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linux-stable/arch/powerpc/net/bpf_jit_comp64.c
Naveen N. Rao b7540d6250 powerpc/bpf: Emit stf barrier instruction sequences for BPF_NOSPEC 
Emit similar instruction sequences to commit a048a07d7f
("powerpc/64s: Add support for a store forwarding barrier at kernel
entry/exit") when encountering BPF_NOSPEC.

Mitigations are enabled depending on what the firmware advertises. In
particular, we do not gate these mitigations based on current settings,
just like in x86. Due to this, we don't need to take any action if
mitigations are enabled or disabled at runtime.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/956570cbc191cd41f8274bed48ee757a86dac62a.1633464148.git.naveen.n.rao@linux.vnet.ibm.com
2021-10-07 19:52:58 +11:00

1079 lines
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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
*/
#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 <asm/security_features.h>
#include "bpf_jit64.h"
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, b2p[BPF_REG_FP]);
}
/*
* When not setting up our own stackframe, the redzone usage is:
*
* [ prev sp ] <-------------
* [ ... ] |
* sp (r1) ---> [ stack pointer ] --------------
* [ nv gpr save area ] 5*8
* [ tail_call_cnt ] 8
* [ local_tmp_var ] 16
* [ 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 + 24);
}
static int bpf_jit_stack_tailcallcnt(struct codegen_context *ctx)
{
return bpf_jit_stack_local(ctx) + 16;
}
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();
}
void bpf_jit_realloc_regs(struct codegen_context *ctx)
{
}
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) {
EMIT(PPC_RAW_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 {
EMIT(PPC_RAW_NOP());
EMIT(PPC_RAW_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_RAW_MFLR(_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, b2p[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, b2p[BPF_REG_FP]))
EMIT(PPC_RAW_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, b2p[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)) {
EMIT(PPC_RAW_ADDI(1, 1, BPF_PPC_STACKFRAME + ctx->stack_size));
if (ctx->seen & SEEN_FUNC) {
PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
EMIT(PPC_RAW_MTLR(0));
}
}
}
void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
{
bpf_jit_emit_common_epilogue(image, ctx);
/* Move result to r3 */
EMIT(PPC_RAW_MR(3, b2p[BPF_REG_0]));
EMIT(PPC_RAW_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 CTR */
EMIT(PPC_RAW_MTCTR(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);
EMIT(PPC_RAW_MTCTR(12));
#endif
EMIT(PPC_RAW_BCTRL());
}
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++)
EMIT(PPC_RAW_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
EMIT(PPC_RAW_MTCTR(12));
EMIT(PPC_RAW_BCTRL());
}
static int 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;
*/
EMIT(PPC_RAW_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries)));
EMIT(PPC_RAW_RLWINM(b2p_index, b2p_index, 0, 0, 31));
EMIT(PPC_RAW_CMPLW(b2p_index, b2p[TMP_REG_1]));
PPC_BCC(COND_GE, out);
/*
* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
* goto out;
*/
PPC_BPF_LL(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
EMIT(PPC_RAW_CMPLWI(b2p[TMP_REG_1], MAX_TAIL_CALL_CNT));
PPC_BCC(COND_GT, out);
/*
* tail_call_cnt++;
*/
EMIT(PPC_RAW_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]; */
EMIT(PPC_RAW_MULI(b2p[TMP_REG_1], b2p_index, 8));
EMIT(PPC_RAW_ADD(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p_bpf_array));
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_array, ptrs));
/*
* if (prog == NULL)
* goto out;
*/
EMIT(PPC_RAW_CMPLDI(b2p[TMP_REG_1], 0));
PPC_BCC(COND_EQ, out);
/* goto *(prog->bpf_func + prologue_size); */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_prog, bpf_func));
#ifdef PPC64_ELF_ABI_v1
/* skip past the function descriptor */
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1],
FUNCTION_DESCR_SIZE + BPF_TAILCALL_PROLOGUE_SIZE));
#else
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], BPF_TAILCALL_PROLOGUE_SIZE));
#endif
EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
/* tear down stack, restore NVRs, ... */
bpf_jit_emit_common_epilogue(image, ctx);
EMIT(PPC_RAW_BCTR());
/* out: */
return 0;
}
/*
* We spill into the redzone always, even if the bpf program has its own stackframe.
* Offsets hardcoded based on BPF_PPC_STACK_SAVE -- see bpf_jit_stack_local()
*/
void bpf_stf_barrier(void);
asm (
" .global bpf_stf_barrier ;"
" bpf_stf_barrier: ;"
" std 21,-64(1) ;"
" std 22,-56(1) ;"
" sync ;"
" ld 21,-64(1) ;"
" ld 22,-56(1) ;"
" ori 31,31,0 ;"
" .rept 14 ;"
" b 1f ;"
" 1: ;"
" .endr ;"
" blr ;"
);
/* Assemble the body code between the prologue & epilogue */
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
u32 *addrs, bool extra_pass)
{
enum stf_barrier_type stf_barrier = stf_barrier_type_get();
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, dst_reg);
if (src_reg >= BPF_PPC_NVR_MIN && src_reg < 32)
bpf_set_seen_register(ctx, 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 */
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_SUB(dst_reg, dst_reg, src_reg));
goto bpf_alu32_trunc;
case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */
case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */
if (!imm) {
goto bpf_alu32_trunc;
} else if (imm >= -32768 && imm < 32768) {
EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm)));
} else {
PPC_LI32(b2p[TMP_REG_1], imm);
EMIT(PPC_RAW_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]));
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */
if (!imm) {
goto bpf_alu32_trunc;
} else if (imm > -32768 && imm <= 32768) {
EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(-imm)));
} else {
PPC_LI32(b2p[TMP_REG_1], imm);
EMIT(PPC_RAW_SUB(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)
EMIT(PPC_RAW_MULW(dst_reg, dst_reg, src_reg));
else
EMIT(PPC_RAW_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)
EMIT(PPC_RAW_MULI(dst_reg, dst_reg, IMM_L(imm)));
else {
PPC_LI32(b2p[TMP_REG_1], imm);
if (BPF_CLASS(code) == BPF_ALU)
EMIT(PPC_RAW_MULW(dst_reg, dst_reg,
b2p[TMP_REG_1]));
else
EMIT(PPC_RAW_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) {
EMIT(PPC_RAW_DIVWU(b2p[TMP_REG_1], dst_reg, src_reg));
EMIT(PPC_RAW_MULW(b2p[TMP_REG_1], src_reg,
b2p[TMP_REG_1]));
EMIT(PPC_RAW_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]));
} else
EMIT(PPC_RAW_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) {
EMIT(PPC_RAW_DIVDU(b2p[TMP_REG_1], dst_reg, src_reg));
EMIT(PPC_RAW_MULD(b2p[TMP_REG_1], src_reg,
b2p[TMP_REG_1]));
EMIT(PPC_RAW_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]));
} else
EMIT(PPC_RAW_DIVDU(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;
if (imm == 1) {
if (BPF_OP(code) == BPF_DIV) {
goto bpf_alu32_trunc;
} else {
EMIT(PPC_RAW_LI(dst_reg, 0));
break;
}
}
PPC_LI32(b2p[TMP_REG_1], imm);
switch (BPF_CLASS(code)) {
case BPF_ALU:
if (BPF_OP(code) == BPF_MOD) {
EMIT(PPC_RAW_DIVWU(b2p[TMP_REG_2],
dst_reg,
b2p[TMP_REG_1]));
EMIT(PPC_RAW_MULW(b2p[TMP_REG_1],
b2p[TMP_REG_1],
b2p[TMP_REG_2]));
EMIT(PPC_RAW_SUB(dst_reg, dst_reg,
b2p[TMP_REG_1]));
} else
EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg,
b2p[TMP_REG_1]));
break;
case BPF_ALU64:
if (BPF_OP(code) == BPF_MOD) {
EMIT(PPC_RAW_DIVDU(b2p[TMP_REG_2],
dst_reg,
b2p[TMP_REG_1]));
EMIT(PPC_RAW_MULD(b2p[TMP_REG_1],
b2p[TMP_REG_1],
b2p[TMP_REG_2]));
EMIT(PPC_RAW_SUB(dst_reg, dst_reg,
b2p[TMP_REG_1]));
} else
EMIT(PPC_RAW_DIVDU(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 */
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_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))
EMIT(PPC_RAW_ANDI(dst_reg, dst_reg, IMM_L(imm)));
else {
/* Sign-extended */
PPC_LI32(b2p[TMP_REG_1], imm);
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_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);
EMIT(PPC_RAW_OR(dst_reg, dst_reg, b2p[TMP_REG_1]));
} else {
if (IMM_L(imm))
EMIT(PPC_RAW_ORI(dst_reg, dst_reg, IMM_L(imm)));
if (IMM_H(imm))
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_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);
EMIT(PPC_RAW_XOR(dst_reg, dst_reg, b2p[TMP_REG_1]));
} else {
if (IMM_L(imm))
EMIT(PPC_RAW_XORI(dst_reg, dst_reg, IMM_L(imm)));
if (IMM_H(imm))
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_SLW(dst_reg, dst_reg, src_reg));
/* skip zero extension move, but set address map. */
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
case BPF_ALU64 | BPF_LSH | BPF_X: /* dst <<= src; */
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_SLWI(dst_reg, dst_reg, imm));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
case BPF_ALU64 | BPF_LSH | BPF_K: /* dst <<== imm */
if (imm != 0)
EMIT(PPC_RAW_SLDI(dst_reg, dst_reg, imm));
break;
case BPF_ALU | BPF_RSH | BPF_X: /* (u32) dst >>= (u32) src */
EMIT(PPC_RAW_SRW(dst_reg, dst_reg, src_reg));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
case BPF_ALU64 | BPF_RSH | BPF_X: /* dst >>= src */
EMIT(PPC_RAW_SRD(dst_reg, dst_reg, src_reg));
break;
case BPF_ALU | BPF_RSH | BPF_K: /* (u32) dst >>= (u32) imm */
EMIT(PPC_RAW_SRWI(dst_reg, dst_reg, imm));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
case BPF_ALU64 | BPF_RSH | BPF_K: /* dst >>= imm */
if (imm != 0)
EMIT(PPC_RAW_SRDI(dst_reg, dst_reg, imm));
break;
case BPF_ALU | BPF_ARSH | BPF_X: /* (s32) dst >>= src */
EMIT(PPC_RAW_SRAW(dst_reg, dst_reg, src_reg));
goto bpf_alu32_trunc;
case BPF_ALU64 | BPF_ARSH | BPF_X: /* (s64) dst >>= src */
EMIT(PPC_RAW_SRAD(dst_reg, dst_reg, src_reg));
break;
case BPF_ALU | BPF_ARSH | BPF_K: /* (s32) dst >>= imm */
EMIT(PPC_RAW_SRAWI(dst_reg, dst_reg, imm));
goto bpf_alu32_trunc;
case BPF_ALU64 | BPF_ARSH | BPF_K: /* (s64) dst >>= imm */
if (imm != 0)
EMIT(PPC_RAW_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 */
if (imm == 1) {
/* special mov32 for zext */
EMIT(PPC_RAW_RLWINM(dst_reg, dst_reg, 0, 0, 31));
break;
}
EMIT(PPC_RAW_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;
else if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
bpf_alu32_trunc:
/* Truncate to 32-bits */
if (BPF_CLASS(code) == BPF_ALU && !fp->aux->verifier_zext)
EMIT(PPC_RAW_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 */
EMIT(PPC_RAW_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 16, 23));
/* Rotate 8 bits right & insert LSB to reg */
EMIT(PPC_RAW_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 24, 31));
/* Move result back to dst_reg */
EMIT(PPC_RAW_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)
*/
EMIT(PPC_RAW_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 0, 31));
/* Rotate 24 bits and insert byte 1 */
EMIT(PPC_RAW_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 0, 7));
/* Rotate 24 bits and insert byte 3 */
EMIT(PPC_RAW_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 16, 23));
EMIT(PPC_RAW_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_BPF_STL(dst_reg, 1, bpf_jit_stack_local(ctx));
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], 1, bpf_jit_stack_local(ctx)));
EMIT(PPC_RAW_LDBRX(dst_reg, 0, b2p[TMP_REG_1]));
break;
}
break;
emit_clear:
switch (imm) {
case 16:
/* zero-extend 16 bits into 64 bits */
EMIT(PPC_RAW_RLDICL(dst_reg, dst_reg, 0, 48));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
case 32:
if (!fp->aux->verifier_zext)
/* zero-extend 32 bits into 64 bits */
EMIT(PPC_RAW_RLDICL(dst_reg, dst_reg, 0, 32));
break;
case 64:
/* nop */
break;
}
break;
/*
* BPF_ST NOSPEC (speculation barrier)
*/
case BPF_ST | BPF_NOSPEC:
if (!security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) ||
!security_ftr_enabled(SEC_FTR_STF_BARRIER))
break;
switch (stf_barrier) {
case STF_BARRIER_EIEIO:
EMIT(PPC_RAW_EIEIO() | 0x02000000);
break;
case STF_BARRIER_SYNC_ORI:
EMIT(PPC_RAW_SYNC());
EMIT(PPC_RAW_LD(b2p[TMP_REG_1], _R13, 0));
EMIT(PPC_RAW_ORI(_R31, _R31, 0));
break;
case STF_BARRIER_FALLBACK:
EMIT(PPC_RAW_MFLR(b2p[TMP_REG_1]));
PPC_LI64(12, dereference_kernel_function_descriptor(bpf_stf_barrier));
EMIT(PPC_RAW_MTCTR(12));
EMIT(PPC_RAW_BCTRL());
EMIT(PPC_RAW_MTLR(b2p[TMP_REG_1]));
break;
case STF_BARRIER_NONE:
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) {
EMIT(PPC_RAW_LI(b2p[TMP_REG_1], imm));
src_reg = b2p[TMP_REG_1];
}
EMIT(PPC_RAW_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) {
EMIT(PPC_RAW_LI(b2p[TMP_REG_1], imm));
src_reg = b2p[TMP_REG_1];
}
EMIT(PPC_RAW_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];
}
EMIT(PPC_RAW_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_BPF_STL(src_reg, dst_reg, off);
break;
/*
* BPF_STX ATOMIC (atomic ops)
*/
case BPF_STX | BPF_ATOMIC | BPF_W:
if (imm != BPF_ADD) {
pr_err_ratelimited(
"eBPF filter atomic op code %02x (@%d) unsupported\n",
code, i);
return -ENOTSUPP;
}
/* *(u32 *)(dst + off) += src */
/* Get EA into TMP_REG_1 */
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], dst_reg, off));
tmp_idx = ctx->idx * 4;
/* load value from memory into TMP_REG_2 */
EMIT(PPC_RAW_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0));
/* add value from src_reg into this */
EMIT(PPC_RAW_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
/* store result back */
EMIT(PPC_RAW_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]));
/* we're done if this succeeded */
PPC_BCC_SHORT(COND_NE, tmp_idx);
break;
case BPF_STX | BPF_ATOMIC | BPF_DW:
if (imm != BPF_ADD) {
pr_err_ratelimited(
"eBPF filter atomic op code %02x (@%d) unsupported\n",
code, i);
return -ENOTSUPP;
}
/* *(u64 *)(dst + off) += src */
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], dst_reg, off));
tmp_idx = ctx->idx * 4;
EMIT(PPC_RAW_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0));
EMIT(PPC_RAW_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
EMIT(PPC_RAW_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:
EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
/* dst = *(u16 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_H:
EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
/* dst = *(u32 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_W:
EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
if (insn_is_zext(&insn[i + 1]))
addrs[++i] = ctx->idx * 4;
break;
/* dst = *(u64 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_DW:
PPC_BPF_LL(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 */
EMIT(PPC_RAW_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:
case BPF_JMP32 | BPF_JGT | BPF_K:
case BPF_JMP32 | BPF_JGT | BPF_X:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_X:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JLE | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JSET | BPF_K:
case BPF_JMP32 | 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:
case BPF_JMP32 | BPF_JGT | BPF_X:
case BPF_JMP32 | BPF_JLT | BPF_X:
case BPF_JMP32 | BPF_JGE | BPF_X:
case BPF_JMP32 | BPF_JLE | BPF_X:
case BPF_JMP32 | BPF_JEQ | BPF_X:
case BPF_JMP32 | BPF_JNE | BPF_X:
/* unsigned comparison */
if (BPF_CLASS(code) == BPF_JMP32)
EMIT(PPC_RAW_CMPLW(dst_reg, src_reg));
else
EMIT(PPC_RAW_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:
case BPF_JMP32 | BPF_JSGT | BPF_X:
case BPF_JMP32 | BPF_JSLT | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_X:
/* signed comparison */
if (BPF_CLASS(code) == BPF_JMP32)
EMIT(PPC_RAW_CMPW(dst_reg, src_reg));
else
EMIT(PPC_RAW_CMPD(dst_reg, src_reg));
break;
case BPF_JMP | BPF_JSET | BPF_X:
case BPF_JMP32 | BPF_JSET | BPF_X:
if (BPF_CLASS(code) == BPF_JMP) {
EMIT(PPC_RAW_AND_DOT(b2p[TMP_REG_1], dst_reg,
src_reg));
} else {
int tmp_reg = b2p[TMP_REG_1];
EMIT(PPC_RAW_AND(tmp_reg, dst_reg, src_reg));
EMIT(PPC_RAW_RLWINM_DOT(tmp_reg, tmp_reg, 0, 0,
31));
}
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:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP32 | BPF_JGT | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_K:
{
bool is_jmp32 = BPF_CLASS(code) == BPF_JMP32;
/*
* Need sign-extended load, so only positive
* values can be used as imm in cmpldi
*/
if (imm >= 0 && imm < 32768) {
if (is_jmp32)
EMIT(PPC_RAW_CMPLWI(dst_reg, imm));
else
EMIT(PPC_RAW_CMPLDI(dst_reg, imm));
} else {
/* sign-extending load */
PPC_LI32(b2p[TMP_REG_1], imm);
/* ... but unsigned comparison */
if (is_jmp32)
EMIT(PPC_RAW_CMPLW(dst_reg,
b2p[TMP_REG_1]));
else
EMIT(PPC_RAW_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:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_K:
{
bool is_jmp32 = BPF_CLASS(code) == BPF_JMP32;
/*
* signed comparison, so any 16-bit value
* can be used in cmpdi
*/
if (imm >= -32768 && imm < 32768) {
if (is_jmp32)
EMIT(PPC_RAW_CMPWI(dst_reg, imm));
else
EMIT(PPC_RAW_CMPDI(dst_reg, imm));
} else {
PPC_LI32(b2p[TMP_REG_1], imm);
if (is_jmp32)
EMIT(PPC_RAW_CMPW(dst_reg,
b2p[TMP_REG_1]));
else
EMIT(PPC_RAW_CMPD(dst_reg,
b2p[TMP_REG_1]));
}
break;
}
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_K:
/* andi does not sign-extend the immediate */
if (imm >= 0 && imm < 32768)
/* PPC_ANDI is _only/always_ dot-form */
EMIT(PPC_RAW_ANDI(b2p[TMP_REG_1], dst_reg, imm));
else {
int tmp_reg = b2p[TMP_REG_1];
PPC_LI32(tmp_reg, imm);
if (BPF_CLASS(code) == BPF_JMP) {
EMIT(PPC_RAW_AND_DOT(tmp_reg, dst_reg,
tmp_reg));
} else {
EMIT(PPC_RAW_AND(tmp_reg, dst_reg,
tmp_reg));
EMIT(PPC_RAW_RLWINM_DOT(tmp_reg, tmp_reg,
0, 0, 31));
}
}
break;
}
PPC_BCC(true_cond, addrs[i + 1 + off]);
break;
/*
* Tail call
*/
case BPF_JMP | BPF_TAIL_CALL:
ctx->seen |= SEEN_TAILCALL;
ret = bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]);
if (ret < 0)
return ret;
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;
}
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