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-rw-r--r--arch/powerpc/net/bpf_jit_comp.c893
1 files changed, 285 insertions, 608 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index d57b46e0dd60..0f9a21783329 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -1,10 +1,11 @@
// SPDX-License-Identifier: GPL-2.0-only
-/* bpf_jit_comp.c: BPF JIT compiler
+/*
+ * eBPF JIT compiler
*
- * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
+ * Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
+ * IBM Corporation
*
- * Based on the x86 BPF compiler, by Eric Dumazet (eric.dumazet@gmail.com)
- * Ported to ppc32 by Denis Kirjanov <kda@linux-powerpc.org>
+ * Based on the powerpc classic BPF JIT compiler by Matt Evans
*/
#include <linux/moduleloader.h>
#include <asm/cacheflush.h>
@@ -12,640 +13,193 @@
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/if_vlan.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/bpf.h>
-#include "bpf_jit32.h"
+#include <asm/kprobes.h>
+#include <asm/code-patching.h>
-static inline void bpf_flush_icache(void *start, void *end)
+#include "bpf_jit.h"
+
+static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
{
- smp_wmb();
- flush_icache_range((unsigned long)start, (unsigned long)end);
+ memset32(area, BREAKPOINT_INSTRUCTION, size / 4);
}
-static void bpf_jit_build_prologue(struct bpf_prog *fp, u32 *image,
- struct codegen_context *ctx)
+int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr)
{
- int i;
- const struct sock_filter *filter = fp->insns;
-
- if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
- /* Make stackframe */
- if (ctx->seen & SEEN_DATAREF) {
- /* If we call any helpers (for loads), save LR */
- EMIT(PPC_INST_MFLR | __PPC_RT(R0));
- PPC_BPF_STL(0, 1, PPC_LR_STKOFF);
-
- /* Back up non-volatile regs. */
- PPC_BPF_STL(r_D, 1, -(REG_SZ*(32-r_D)));
- PPC_BPF_STL(r_HL, 1, -(REG_SZ*(32-r_HL)));
- }
- if (ctx->seen & SEEN_MEM) {
- /*
- * Conditionally save regs r15-r31 as some will be used
- * for M[] data.
- */
- for (i = r_M; i < (r_M+16); i++) {
- if (ctx->seen & (1 << (i-r_M)))
- PPC_BPF_STL(i, 1, -(REG_SZ*(32-i)));
- }
- }
- PPC_BPF_STLU(1, 1, -BPF_PPC_STACKFRAME);
- }
-
- if (ctx->seen & SEEN_DATAREF) {
- /*
- * If this filter needs to access skb data,
- * prepare r_D and r_HL:
- * r_HL = skb->len - skb->data_len
- * r_D = skb->data
- */
- PPC_LWZ_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
- data_len));
- PPC_LWZ_OFFS(r_HL, r_skb, offsetof(struct sk_buff, len));
- PPC_SUB(r_HL, r_HL, r_scratch1);
- PPC_LL_OFFS(r_D, r_skb, offsetof(struct sk_buff, data));
- }
-
- if (ctx->seen & SEEN_XREG) {
- /*
- * TODO: Could also detect whether first instr. sets X and
- * avoid this (as below, with A).
- */
- PPC_LI(r_X, 0);
+ if (!exit_addr || is_offset_in_branch_range(exit_addr - (ctx->idx * 4))) {
+ PPC_JMP(exit_addr);
+ } else if (ctx->alt_exit_addr) {
+ if (WARN_ON(!is_offset_in_branch_range((long)ctx->alt_exit_addr - (ctx->idx * 4))))
+ return -1;
+ PPC_JMP(ctx->alt_exit_addr);
+ } else {
+ ctx->alt_exit_addr = ctx->idx * 4;
+ bpf_jit_build_epilogue(image, ctx);
}
- /* make sure we dont leak kernel information to user */
- if (bpf_needs_clear_a(&filter[0]))
- PPC_LI(r_A, 0);
+ return 0;
}
-static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
+struct powerpc_jit_data {
+ /* address of rw header */
+ struct bpf_binary_header *hdr;
+ /* address of ro final header */
+ struct bpf_binary_header *fhdr;
+ u32 *addrs;
+ u8 *fimage;
+ u32 proglen;
+ struct codegen_context ctx;
+};
+
+bool bpf_jit_needs_zext(void)
{
- int i;
-
- if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
- PPC_ADDI(1, 1, BPF_PPC_STACKFRAME);
- if (ctx->seen & SEEN_DATAREF) {
- PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
- PPC_MTLR(0);
- PPC_BPF_LL(r_D, 1, -(REG_SZ*(32-r_D)));
- PPC_BPF_LL(r_HL, 1, -(REG_SZ*(32-r_HL)));
- }
- if (ctx->seen & SEEN_MEM) {
- /* Restore any saved non-vol registers */
- for (i = r_M; i < (r_M+16); i++) {
- if (ctx->seen & (1 << (i-r_M)))
- PPC_BPF_LL(i, 1, -(REG_SZ*(32-i)));
- }
- }
- }
- /* The RETs have left a return value in R3. */
-
- PPC_BLR();
+ return true;
}
-#define CHOOSE_LOAD_FUNC(K, func) \
- ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
-
-/* Assemble the body code between the prologue & epilogue. */
-static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
- struct codegen_context *ctx,
- unsigned int *addrs)
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
{
- const struct sock_filter *filter = fp->insns;
- int flen = fp->len;
- u8 *func;
- unsigned int true_cond;
- int i;
-
- /* Start of epilogue code */
- unsigned int exit_addr = addrs[flen];
+ u32 proglen;
+ u32 alloclen;
+ u8 *image = NULL;
+ u32 *code_base;
+ u32 *addrs;
+ struct powerpc_jit_data *jit_data;
+ struct codegen_context cgctx;
+ int pass;
+ int flen;
+ struct bpf_binary_header *fhdr = NULL;
+ struct bpf_binary_header *hdr = NULL;
+ struct bpf_prog *org_fp = fp;
+ struct bpf_prog *tmp_fp;
+ bool bpf_blinded = false;
+ bool extra_pass = false;
+ u8 *fimage = NULL;
+ u32 *fcode_base;
+ u32 extable_len;
+ u32 fixup_len;
+
+ 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;
+ }
- for (i = 0; i < flen; i++) {
- unsigned int K = filter[i].k;
- u16 code = bpf_anc_helper(&filter[i]);
+ 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;
/*
- * addrs[] maps a BPF bytecode address into a real offset from
- * the start of the body code.
+ * JIT compiled to a writable location (image/code_base) first.
+ * It is then moved to the readonly final location (fimage/fcode_base)
+ * using instruction patching.
*/
- addrs[i] = ctx->idx * 4;
-
- switch (code) {
- /*** ALU ops ***/
- case BPF_ALU | BPF_ADD | BPF_X: /* A += X; */
- ctx->seen |= SEEN_XREG;
- PPC_ADD(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_ADD | BPF_K: /* A += K; */
- if (!K)
- break;
- PPC_ADDI(r_A, r_A, IMM_L(K));
- if (K >= 32768)
- PPC_ADDIS(r_A, r_A, IMM_HA(K));
- break;
- case BPF_ALU | BPF_SUB | BPF_X: /* A -= X; */
- ctx->seen |= SEEN_XREG;
- PPC_SUB(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_SUB | BPF_K: /* A -= K */
- if (!K)
- break;
- PPC_ADDI(r_A, r_A, IMM_L(-K));
- if (K >= 32768)
- PPC_ADDIS(r_A, r_A, IMM_HA(-K));
- break;
- case BPF_ALU | BPF_MUL | BPF_X: /* A *= X; */
- ctx->seen |= SEEN_XREG;
- PPC_MULW(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_MUL | BPF_K: /* A *= K */
- if (K < 32768)
- PPC_MULI(r_A, r_A, K);
- else {
- PPC_LI32(r_scratch1, K);
- PPC_MULW(r_A, r_A, r_scratch1);
- }
- break;
- case BPF_ALU | BPF_MOD | BPF_X: /* A %= X; */
- case BPF_ALU | BPF_DIV | BPF_X: /* A /= X; */
- ctx->seen |= SEEN_XREG;
- PPC_CMPWI(r_X, 0);
- if (ctx->pc_ret0 != -1) {
- PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
- } else {
- PPC_BCC_SHORT(COND_NE, (ctx->idx*4)+12);
- PPC_LI(r_ret, 0);
- PPC_JMP(exit_addr);
- }
- if (code == (BPF_ALU | BPF_MOD | BPF_X)) {
- PPC_DIVWU(r_scratch1, r_A, r_X);
- PPC_MULW(r_scratch1, r_X, r_scratch1);
- PPC_SUB(r_A, r_A, r_scratch1);
- } else {
- PPC_DIVWU(r_A, r_A, r_X);
- }
- break;
- case BPF_ALU | BPF_MOD | BPF_K: /* A %= K; */
- PPC_LI32(r_scratch2, K);
- PPC_DIVWU(r_scratch1, r_A, r_scratch2);
- PPC_MULW(r_scratch1, r_scratch2, r_scratch1);
- PPC_SUB(r_A, r_A, r_scratch1);
- break;
- case BPF_ALU | BPF_DIV | BPF_K: /* A /= K */
- if (K == 1)
- break;
- PPC_LI32(r_scratch1, K);
- PPC_DIVWU(r_A, r_A, r_scratch1);
- break;
- case BPF_ALU | BPF_AND | BPF_X:
- ctx->seen |= SEEN_XREG;
- PPC_AND(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_AND | BPF_K:
- if (!IMM_H(K))
- PPC_ANDI(r_A, r_A, K);
- else {
- PPC_LI32(r_scratch1, K);
- PPC_AND(r_A, r_A, r_scratch1);
- }
- break;
- case BPF_ALU | BPF_OR | BPF_X:
- ctx->seen |= SEEN_XREG;
- PPC_OR(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_OR | BPF_K:
- if (IMM_L(K))
- PPC_ORI(r_A, r_A, IMM_L(K));
- if (K >= 65536)
- PPC_ORIS(r_A, r_A, IMM_H(K));
- break;
- case BPF_ANC | SKF_AD_ALU_XOR_X:
- case BPF_ALU | BPF_XOR | BPF_X: /* A ^= X */
- ctx->seen |= SEEN_XREG;
- PPC_XOR(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_XOR | BPF_K: /* A ^= K */
- if (IMM_L(K))
- PPC_XORI(r_A, r_A, IMM_L(K));
- if (K >= 65536)
- PPC_XORIS(r_A, r_A, IMM_H(K));
- break;
- case BPF_ALU | BPF_LSH | BPF_X: /* A <<= X; */
- ctx->seen |= SEEN_XREG;
- PPC_SLW(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_LSH | BPF_K:
- if (K == 0)
- break;
- else
- PPC_SLWI(r_A, r_A, K);
- break;
- case BPF_ALU | BPF_RSH | BPF_X: /* A >>= X; */
- ctx->seen |= SEEN_XREG;
- PPC_SRW(r_A, r_A, r_X);
- break;
- case BPF_ALU | BPF_RSH | BPF_K: /* A >>= K; */
- if (K == 0)
- break;
- else
- PPC_SRWI(r_A, r_A, K);
- break;
- case BPF_ALU | BPF_NEG:
- PPC_NEG(r_A, r_A);
- break;
- case BPF_RET | BPF_K:
- PPC_LI32(r_ret, K);
- if (!K) {
- if (ctx->pc_ret0 == -1)
- ctx->pc_ret0 = i;
- }
- /*
- * If this isn't the very last instruction, branch to
- * the epilogue if we've stuff to clean up. Otherwise,
- * if there's nothing to tidy, just return. If we /are/
- * the last instruction, we're about to fall through to
- * the epilogue to return.
- */
- if (i != flen - 1) {
- /*
- * Note: 'seen' is properly valid only on pass
- * #2. Both parts of this conditional are the
- * same instruction size though, meaning the
- * first pass will still correctly determine the
- * code size/addresses.
- */
- if (ctx->seen)
- PPC_JMP(exit_addr);
- else
- PPC_BLR();
- }
- break;
- case BPF_RET | BPF_A:
- PPC_MR(r_ret, r_A);
- if (i != flen - 1) {
- if (ctx->seen)
- PPC_JMP(exit_addr);
- else
- PPC_BLR();
- }
- break;
- case BPF_MISC | BPF_TAX: /* X = A */
- PPC_MR(r_X, r_A);
- break;
- case BPF_MISC | BPF_TXA: /* A = X */
- ctx->seen |= SEEN_XREG;
- PPC_MR(r_A, r_X);
- break;
-
- /*** Constant loads/M[] access ***/
- case BPF_LD | BPF_IMM: /* A = K */
- PPC_LI32(r_A, K);
- break;
- case BPF_LDX | BPF_IMM: /* X = K */
- PPC_LI32(r_X, K);
- break;
- case BPF_LD | BPF_MEM: /* A = mem[K] */
- PPC_MR(r_A, r_M + (K & 0xf));
- ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_LDX | BPF_MEM: /* X = mem[K] */
- PPC_MR(r_X, r_M + (K & 0xf));
- ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_ST: /* mem[K] = A */
- PPC_MR(r_M + (K & 0xf), r_A);
- ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_STX: /* mem[K] = X */
- PPC_MR(r_M + (K & 0xf), r_X);
- ctx->seen |= SEEN_XREG | SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_LD | BPF_W | BPF_LEN: /* A = skb->len; */
- BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
- PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff, len));
- break;
- case BPF_LDX | BPF_W | BPF_ABS: /* A = *((u32 *)(seccomp_data + K)); */
- PPC_LWZ_OFFS(r_A, r_skb, K);
- break;
- case BPF_LDX | BPF_W | BPF_LEN: /* X = skb->len; */
- PPC_LWZ_OFFS(r_X, r_skb, offsetof(struct sk_buff, len));
- break;
-
- /*** Ancillary info loads ***/
- case BPF_ANC | SKF_AD_PROTOCOL: /* A = ntohs(skb->protocol); */
- BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
- protocol) != 2);
- PPC_NTOHS_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- protocol));
- break;
- case BPF_ANC | SKF_AD_IFINDEX:
- case BPF_ANC | SKF_AD_HATYPE:
- BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
- ifindex) != 4);
- BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
- type) != 2);
- PPC_LL_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
- dev));
- PPC_CMPDI(r_scratch1, 0);
- if (ctx->pc_ret0 != -1) {
- PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
- } else {
- /* Exit, returning 0; first pass hits here. */
- PPC_BCC_SHORT(COND_NE, ctx->idx * 4 + 12);
- PPC_LI(r_ret, 0);
- PPC_JMP(exit_addr);
- }
- if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
- PPC_LWZ_OFFS(r_A, r_scratch1,
- offsetof(struct net_device, ifindex));
- } else {
- PPC_LHZ_OFFS(r_A, r_scratch1,
- offsetof(struct net_device, type));
- }
-
- break;
- case BPF_ANC | SKF_AD_MARK:
- BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
- PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- mark));
- break;
- case BPF_ANC | SKF_AD_RXHASH:
- BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
- PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- hash));
- break;
- case BPF_ANC | SKF_AD_VLAN_TAG:
- BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
-
- PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- vlan_tci));
- break;
- case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
- PPC_LBZ_OFFS(r_A, r_skb, PKT_VLAN_PRESENT_OFFSET());
- if (PKT_VLAN_PRESENT_BIT)
- PPC_SRWI(r_A, r_A, PKT_VLAN_PRESENT_BIT);
- if (PKT_VLAN_PRESENT_BIT < 7)
- PPC_ANDI(r_A, r_A, 1);
- break;
- case BPF_ANC | SKF_AD_QUEUE:
- BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
- queue_mapping) != 2);
- PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- queue_mapping));
- break;
- case BPF_ANC | SKF_AD_PKTTYPE:
- PPC_LBZ_OFFS(r_A, r_skb, PKT_TYPE_OFFSET());
- PPC_ANDI(r_A, r_A, PKT_TYPE_MAX);
- PPC_SRWI(r_A, r_A, 5);
- break;
- case BPF_ANC | SKF_AD_CPU:
- PPC_BPF_LOAD_CPU(r_A);
- break;
- /*** Absolute loads from packet header/data ***/
- case BPF_LD | BPF_W | BPF_ABS:
- func = CHOOSE_LOAD_FUNC(K, sk_load_word);
- goto common_load;
- case BPF_LD | BPF_H | BPF_ABS:
- func = CHOOSE_LOAD_FUNC(K, sk_load_half);
- goto common_load;
- case BPF_LD | BPF_B | BPF_ABS:
- func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
- common_load:
- /* Load from [K]. */
- ctx->seen |= SEEN_DATAREF;
- PPC_FUNC_ADDR(r_scratch1, func);
- PPC_MTLR(r_scratch1);
- PPC_LI32(r_addr, K);
- PPC_BLRL();
- /*
- * Helper returns 'lt' condition on error, and an
- * appropriate return value in r3
- */
- PPC_BCC(COND_LT, exit_addr);
- break;
-
- /*** Indirect loads from packet header/data ***/
- case BPF_LD | BPF_W | BPF_IND:
- func = sk_load_word;
- goto common_load_ind;
- case BPF_LD | BPF_H | BPF_IND:
- func = sk_load_half;
- goto common_load_ind;
- case BPF_LD | BPF_B | BPF_IND:
- func = sk_load_byte;
- common_load_ind:
- /*
- * Load from [X + K]. Negative offsets are tested for
- * in the helper functions.
- */
- ctx->seen |= SEEN_DATAREF | SEEN_XREG;
- PPC_FUNC_ADDR(r_scratch1, func);
- PPC_MTLR(r_scratch1);
- PPC_ADDI(r_addr, r_X, IMM_L(K));
- if (K >= 32768)
- PPC_ADDIS(r_addr, r_addr, IMM_HA(K));
- PPC_BLRL();
- /* If error, cr0.LT set */
- PPC_BCC(COND_LT, exit_addr);
- break;
-
- case BPF_LDX | BPF_B | BPF_MSH:
- func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
- goto common_load;
- break;
-
- /*** Jump and branches ***/
- case BPF_JMP | BPF_JA:
- if (K != 0)
- PPC_JMP(addrs[i + 1 + K]);
- break;
-
- case BPF_JMP | BPF_JGT | BPF_K:
- case BPF_JMP | BPF_JGT | BPF_X:
- true_cond = COND_GT;
- goto cond_branch;
- case BPF_JMP | BPF_JGE | BPF_K:
- case BPF_JMP | BPF_JGE | BPF_X:
- true_cond = COND_GE;
- 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_JSET | BPF_K:
- case BPF_JMP | BPF_JSET | BPF_X:
- true_cond = COND_NE;
- /* Fall through */
- cond_branch:
- /* same targets, can avoid doing the test :) */
- if (filter[i].jt == filter[i].jf) {
- if (filter[i].jt > 0)
- PPC_JMP(addrs[i + 1 + filter[i].jt]);
- break;
- }
-
- switch (code) {
- case BPF_JMP | BPF_JGT | BPF_X:
- case BPF_JMP | BPF_JGE | BPF_X:
- case BPF_JMP | BPF_JEQ | BPF_X:
- ctx->seen |= SEEN_XREG;
- PPC_CMPLW(r_A, r_X);
- break;
- case BPF_JMP | BPF_JSET | BPF_X:
- ctx->seen |= SEEN_XREG;
- PPC_AND_DOT(r_scratch1, r_A, r_X);
- break;
- case BPF_JMP | BPF_JEQ | BPF_K:
- case BPF_JMP | BPF_JGT | BPF_K:
- case BPF_JMP | BPF_JGE | BPF_K:
- if (K < 32768)
- PPC_CMPLWI(r_A, K);
- else {
- PPC_LI32(r_scratch1, K);
- PPC_CMPLW(r_A, r_scratch1);
- }
- break;
- case BPF_JMP | BPF_JSET | BPF_K:
- if (K < 32768)
- /* PPC_ANDI is /only/ dot-form */
- PPC_ANDI(r_scratch1, r_A, K);
- else {
- PPC_LI32(r_scratch1, K);
- PPC_AND_DOT(r_scratch1, r_A,
- r_scratch1);
- }
- break;
- }
- /* Sometimes branches are constructed "backward", with
- * the false path being the branch and true path being
- * a fallthrough to the next instruction.
- */
- if (filter[i].jt == 0)
- /* Swap the sense of the branch */
- PPC_BCC(true_cond ^ COND_CMP_TRUE,
- addrs[i + 1 + filter[i].jf]);
- else {
- PPC_BCC(true_cond, addrs[i + 1 + filter[i].jt]);
- if (filter[i].jf != 0)
- PPC_JMP(addrs[i + 1 + filter[i].jf]);
- }
- break;
- default:
- /* The filter contains something cruel & unusual.
- * We don't handle it, but also there shouldn't be
- * anything missing from our list.
- */
- if (printk_ratelimit())
- pr_err("BPF filter opcode %04x (@%d) unsupported\n",
- filter[i].code, i);
- return -ENOTSUPP;
- }
-
+ fimage = jit_data->fimage;
+ fhdr = jit_data->fhdr;
+ proglen = jit_data->proglen;
+ hdr = jit_data->hdr;
+ image = (void *)hdr + ((void *)fimage - (void *)fhdr);
+ extra_pass = true;
+ /* During extra pass, ensure index is reset before repopulating extable entries */
+ cgctx.exentry_idx = 0;
+ goto skip_init_ctx;
}
- /* Set end-of-body-code address for exit. */
- addrs[i] = ctx->idx * 4;
- return 0;
-}
+ addrs = kcalloc(flen + 1, sizeof(*addrs), GFP_KERNEL);
+ if (addrs == NULL) {
+ fp = org_fp;
+ goto out_addrs;
+ }
-void bpf_jit_compile(struct bpf_prog *fp)
-{
- unsigned int proglen;
- unsigned int alloclen;
- u32 *image = NULL;
- u32 *code_base;
- unsigned int *addrs;
- struct codegen_context cgctx;
- int pass;
- int flen = fp->len;
+ memset(&cgctx, 0, sizeof(struct codegen_context));
+ bpf_jit_init_reg_mapping(&cgctx);
- if (!bpf_jit_enable)
- return;
+ /* Make sure that the stack is quadword aligned. */
+ cgctx.stack_size = round_up(fp->aux->stack_depth, 16);
- addrs = kcalloc(flen + 1, sizeof(*addrs), GFP_KERNEL);
- if (addrs == NULL)
- return;
+ /* Scouting faux-generate pass 0 */
+ if (bpf_jit_build_body(fp, NULL, NULL, &cgctx, addrs, 0, false)) {
+ /* We hit something illegal or unsupported. */
+ fp = org_fp;
+ goto out_addrs;
+ }
/*
- * There are multiple assembly passes as the generated code will change
- * size as it settles down, figuring out the max branch offsets/exit
- * paths required.
- *
- * The range of standard conditional branches is +/- 32Kbytes. Since
- * BPF_MAXINSNS = 4096, we can only jump from (worst case) start to
- * finish with 8 bytes/instruction. Not feasible, so long jumps are
- * used, distinct from short branches.
- *
- * Current:
- *
- * For now, both branch types assemble to 2 words (short branches padded
- * with a NOP); this is less efficient, but assembly will always complete
- * after exactly 3 passes:
- *
- * First pass: No code buffer; Program is "faux-generated" -- no code
- * emitted but maximum size of output determined (and addrs[] filled
- * in). Also, we note whether we use M[], whether we use skb data, etc.
- * All generation choices assumed to be 'worst-case', e.g. branches all
- * far (2 instructions), return path code reduction not available, etc.
- *
- * Second pass: Code buffer allocated with size determined previously.
- * Prologue generated to support features we have seen used. Exit paths
- * determined and addrs[] is filled in again, as code may be slightly
- * smaller as a result.
- *
- * Third pass: Code generated 'for real', and branch destinations
- * determined from now-accurate addrs[] map.
- *
- * Ideal:
- *
- * If we optimise this, near branches will be shorter. On the
- * first assembly pass, we should err on the side of caution and
- * generate the biggest code. On subsequent passes, branches will be
- * generated short or long and code size will reduce. With smaller
- * code, more branches may fall into the short category, and code will
- * reduce more.
- *
- * Finally, if we see one pass generate code the same size as the
- * previous pass we have converged and should now generate code for
- * real. Allocating at the end will also save the memory that would
- * otherwise be wasted by the (small) current code shrinkage.
- * Preferably, we should do a small number of passes (e.g. 5) and if we
- * haven't converged by then, get impatient and force code to generate
- * as-is, even if the odd branch would be left long. The chances of a
- * long jump are tiny with all but the most enormous of BPF filter
- * inputs, so we should usually converge on the third pass.
+ * If we have seen a tail call, we need a second pass.
+ * This is because bpf_jit_emit_common_epilogue() is called
+ * from bpf_jit_emit_tail_call() with a not yet stable ctx->seen.
+ * We also need a second pass if we ended up with too large
+ * a program so as to ensure BPF_EXIT branches are in range.
*/
+ if (cgctx.seen & SEEN_TAILCALL || !is_offset_in_branch_range((long)cgctx.idx * 4)) {
+ cgctx.idx = 0;
+ if (bpf_jit_build_body(fp, NULL, NULL, &cgctx, addrs, 0, false)) {
+ fp = org_fp;
+ goto out_addrs;
+ }
+ }
- cgctx.idx = 0;
- cgctx.seen = 0;
- cgctx.pc_ret0 = -1;
- /* Scouting faux-generate pass 0 */
- if (bpf_jit_build_body(fp, 0, &cgctx, addrs))
- /* We hit something illegal or unsupported. */
- goto out;
-
+ bpf_jit_realloc_regs(&cgctx);
/*
* 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(fp, 0, &cgctx);
- bpf_jit_build_epilogue(0, &cgctx);
+ bpf_jit_build_prologue(NULL, &cgctx);
+ addrs[fp->len] = cgctx.idx * 4;
+ bpf_jit_build_epilogue(NULL, &cgctx);
+
+ fixup_len = fp->aux->num_exentries * BPF_FIXUP_LEN * 4;
+ extable_len = fp->aux->num_exentries * sizeof(struct exception_table_entry);
proglen = cgctx.idx * 4;
- alloclen = proglen + FUNCTION_DESCR_SIZE;
- image = module_alloc(alloclen);
- if (!image)
- goto out;
+ alloclen = proglen + FUNCTION_DESCR_SIZE + fixup_len + extable_len;
- code_base = image + (FUNCTION_DESCR_SIZE/4);
+ fhdr = bpf_jit_binary_pack_alloc(alloclen, &fimage, 4, &hdr, &image,
+ bpf_jit_fill_ill_insns);
+ if (!fhdr) {
+ fp = org_fp;
+ goto out_addrs;
+ }
+
+ if (extable_len)
+ fp->aux->extable = (void *)fimage + FUNCTION_DESCR_SIZE + proglen + fixup_len;
+
+skip_init_ctx:
+ code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);
+ fcode_base = (u32 *)(fimage + FUNCTION_DESCR_SIZE);
/* 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(fp, code_base, &cgctx);
- bpf_jit_build_body(fp, code_base, &cgctx, addrs);
+ cgctx.alt_exit_addr = 0;
+ bpf_jit_build_prologue(code_base, &cgctx);
+ if (bpf_jit_build_body(fp, code_base, fcode_base, &cgctx, addrs, pass,
+ extra_pass)) {
+ bpf_arch_text_copy(&fhdr->size, &hdr->size, sizeof(hdr->size));
+ bpf_jit_binary_pack_free(fhdr, hdr);
+ fp = org_fp;
+ goto out_addrs;
+ }
bpf_jit_build_epilogue(code_base, &cgctx);
if (bpf_jit_enable > 1)
@@ -654,31 +208,154 @@ void bpf_jit_compile(struct bpf_prog *fp)
}
if (bpf_jit_enable > 1)
- /* Note that we output the base address of the code_base
+ /*
+ * 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);
- bpf_flush_icache(code_base, code_base + (proglen/4));
-
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_PPC64_ELF_ABI_V1
/* Function descriptor nastiness: Address + TOC */
- ((u64 *)image)[0] = (u64)code_base;
+ ((u64 *)image)[0] = (u64)fcode_base;
((u64 *)image)[1] = local_paca->kernel_toc;
#endif
- fp->bpf_func = (void *)image;
+ fp->bpf_func = (void *)fimage;
fp->jited = 1;
+ fp->jited_len = proglen + FUNCTION_DESCR_SIZE;
+
+ if (!fp->is_func || extra_pass) {
+ if (bpf_jit_binary_pack_finalize(fp, fhdr, hdr)) {
+ fp = org_fp;
+ goto out_addrs;
+ }
+ bpf_prog_fill_jited_linfo(fp, addrs);
+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->fimage = fimage;
+ jit_data->fhdr = fhdr;
+ jit_data->hdr = hdr;
+ }
out:
- kfree(addrs);
- return;
+ if (bpf_blinded)
+ bpf_jit_prog_release_other(fp, fp == org_fp ? tmp_fp : org_fp);
+
+ return fp;
+}
+
+/*
+ * The caller should check for (BPF_MODE(code) == BPF_PROBE_MEM) before calling
+ * this function, as this only applies to BPF_PROBE_MEM, for now.
+ */
+int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, int pass,
+ struct codegen_context *ctx, int insn_idx, int jmp_off,
+ int dst_reg)
+{
+ off_t offset;
+ unsigned long pc;
+ struct exception_table_entry *ex, *ex_entry;
+ u32 *fixup;
+
+ /* Populate extable entries only in the last pass */
+ if (pass != 2)
+ return 0;
+
+ if (!fp->aux->extable ||
+ WARN_ON_ONCE(ctx->exentry_idx >= fp->aux->num_exentries))
+ return -EINVAL;
+
+ /*
+ * Program is first written to image before copying to the
+ * final location (fimage). Accordingly, update in the image first.
+ * As all offsets used are relative, copying as is to the
+ * final location should be alright.
+ */
+ pc = (unsigned long)&image[insn_idx];
+ ex = (void *)fp->aux->extable - (void *)fimage + (void *)image;
+
+ fixup = (void *)ex -
+ (fp->aux->num_exentries * BPF_FIXUP_LEN * 4) +
+ (ctx->exentry_idx * BPF_FIXUP_LEN * 4);
+
+ fixup[0] = PPC_RAW_LI(dst_reg, 0);
+ if (IS_ENABLED(CONFIG_PPC32))
+ fixup[1] = PPC_RAW_LI(dst_reg - 1, 0); /* clear higher 32-bit register too */
+
+ fixup[BPF_FIXUP_LEN - 1] =
+ PPC_RAW_BRANCH((long)(pc + jmp_off) - (long)&fixup[BPF_FIXUP_LEN - 1]);
+
+ ex_entry = &ex[ctx->exentry_idx];
+
+ offset = pc - (long)&ex_entry->insn;
+ if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+ return -ERANGE;
+ ex_entry->insn = offset;
+
+ offset = (long)fixup - (long)&ex_entry->fixup;
+ if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
+ return -ERANGE;
+ ex_entry->fixup = offset;
+
+ ctx->exentry_idx++;
+ return 0;
+}
+
+void *bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+ int err;
+
+ if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&text_mutex);
+ err = patch_instructions(dst, src, len, false);
+ mutex_unlock(&text_mutex);
+
+ return err ? ERR_PTR(err) : dst;
+}
+
+int bpf_arch_text_invalidate(void *dst, size_t len)
+{
+ u32 insn = BREAKPOINT_INSTRUCTION;
+ int ret;
+
+ if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+ return -EINVAL;
+
+ mutex_lock(&text_mutex);
+ ret = patch_instructions(dst, &insn, len, true);
+ mutex_unlock(&text_mutex);
+
+ return ret;
}
void bpf_jit_free(struct bpf_prog *fp)
{
- if (fp->jited)
- module_memfree(fp->bpf_func);
+ if (fp->jited) {
+ struct powerpc_jit_data *jit_data = fp->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_jit_binary_pack_finalize(fp, jit_data->fhdr, jit_data->hdr);
+ kvfree(jit_data->addrs);
+ kfree(jit_data);
+ }
+ hdr = bpf_jit_binary_pack_hdr(fp);
+ bpf_jit_binary_pack_free(hdr, NULL);
+ WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
+ }
bpf_prog_unlock_free(fp);
}
generated by cgit (git 2.34.1) at 2024-04-26 12:57:24 +0000