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Diffstat (limited to 'arch/arm64/net/bpf_jit_comp.c')
-rw-r--r--arch/arm64/net/bpf_jit_comp.c1472
1 files changed, 1100 insertions, 372 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 7ca8779ae34f..da8b89dd2910 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -7,6 +7,7 @@
#define pr_fmt(fmt) "bpf_jit: " fmt
+#include <linux/arm-smccc.h>
#include <linux/bitfield.h>
#include <linux/bpf.h>
#include <linux/filter.h>
@@ -17,18 +18,19 @@
#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>
-#include <asm/patching.h>
+#include <asm/text-patching.h>
#include <asm/set_memory.h>
#include "bpf_jit.h"
#define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
#define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
-#define TCALL_CNT (MAX_BPF_JIT_REG + 2)
+#define TCCNT_PTR (MAX_BPF_JIT_REG + 2)
#define TMP_REG_3 (MAX_BPF_JIT_REG + 3)
-#define FP_BOTTOM (MAX_BPF_JIT_REG + 4)
+#define ARENA_VM_START (MAX_BPF_JIT_REG + 5)
#define check_imm(bits, imm) do { \
if ((((imm) > 0) && ((imm) >> (bits))) || \
@@ -62,11 +64,12 @@ static const int bpf2a64[] = {
[TMP_REG_1] = A64_R(10),
[TMP_REG_2] = A64_R(11),
[TMP_REG_3] = A64_R(12),
- /* tail_call_cnt */
- [TCALL_CNT] = A64_R(26),
+ /* tail_call_cnt_ptr */
+ [TCCNT_PTR] = A64_R(26),
/* temporary register for blinding constants */
[BPF_REG_AX] = A64_R(9),
- [FP_BOTTOM] = A64_R(27),
+ /* callee saved register for kern_vm_start address */
+ [ARENA_VM_START] = A64_R(28),
};
struct jit_ctx {
@@ -75,9 +78,15 @@ struct jit_ctx {
int epilogue_offset;
int *offset;
int exentry_idx;
+ int nr_used_callee_reg;
+ u8 used_callee_reg[8]; /* r6~r9, fp, arena_vm_start */
__le32 *image;
+ __le32 *ro_image;
u32 stack_size;
- int fpb_offset;
+ u64 user_vm_start;
+ u64 arena_vm_start;
+ bool fp_used;
+ bool write;
};
struct bpf_plt {
@@ -91,7 +100,7 @@ struct bpf_plt {
static inline void emit(const u32 insn, struct jit_ctx *ctx)
{
- if (ctx->image != NULL)
+ if (ctx->image != NULL && ctx->write)
ctx->image[ctx->idx] = cpu_to_le32(insn);
ctx->idx++;
@@ -176,14 +185,47 @@ static inline void emit_addr_mov_i64(const int reg, const u64 val,
}
}
-static inline void emit_call(u64 target, struct jit_ctx *ctx)
+static bool should_emit_indirect_call(long target, const struct jit_ctx *ctx)
{
- u8 tmp = bpf2a64[TMP_REG_1];
+ long offset;
+
+ /* when ctx->ro_image is not allocated or the target is unknown,
+ * emit indirect call
+ */
+ if (!ctx->ro_image || !target)
+ return true;
+
+ offset = target - (long)&ctx->ro_image[ctx->idx];
+ return offset < -SZ_128M || offset >= SZ_128M;
+}
+
+static void emit_direct_call(u64 target, struct jit_ctx *ctx)
+{
+ u32 insn;
+ unsigned long pc;
+
+ pc = (unsigned long)&ctx->ro_image[ctx->idx];
+ insn = aarch64_insn_gen_branch_imm(pc, target, AARCH64_INSN_BRANCH_LINK);
+ emit(insn, ctx);
+}
+
+static void emit_indirect_call(u64 target, struct jit_ctx *ctx)
+{
+ u8 tmp;
+ tmp = bpf2a64[TMP_REG_1];
emit_addr_mov_i64(tmp, target, ctx);
emit(A64_BLR(tmp), ctx);
}
+static void emit_call(u64 target, struct jit_ctx *ctx)
+{
+ if (should_emit_indirect_call((long)target, ctx))
+ emit_indirect_call(target, ctx);
+ else
+ emit_direct_call(target, ctx);
+}
+
static inline int bpf2a64_offset(int bpf_insn, int off,
const struct jit_ctx *ctx)
{
@@ -205,6 +247,14 @@ static void jit_fill_hole(void *area, unsigned int size)
*ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT);
}
+int bpf_arch_text_invalidate(void *dst, size_t len)
+{
+ if (!aarch64_insn_set(dst, AARCH64_BREAK_FAULT, len))
+ return -EINVAL;
+
+ return 0;
+}
+
static inline int epilogue_offset(const struct jit_ctx *ctx)
{
int to = ctx->epilogue_offset;
@@ -219,6 +269,19 @@ static bool is_addsub_imm(u32 imm)
return !(imm & ~0xfff) || !(imm & ~0xfff000);
}
+static inline void emit_a64_add_i(const bool is64, const int dst, const int src,
+ const int tmp, const s32 imm, struct jit_ctx *ctx)
+{
+ if (is_addsub_imm(imm)) {
+ emit(A64_ADD_I(is64, dst, src, imm), ctx);
+ } else if (is_addsub_imm(-(u32)imm)) {
+ emit(A64_SUB_I(is64, dst, src, -imm), ctx);
+ } else {
+ emit_a64_mov_i(is64, tmp, imm, ctx);
+ emit(A64_ADD(is64, dst, src, tmp), ctx);
+ }
+}
+
/*
* There are 3 types of AArch64 LDR/STR (immediate) instruction:
* Post-index, Pre-index, Unsigned offset.
@@ -260,21 +323,143 @@ static bool is_lsi_offset(int offset, int scale)
return true;
}
-/* generated prologue:
+/* generated main prog prologue:
* bti c // if CONFIG_ARM64_BTI_KERNEL
* mov x9, lr
* nop // POKE_OFFSET
* paciasp // if CONFIG_ARM64_PTR_AUTH_KERNEL
* stp x29, lr, [sp, #-16]!
* mov x29, sp
- * stp x19, x20, [sp, #-16]!
- * stp x21, x22, [sp, #-16]!
- * stp x25, x26, [sp, #-16]!
- * stp x27, x28, [sp, #-16]!
- * mov x25, sp
- * mov tcc, #0
+ * stp xzr, x26, [sp, #-16]!
+ * mov x26, sp
* // PROLOGUE_OFFSET
+ * // save callee-saved registers
*/
+static void prepare_bpf_tail_call_cnt(struct jit_ctx *ctx)
+{
+ const bool is_main_prog = !bpf_is_subprog(ctx->prog);
+ const u8 ptr = bpf2a64[TCCNT_PTR];
+
+ if (is_main_prog) {
+ /* Initialize tail_call_cnt. */
+ emit(A64_PUSH(A64_ZR, ptr, A64_SP), ctx);
+ emit(A64_MOV(1, ptr, A64_SP), ctx);
+ } else
+ emit(A64_PUSH(ptr, ptr, A64_SP), ctx);
+}
+
+static void find_used_callee_regs(struct jit_ctx *ctx)
+{
+ int i;
+ const struct bpf_prog *prog = ctx->prog;
+ const struct bpf_insn *insn = &prog->insnsi[0];
+ int reg_used = 0;
+
+ for (i = 0; i < prog->len; i++, insn++) {
+ if (insn->dst_reg == BPF_REG_6 || insn->src_reg == BPF_REG_6)
+ reg_used |= 1;
+
+ if (insn->dst_reg == BPF_REG_7 || insn->src_reg == BPF_REG_7)
+ reg_used |= 2;
+
+ if (insn->dst_reg == BPF_REG_8 || insn->src_reg == BPF_REG_8)
+ reg_used |= 4;
+
+ if (insn->dst_reg == BPF_REG_9 || insn->src_reg == BPF_REG_9)
+ reg_used |= 8;
+
+ if (insn->dst_reg == BPF_REG_FP || insn->src_reg == BPF_REG_FP) {
+ ctx->fp_used = true;
+ reg_used |= 16;
+ }
+ }
+
+ i = 0;
+ if (reg_used & 1)
+ ctx->used_callee_reg[i++] = bpf2a64[BPF_REG_6];
+
+ if (reg_used & 2)
+ ctx->used_callee_reg[i++] = bpf2a64[BPF_REG_7];
+
+ if (reg_used & 4)
+ ctx->used_callee_reg[i++] = bpf2a64[BPF_REG_8];
+
+ if (reg_used & 8)
+ ctx->used_callee_reg[i++] = bpf2a64[BPF_REG_9];
+
+ if (reg_used & 16)
+ ctx->used_callee_reg[i++] = bpf2a64[BPF_REG_FP];
+
+ if (ctx->arena_vm_start)
+ ctx->used_callee_reg[i++] = bpf2a64[ARENA_VM_START];
+
+ ctx->nr_used_callee_reg = i;
+}
+
+/* Save callee-saved registers */
+static void push_callee_regs(struct jit_ctx *ctx)
+{
+ int reg1, reg2, i;
+
+ /*
+ * Program acting as exception boundary should save all ARM64
+ * Callee-saved registers as the exception callback needs to recover
+ * all ARM64 Callee-saved registers in its epilogue.
+ */
+ if (ctx->prog->aux->exception_boundary) {
+ emit(A64_PUSH(A64_R(19), A64_R(20), A64_SP), ctx);
+ emit(A64_PUSH(A64_R(21), A64_R(22), A64_SP), ctx);
+ emit(A64_PUSH(A64_R(23), A64_R(24), A64_SP), ctx);
+ emit(A64_PUSH(A64_R(25), A64_R(26), A64_SP), ctx);
+ emit(A64_PUSH(A64_R(27), A64_R(28), A64_SP), ctx);
+ } else {
+ find_used_callee_regs(ctx);
+ for (i = 0; i + 1 < ctx->nr_used_callee_reg; i += 2) {
+ reg1 = ctx->used_callee_reg[i];
+ reg2 = ctx->used_callee_reg[i + 1];
+ emit(A64_PUSH(reg1, reg2, A64_SP), ctx);
+ }
+ if (i < ctx->nr_used_callee_reg) {
+ reg1 = ctx->used_callee_reg[i];
+ /* keep SP 16-byte aligned */
+ emit(A64_PUSH(reg1, A64_ZR, A64_SP), ctx);
+ }
+ }
+}
+
+/* Restore callee-saved registers */
+static void pop_callee_regs(struct jit_ctx *ctx)
+{
+ struct bpf_prog_aux *aux = ctx->prog->aux;
+ int reg1, reg2, i;
+
+ /*
+ * Program acting as exception boundary pushes R23 and R24 in addition
+ * to BPF callee-saved registers. Exception callback uses the boundary
+ * program's stack frame, so recover these extra registers in the above
+ * two cases.
+ */
+ if (aux->exception_boundary || aux->exception_cb) {
+ emit(A64_POP(A64_R(27), A64_R(28), A64_SP), ctx);
+ emit(A64_POP(A64_R(25), A64_R(26), A64_SP), ctx);
+ emit(A64_POP(A64_R(23), A64_R(24), A64_SP), ctx);
+ emit(A64_POP(A64_R(21), A64_R(22), A64_SP), ctx);
+ emit(A64_POP(A64_R(19), A64_R(20), A64_SP), ctx);
+ } else {
+ i = ctx->nr_used_callee_reg - 1;
+ if (ctx->nr_used_callee_reg % 2 != 0) {
+ reg1 = ctx->used_callee_reg[i];
+ emit(A64_POP(reg1, A64_ZR, A64_SP), ctx);
+ i--;
+ }
+ while (i > 0) {
+ reg1 = ctx->used_callee_reg[i - 1];
+ reg2 = ctx->used_callee_reg[i];
+ emit(A64_POP(reg1, reg2, A64_SP), ctx);
+ i -= 2;
+ }
+ }
+}
#define BTI_INSNS (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) ? 1 : 0)
#define PAC_INSNS (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL) ? 1 : 0)
@@ -283,19 +468,14 @@ static bool is_lsi_offset(int offset, int scale)
#define POKE_OFFSET (BTI_INSNS + 1)
/* Tail call offset to jump into */
-#define PROLOGUE_OFFSET (BTI_INSNS + 2 + PAC_INSNS + 8)
+#define PROLOGUE_OFFSET (BTI_INSNS + 2 + PAC_INSNS + 4)
static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf)
{
const struct bpf_prog *prog = ctx->prog;
- const bool is_main_prog = prog->aux->func_idx == 0;
- const u8 r6 = bpf2a64[BPF_REG_6];
- const u8 r7 = bpf2a64[BPF_REG_7];
- const u8 r8 = bpf2a64[BPF_REG_8];
- const u8 r9 = bpf2a64[BPF_REG_9];
+ const bool is_main_prog = !bpf_is_subprog(prog);
const u8 fp = bpf2a64[BPF_REG_FP];
- const u8 tcc = bpf2a64[TCALL_CNT];
- const u8 fpb = bpf2a64[FP_BOTTOM];
+ const u8 arena_vm_base = bpf2a64[ARENA_VM_START];
const int idx0 = ctx->idx;
int cur_offset;
@@ -322,54 +502,72 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf)
*
*/
- emit_bti(A64_BTI_C, ctx);
+ /* bpf function may be invoked by 3 instruction types:
+ * 1. bl, attached via freplace to bpf prog via short jump
+ * 2. br, attached via freplace to bpf prog via long jump
+ * 3. blr, working as a function pointer, used by emit_call.
+ * So BTI_JC should used here to support both br and blr.
+ */
+ emit_bti(A64_BTI_JC, ctx);
emit(A64_MOV(1, A64_R(9), A64_LR), ctx);
emit(A64_NOP, ctx);
- /* Sign lr */
- if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL))
- emit(A64_PACIASP, ctx);
-
- /* 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 registers */
- emit(A64_PUSH(r6, r7, A64_SP), ctx);
- emit(A64_PUSH(r8, r9, A64_SP), ctx);
- emit(A64_PUSH(fp, tcc, A64_SP), ctx);
- emit(A64_PUSH(fpb, A64_R(28), A64_SP), ctx);
+ if (!prog->aux->exception_cb) {
+ /* Sign lr */
+ if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL))
+ emit(A64_PACIASP, ctx);
- /* Set up BPF prog stack base register */
- emit(A64_MOV(1, fp, A64_SP), ctx);
+ /* 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);
- if (!ebpf_from_cbpf && is_main_prog) {
- /* Initialize tail_call_cnt */
- emit(A64_MOVZ(1, tcc, 0, 0), ctx);
+ prepare_bpf_tail_call_cnt(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;
+ if (!ebpf_from_cbpf && is_main_prog) {
+ 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;
+ }
+ /* BTI landing pad for the tail call, done with a BR */
+ emit_bti(A64_BTI_J, ctx);
}
-
- /* BTI landing pad for the tail call, done with a BR */
- emit_bti(A64_BTI_J, ctx);
+ push_callee_regs(ctx);
+ } else {
+ /*
+ * Exception callback receives FP of Main Program as third
+ * parameter
+ */
+ emit(A64_MOV(1, A64_FP, A64_R(2)), ctx);
+ /*
+ * Main Program already pushed the frame record and the
+ * callee-saved registers. The exception callback will not push
+ * anything and re-use the main program's stack.
+ *
+ * 12 registers are on the stack
+ */
+ emit(A64_SUB_I(1, A64_SP, A64_FP, 96), ctx);
}
- emit(A64_SUB_I(1, fpb, fp, ctx->fpb_offset), ctx);
+ if (ctx->fp_used)
+ /* Set up BPF prog stack base register */
+ emit(A64_MOV(1, fp, A64_SP), ctx);
/* Stack must be multiples of 16B */
ctx->stack_size = round_up(prog->aux->stack_depth, 16);
/* Set up function call stack */
- emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+ if (ctx->stack_size)
+ emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+
+ if (ctx->arena_vm_start)
+ emit_a64_mov_i64(arena_vm_base, ctx->arena_vm_start, ctx);
+
return 0;
}
-static int out_offset = -1; /* initialized on the first pass of build_body() */
static int emit_bpf_tail_call(struct jit_ctx *ctx)
{
/* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
@@ -378,11 +576,12 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
const u8 tmp = bpf2a64[TMP_REG_1];
const u8 prg = bpf2a64[TMP_REG_2];
- const u8 tcc = bpf2a64[TCALL_CNT];
- const int idx0 = ctx->idx;
-#define cur_offset (ctx->idx - idx0)
-#define jmp_offset (out_offset - (cur_offset))
+ const u8 tcc = bpf2a64[TMP_REG_3];
+ const u8 ptr = bpf2a64[TCCNT_PTR];
size_t off;
+ __le32 *branch1 = NULL;
+ __le32 *branch2 = NULL;
+ __le32 *branch3 = NULL;
/* if (index >= array->map.max_entries)
* goto out;
@@ -392,16 +591,20 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
emit(A64_LDR32(tmp, r2, tmp), ctx);
emit(A64_MOV(0, r3, r3), ctx);
emit(A64_CMP(0, r3, tmp), ctx);
- emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
+ branch1 = ctx->image + ctx->idx;
+ emit(A64_NOP, ctx);
/*
- * if (tail_call_cnt >= MAX_TAIL_CALL_CNT)
+ * if ((*tail_call_cnt_ptr) >= MAX_TAIL_CALL_CNT)
* goto out;
- * tail_call_cnt++;
*/
emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
+ emit(A64_LDR64I(tcc, ptr, 0), ctx);
emit(A64_CMP(1, tcc, tmp), ctx);
- emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
+ branch2 = ctx->image + ctx->idx;
+ emit(A64_NOP, ctx);
+
+ /* (*tail_call_cnt_ptr)++; */
emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
/* prog = array->ptrs[index];
@@ -413,46 +616,134 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
emit(A64_ADD(1, tmp, r2, tmp), ctx);
emit(A64_LSL(1, prg, r3, 3), ctx);
emit(A64_LDR64(prg, tmp, prg), ctx);
- emit(A64_CBZ(1, prg, jmp_offset), ctx);
+ branch3 = ctx->image + ctx->idx;
+ emit(A64_NOP, ctx);
+
+ /* Update tail_call_cnt if the slot is populated. */
+ emit(A64_STR64I(tcc, ptr, 0), ctx);
+
+ /* restore SP */
+ if (ctx->stack_size)
+ emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+
+ pop_callee_regs(ctx);
/* goto *(prog->bpf_func + prologue_offset); */
off = offsetof(struct bpf_prog, bpf_func);
emit_a64_mov_i64(tmp, off, ctx);
emit(A64_LDR64(tmp, prg, tmp), ctx);
emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
- emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
emit(A64_BR(tmp), ctx);
- /* out: */
- if (out_offset == -1)
- out_offset = cur_offset;
- if (cur_offset != out_offset) {
- pr_err_once("tail_call out_offset = %d, expected %d!\n",
- cur_offset, out_offset);
- return -1;
+ if (ctx->image) {
+ off = &ctx->image[ctx->idx] - branch1;
+ *branch1 = cpu_to_le32(A64_B_(A64_COND_CS, off));
+
+ off = &ctx->image[ctx->idx] - branch2;
+ *branch2 = cpu_to_le32(A64_B_(A64_COND_CS, off));
+
+ off = &ctx->image[ctx->idx] - branch3;
+ *branch3 = cpu_to_le32(A64_CBZ(1, prg, off));
+ }
+
+ return 0;
+}
+
+static int emit_atomic_ld_st(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+ const s32 imm = insn->imm;
+ const s16 off = insn->off;
+ const u8 code = insn->code;
+ const bool arena = BPF_MODE(code) == BPF_PROBE_ATOMIC;
+ const u8 arena_vm_base = bpf2a64[ARENA_VM_START];
+ const u8 dst = bpf2a64[insn->dst_reg];
+ const u8 src = bpf2a64[insn->src_reg];
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ u8 reg;
+
+ switch (imm) {
+ case BPF_LOAD_ACQ:
+ reg = src;
+ break;
+ case BPF_STORE_REL:
+ reg = dst;
+ break;
+ default:
+ pr_err_once("unknown atomic load/store op code %02x\n", imm);
+ return -EINVAL;
+ }
+
+ if (off) {
+ emit_a64_add_i(1, tmp, reg, tmp, off, ctx);
+ reg = tmp;
}
+ if (arena) {
+ emit(A64_ADD(1, tmp, reg, arena_vm_base), ctx);
+ reg = tmp;
+ }
+
+ switch (imm) {
+ case BPF_LOAD_ACQ:
+ switch (BPF_SIZE(code)) {
+ case BPF_B:
+ emit(A64_LDARB(dst, reg), ctx);
+ break;
+ case BPF_H:
+ emit(A64_LDARH(dst, reg), ctx);
+ break;
+ case BPF_W:
+ emit(A64_LDAR32(dst, reg), ctx);
+ break;
+ case BPF_DW:
+ emit(A64_LDAR64(dst, reg), ctx);
+ break;
+ }
+ break;
+ case BPF_STORE_REL:
+ switch (BPF_SIZE(code)) {
+ case BPF_B:
+ emit(A64_STLRB(src, reg), ctx);
+ break;
+ case BPF_H:
+ emit(A64_STLRH(src, reg), ctx);
+ break;
+ case BPF_W:
+ emit(A64_STLR32(src, reg), ctx);
+ break;
+ case BPF_DW:
+ emit(A64_STLR64(src, reg), ctx);
+ break;
+ }
+ break;
+ default:
+ pr_err_once("unexpected atomic load/store op code %02x\n",
+ imm);
+ return -EINVAL;
+ }
+
return 0;
-#undef cur_offset
-#undef jmp_offset
}
#ifdef CONFIG_ARM64_LSE_ATOMICS
static int emit_lse_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
{
const u8 code = insn->code;
+ const u8 arena_vm_base = bpf2a64[ARENA_VM_START];
const u8 dst = bpf2a64[insn->dst_reg];
const u8 src = bpf2a64[insn->src_reg];
const u8 tmp = bpf2a64[TMP_REG_1];
const u8 tmp2 = bpf2a64[TMP_REG_2];
const bool isdw = BPF_SIZE(code) == BPF_DW;
+ const bool arena = BPF_MODE(code) == BPF_PROBE_ATOMIC;
const s16 off = insn->off;
- u8 reg;
+ u8 reg = dst;
- if (!off) {
- reg = dst;
- } else {
- emit_a64_mov_i(1, tmp, off, ctx);
- emit(A64_ADD(1, tmp, tmp, dst), ctx);
+ if (off) {
+ emit_a64_add_i(1, tmp, reg, tmp, off, ctx);
+ reg = tmp;
+ }
+ if (arena) {
+ emit(A64_ADD(1, tmp, reg, arena_vm_base), ctx);
reg = tmp;
}
@@ -519,14 +810,17 @@ static int emit_ll_sc_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
const s32 imm = insn->imm;
const s16 off = insn->off;
const bool isdw = BPF_SIZE(code) == BPF_DW;
- u8 reg;
+ u8 reg = dst;
s32 jmp_offset;
- if (!off) {
- reg = dst;
- } else {
- emit_a64_mov_i(1, tmp, off, ctx);
- emit(A64_ADD(1, tmp, tmp, dst), ctx);
+ if (BPF_MODE(code) == BPF_PROBE_ATOMIC) {
+ /* ll_sc based atomics don't support unsafe pointers yet. */
+ pr_err_once("unknown atomic opcode %02x\n", code);
+ return -EINVAL;
+ }
+
+ if (off) {
+ emit_a64_add_i(1, tmp, reg, tmp, off, ctx);
reg = tmp;
}
@@ -647,32 +941,70 @@ static void build_plt(struct jit_ctx *ctx)
plt->target = (u64)&dummy_tramp;
}
-static void build_epilogue(struct jit_ctx *ctx)
+/* Clobbers BPF registers 1-4, aka x0-x3 */
+static void __maybe_unused build_bhb_mitigation(struct jit_ctx *ctx)
+{
+ const u8 r1 = bpf2a64[BPF_REG_1]; /* aka x0 */
+ u8 k = get_spectre_bhb_loop_value();
+
+ if (!IS_ENABLED(CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY) ||
+ cpu_mitigations_off() || __nospectre_bhb ||
+ arm64_get_spectre_v2_state() == SPECTRE_VULNERABLE)
+ return;
+
+ if (capable(CAP_SYS_ADMIN))
+ return;
+
+ if (supports_clearbhb(SCOPE_SYSTEM)) {
+ emit(aarch64_insn_gen_hint(AARCH64_INSN_HINT_CLEARBHB), ctx);
+ return;
+ }
+
+ if (k) {
+ emit_a64_mov_i64(r1, k, ctx);
+ emit(A64_B(1), ctx);
+ emit(A64_SUBS_I(true, r1, r1, 1), ctx);
+ emit(A64_B_(A64_COND_NE, -2), ctx);
+ emit(aarch64_insn_gen_dsb(AARCH64_INSN_MB_ISH), ctx);
+ emit(aarch64_insn_get_isb_value(), ctx);
+ }
+
+ if (is_spectre_bhb_fw_mitigated()) {
+ emit(A64_ORR_I(false, r1, AARCH64_INSN_REG_ZR,
+ ARM_SMCCC_ARCH_WORKAROUND_3), ctx);
+ switch (arm_smccc_1_1_get_conduit()) {
+ case SMCCC_CONDUIT_HVC:
+ emit(aarch64_insn_get_hvc_value(), ctx);
+ break;
+ case SMCCC_CONDUIT_SMC:
+ emit(aarch64_insn_get_smc_value(), ctx);
+ break;
+ default:
+ pr_err_once("Firmware mitigation enabled with unknown conduit\n");
+ }
+ }
+}
+
+static void build_epilogue(struct jit_ctx *ctx, bool was_classic)
{
const u8 r0 = bpf2a64[BPF_REG_0];
- const u8 r6 = bpf2a64[BPF_REG_6];
- const u8 r7 = bpf2a64[BPF_REG_7];
- const u8 r8 = bpf2a64[BPF_REG_8];
- const u8 r9 = bpf2a64[BPF_REG_9];
- const u8 fp = bpf2a64[BPF_REG_FP];
- const u8 fpb = bpf2a64[FP_BOTTOM];
+ const u8 ptr = bpf2a64[TCCNT_PTR];
/* We're done with BPF stack */
- emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
+ if (ctx->stack_size)
+ emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
- /* Restore x27 and x28 */
- emit(A64_POP(fpb, A64_R(28), A64_SP), ctx);
- /* Restore fs (x25) and x26 */
- emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
+ pop_callee_regs(ctx);
- /* Restore callee-saved register */
- emit(A64_POP(r8, r9, A64_SP), ctx);
- emit(A64_POP(r6, r7, A64_SP), ctx);
+ emit(A64_POP(A64_ZR, ptr, A64_SP), ctx);
+
+ if (was_classic)
+ build_bhb_mitigation(ctx);
/* Restore FP/LR registers */
emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
- /* Set return value */
+ /* Move the return value from bpf:r0 (aka x7) to x0 */
emit(A64_MOV(1, A64_R(0), r0), ctx);
/* Authenticate lr */
@@ -684,6 +1016,7 @@ static void build_epilogue(struct jit_ctx *ctx)
#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0)
#define BPF_FIXUP_REG_MASK GENMASK(31, 27)
+#define DONT_CLEAR 5 /* Unused ARM64 register from BPF's POV */
bool ex_handler_bpf(const struct exception_table_entry *ex,
struct pt_regs *regs)
@@ -691,7 +1024,8 @@ bool ex_handler_bpf(const struct exception_table_entry *ex,
off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup);
int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup);
- regs->regs[dst_reg] = 0;
+ if (dst_reg != DONT_CLEAR)
+ regs->regs[dst_reg] = 0;
regs->pc = (unsigned long)&ex->fixup - offset;
return true;
}
@@ -701,7 +1035,8 @@ static int add_exception_handler(const struct bpf_insn *insn,
struct jit_ctx *ctx,
int dst_reg)
{
- off_t offset;
+ off_t ins_offset;
+ off_t fixup_offset;
unsigned long pc;
struct exception_table_entry *ex;
@@ -709,7 +1044,10 @@ static int add_exception_handler(const struct bpf_insn *insn,
/* First pass */
return 0;
- if (BPF_MODE(insn->code) != BPF_PROBE_MEM)
+ if (BPF_MODE(insn->code) != BPF_PROBE_MEM &&
+ BPF_MODE(insn->code) != BPF_PROBE_MEMSX &&
+ BPF_MODE(insn->code) != BPF_PROBE_MEM32 &&
+ BPF_MODE(insn->code) != BPF_PROBE_ATOMIC)
return 0;
if (!ctx->prog->aux->extable ||
@@ -717,12 +1055,17 @@ static int add_exception_handler(const struct bpf_insn *insn,
return -EINVAL;
ex = &ctx->prog->aux->extable[ctx->exentry_idx];
- pc = (unsigned long)&ctx->image[ctx->idx - 1];
+ pc = (unsigned long)&ctx->ro_image[ctx->idx - 1];
- offset = pc - (long)&ex->insn;
- if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+ /*
+ * This is the relative offset of the instruction that may fault from
+ * the exception table itself. This will be written to the exception
+ * table and if this instruction faults, the destination register will
+ * be set to '0' and the execution will jump to the next instruction.
+ */
+ ins_offset = pc - (long)&ex->insn;
+ if (WARN_ON_ONCE(ins_offset >= 0 || ins_offset < INT_MIN))
return -ERANGE;
- ex->insn = offset;
/*
* Since the extable follows the program, the fixup offset is always
@@ -731,12 +1074,28 @@ static int add_exception_handler(const struct bpf_insn *insn,
* bits. We don't need to worry about buildtime or runtime sort
* modifying the upper bits because the table is already sorted, and
* isn't part of the main exception table.
+ *
+ * The fixup_offset is set to the next instruction from the instruction
+ * that may fault. The execution will jump to this after handling the
+ * fault.
*/
- offset = (long)&ex->fixup - (pc + AARCH64_INSN_SIZE);
- if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, offset))
+ fixup_offset = (long)&ex->fixup - (pc + AARCH64_INSN_SIZE);
+ if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, fixup_offset))
return -ERANGE;
- ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, offset) |
+ /*
+ * The offsets above have been calculated using the RO buffer but we
+ * need to use the R/W buffer for writes.
+ * switch ex to rw buffer for writing.
+ */
+ ex = (void *)ctx->image + ((void *)ex - (void *)ctx->ro_image);
+
+ ex->insn = ins_offset;
+
+ if (BPF_CLASS(insn->code) != BPF_LDX)
+ dst_reg = DONT_CLEAR;
+
+ ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, fixup_offset) |
FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg);
ex->type = EX_TYPE_BPF;
@@ -755,12 +1114,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
bool extra_pass)
{
const u8 code = insn->code;
- const u8 dst = bpf2a64[insn->dst_reg];
- const u8 src = bpf2a64[insn->src_reg];
+ u8 dst = bpf2a64[insn->dst_reg];
+ u8 src = bpf2a64[insn->src_reg];
const u8 tmp = bpf2a64[TMP_REG_1];
const u8 tmp2 = bpf2a64[TMP_REG_2];
const u8 fp = bpf2a64[BPF_REG_FP];
- const u8 fpb = bpf2a64[FP_BOTTOM];
+ const u8 arena_vm_base = bpf2a64[ARENA_VM_START];
const s16 off = insn->off;
const s32 imm = insn->imm;
const int i = insn - ctx->prog->insnsi;
@@ -773,12 +1132,44 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
u8 dst_adj;
int off_adj;
int ret;
+ bool sign_extend;
switch (code) {
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_X:
case BPF_ALU64 | BPF_MOV | BPF_X:
- emit(A64_MOV(is64, dst, src), ctx);
+ if (insn_is_cast_user(insn)) {
+ emit(A64_MOV(0, tmp, src), ctx); // 32-bit mov clears the upper 32 bits
+ emit_a64_mov_i(0, dst, ctx->user_vm_start >> 32, ctx);
+ emit(A64_LSL(1, dst, dst, 32), ctx);
+ emit(A64_CBZ(1, tmp, 2), ctx);
+ emit(A64_ORR(1, tmp, dst, tmp), ctx);
+ emit(A64_MOV(1, dst, tmp), ctx);
+ break;
+ } else if (insn_is_mov_percpu_addr(insn)) {
+ if (dst != src)
+ emit(A64_MOV(1, dst, src), ctx);
+ if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
+ emit(A64_MRS_TPIDR_EL2(tmp), ctx);
+ else
+ emit(A64_MRS_TPIDR_EL1(tmp), ctx);
+ emit(A64_ADD(1, dst, dst, tmp), ctx);
+ break;
+ }
+ switch (insn->off) {
+ case 0:
+ emit(A64_MOV(is64, dst, src), ctx);
+ break;
+ case 8:
+ emit(A64_SXTB(is64, dst, src), ctx);
+ break;
+ case 16:
+ emit(A64_SXTH(is64, dst, src), ctx);
+ break;
+ case 32:
+ emit(A64_SXTW(is64, dst, src), ctx);
+ break;
+ }
break;
/* dst = dst OP src */
case BPF_ALU | BPF_ADD | BPF_X:
@@ -807,11 +1198,17 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
break;
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
- emit(A64_UDIV(is64, dst, dst, src), ctx);
+ if (!off)
+ emit(A64_UDIV(is64, dst, dst, src), ctx);
+ else
+ emit(A64_SDIV(is64, dst, dst, src), ctx);
break;
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_X:
- emit(A64_UDIV(is64, tmp, dst, src), ctx);
+ if (!off)
+ emit(A64_UDIV(is64, tmp, dst, src), ctx);
+ else
+ emit(A64_SDIV(is64, tmp, dst, src), ctx);
emit(A64_MSUB(is64, dst, dst, tmp, src), ctx);
break;
case BPF_ALU | BPF_LSH | BPF_X:
@@ -834,11 +1231,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
/* dst = BSWAP##imm(dst) */
case BPF_ALU | BPF_END | BPF_FROM_LE:
case BPF_ALU | BPF_END | BPF_FROM_BE:
+ case BPF_ALU64 | BPF_END | BPF_FROM_LE:
#ifdef CONFIG_CPU_BIG_ENDIAN
- if (BPF_SRC(code) == BPF_FROM_BE)
+ if (BPF_CLASS(code) == BPF_ALU && BPF_SRC(code) == BPF_FROM_BE)
goto emit_bswap_uxt;
#else /* !CONFIG_CPU_BIG_ENDIAN */
- if (BPF_SRC(code) == BPF_FROM_LE)
+ if (BPF_CLASS(code) == BPF_ALU && BPF_SRC(code) == BPF_FROM_LE)
goto emit_bswap_uxt;
#endif
switch (imm) {
@@ -848,7 +1246,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
emit(A64_UXTH(is64, dst, dst), ctx);
break;
case 32:
- emit(A64_REV32(is64, dst, dst), ctx);
+ emit(A64_REV32(0, dst, dst), ctx);
/* upper 32 bits already cleared */
break;
case 64:
@@ -879,20 +1277,13 @@ emit_bswap_uxt:
/* dst = dst OP imm */
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_K:
- if (is_addsub_imm(imm)) {
- emit(A64_ADD_I(is64, dst, dst, imm), ctx);
- } else if (is_addsub_imm(-imm)) {
- emit(A64_SUB_I(is64, dst, dst, -imm), ctx);
- } else {
- emit_a64_mov_i(is64, tmp, imm, ctx);
- emit(A64_ADD(is64, dst, dst, tmp), ctx);
- }
+ emit_a64_add_i(is64, dst, dst, tmp, imm, ctx);
break;
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
if (is_addsub_imm(imm)) {
emit(A64_SUB_I(is64, dst, dst, imm), ctx);
- } else if (is_addsub_imm(-imm)) {
+ } else if (is_addsub_imm(-(u32)imm)) {
emit(A64_ADD_I(is64, dst, dst, -imm), ctx);
} else {
emit_a64_mov_i(is64, tmp, imm, ctx);
@@ -937,12 +1328,18 @@ emit_bswap_uxt:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
emit_a64_mov_i(is64, tmp, imm, ctx);
- emit(A64_UDIV(is64, dst, dst, tmp), ctx);
+ if (!off)
+ emit(A64_UDIV(is64, dst, dst, tmp), ctx);
+ else
+ emit(A64_SDIV(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
emit_a64_mov_i(is64, tmp2, imm, ctx);
- emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
+ if (!off)
+ emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
+ else
+ emit(A64_SDIV(is64, tmp, dst, tmp2), ctx);
emit(A64_MSUB(is64, dst, dst, tmp, tmp2), ctx);
break;
case BPF_ALU | BPF_LSH | BPF_K:
@@ -960,7 +1357,11 @@ emit_bswap_uxt:
/* JUMP off */
case BPF_JMP | BPF_JA:
- jmp_offset = bpf2a64_offset(i, off, ctx);
+ case BPF_JMP32 | BPF_JA:
+ if (BPF_CLASS(code) == BPF_JMP)
+ jmp_offset = bpf2a64_offset(i, off, ctx);
+ else
+ jmp_offset = bpf2a64_offset(i, imm, ctx);
check_imm26(jmp_offset);
emit(A64_B(jmp_offset), ctx);
break;
@@ -1053,7 +1454,7 @@ emit_cond_jmp:
case BPF_JMP32 | BPF_JSLE | BPF_K:
if (is_addsub_imm(imm)) {
emit(A64_CMP_I(is64, dst, imm), ctx);
- } else if (is_addsub_imm(-imm)) {
+ } else if (is_addsub_imm(-(u32)imm)) {
emit(A64_CMN_I(is64, dst, -imm), ctx);
} else {
emit_a64_mov_i(is64, tmp, imm, ctx);
@@ -1076,6 +1477,28 @@ emit_cond_jmp:
const u8 r0 = bpf2a64[BPF_REG_0];
bool func_addr_fixed;
u64 func_addr;
+ u32 cpu_offset;
+
+ /* Implement helper call to bpf_get_smp_processor_id() inline */
+ if (insn->src_reg == 0 && insn->imm == BPF_FUNC_get_smp_processor_id) {
+ cpu_offset = offsetof(struct thread_info, cpu);
+
+ emit(A64_MRS_SP_EL0(tmp), ctx);
+ if (is_lsi_offset(cpu_offset, 2)) {
+ emit(A64_LDR32I(r0, tmp, cpu_offset), ctx);
+ } else {
+ emit_a64_mov_i(1, tmp2, cpu_offset, ctx);
+ emit(A64_LDR32(r0, tmp, tmp2), ctx);
+ }
+ break;
+ }
+
+ /* Implement helper call to bpf_get_current_task/_btf() inline */
+ if (insn->src_reg == 0 && (insn->imm == BPF_FUNC_get_current_task ||
+ insn->imm == BPF_FUNC_get_current_task_btf)) {
+ emit(A64_MRS_SP_EL0(r0), ctx);
+ break;
+ }
ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
&func_addr, &func_addr_fixed);
@@ -1116,7 +1539,7 @@ emit_cond_jmp:
return 1;
}
- /* LDX: dst = *(size *)(src + off) */
+ /* LDX: dst = (u64)*(unsigned size *)(src + off) */
case BPF_LDX | BPF_MEM | BPF_W:
case BPF_LDX | BPF_MEM | BPF_H:
case BPF_LDX | BPF_MEM | BPF_B:
@@ -1125,36 +1548,71 @@ emit_cond_jmp:
case BPF_LDX | BPF_PROBE_MEM | BPF_W:
case BPF_LDX | BPF_PROBE_MEM | BPF_H:
case BPF_LDX | BPF_PROBE_MEM | BPF_B:
- if (ctx->fpb_offset > 0 && src == fp) {
- src_adj = fpb;
- off_adj = off + ctx->fpb_offset;
+ /* LDXS: dst_reg = (s64)*(signed size *)(src_reg + off) */
+ case BPF_LDX | BPF_MEMSX | BPF_B:
+ case BPF_LDX | BPF_MEMSX | BPF_H:
+ case BPF_LDX | BPF_MEMSX | BPF_W:
+ case BPF_LDX | BPF_PROBE_MEMSX | BPF_B:
+ case BPF_LDX | BPF_PROBE_MEMSX | BPF_H:
+ case BPF_LDX | BPF_PROBE_MEMSX | BPF_W:
+ case BPF_LDX | BPF_PROBE_MEM32 | BPF_B:
+ case BPF_LDX | BPF_PROBE_MEM32 | BPF_H:
+ case BPF_LDX | BPF_PROBE_MEM32 | BPF_W:
+ case BPF_LDX | BPF_PROBE_MEM32 | BPF_DW:
+ if (BPF_MODE(insn->code) == BPF_PROBE_MEM32) {
+ emit(A64_ADD(1, tmp2, src, arena_vm_base), ctx);
+ src = tmp2;
+ }
+ if (src == fp) {
+ src_adj = A64_SP;
+ off_adj = off + ctx->stack_size;
} else {
src_adj = src;
off_adj = off;
}
+ sign_extend = (BPF_MODE(insn->code) == BPF_MEMSX ||
+ BPF_MODE(insn->code) == BPF_PROBE_MEMSX);
switch (BPF_SIZE(code)) {
case BPF_W:
if (is_lsi_offset(off_adj, 2)) {
- emit(A64_LDR32I(dst, src_adj, off_adj), ctx);
+ if (sign_extend)
+ emit(A64_LDRSWI(dst, src_adj, off_adj), ctx);
+ else
+ emit(A64_LDR32I(dst, src_adj, off_adj), ctx);
} else {
emit_a64_mov_i(1, tmp, off, ctx);
- emit(A64_LDR32(dst, src, tmp), ctx);
+ if (sign_extend)
+ emit(A64_LDRSW(dst, src, tmp), ctx);
+ else
+ emit(A64_LDR32(dst, src, tmp), ctx);
}
break;
case BPF_H:
if (is_lsi_offset(off_adj, 1)) {
- emit(A64_LDRHI(dst, src_adj, off_adj), ctx);
+ if (sign_extend)
+ emit(A64_LDRSHI(dst, src_adj, off_adj), ctx);
+ else
+ emit(A64_LDRHI(dst, src_adj, off_adj), ctx);
} else {
emit_a64_mov_i(1, tmp, off, ctx);
- emit(A64_LDRH(dst, src, tmp), ctx);
+ if (sign_extend)
+ emit(A64_LDRSH(dst, src, tmp), ctx);
+ else
+ emit(A64_LDRH(dst, src, tmp), ctx);
}
break;
case BPF_B:
if (is_lsi_offset(off_adj, 0)) {
- emit(A64_LDRBI(dst, src_adj, off_adj), ctx);
+ if (sign_extend)
+ emit(A64_LDRSBI(dst, src_adj, off_adj), ctx);
+ else
+ emit(A64_LDRBI(dst, src_adj, off_adj), ctx);
} else {
emit_a64_mov_i(1, tmp, off, ctx);
- emit(A64_LDRB(dst, src, tmp), ctx);
+ if (sign_extend)
+ emit(A64_LDRSB(dst, src, tmp), ctx);
+ else
+ emit(A64_LDRB(dst, src, tmp), ctx);
}
break;
case BPF_DW:
@@ -1190,9 +1648,17 @@ emit_cond_jmp:
case BPF_ST | BPF_MEM | BPF_H:
case BPF_ST | BPF_MEM | BPF_B:
case BPF_ST | BPF_MEM | BPF_DW:
- if (ctx->fpb_offset > 0 && dst == fp) {
- dst_adj = fpb;
- off_adj = off + ctx->fpb_offset;
+ case BPF_ST | BPF_PROBE_MEM32 | BPF_B:
+ case BPF_ST | BPF_PROBE_MEM32 | BPF_H:
+ case BPF_ST | BPF_PROBE_MEM32 | BPF_W:
+ case BPF_ST | BPF_PROBE_MEM32 | BPF_DW:
+ if (BPF_MODE(insn->code) == BPF_PROBE_MEM32) {
+ emit(A64_ADD(1, tmp2, dst, arena_vm_base), ctx);
+ dst = tmp2;
+ }
+ if (dst == fp) {
+ dst_adj = A64_SP;
+ off_adj = off + ctx->stack_size;
} else {
dst_adj = dst;
off_adj = off;
@@ -1233,6 +1699,10 @@ emit_cond_jmp:
}
break;
}
+
+ ret = add_exception_handler(insn, ctx, dst);
+ if (ret)
+ return ret;
break;
/* STX: *(size *)(dst + off) = src */
@@ -1240,9 +1710,17 @@ emit_cond_jmp:
case BPF_STX | BPF_MEM | BPF_H:
case BPF_STX | BPF_MEM | BPF_B:
case BPF_STX | BPF_MEM | BPF_DW:
- if (ctx->fpb_offset > 0 && dst == fp) {
- dst_adj = fpb;
- off_adj = off + ctx->fpb_offset;
+ case BPF_STX | BPF_PROBE_MEM32 | BPF_B:
+ case BPF_STX | BPF_PROBE_MEM32 | BPF_H:
+ case BPF_STX | BPF_PROBE_MEM32 | BPF_W:
+ case BPF_STX | BPF_PROBE_MEM32 | BPF_DW:
+ if (BPF_MODE(insn->code) == BPF_PROBE_MEM32) {
+ emit(A64_ADD(1, tmp2, dst, arena_vm_base), ctx);
+ dst = tmp2;
+ }
+ if (dst == fp) {
+ dst_adj = A64_SP;
+ off_adj = off + ctx->stack_size;
} else {
dst_adj = dst;
off_adj = off;
@@ -1281,16 +1759,32 @@ emit_cond_jmp:
}
break;
}
+
+ ret = add_exception_handler(insn, ctx, dst);
+ if (ret)
+ return ret;
break;
+ case BPF_STX | BPF_ATOMIC | BPF_B:
+ case BPF_STX | BPF_ATOMIC | BPF_H:
case BPF_STX | BPF_ATOMIC | BPF_W:
case BPF_STX | BPF_ATOMIC | BPF_DW:
- if (cpus_have_cap(ARM64_HAS_LSE_ATOMICS))
+ case BPF_STX | BPF_PROBE_ATOMIC | BPF_B:
+ case BPF_STX | BPF_PROBE_ATOMIC | BPF_H:
+ case BPF_STX | BPF_PROBE_ATOMIC | BPF_W:
+ case BPF_STX | BPF_PROBE_ATOMIC | BPF_DW:
+ if (bpf_atomic_is_load_store(insn))
+ ret = emit_atomic_ld_st(insn, ctx);
+ else if (cpus_have_cap(ARM64_HAS_LSE_ATOMICS))
ret = emit_lse_atomic(insn, ctx);
else
ret = emit_ll_sc_atomic(insn, ctx);
if (ret)
return ret;
+
+ ret = add_exception_handler(insn, ctx, dst);
+ if (ret)
+ return ret;
break;
default:
@@ -1301,79 +1795,6 @@ emit_cond_jmp:
return 0;
}
-/*
- * Return 0 if FP may change at runtime, otherwise find the minimum negative
- * offset to FP, converts it to positive number, and align down to 8 bytes.
- */
-static int find_fpb_offset(struct bpf_prog *prog)
-{
- int i;
- int offset = 0;
-
- for (i = 0; i < prog->len; i++) {
- const struct bpf_insn *insn = &prog->insnsi[i];
- const u8 class = BPF_CLASS(insn->code);
- const u8 mode = BPF_MODE(insn->code);
- const u8 src = insn->src_reg;
- const u8 dst = insn->dst_reg;
- const s32 imm = insn->imm;
- const s16 off = insn->off;
-
- switch (class) {
- case BPF_STX:
- case BPF_ST:
- /* fp holds atomic operation result */
- if (class == BPF_STX && mode == BPF_ATOMIC &&
- ((imm == BPF_XCHG ||
- imm == (BPF_FETCH | BPF_ADD) ||
- imm == (BPF_FETCH | BPF_AND) ||
- imm == (BPF_FETCH | BPF_XOR) ||
- imm == (BPF_FETCH | BPF_OR)) &&
- src == BPF_REG_FP))
- return 0;
-
- if (mode == BPF_MEM && dst == BPF_REG_FP &&
- off < offset)
- offset = insn->off;
- break;
-
- case BPF_JMP32:
- case BPF_JMP:
- break;
-
- case BPF_LDX:
- case BPF_LD:
- /* fp holds load result */
- if (dst == BPF_REG_FP)
- return 0;
-
- if (class == BPF_LDX && mode == BPF_MEM &&
- src == BPF_REG_FP && off < offset)
- offset = off;
- break;
-
- case BPF_ALU:
- case BPF_ALU64:
- default:
- /* fp holds ALU result */
- if (dst == BPF_REG_FP)
- return 0;
- }
- }
-
- if (offset < 0) {
- /*
- * safely be converted to a positive 'int', since insn->off
- * is 's16'
- */
- offset = -offset;
- /* align down to 8 bytes */
- offset = ALIGN_DOWN(offset, 8);
- }
-
- return offset;
-}
-
static int build_body(struct jit_ctx *ctx, bool extra_pass)
{
const struct bpf_prog *prog = ctx->prog;
@@ -1392,13 +1813,11 @@ static int build_body(struct jit_ctx *ctx, bool extra_pass)
const struct bpf_insn *insn = &prog->insnsi[i];
int ret;
- if (ctx->image == NULL)
- ctx->offset[i] = ctx->idx;
+ ctx->offset[i] = ctx->idx;
ret = build_insn(insn, ctx, extra_pass);
if (ret > 0) {
i++;
- if (ctx->image == NULL)
- ctx->offset[i] = ctx->idx;
+ ctx->offset[i] = ctx->idx;
continue;
}
if (ret)
@@ -1409,8 +1828,7 @@ static int build_body(struct jit_ctx *ctx, bool extra_pass)
* the last element with the offset after the last
* instruction (end of program)
*/
- if (ctx->image == NULL)
- ctx->offset[i] = ctx->idx;
+ ctx->offset[i] = ctx->idx;
return 0;
}
@@ -1446,7 +1864,8 @@ static inline void bpf_flush_icache(void *start, void *end)
struct arm64_jit_data {
struct bpf_binary_header *header;
- u8 *image;
+ u8 *ro_image;
+ struct bpf_binary_header *ro_header;
struct jit_ctx ctx;
};
@@ -1455,12 +1874,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
int image_size, prog_size, extable_size, extable_align, extable_offset;
struct bpf_prog *tmp, *orig_prog = prog;
struct bpf_binary_header *header;
+ struct bpf_binary_header *ro_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;
u8 *image_ptr;
+ u8 *ro_image_ptr;
+ int body_idx;
+ int exentry_idx;
if (!prog->jit_requested)
return orig_prog;
@@ -1487,8 +1910,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
}
if (jit_data->ctx.offset) {
ctx = jit_data->ctx;
- image_ptr = jit_data->image;
+ ro_image_ptr = jit_data->ro_image;
+ ro_header = jit_data->ro_header;
header = jit_data->header;
+ image_ptr = (void *)header + ((void *)ro_image_ptr
+ - (void *)ro_header);
extra_pass = true;
prog_size = sizeof(u32) * ctx.idx;
goto skip_init_ctx;
@@ -1496,16 +1922,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
memset(&ctx, 0, sizeof(ctx));
ctx.prog = prog;
- ctx.offset = kcalloc(prog->len + 1, sizeof(int), GFP_KERNEL);
+ ctx.offset = kvcalloc(prog->len + 1, sizeof(int), GFP_KERNEL);
if (ctx.offset == NULL) {
prog = orig_prog;
goto out_off;
}
- ctx.fpb_offset = find_fpb_offset(prog);
+ ctx.user_vm_start = bpf_arena_get_user_vm_start(prog->aux->arena);
+ ctx.arena_vm_start = bpf_arena_get_kern_vm_start(prog->aux->arena);
- /*
- * 1. Initial fake pass to compute ctx->idx and ctx->offset.
+ /* Pass 1: Estimate the maximum image size.
*
* BPF line info needs ctx->offset[i] to be the offset of
* instruction[i] in jited image, so build prologue first.
@@ -1521,75 +1947,118 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
}
ctx.epilogue_offset = ctx.idx;
- build_epilogue(&ctx);
+ build_epilogue(&ctx, was_classic);
build_plt(&ctx);
extable_align = __alignof__(struct exception_table_entry);
extable_size = prog->aux->num_exentries *
sizeof(struct exception_table_entry);
- /* Now we know the actual image size. */
+ /* Now we know the maximum image size. */
prog_size = sizeof(u32) * ctx.idx;
/* also allocate space for plt target */
extable_offset = round_up(prog_size + PLT_TARGET_SIZE, extable_align);
image_size = extable_offset + extable_size;
- header = bpf_jit_binary_alloc(image_size, &image_ptr,
- sizeof(u32), jit_fill_hole);
- if (header == NULL) {
+ ro_header = bpf_jit_binary_pack_alloc(image_size, &ro_image_ptr,
+ sizeof(u32), &header, &image_ptr,
+ jit_fill_hole);
+ if (!ro_header) {
prog = orig_prog;
goto out_off;
}
- /* 2. Now, the actual pass. */
+ /* Pass 2: Determine jited position and result for each instruction */
+ /*
+ * Use the image(RW) for writing the JITed instructions. But also save
+ * the ro_image(RX) for calculating the offsets in the image. The RW
+ * image will be later copied to the RX image from where the program
+ * will run. The bpf_jit_binary_pack_finalize() will do this copy in the
+ * final step.
+ */
ctx.image = (__le32 *)image_ptr;
+ ctx.ro_image = (__le32 *)ro_image_ptr;
if (extable_size)
- prog->aux->extable = (void *)image_ptr + extable_offset;
+ prog->aux->extable = (void *)ro_image_ptr + extable_offset;
skip_init_ctx:
ctx.idx = 0;
ctx.exentry_idx = 0;
+ ctx.write = true;
build_prologue(&ctx, was_classic);
+ /* Record exentry_idx and body_idx before first build_body */
+ exentry_idx = ctx.exentry_idx;
+ body_idx = ctx.idx;
+ /* Dont write body instructions to memory for now */
+ ctx.write = false;
+
if (build_body(&ctx, extra_pass)) {
- bpf_jit_binary_free(header);
prog = orig_prog;
- goto out_off;
+ goto out_free_hdr;
+ }
+
+ ctx.epilogue_offset = ctx.idx;
+ ctx.exentry_idx = exentry_idx;
+ ctx.idx = body_idx;
+ ctx.write = true;
+
+ /* Pass 3: Adjust jump offset and write final image */
+ if (build_body(&ctx, extra_pass) ||
+ WARN_ON_ONCE(ctx.idx != ctx.epilogue_offset)) {
+ prog = orig_prog;
+ goto out_free_hdr;
}
- build_epilogue(&ctx);
+ build_epilogue(&ctx, was_classic);
build_plt(&ctx);
- /* 3. Extra pass to validate JITed code. */
+ /* Extra pass to validate JITed code. */
if (validate_ctx(&ctx)) {
- bpf_jit_binary_free(header);
prog = orig_prog;
- goto out_off;
+ goto out_free_hdr;
}
+ /* update the real prog size */
+ prog_size = sizeof(u32) * ctx.idx;
+
/* And we're done. */
if (bpf_jit_enable > 1)
bpf_jit_dump(prog->len, prog_size, 2, ctx.image);
- bpf_flush_icache(header, ctx.image + ctx.idx);
-
if (!prog->is_func || extra_pass) {
- if (extra_pass && ctx.idx != jit_data->ctx.idx) {
- pr_err_once("multi-func JIT bug %d != %d\n",
+ /* The jited image may shrink since the jited result for
+ * BPF_CALL to subprog may be changed from indirect call
+ * to direct call.
+ */
+ if (extra_pass && ctx.idx > jit_data->ctx.idx) {
+ pr_err_once("multi-func JIT bug %d > %d\n",
ctx.idx, jit_data->ctx.idx);
- bpf_jit_binary_free(header);
prog->bpf_func = NULL;
prog->jited = 0;
prog->jited_len = 0;
+ goto out_free_hdr;
+ }
+ if (WARN_ON(bpf_jit_binary_pack_finalize(ro_header, header))) {
+ /* ro_header has been freed */
+ ro_header = NULL;
+ prog = orig_prog;
goto out_off;
}
- bpf_jit_binary_lock_ro(header);
+ /*
+ * 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->image = image_ptr;
+ jit_data->ro_image = ro_image_ptr;
jit_data->header = header;
+ jit_data->ro_header = ro_header;
}
- prog->bpf_func = (void *)ctx.image;
+
+ prog->bpf_func = (void *)ctx.ro_image;
prog->jited = 1;
prog->jited_len = prog_size;
@@ -1601,7 +2070,7 @@ skip_init_ctx:
ctx.offset[i] *= AARCH64_INSN_SIZE;
bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
out_off:
- kfree(ctx.offset);
+ kvfree(ctx.offset);
kfree(jit_data);
prog->aux->jit_data = NULL;
}
@@ -1610,6 +2079,14 @@ out:
bpf_jit_prog_release_other(prog, prog == orig_prog ?
tmp : orig_prog);
return prog;
+
+out_free_hdr:
+ if (header) {
+ bpf_arch_text_copy(&ro_header->size, &header->size,
+ sizeof(header->size));
+ bpf_jit_binary_pack_free(ro_header, header);
+ }
+ goto out_off;
}
bool bpf_jit_supports_kfunc_call(void)
@@ -1617,20 +2094,16 @@ bool bpf_jit_supports_kfunc_call(void)
return true;
}
-u64 bpf_jit_alloc_exec_limit(void)
-{
- return VMALLOC_END - VMALLOC_START;
-}
-
-void *bpf_jit_alloc_exec(unsigned long size)
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
{
- /* Memory is intended to be executable, reset the pointer tag. */
- return kasan_reset_tag(vmalloc(size));
+ if (!aarch64_insn_copy(dst, src, len))
+ return ERR_PTR(-EINVAL);
+ return dst;
}
-void bpf_jit_free_exec(void *addr)
+u64 bpf_jit_alloc_exec_limit(void)
{
- return vfree(addr);
+ return VMALLOC_END - VMALLOC_START;
}
/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
@@ -1640,22 +2113,17 @@ bool bpf_jit_supports_subprog_tailcalls(void)
}
static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
- int args_off, int retval_off, int run_ctx_off,
+ int bargs_off, int retval_off, int run_ctx_off,
bool save_ret)
{
- u32 *branch;
+ __le32 *branch;
u64 enter_prog;
u64 exit_prog;
struct bpf_prog *p = l->link.prog;
int cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
- if (p->aux->sleepable) {
- enter_prog = (u64)__bpf_prog_enter_sleepable;
- exit_prog = (u64)__bpf_prog_exit_sleepable;
- } else {
- enter_prog = (u64)__bpf_prog_enter;
- exit_prog = (u64)__bpf_prog_exit;
- }
+ enter_prog = (u64)bpf_trampoline_enter(p);
+ exit_prog = (u64)bpf_trampoline_exit(p);
if (l->cookie == 0) {
/* if cookie is zero, one instruction is enough to store it */
@@ -1678,16 +2146,16 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
emit_call(enter_prog, ctx);
+ /* save return value to callee saved register x20 */
+ emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
+
/* if (__bpf_prog_enter(prog) == 0)
* goto skip_exec_of_prog;
*/
branch = ctx->image + ctx->idx;
emit(A64_NOP, ctx);
- /* save return value to callee saved register x20 */
- emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
-
- emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx);
+ emit(A64_ADD_I(1, A64_R(0), A64_SP, bargs_off), ctx);
if (!p->jited)
emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx);
@@ -1698,7 +2166,7 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
if (ctx->image) {
int offset = &ctx->image[ctx->idx] - branch;
- *branch = A64_CBZ(1, A64_R(0), offset);
+ *branch = cpu_to_le32(A64_CBZ(1, A64_R(0), offset));
}
/* arg1: prog */
@@ -1712,8 +2180,8 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
}
static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_links *tl,
- int args_off, int retval_off, int run_ctx_off,
- u32 **branches)
+ int bargs_off, int retval_off, int run_ctx_off,
+ __le32 **branches)
{
int i;
@@ -1722,7 +2190,7 @@ static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_links *tl,
*/
emit(A64_STR64I(A64_ZR, A64_SP, retval_off), ctx);
for (i = 0; i < tl->nr_links; i++) {
- invoke_bpf_prog(ctx, tl->links[i], args_off, retval_off,
+ invoke_bpf_prog(ctx, tl->links[i], bargs_off, retval_off,
run_ctx_off, true);
/* if (*(u64 *)(sp + retval_off) != 0)
* goto do_fexit;
@@ -1736,26 +2204,134 @@ static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_links *tl,
}
}
-static void save_args(struct jit_ctx *ctx, int args_off, int nargs)
+struct arg_aux {
+ /* how many args are passed through registers, the rest of the args are
+ * passed through stack
+ */
+ int args_in_regs;
+ /* how many registers are used to pass arguments */
+ int regs_for_args;
+ /* how much stack is used for additional args passed to bpf program
+ * that did not fit in original function registers
+ */
+ int bstack_for_args;
+ /* home much stack is used for additional args passed to the
+ * original function when called from trampoline (this one needs
+ * arguments to be properly aligned)
+ */
+ int ostack_for_args;
+};
+
+static int calc_arg_aux(const struct btf_func_model *m,
+ struct arg_aux *a)
{
- int i;
+ int stack_slots, nregs, slots, i;
- for (i = 0; i < nargs; i++) {
- emit(A64_STR64I(i, A64_SP, args_off), ctx);
- args_off += 8;
+ /* verifier ensures m->nr_args <= MAX_BPF_FUNC_ARGS */
+ for (i = 0, nregs = 0; i < m->nr_args; i++) {
+ slots = (m->arg_size[i] + 7) / 8;
+ if (nregs + slots <= 8) /* passed through register ? */
+ nregs += slots;
+ else
+ break;
}
+
+ a->args_in_regs = i;
+ a->regs_for_args = nregs;
+ a->ostack_for_args = 0;
+ a->bstack_for_args = 0;
+
+ /* the rest arguments are passed through stack */
+ for (; i < m->nr_args; i++) {
+ /* We can not know for sure about exact alignment needs for
+ * struct passed on stack, so deny those
+ */
+ if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+ return -ENOTSUPP;
+ stack_slots = (m->arg_size[i] + 7) / 8;
+ a->bstack_for_args += stack_slots * 8;
+ a->ostack_for_args = a->ostack_for_args + stack_slots * 8;
+ }
+
+ return 0;
}
-static void restore_args(struct jit_ctx *ctx, int args_off, int nargs)
+static void clear_garbage(struct jit_ctx *ctx, int reg, int effective_bytes)
+{
+ if (effective_bytes) {
+ int garbage_bits = 64 - 8 * effective_bytes;
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ /* garbage bits are at the right end */
+ emit(A64_LSR(1, reg, reg, garbage_bits), ctx);
+ emit(A64_LSL(1, reg, reg, garbage_bits), ctx);
+#else
+ /* garbage bits are at the left end */
+ emit(A64_LSL(1, reg, reg, garbage_bits), ctx);
+ emit(A64_LSR(1, reg, reg, garbage_bits), ctx);
+#endif
+ }
+}
+
+static void save_args(struct jit_ctx *ctx, int bargs_off, int oargs_off,
+ const struct btf_func_model *m,
+ const struct arg_aux *a,
+ bool for_call_origin)
{
int i;
+ int reg;
+ int doff;
+ int soff;
+ int slots;
+ u8 tmp = bpf2a64[TMP_REG_1];
+
+ /* store arguments to the stack for the bpf program, or restore
+ * arguments from stack for the original function
+ */
+ for (reg = 0; reg < a->regs_for_args; reg++) {
+ emit(for_call_origin ?
+ A64_LDR64I(reg, A64_SP, bargs_off) :
+ A64_STR64I(reg, A64_SP, bargs_off),
+ ctx);
+ bargs_off += 8;
+ }
- for (i = 0; i < nargs; i++) {
- emit(A64_LDR64I(i, A64_SP, args_off), ctx);
- args_off += 8;
+ soff = 32; /* on stack arguments start from FP + 32 */
+ doff = (for_call_origin ? oargs_off : bargs_off);
+
+ /* save on stack arguments */
+ for (i = a->args_in_regs; i < m->nr_args; i++) {
+ slots = (m->arg_size[i] + 7) / 8;
+ /* verifier ensures arg_size <= 16, so slots equals 1 or 2 */
+ while (slots-- > 0) {
+ emit(A64_LDR64I(tmp, A64_FP, soff), ctx);
+ /* if there is unused space in the last slot, clear
+ * the garbage contained in the space.
+ */
+ if (slots == 0 && !for_call_origin)
+ clear_garbage(ctx, tmp, m->arg_size[i] % 8);
+ emit(A64_STR64I(tmp, A64_SP, doff), ctx);
+ soff += 8;
+ doff += 8;
+ }
}
}
+static void restore_args(struct jit_ctx *ctx, int bargs_off, int nregs)
+{
+ int reg;
+
+ for (reg = 0; reg < nregs; reg++) {
+ emit(A64_LDR64I(reg, A64_SP, bargs_off), ctx);
+ bargs_off += 8;
+ }
+}
+
+static bool is_struct_ops_tramp(const struct bpf_tramp_links *fentry_links)
+{
+ return fentry_links->nr_links == 1 &&
+ fentry_links->links[0]->link.type == BPF_LINK_TYPE_STRUCT_OPS;
+}
+
/* Based on the x86's implementation of arch_prepare_bpf_trampoline().
*
* bpf prog and function entry before bpf trampoline hooked:
@@ -1768,50 +2344,62 @@ static void restore_args(struct jit_ctx *ctx, int args_off, int nargs)
*
*/
static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
- struct bpf_tramp_links *tlinks, void *orig_call,
- int nargs, u32 flags)
+ struct bpf_tramp_links *tlinks, void *func_addr,
+ const struct btf_func_model *m,
+ const struct arg_aux *a,
+ u32 flags)
{
int i;
int stack_size;
int retaddr_off;
int regs_off;
int retval_off;
- int args_off;
- int nargs_off;
+ int bargs_off;
+ int nfuncargs_off;
int ip_off;
int run_ctx_off;
+ int oargs_off;
+ int nfuncargs;
struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
bool save_ret;
- u32 **branches = NULL;
+ __le32 **branches = NULL;
+ bool is_struct_ops = is_struct_ops_tramp(fentry);
/* trampoline stack layout:
- * [ parent ip ]
- * [ FP ]
- * SP + retaddr_off [ self ip ]
- * [ FP ]
+ * [ parent ip ]
+ * [ FP ]
+ * SP + retaddr_off [ self ip ]
+ * [ FP ]
*
- * [ padding ] align SP to multiples of 16
+ * [ padding ] align SP to multiples of 16
*
- * [ x20 ] callee saved reg x20
- * SP + regs_off [ x19 ] callee saved reg x19
+ * [ x20 ] callee saved reg x20
+ * SP + regs_off [ x19 ] callee saved reg x19
*
- * SP + retval_off [ return value ] BPF_TRAMP_F_CALL_ORIG or
- * BPF_TRAMP_F_RET_FENTRY_RET
+ * SP + retval_off [ return value ] BPF_TRAMP_F_CALL_ORIG or
+ * BPF_TRAMP_F_RET_FENTRY_RET
+ * [ arg reg N ]
+ * [ ... ]
+ * SP + bargs_off [ arg reg 1 ] for bpf
*
- * [ argN ]
- * [ ... ]
- * SP + args_off [ arg1 ]
+ * SP + nfuncargs_off [ arg regs count ]
*
- * SP + nargs_off [ args count ]
+ * SP + ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag
*
- * SP + ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag
+ * SP + run_ctx_off [ bpf_tramp_run_ctx ]
*
- * SP + run_ctx_off [ bpf_tramp_run_ctx ]
+ * [ stack arg N ]
+ * [ ... ]
+ * SP + oargs_off [ stack arg 1 ] for original func
*/
stack_size = 0;
+ oargs_off = stack_size;
+ if (flags & BPF_TRAMP_F_CALL_ORIG)
+ stack_size += a->ostack_for_args;
+
run_ctx_off = stack_size;
/* room for bpf_tramp_run_ctx */
stack_size += round_up(sizeof(struct bpf_tramp_run_ctx), 8);
@@ -1821,13 +2409,14 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
if (flags & BPF_TRAMP_F_IP_ARG)
stack_size += 8;
- nargs_off = stack_size;
+ nfuncargs_off = stack_size;
/* room for args count */
stack_size += 8;
- args_off = stack_size;
+ bargs_off = stack_size;
/* room for args */
- stack_size += nargs * 8;
+ nfuncargs = a->regs_for_args + a->bstack_for_args / 8;
+ stack_size += 8 * nfuncargs;
/* room for return value */
retval_off = stack_size;
@@ -1853,11 +2442,14 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
*/
emit_bti(A64_BTI_JC, ctx);
- /* frame for parent function */
- emit(A64_PUSH(A64_FP, A64_R(9), A64_SP), ctx);
- emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+ /* x9 is not set for struct_ops */
+ if (!is_struct_ops) {
+ /* frame for parent function */
+ emit(A64_PUSH(A64_FP, A64_R(9), A64_SP), ctx);
+ emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+ }
- /* frame for patched function */
+ /* frame for patched function for tracing, or caller for struct_ops */
emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
emit(A64_MOV(1, A64_FP, A64_SP), ctx);
@@ -1866,71 +2458,81 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
if (flags & BPF_TRAMP_F_IP_ARG) {
/* save ip address of the traced function */
- emit_addr_mov_i64(A64_R(10), (const u64)orig_call, ctx);
+ emit_addr_mov_i64(A64_R(10), (const u64)func_addr, ctx);
emit(A64_STR64I(A64_R(10), A64_SP, ip_off), ctx);
}
- /* save args count*/
- emit(A64_MOVZ(1, A64_R(10), nargs, 0), ctx);
- emit(A64_STR64I(A64_R(10), A64_SP, nargs_off), ctx);
+ /* save arg regs count*/
+ emit(A64_MOVZ(1, A64_R(10), nfuncargs, 0), ctx);
+ emit(A64_STR64I(A64_R(10), A64_SP, nfuncargs_off), ctx);
- /* save args */
- save_args(ctx, args_off, nargs);
+ /* save args for bpf */
+ save_args(ctx, bargs_off, oargs_off, m, a, false);
/* save callee saved registers */
emit(A64_STR64I(A64_R(19), A64_SP, regs_off), ctx);
emit(A64_STR64I(A64_R(20), A64_SP, regs_off + 8), ctx);
if (flags & BPF_TRAMP_F_CALL_ORIG) {
- emit_addr_mov_i64(A64_R(0), (const u64)im, ctx);
+ /* for the first pass, assume the worst case */
+ if (!ctx->image)
+ ctx->idx += 4;
+ else
+ emit_a64_mov_i64(A64_R(0), (const u64)im, ctx);
emit_call((const u64)__bpf_tramp_enter, ctx);
}
for (i = 0; i < fentry->nr_links; i++)
- invoke_bpf_prog(ctx, fentry->links[i], args_off,
+ invoke_bpf_prog(ctx, fentry->links[i], bargs_off,
retval_off, run_ctx_off,
flags & BPF_TRAMP_F_RET_FENTRY_RET);
if (fmod_ret->nr_links) {
- branches = kcalloc(fmod_ret->nr_links, sizeof(u32 *),
+ branches = kcalloc(fmod_ret->nr_links, sizeof(__le32 *),
GFP_KERNEL);
if (!branches)
return -ENOMEM;
- invoke_bpf_mod_ret(ctx, fmod_ret, args_off, retval_off,
+ invoke_bpf_mod_ret(ctx, fmod_ret, bargs_off, retval_off,
run_ctx_off, branches);
}
if (flags & BPF_TRAMP_F_CALL_ORIG) {
- restore_args(ctx, args_off, nargs);
+ /* save args for original func */
+ save_args(ctx, bargs_off, oargs_off, m, a, true);
/* call original func */
emit(A64_LDR64I(A64_R(10), A64_SP, retaddr_off), ctx);
- emit(A64_BLR(A64_R(10)), ctx);
+ emit(A64_ADR(A64_LR, AARCH64_INSN_SIZE * 2), ctx);
+ emit(A64_RET(A64_R(10)), ctx);
/* store return value */
emit(A64_STR64I(A64_R(0), A64_SP, retval_off), ctx);
/* reserve a nop for bpf_tramp_image_put */
- im->ip_after_call = ctx->image + ctx->idx;
+ im->ip_after_call = ctx->ro_image + ctx->idx;
emit(A64_NOP, ctx);
}
/* update the branches saved in invoke_bpf_mod_ret with cbnz */
for (i = 0; i < fmod_ret->nr_links && ctx->image != NULL; i++) {
int offset = &ctx->image[ctx->idx] - branches[i];
- *branches[i] = A64_CBNZ(1, A64_R(10), offset);
+ *branches[i] = cpu_to_le32(A64_CBNZ(1, A64_R(10), offset));
}
for (i = 0; i < fexit->nr_links; i++)
- invoke_bpf_prog(ctx, fexit->links[i], args_off, retval_off,
+ invoke_bpf_prog(ctx, fexit->links[i], bargs_off, retval_off,
run_ctx_off, false);
if (flags & BPF_TRAMP_F_CALL_ORIG) {
- im->ip_epilogue = ctx->image + ctx->idx;
- emit_addr_mov_i64(A64_R(0), (const u64)im, ctx);
+ im->ip_epilogue = ctx->ro_image + ctx->idx;
+ /* for the first pass, assume the worst case */
+ if (!ctx->image)
+ ctx->idx += 4;
+ else
+ emit_a64_mov_i64(A64_R(0), (const u64)im, ctx);
emit_call((const u64)__bpf_tramp_exit, ctx);
}
if (flags & BPF_TRAMP_F_RESTORE_REGS)
- restore_args(ctx, args_off, nargs);
+ restore_args(ctx, bargs_off, a->regs_for_args);
/* restore callee saved register x19 and x20 */
emit(A64_LDR64I(A64_R(19), A64_SP, regs_off), ctx);
@@ -1942,65 +2544,116 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im,
/* reset SP */
emit(A64_MOV(1, A64_SP, A64_FP), ctx);
- /* pop frames */
- emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
- emit(A64_POP(A64_FP, A64_R(9), A64_SP), ctx);
-
- if (flags & BPF_TRAMP_F_SKIP_FRAME) {
- /* skip patched function, return to parent */
- emit(A64_MOV(1, A64_LR, A64_R(9)), ctx);
- emit(A64_RET(A64_R(9)), ctx);
+ if (is_struct_ops) {
+ emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+ emit(A64_RET(A64_LR), ctx);
} else {
- /* return to patched function */
- emit(A64_MOV(1, A64_R(10), A64_LR), ctx);
- emit(A64_MOV(1, A64_LR, A64_R(9)), ctx);
- emit(A64_RET(A64_R(10)), ctx);
+ /* pop frames */
+ emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+ emit(A64_POP(A64_FP, A64_R(9), A64_SP), ctx);
+
+ if (flags & BPF_TRAMP_F_SKIP_FRAME) {
+ /* skip patched function, return to parent */
+ emit(A64_MOV(1, A64_LR, A64_R(9)), ctx);
+ emit(A64_RET(A64_R(9)), ctx);
+ } else {
+ /* return to patched function */
+ emit(A64_MOV(1, A64_R(10), A64_LR), ctx);
+ emit(A64_MOV(1, A64_LR, A64_R(9)), ctx);
+ emit(A64_RET(A64_R(10)), ctx);
+ }
}
- if (ctx->image)
- bpf_flush_icache(ctx->image, ctx->image + ctx->idx);
-
kfree(branches);
return ctx->idx;
}
-int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
- void *image_end, const struct btf_func_model *m,
- u32 flags, struct bpf_tramp_links *tlinks,
- void *orig_call)
+int arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags,
+ struct bpf_tramp_links *tlinks, void *func_addr)
{
- int ret;
- int nargs = m->nr_args;
- int max_insns = ((long)image_end - (long)image) / AARCH64_INSN_SIZE;
struct jit_ctx ctx = {
.image = NULL,
.idx = 0,
};
+ struct bpf_tramp_image im;
+ struct arg_aux aaux;
+ int ret;
- /* the first 8 arguments are passed by registers */
- if (nargs > 8)
- return -ENOTSUPP;
+ ret = calc_arg_aux(m, &aaux);
+ if (ret < 0)
+ return ret;
- ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags);
+ ret = prepare_trampoline(&ctx, &im, tlinks, func_addr, m, &aaux, flags);
if (ret < 0)
return ret;
- if (ret > max_insns)
- return -EFBIG;
+ return ret < 0 ? ret : ret * AARCH64_INSN_SIZE;
+}
- ctx.image = image;
- ctx.idx = 0;
+void *arch_alloc_bpf_trampoline(unsigned int size)
+{
+ return bpf_prog_pack_alloc(size, jit_fill_hole);
+}
+
+void arch_free_bpf_trampoline(void *image, unsigned int size)
+{
+ bpf_prog_pack_free(image, size);
+}
- jit_fill_hole(image, (unsigned int)(image_end - image));
- ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags);
+int arch_protect_bpf_trampoline(void *image, unsigned int size)
+{
+ return 0;
+}
+
+int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *ro_image,
+ void *ro_image_end, const struct btf_func_model *m,
+ u32 flags, struct bpf_tramp_links *tlinks,
+ void *func_addr)
+{
+ u32 size = ro_image_end - ro_image;
+ struct arg_aux aaux;
+ void *image, *tmp;
+ int ret;
+
+ /* image doesn't need to be in module memory range, so we can
+ * use kvmalloc.
+ */
+ image = kvmalloc(size, GFP_KERNEL);
+ if (!image)
+ return -ENOMEM;
- if (ret > 0 && validate_code(&ctx) < 0)
+ struct jit_ctx ctx = {
+ .image = image,
+ .ro_image = ro_image,
+ .idx = 0,
+ .write = true,
+ };
+
+
+ jit_fill_hole(image, (unsigned int)(ro_image_end - ro_image));
+ ret = calc_arg_aux(m, &aaux);
+ if (ret)
+ goto out;
+ ret = prepare_trampoline(&ctx, im, tlinks, func_addr, m, &aaux, flags);
+
+ if (ret > 0 && validate_code(&ctx) < 0) {
ret = -EINVAL;
+ goto out;
+ }
if (ret > 0)
ret *= AARCH64_INSN_SIZE;
+ tmp = bpf_arch_text_copy(ro_image, image, size);
+ if (IS_ERR(tmp)) {
+ ret = PTR_ERR(tmp);
+ goto out;
+ }
+
+ bpf_flush_icache(ro_image, ro_image + size);
+out:
+ kvfree(image);
return ret;
}
@@ -2218,3 +2871,78 @@ out:
return ret;
}
+
+bool bpf_jit_supports_ptr_xchg(void)
+{
+ return true;
+}
+
+bool bpf_jit_supports_exceptions(void)
+{
+ /* We unwind through both kernel frames starting from within bpf_throw
+ * call and BPF frames. Therefore we require FP unwinder to be enabled
+ * to walk kernel frames and reach BPF frames in the stack trace.
+ * ARM64 kernel is aways compiled with CONFIG_FRAME_POINTER=y
+ */
+ return true;
+}
+
+bool bpf_jit_supports_arena(void)
+{
+ return true;
+}
+
+bool bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena)
+{
+ if (!in_arena)
+ return true;
+ switch (insn->code) {
+ case BPF_STX | BPF_ATOMIC | BPF_W:
+ case BPF_STX | BPF_ATOMIC | BPF_DW:
+ if (!bpf_atomic_is_load_store(insn) &&
+ !cpus_have_cap(ARM64_HAS_LSE_ATOMICS))
+ return false;
+ }
+ return true;
+}
+
+bool bpf_jit_supports_percpu_insn(void)
+{
+ return true;
+}
+
+bool bpf_jit_inlines_helper_call(s32 imm)
+{
+ switch (imm) {
+ case BPF_FUNC_get_smp_processor_id:
+ case BPF_FUNC_get_current_task:
+ case BPF_FUNC_get_current_task_btf:
+ return true;
+ default:
+ return false;
+ }
+}
+
+void bpf_jit_free(struct bpf_prog *prog)
+{
+ if (prog->jited) {
+ struct arm64_jit_data *jit_data = prog->aux->jit_data;
+ struct bpf_binary_header *hdr;
+
+ /*
+ * If we fail the final pass of JIT (from jit_subprogs),
+ * the program may not be finalized yet. Call finalize here
+ * before freeing it.
+ */
+ if (jit_data) {
+ bpf_arch_text_copy(&jit_data->ro_header->size, &jit_data->header->size,
+ sizeof(jit_data->header->size));
+ kfree(jit_data);
+ }
+ hdr = bpf_jit_binary_pack_hdr(prog);
+ bpf_jit_binary_pack_free(hdr, NULL);
+ WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
+ }
+
+ bpf_prog_unlock_free(prog);
+}