */
+ EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_1, REG_0,
+ offsetof(struct bpf_prog, bpf_func));
+ /* bc 0xf,tail_call_start(%r1) */
+ _EMIT4(0x47f01000 + jit->tail_call_start);
+ /* out: */
+ jit->labels[0] = jit->prg;
+ break;
case BPF_JMP | BPF_EXIT: /* return b0 */
last = (i == fp->len - 1) ? 1 : 0;
if (last && !(jit->seen & SEEN_RET0))
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index ddeff4844a10..579a8fd74be0 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -12,6 +12,7 @@
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <asm/cacheflush.h>
+#include <linux/bpf.h>
int bpf_jit_enable __read_mostly;
@@ -37,7 +38,8 @@ static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
return ptr + len;
}
-#define EMIT(bytes, len) do { prog = emit_code(prog, bytes, len); } while (0)
+#define EMIT(bytes, len) \
+ do { prog = emit_code(prog, bytes, len); cnt += len; } while (0)
#define EMIT1(b1) EMIT(b1, 1)
#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
@@ -186,31 +188,31 @@ struct jit_context {
#define BPF_MAX_INSN_SIZE 128
#define BPF_INSN_SAFETY 64
-static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
- int oldproglen, struct jit_context *ctx)
+#define STACKSIZE \
+ (MAX_BPF_STACK + \
+ 32 /* space for rbx, r13, r14, r15 */ + \
+ 8 /* space for skb_copy_bits() buffer */)
+
+#define PROLOGUE_SIZE 51
+
+/* emit x64 prologue code for BPF program and check it's size.
+ * bpf_tail_call helper will skip it while jumping into another program
+ */
+static void emit_prologue(u8 **pprog)
{
- struct bpf_insn *insn = bpf_prog->insnsi;
- int insn_cnt = bpf_prog->len;
- bool seen_ld_abs = ctx->seen_ld_abs | (oldproglen == 0);
- bool seen_exit = false;
- u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
- int i;
- int proglen = 0;
- u8 *prog = temp;
- int stacksize = MAX_BPF_STACK +
- 32 /* space for rbx, r13, r14, r15 */ +
- 8 /* space for skb_copy_bits() buffer */;
+ u8 *prog = *pprog;
+ int cnt = 0;
EMIT1(0x55); /* push rbp */
EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */
- /* sub rsp, stacksize */
- EMIT3_off32(0x48, 0x81, 0xEC, stacksize);
+ /* sub rsp, STACKSIZE */
+ EMIT3_off32(0x48, 0x81, 0xEC, STACKSIZE);
/* all classic BPF filters use R6(rbx) save it */
/* mov qword ptr [rbp-X],rbx */
- EMIT3_off32(0x48, 0x89, 0x9D, -stacksize);
+ EMIT3_off32(0x48, 0x89, 0x9D, -STACKSIZE);
/* bpf_convert_filter() maps classic BPF register X to R7 and uses R8
* as temporary, so all tcpdump filters need to spill/fill R7(r13) and
@@ -221,16 +223,112 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
*/
/* mov qword ptr [rbp-X],r13 */
- EMIT3_off32(0x4C, 0x89, 0xAD, -stacksize + 8);
+ EMIT3_off32(0x4C, 0x89, 0xAD, -STACKSIZE + 8);
/* mov qword ptr [rbp-X],r14 */
- EMIT3_off32(0x4C, 0x89, 0xB5, -stacksize + 16);
+ EMIT3_off32(0x4C, 0x89, 0xB5, -STACKSIZE + 16);
/* mov qword ptr [rbp-X],r15 */
- EMIT3_off32(0x4C, 0x89, 0xBD, -stacksize + 24);
+ EMIT3_off32(0x4C, 0x89, 0xBD, -STACKSIZE + 24);
/* clear A and X registers */
EMIT2(0x31, 0xc0); /* xor eax, eax */
EMIT3(0x4D, 0x31, 0xED); /* xor r13, r13 */
+ /* clear tail_cnt: mov qword ptr [rbp-X], rax */
+ EMIT3_off32(0x48, 0x89, 0x85, -STACKSIZE + 32);
+
+ BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
+ *pprog = prog;
+}
+
+/* generate the following code:
+ * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
+ * if (index >= array->map.max_entries)
+ * goto out;
+ * if (++tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ * prog = array->prog[index];
+ * if (prog == NULL)
+ * goto out;
+ * goto *(prog->bpf_func + prologue_size);
+ * out:
+ */
+static void emit_bpf_tail_call(u8 **pprog)
+{
+ u8 *prog = *pprog;
+ int label1, label2, label3;
+ int cnt = 0;
+
+ /* rdi - pointer to ctx
+ * rsi - pointer to bpf_array
+ * rdx - index in bpf_array
+ */
+
+ /* if (index >= array->map.max_entries)
+ * goto out;
+ */
+ EMIT4(0x48, 0x8B, 0x46, /* mov rax, qword ptr [rsi + 16] */
+ offsetof(struct bpf_array, map.max_entries));
+ EMIT3(0x48, 0x39, 0xD0); /* cmp rax, rdx */
+#define OFFSET1 44 /* number of bytes to jump */
+ EMIT2(X86_JBE, OFFSET1); /* jbe out */
+ label1 = cnt;
+
+ /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ */
+ EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */
+ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
+#define OFFSET2 33
+ EMIT2(X86_JA, OFFSET2); /* ja out */
+ label2 = cnt;
+ EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
+ EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */
+
+ /* prog = array->prog[index]; */
+ EMIT4(0x48, 0x8D, 0x44, 0xD6); /* lea rax, [rsi + rdx * 8 + 0x50] */
+ EMIT1(offsetof(struct bpf_array, prog));
+ EMIT3(0x48, 0x8B, 0x00); /* mov rax, qword ptr [rax] */
+
+ /* if (prog == NULL)
+ * goto out;
+ */
+ EMIT4(0x48, 0x83, 0xF8, 0x00); /* cmp rax, 0 */
+#define OFFSET3 10
+ EMIT2(X86_JE, OFFSET3); /* je out */
+ label3 = cnt;
+
+ /* goto *(prog->bpf_func + prologue_size); */
+ EMIT4(0x48, 0x8B, 0x40, /* mov rax, qword ptr [rax + 32] */
+ offsetof(struct bpf_prog, bpf_func));
+ EMIT4(0x48, 0x83, 0xC0, PROLOGUE_SIZE); /* add rax, prologue_size */
+
+ /* now we're ready to jump into next BPF program
+ * rdi == ctx (1st arg)
+ * rax == prog->bpf_func + prologue_size
+ */
+ EMIT2(0xFF, 0xE0); /* jmp rax */
+
+ /* out: */
+ BUILD_BUG_ON(cnt - label1 != OFFSET1);
+ BUILD_BUG_ON(cnt - label2 != OFFSET2);
+ BUILD_BUG_ON(cnt - label3 != OFFSET3);
+ *pprog = prog;
+}
+
+static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
+ int oldproglen, struct jit_context *ctx)
+{
+ struct bpf_insn *insn = bpf_prog->insnsi;
+ int insn_cnt = bpf_prog->len;
+ bool seen_ld_abs = ctx->seen_ld_abs | (oldproglen == 0);
+ bool seen_exit = false;
+ u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
+ int i, cnt = 0;
+ int proglen = 0;
+ u8 *prog = temp;
+
+ emit_prologue(&prog);
+
if (seen_ld_abs) {
/* r9d : skb->len - skb->data_len (headlen)
* r10 : skb->data
@@ -739,6 +837,10 @@ xadd: if (is_imm8(insn->off))
}
break;
+ case BPF_JMP | BPF_CALL | BPF_X:
+ emit_bpf_tail_call(&prog);
+ break;
+
/* cond jump */
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
@@ -891,13 +993,13 @@ common_load:
/* update cleanup_addr */
ctx->cleanup_addr = proglen;
/* mov rbx, qword ptr [rbp-X] */
- EMIT3_off32(0x48, 0x8B, 0x9D, -stacksize);
+ EMIT3_off32(0x48, 0x8B, 0x9D, -STACKSIZE);
/* mov r13, qword ptr [rbp-X] */
- EMIT3_off32(0x4C, 0x8B, 0xAD, -stacksize + 8);
+ EMIT3_off32(0x4C, 0x8B, 0xAD, -STACKSIZE + 8);
/* mov r14, qword ptr [rbp-X] */
- EMIT3_off32(0x4C, 0x8B, 0xB5, -stacksize + 16);
+ EMIT3_off32(0x4C, 0x8B, 0xB5, -STACKSIZE + 16);
/* mov r15, qword ptr [rbp-X] */
- EMIT3_off32(0x4C, 0x8B, 0xBD, -stacksize + 24);
+ EMIT3_off32(0x4C, 0x8B, 0xBD, -STACKSIZE + 24);
EMIT1(0xC9); /* leave */
EMIT1(0xC3); /* ret */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-01 04:10:37 +0000