Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-24 05:02:12 +00:00
Code Issues Packages Projects Releases Wiki Activity
4cc1feeb6f
linux/arch/powerpc/net/bpf_jit_comp64.c
Sandipan Das 025dceb0fa bpf: powerpc64: optimize JIT passes for bpf function calls 
Once the JITed images for each function in a multi-function program
are generated after the first three JIT passes, we only need to fix
the target address for the branch instruction corresponding to each
bpf-to-bpf function call.

This introduces the following optimizations for reducing the work
done by the JIT compiler when handling multi-function programs:

  [1] Instead of doing two extra passes to fix the bpf function calls,
      do just one as that would be sufficient.

  [2] During the extra pass, only overwrite the instruction sequences
      for the bpf-to-bpf function calls as everything else would still
      remain exactly the same. This also reduces the number of writes
      to the JITed image.

  [3] Do not regenerate the prologue and the epilogue during the extra
      pass as that would be redundant.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-12-03 23:47:05 +01:00

1120 lines
31 KiB
C
Raw Blame History

/*
* bpf_jit_comp64.c: eBPF JIT compiler
*
* Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
* IBM Corporation
*
* Based on the powerpc classic BPF JIT compiler by Matt Evans
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*/
#include <linux/moduleloader.h>
#include <asm/cacheflush.h>
#include <asm/asm-compat.h>
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/if_vlan.h>
#include <asm/kprobes.h>
#include <linux/bpf.h>
#include "bpf_jit64.h"
static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
{
memset32(area, BREAKPOINT_INSTRUCTION, size/4);
}
static inline void bpf_flush_icache(void *start, void *end)
{
smp_wmb();
flush_icache_range((unsigned long)start, (unsigned long)end);
}
static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
{
return (ctx->seen & (1 << (31 - b2p[i])));
}
static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
{
ctx->seen |= (1 << (31 - b2p[i]));
}
static inline bool bpf_has_stack_frame(struct codegen_context *ctx)
{
/*
* We only need a stack frame if:
* - we call other functions (kernel helpers), or
* - the bpf program uses its stack area
* The latter condition is deduced from the usage of BPF_REG_FP
*/
return ctx->seen & SEEN_FUNC || bpf_is_seen_register(ctx, BPF_REG_FP);
}
/*
* When not setting up our own stackframe, the redzone usage is:
*
* [ prev sp ] <-------------
* [ ... ] |
* sp (r1) ---> [ stack pointer ] --------------
* [ nv gpr save area ] 6*8
* [ tail_call_cnt ] 8
* [ local_tmp_var ] 8
* [ unused red zone ] 208 bytes protected
*/
static int bpf_jit_stack_local(struct codegen_context *ctx)
{
if (bpf_has_stack_frame(ctx))
return STACK_FRAME_MIN_SIZE + ctx->stack_size;
else
return -(BPF_PPC_STACK_SAVE + 16);
}
static int bpf_jit_stack_tailcallcnt(struct codegen_context *ctx)
{
return bpf_jit_stack_local(ctx) + 8;
}
static int bpf_jit_stack_offsetof(struct codegen_context *ctx, int reg)
{
if (reg >= BPF_PPC_NVR_MIN && reg < 32)
return (bpf_has_stack_frame(ctx) ?
(BPF_PPC_STACKFRAME + ctx->stack_size) : 0)
- (8 * (32 - reg));
pr_err("BPF JIT is asking about unknown registers");
BUG();
}
static void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
{
int i;
/*
* Initialize tail_call_cnt if we do tail calls.
* Otherwise, put in NOPs so that it can be skipped when we are
* invoked through a tail call.
*/
if (ctx->seen & SEEN_TAILCALL) {
PPC_LI(b2p[TMP_REG_1], 0);
/* this goes in the redzone */
PPC_BPF_STL(b2p[TMP_REG_1], 1, -(BPF_PPC_STACK_SAVE + 8));
} else {
PPC_NOP();
PPC_NOP();
}
#define BPF_TAILCALL_PROLOGUE_SIZE 8
if (bpf_has_stack_frame(ctx)) {
/*
* We need a stack frame, but we don't necessarily need to
* save/restore LR unless we call other functions
*/
if (ctx->seen & SEEN_FUNC) {
EMIT(PPC_INST_MFLR | __PPC_RT(R0));
PPC_BPF_STL(0, 1, PPC_LR_STKOFF);
}
PPC_BPF_STLU(1, 1, -(BPF_PPC_STACKFRAME + ctx->stack_size));
}
/*
* Back up non-volatile regs -- BPF registers 6-10
* If we haven't created our own stack frame, we save these
* in the protected zone below the previous stack frame
*/
for (i = BPF_REG_6; i <= BPF_REG_10; i++)
if (bpf_is_seen_register(ctx, i))
PPC_BPF_STL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
/* Setup frame pointer to point to the bpf stack area */
if (bpf_is_seen_register(ctx, BPF_REG_FP))
PPC_ADDI(b2p[BPF_REG_FP], 1,
STACK_FRAME_MIN_SIZE + ctx->stack_size);
}
static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx)
{
int i;
/* Restore NVRs */
for (i = BPF_REG_6; i <= BPF_REG_10; i++)
if (bpf_is_seen_register(ctx, i))
PPC_BPF_LL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
/* Tear down our stack frame */
if (bpf_has_stack_frame(ctx)) {
PPC_ADDI(1, 1, BPF_PPC_STACKFRAME + ctx->stack_size);
if (ctx->seen & SEEN_FUNC) {
PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
PPC_MTLR(0);
}
}
}
static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
{
bpf_jit_emit_common_epilogue(image, ctx);
/* Move result to r3 */
PPC_MR(3, b2p[BPF_REG_0]);
PPC_BLR();
}
static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
u64 func)
{
#ifdef PPC64_ELF_ABI_v1
/* func points to the function descriptor */
PPC_LI64(b2p[TMP_REG_2], func);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
/* ... and move it to LR */
PPC_MTLR(b2p[TMP_REG_1]);
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
#else
/* We can clobber r12 */
PPC_FUNC_ADDR(12, func);
PPC_MTLR(12);
#endif
PPC_BLRL();
}
static void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx,
u64 func)
{
unsigned int i, ctx_idx = ctx->idx;
/* Load function address into r12 */
PPC_LI64(12, func);
/* For bpf-to-bpf function calls, the callee's address is unknown
* until the last extra pass. As seen above, we use PPC_LI64() to
* load the callee's address, but this may optimize the number of
* instructions required based on the nature of the address.
*
* Since we don't want the number of instructions emitted to change,
* we pad the optimized PPC_LI64() call with NOPs to guarantee that
* we always have a five-instruction sequence, which is the maximum
* that PPC_LI64() can emit.
*/
for (i = ctx->idx - ctx_idx; i < 5; i++)
PPC_NOP();
#ifdef PPC64_ELF_ABI_v1
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
PPC_BPF_LL(2, 12, 8);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(12, 12, 0);
#endif
PPC_MTLR(12);
PPC_BLRL();
}
static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
{
/*
* By now, the eBPF program has already setup parameters in r3, r4 and r5
* r3/BPF_REG_1 - pointer to ctx -- passed as is to the next bpf program
* r4/BPF_REG_2 - pointer to bpf_array
* r5/BPF_REG_3 - index in bpf_array
*/
int b2p_bpf_array = b2p[BPF_REG_2];
int b2p_index = b2p[BPF_REG_3];
/*
* if (index >= array->map.max_entries)
* goto out;
*/
PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries));
PPC_RLWINM(b2p_index, b2p_index, 0, 0, 31);
PPC_CMPLW(b2p_index, b2p[TMP_REG_1]);
PPC_BCC(COND_GE, out);
/*
* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
* goto out;
*/
PPC_LD(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
PPC_CMPLWI(b2p[TMP_REG_1], MAX_TAIL_CALL_CNT);
PPC_BCC(COND_GT, out);
/*
* tail_call_cnt++;
*/
PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], 1);
PPC_BPF_STL(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
/* prog = array->ptrs[index]; */
PPC_MULI(b2p[TMP_REG_1], b2p_index, 8);
PPC_ADD(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p_bpf_array);
PPC_LD(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_array, ptrs));
/*
* if (prog == NULL)
* goto out;
*/
PPC_CMPLDI(b2p[TMP_REG_1], 0);
PPC_BCC(COND_EQ, out);
/* goto *(prog->bpf_func + prologue_size); */
PPC_LD(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_prog, bpf_func));
#ifdef PPC64_ELF_ABI_v1
/* skip past the function descriptor */
PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1],
FUNCTION_DESCR_SIZE + BPF_TAILCALL_PROLOGUE_SIZE);
#else
PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], BPF_TAILCALL_PROLOGUE_SIZE);
#endif
PPC_MTCTR(b2p[TMP_REG_1]);
/* tear down stack, restore NVRs, ... */
bpf_jit_emit_common_epilogue(image, ctx);
PPC_BCTR();
/* out: */
}
/* Assemble the body code between the prologue & epilogue */
static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
struct codegen_context *ctx,
u32 *addrs, bool extra_pass)
{
const struct bpf_insn *insn = fp->insnsi;
int flen = fp->len;
int i, ret;
/* Start of epilogue code - will only be valid 2nd pass onwards */
u32 exit_addr = addrs[flen];
for (i = 0; i < flen; i++) {
u32 code = insn[i].code;
u32 dst_reg = b2p[insn[i].dst_reg];
u32 src_reg = b2p[insn[i].src_reg];
s16 off = insn[i].off;
s32 imm = insn[i].imm;
bool func_addr_fixed;
u64 func_addr;
u64 imm64;
u32 true_cond;
u32 tmp_idx;
/*
* addrs[] maps a BPF bytecode address into a real offset from
* the start of the body code.
*/
addrs[i] = ctx->idx * 4;
/*
* As an optimization, we note down which non-volatile registers
* are used so that we can only save/restore those in our
* prologue and epilogue. We do this here regardless of whether
* the actual BPF instruction uses src/dst registers or not
* (for instance, BPF_CALL does not use them). The expectation
* is that those instructions will have src_reg/dst_reg set to
* 0. Even otherwise, we just lose some prologue/epilogue
* optimization but everything else should work without
* any issues.
*/
if (dst_reg >= BPF_PPC_NVR_MIN && dst_reg < 32)
bpf_set_seen_register(ctx, insn[i].dst_reg);
if (src_reg >= BPF_PPC_NVR_MIN && src_reg < 32)
bpf_set_seen_register(ctx, insn[i].src_reg);
switch (code) {
/*
* Arithmetic operations: ADD/SUB/MUL/DIV/MOD/NEG
*/
case BPF_ALU | BPF_ADD | BPF_X: /* (u32) dst += (u32) src */
case BPF_ALU64 | BPF_ADD | BPF_X: /* dst += src */
PPC_ADD(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_SUB | BPF_X: /* (u32) dst -= (u32) src */
case BPF_ALU64 | BPF_SUB | BPF_X: /* dst -= src */
PPC_SUB(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */
case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */
if (BPF_OP(code) == BPF_SUB)
imm = -imm;
if (imm) {
if (imm >= -32768 && imm < 32768)
PPC_ADDI(dst_reg, dst_reg, IMM_L(imm));
else {
PPC_LI32(b2p[TMP_REG_1], imm);
PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]);
}
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */
case BPF_ALU64 | BPF_MUL | BPF_X: /* dst *= src */
if (BPF_CLASS(code) == BPF_ALU)
PPC_MULW(dst_reg, dst_reg, src_reg);
else
PPC_MULD(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_MUL | BPF_K: /* (u32) dst *= (u32) imm */
case BPF_ALU64 | BPF_MUL | BPF_K: /* dst *= imm */
if (imm >= -32768 && imm < 32768)
PPC_MULI(dst_reg, dst_reg, IMM_L(imm));
else {
PPC_LI32(b2p[TMP_REG_1], imm);
if (BPF_CLASS(code) == BPF_ALU)
PPC_MULW(dst_reg, dst_reg,
b2p[TMP_REG_1]);
else
PPC_MULD(dst_reg, dst_reg,
b2p[TMP_REG_1]);
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_DIV | BPF_X: /* (u32) dst /= (u32) src */
case BPF_ALU | BPF_MOD | BPF_X: /* (u32) dst %= (u32) src */
if (BPF_OP(code) == BPF_MOD) {
PPC_DIVWU(b2p[TMP_REG_1], dst_reg, src_reg);
PPC_MULW(b2p[TMP_REG_1], src_reg,
b2p[TMP_REG_1]);
PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]);
} else
PPC_DIVWU(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
if (BPF_OP(code) == BPF_MOD) {
PPC_DIVD(b2p[TMP_REG_1], dst_reg, src_reg);
PPC_MULD(b2p[TMP_REG_1], src_reg,
b2p[TMP_REG_1]);
PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]);
} else
PPC_DIVD(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MOD | BPF_K: /* (u32) dst %= (u32) imm */
case BPF_ALU | BPF_DIV | BPF_K: /* (u32) dst /= (u32) imm */
case BPF_ALU64 | BPF_MOD | BPF_K: /* dst %= imm */
case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */
if (imm == 0)
return -EINVAL;
else if (imm == 1)
goto bpf_alu32_trunc;
PPC_LI32(b2p[TMP_REG_1], imm);
switch (BPF_CLASS(code)) {
case BPF_ALU:
if (BPF_OP(code) == BPF_MOD) {
PPC_DIVWU(b2p[TMP_REG_2], dst_reg,
b2p[TMP_REG_1]);
PPC_MULW(b2p[TMP_REG_1],
b2p[TMP_REG_1],
b2p[TMP_REG_2]);
PPC_SUB(dst_reg, dst_reg,
b2p[TMP_REG_1]);
} else
PPC_DIVWU(dst_reg, dst_reg,
b2p[TMP_REG_1]);
break;
case BPF_ALU64:
if (BPF_OP(code) == BPF_MOD) {
PPC_DIVD(b2p[TMP_REG_2], dst_reg,
b2p[TMP_REG_1]);
PPC_MULD(b2p[TMP_REG_1],
b2p[TMP_REG_1],
b2p[TMP_REG_2]);
PPC_SUB(dst_reg, dst_reg,
b2p[TMP_REG_1]);
} else
PPC_DIVD(dst_reg, dst_reg,
b2p[TMP_REG_1]);
break;
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_NEG: /* (u32) dst = -dst */
case BPF_ALU64 | BPF_NEG: /* dst = -dst */
PPC_NEG(dst_reg, dst_reg);
goto bpf_alu32_trunc;
/*
* Logical operations: AND/OR/XOR/[A]LSH/[A]RSH
*/
case BPF_ALU | BPF_AND | BPF_X: /* (u32) dst = dst & src */
case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
PPC_AND(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_AND | BPF_K: /* (u32) dst = dst & imm */
case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
if (!IMM_H(imm))
PPC_ANDI(dst_reg, dst_reg, IMM_L(imm));
else {
/* Sign-extended */
PPC_LI32(b2p[TMP_REG_1], imm);
PPC_AND(dst_reg, dst_reg, b2p[TMP_REG_1]);
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
PPC_OR(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_OR | BPF_K:/* dst = (u32) dst | (u32) imm */
case BPF_ALU64 | BPF_OR | BPF_K:/* dst = dst | imm */
if (imm < 0 && BPF_CLASS(code) == BPF_ALU64) {
/* Sign-extended */
PPC_LI32(b2p[TMP_REG_1], imm);
PPC_OR(dst_reg, dst_reg, b2p[TMP_REG_1]);
} else {
if (IMM_L(imm))
PPC_ORI(dst_reg, dst_reg, IMM_L(imm));
if (IMM_H(imm))
PPC_ORIS(dst_reg, dst_reg, IMM_H(imm));
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_XOR | BPF_X: /* (u32) dst ^= src */
case BPF_ALU64 | BPF_XOR | BPF_X: /* dst ^= src */
PPC_XOR(dst_reg, dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_XOR | BPF_K: /* (u32) dst ^= (u32) imm */
case BPF_ALU64 | BPF_XOR | BPF_K: /* dst ^= imm */
if (imm < 0 && BPF_CLASS(code) == BPF_ALU64) {
/* Sign-extended */
PPC_LI32(b2p[TMP_REG_1], imm);
PPC_XOR(dst_reg, dst_reg, b2p[TMP_REG_1]);
} else {
if (IMM_L(imm))
PPC_XORI(dst_reg, dst_reg, IMM_L(imm));
if (IMM_H(imm))
PPC_XORIS(dst_reg, dst_reg, IMM_H(imm));
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_LSH | BPF_X: /* (u32) dst <<= (u32) src */
/* slw clears top 32 bits */
PPC_SLW(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU64 | BPF_LSH | BPF_X: /* dst <<= src; */
PPC_SLD(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU | BPF_LSH | BPF_K: /* (u32) dst <<== (u32) imm */
/* with imm 0, we still need to clear top 32 bits */
PPC_SLWI(dst_reg, dst_reg, imm);
break;
case BPF_ALU64 | BPF_LSH | BPF_K: /* dst <<== imm */
if (imm != 0)
PPC_SLDI(dst_reg, dst_reg, imm);
break;
case BPF_ALU | BPF_RSH | BPF_X: /* (u32) dst >>= (u32) src */
PPC_SRW(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU64 | BPF_RSH | BPF_X: /* dst >>= src */
PPC_SRD(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU | BPF_RSH | BPF_K: /* (u32) dst >>= (u32) imm */
PPC_SRWI(dst_reg, dst_reg, imm);
break;
case BPF_ALU64 | BPF_RSH | BPF_K: /* dst >>= imm */
if (imm != 0)
PPC_SRDI(dst_reg, dst_reg, imm);
break;
case BPF_ALU64 | BPF_ARSH | BPF_X: /* (s64) dst >>= src */
PPC_SRAD(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU64 | BPF_ARSH | BPF_K: /* (s64) dst >>= imm */
if (imm != 0)
PPC_SRADI(dst_reg, dst_reg, imm);
break;
/*
* MOV
*/
case BPF_ALU | BPF_MOV | BPF_X: /* (u32) dst = src */
case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
PPC_MR(dst_reg, src_reg);
goto bpf_alu32_trunc;
case BPF_ALU | BPF_MOV | BPF_K: /* (u32) dst = imm */
case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = (s64) imm */
PPC_LI32(dst_reg, imm);
if (imm < 0)
goto bpf_alu32_trunc;
break;
bpf_alu32_trunc:
/* Truncate to 32-bits */
if (BPF_CLASS(code) == BPF_ALU)
PPC_RLWINM(dst_reg, dst_reg, 0, 0, 31);
break;
/*
* BPF_FROM_BE/LE
*/
case BPF_ALU | BPF_END | BPF_FROM_LE:
case BPF_ALU | BPF_END | BPF_FROM_BE:
#ifdef __BIG_ENDIAN__
if (BPF_SRC(code) == BPF_FROM_BE)
goto emit_clear;
#else /* !__BIG_ENDIAN__ */
if (BPF_SRC(code) == BPF_FROM_LE)
goto emit_clear;
#endif
switch (imm) {
case 16:
/* Rotate 8 bits left & mask with 0x0000ff00 */
PPC_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 16, 23);
/* Rotate 8 bits right & insert LSB to reg */
PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 24, 31);
/* Move result back to dst_reg */
PPC_MR(dst_reg, b2p[TMP_REG_1]);
break;
case 32:
/*
* Rotate word left by 8 bits:
* 2 bytes are already in their final position
* -- byte 2 and 4 (of bytes 1, 2, 3 and 4)
*/
PPC_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 0, 31);
/* Rotate 24 bits and insert byte 1 */
PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 0, 7);
/* Rotate 24 bits and insert byte 3 */
PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 16, 23);
PPC_MR(dst_reg, b2p[TMP_REG_1]);
break;
case 64:
/*
* Way easier and faster(?) to store the value
* into stack and then use ldbrx
*
* ctx->seen will be reliable in pass2, but
* the instructions generated will remain the
* same across all passes
*/
PPC_STD(dst_reg, 1, bpf_jit_stack_local(ctx));
PPC_ADDI(b2p[TMP_REG_1], 1, bpf_jit_stack_local(ctx));
PPC_LDBRX(dst_reg, 0, b2p[TMP_REG_1]);
break;
}
break;
emit_clear:
switch (imm) {
case 16:
/* zero-extend 16 bits into 64 bits */
PPC_RLDICL(dst_reg, dst_reg, 0, 48);
break;
case 32:
/* zero-extend 32 bits into 64 bits */
PPC_RLDICL(dst_reg, dst_reg, 0, 32);
break;
case 64:
/* nop */
break;
}
break;
/*
* BPF_ST(X)
*/
case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src */
case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
if (BPF_CLASS(code) == BPF_ST) {
PPC_LI(b2p[TMP_REG_1], imm);
src_reg = b2p[TMP_REG_1];
}
PPC_STB(src_reg, dst_reg, off);
break;
case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
if (BPF_CLASS(code) == BPF_ST) {
PPC_LI(b2p[TMP_REG_1], imm);
src_reg = b2p[TMP_REG_1];
}
PPC_STH(src_reg, dst_reg, off);
break;
case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
if (BPF_CLASS(code) == BPF_ST) {
PPC_LI32(b2p[TMP_REG_1], imm);
src_reg = b2p[TMP_REG_1];
}
PPC_STW(src_reg, dst_reg, off);
break;
case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
if (BPF_CLASS(code) == BPF_ST) {
PPC_LI32(b2p[TMP_REG_1], imm);
src_reg = b2p[TMP_REG_1];
}
PPC_STD(src_reg, dst_reg, off);
break;
/*
* BPF_STX XADD (atomic_add)
*/
/* *(u32 *)(dst + off) += src */
case BPF_STX | BPF_XADD | BPF_W:
/* Get EA into TMP_REG_1 */
PPC_ADDI(b2p[TMP_REG_1], dst_reg, off);
tmp_idx = ctx->idx * 4;
/* load value from memory into TMP_REG_2 */
PPC_BPF_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
/* add value from src_reg into this */
PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
/* store result back */
PPC_BPF_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
/* we're done if this succeeded */
PPC_BCC_SHORT(COND_NE, tmp_idx);
break;
/* *(u64 *)(dst + off) += src */
case BPF_STX | BPF_XADD | BPF_DW:
PPC_ADDI(b2p[TMP_REG_1], dst_reg, off);
tmp_idx = ctx->idx * 4;
PPC_BPF_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
PPC_BPF_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
PPC_BCC_SHORT(COND_NE, tmp_idx);
break;
/*
* BPF_LDX
*/
/* dst = *(u8 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_B:
PPC_LBZ(dst_reg, src_reg, off);
break;
/* dst = *(u16 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_H:
PPC_LHZ(dst_reg, src_reg, off);
break;
/* dst = *(u32 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_W:
PPC_LWZ(dst_reg, src_reg, off);
break;
/* dst = *(u64 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_DW:
PPC_LD(dst_reg, src_reg, off);
break;
/*
* Doubleword load
* 16 byte instruction that uses two 'struct bpf_insn'
*/
case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
imm64 = ((u64)(u32) insn[i].imm) |
(((u64)(u32) insn[i+1].imm) << 32);
/* Adjust for two bpf instructions */
addrs[++i] = ctx->idx * 4;
PPC_LI64(dst_reg, imm64);
break;
/*
* Return/Exit
*/
case BPF_JMP | BPF_EXIT:
/*
* If this isn't the very last instruction, branch to
* the epilogue. If we _are_ the last instruction,
* we'll just fall through to the epilogue.
*/
if (i != flen - 1)
PPC_JMP(exit_addr);
/* else fall through to the epilogue */
break;
/*
* Call kernel helper or bpf function
*/
case BPF_JMP | BPF_CALL:
ctx->seen |= SEEN_FUNC;
ret = bpf_jit_get_func_addr(fp, &insn[i], extra_pass,
&func_addr, &func_addr_fixed);
if (ret < 0)
return ret;
if (func_addr_fixed)
bpf_jit_emit_func_call_hlp(image, ctx, func_addr);
else
bpf_jit_emit_func_call_rel(image, ctx, func_addr);
/* move return value from r3 to BPF_REG_0 */
PPC_MR(b2p[BPF_REG_0], 3);
break;
/*
* Jumps and branches
*/
case BPF_JMP | BPF_JA:
PPC_JMP(addrs[i + 1 + off]);
break;
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_X:
true_cond = COND_GT;
goto cond_branch;
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JLT | BPF_X:
case BPF_JMP | BPF_JSLT | BPF_K:
case BPF_JMP | BPF_JSLT | BPF_X:
true_cond = COND_LT;
goto cond_branch;
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_X:
true_cond = COND_GE;
goto cond_branch;
case BPF_JMP | BPF_JLE | BPF_K:
case BPF_JMP | BPF_JLE | BPF_X:
case BPF_JMP | BPF_JSLE | BPF_K:
case BPF_JMP | BPF_JSLE | BPF_X:
true_cond = COND_LE;
goto cond_branch;
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JEQ | BPF_X:
true_cond = COND_EQ;
goto cond_branch;
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JNE | BPF_X:
true_cond = COND_NE;
goto cond_branch;
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP | BPF_JSET | BPF_X:
true_cond = COND_NE;
/* Fall through */
cond_branch:
switch (code) {
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JLT | BPF_X:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JLE | BPF_X:
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
/* unsigned comparison */
PPC_CMPLD(dst_reg, src_reg);
break;
case BPF_JMP | BPF_JSGT | BPF_X:
case BPF_JMP | BPF_JSLT | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_X:
case BPF_JMP | BPF_JSLE | BPF_X:
/* signed comparison */
PPC_CMPD(dst_reg, src_reg);
break;
case BPF_JMP | BPF_JSET | BPF_X:
PPC_AND_DOT(b2p[TMP_REG_1], dst_reg, src_reg);
break;
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JLE | BPF_K:
/*
* Need sign-extended load, so only positive
* values can be used as imm in cmpldi
*/
if (imm >= 0 && imm < 32768)
PPC_CMPLDI(dst_reg, imm);
else {
/* sign-extending load */
PPC_LI32(b2p[TMP_REG_1], imm);
/* ... but unsigned comparison */
PPC_CMPLD(dst_reg, b2p[TMP_REG_1]);
}
break;
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSLT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSLE | BPF_K:
/*
* signed comparison, so any 16-bit value
* can be used in cmpdi
*/
if (imm >= -32768 && imm < 32768)
PPC_CMPDI(dst_reg, imm);
else {
PPC_LI32(b2p[TMP_REG_1], imm);
PPC_CMPD(dst_reg, b2p[TMP_REG_1]);
}
break;
case BPF_JMP | BPF_JSET | BPF_K:
/* andi does not sign-extend the immediate */
if (imm >= 0 && imm < 32768)
/* PPC_ANDI is _only/always_ dot-form */
PPC_ANDI(b2p[TMP_REG_1], dst_reg, imm);
else {
PPC_LI32(b2p[TMP_REG_1], imm);
PPC_AND_DOT(b2p[TMP_REG_1], dst_reg,
b2p[TMP_REG_1]);
}
break;
}
PPC_BCC(true_cond, addrs[i + 1 + off]);
break;
/*
* Tail call
*/
case BPF_JMP | BPF_TAIL_CALL:
ctx->seen |= SEEN_TAILCALL;
bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]);
break;
default:
/*
* The filter contains something cruel & unusual.
* We don't handle it, but also there shouldn't be
* anything missing from our list.
*/
pr_err_ratelimited("eBPF filter opcode %04x (@%d) unsupported\n",
code, i);
return -ENOTSUPP;
}
}
/* Set end-of-body-code address for exit. */
addrs[i] = ctx->idx * 4;
return 0;
}
/* Fix the branch target addresses for subprog calls */
static int bpf_jit_fixup_subprog_calls(struct bpf_prog *fp, u32 *image,
struct codegen_context *ctx, u32 *addrs)
{
const struct bpf_insn *insn = fp->insnsi;
bool func_addr_fixed;
u64 func_addr;
u32 tmp_idx;
int i, ret;
for (i = 0; i < fp->len; i++) {
/*
* During the extra pass, only the branch target addresses for
* the subprog calls need to be fixed. All other instructions
* can left untouched.
*
* The JITed image length does not change because we already
* ensure that the JITed instruction sequence for these calls
* are of fixed length by padding them with NOPs.
*/
if (insn[i].code == (BPF_JMP | BPF_CALL) &&
insn[i].src_reg == BPF_PSEUDO_CALL) {
ret = bpf_jit_get_func_addr(fp, &insn[i], true,
&func_addr,
&func_addr_fixed);
if (ret < 0)
return ret;
/*
* Save ctx->idx as this would currently point to the
* end of the JITed image and set it to the offset of
* the instruction sequence corresponding to the
* subprog call temporarily.
*/
tmp_idx = ctx->idx;
ctx->idx = addrs[i] / 4;
bpf_jit_emit_func_call_rel(image, ctx, func_addr);
/*
* Restore ctx->idx here. This is safe as the length
* of the JITed sequence remains unchanged.
*/
ctx->idx = tmp_idx;
}
}
return 0;
}
struct powerpc64_jit_data {
struct bpf_binary_header *header;
u32 *addrs;
u8 *image;
u32 proglen;
struct codegen_context ctx;
};
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
{
u32 proglen;
u32 alloclen;
u8 *image = NULL;
u32 *code_base;
u32 *addrs;
struct powerpc64_jit_data *jit_data;
struct codegen_context cgctx;
int pass;
int flen;
struct bpf_binary_header *bpf_hdr;
struct bpf_prog *org_fp = fp;
struct bpf_prog *tmp_fp;
bool bpf_blinded = false;
bool extra_pass = false;
if (!fp->jit_requested)
return org_fp;
tmp_fp = bpf_jit_blind_constants(org_fp);
if (IS_ERR(tmp_fp))
return org_fp;
if (tmp_fp != org_fp) {
bpf_blinded = true;
fp = tmp_fp;
}
jit_data = fp->aux->jit_data;
if (!jit_data) {
jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
if (!jit_data) {
fp = org_fp;
goto out;
}
fp->aux->jit_data = jit_data;
}
flen = fp->len;
addrs = jit_data->addrs;
if (addrs) {
cgctx = jit_data->ctx;
image = jit_data->image;
bpf_hdr = jit_data->header;
proglen = jit_data->proglen;
alloclen = proglen + FUNCTION_DESCR_SIZE;
extra_pass = true;
goto skip_init_ctx;
}
addrs = kcalloc(flen + 1, sizeof(*addrs), GFP_KERNEL);
if (addrs == NULL) {
fp = org_fp;
goto out_addrs;
}
memset(&cgctx, 0, sizeof(struct codegen_context));
/* Make sure that the stack is quadword aligned. */
cgctx.stack_size = round_up(fp->aux->stack_depth, 16);
/* Scouting faux-generate pass 0 */
if (bpf_jit_build_body(fp, 0, &cgctx, addrs, false)) {
/* We hit something illegal or unsupported. */
fp = org_fp;
goto out_addrs;
}
/*
* Pretend to build prologue, given the features we've seen. This will
* update ctgtx.idx as it pretends to output instructions, then we can
* calculate total size from idx.
*/
bpf_jit_build_prologue(0, &cgctx);
bpf_jit_build_epilogue(0, &cgctx);
proglen = cgctx.idx * 4;
alloclen = proglen + FUNCTION_DESCR_SIZE;
bpf_hdr = bpf_jit_binary_alloc(alloclen, &image, 4,
bpf_jit_fill_ill_insns);
if (!bpf_hdr) {
fp = org_fp;
goto out_addrs;
}
skip_init_ctx:
code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);
if (extra_pass) {
/*
* Do not touch the prologue and epilogue as they will remain
* unchanged. Only fix the branch target address for subprog
* calls in the body.
*
* This does not change the offsets and lengths of the subprog
* call instruction sequences and hence, the size of the JITed
* image as well.
*/
bpf_jit_fixup_subprog_calls(fp, code_base, &cgctx, addrs);
/* There is no need to perform the usual passes. */
goto skip_codegen_passes;
}
/* Code generation passes 1-2 */
for (pass = 1; pass < 3; pass++) {
/* Now build the prologue, body code & epilogue for real. */
cgctx.idx = 0;
bpf_jit_build_prologue(code_base, &cgctx);
bpf_jit_build_body(fp, code_base, &cgctx, addrs, extra_pass);
bpf_jit_build_epilogue(code_base, &cgctx);
if (bpf_jit_enable > 1)
pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass,
proglen - (cgctx.idx * 4), cgctx.seen);
}
skip_codegen_passes:
if (bpf_jit_enable > 1)
/*
* Note that we output the base address of the code_base
* rather than image, since opcodes are in code_base.
*/
bpf_jit_dump(flen, proglen, pass, code_base);
#ifdef PPC64_ELF_ABI_v1
/* Function descriptor nastiness: Address + TOC */
((u64 *)image)[0] = (u64)code_base;
((u64 *)image)[1] = local_paca->kernel_toc;
#endif
fp->bpf_func = (void *)image;
fp->jited = 1;
fp->jited_len = alloclen;
bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + (bpf_hdr->pages * PAGE_SIZE));
if (!fp->is_func || extra_pass) {
out_addrs:
kfree(addrs);
kfree(jit_data);
fp->aux->jit_data = NULL;
} else {
jit_data->addrs = addrs;
jit_data->ctx = cgctx;
jit_data->proglen = proglen;
jit_data->image = image;
jit_data->header = bpf_hdr;
}
out:
if (bpf_blinded)
bpf_jit_prog_release_other(fp, fp == org_fp ? tmp_fp : org_fp);
return fp;
}
/* Overriding bpf_jit_free() as we don't set images read-only. */
void bpf_jit_free(struct bpf_prog *fp)
{
unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
struct bpf_binary_header *bpf_hdr = (void *)addr;
if (fp->jited)
bpf_jit_binary_free(bpf_hdr);
bpf_prog_unlock_free(fp);
}
Reference in New Issue View Git Blame Copy Permalink