diff options
Diffstat (limited to 'arch/s390/net/bpf_jit_comp.c')
-rw-r--r-- | arch/s390/net/bpf_jit_comp.c | 63 |
1 files changed, 61 insertions, 2 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 78a19c93b380..dd2bcf0e7d00 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -25,6 +25,8 @@ #include <linux/bpf.h> #include <asm/cacheflush.h> #include <asm/dis.h> +#include <asm/facility.h> +#include <asm/nospec-branch.h> #include <asm/set_memory.h> #include "bpf_jit.h" @@ -41,6 +43,8 @@ struct bpf_jit { int base_ip; /* Base address for literal pool */ int ret0_ip; /* Address of return 0 */ int exit_ip; /* Address of exit */ + int r1_thunk_ip; /* Address of expoline thunk for 'br %r1' */ + int r14_thunk_ip; /* Address of expoline thunk for 'br %r14' */ int tail_call_start; /* Tail call start offset */ int labels[1]; /* Labels for local jumps */ }; @@ -250,6 +254,19 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) REG_SET_SEEN(b2); \ }) +#define EMIT6_PCREL_RILB(op, b, target) \ +({ \ + int rel = (target - jit->prg) / 2; \ + _EMIT6(op | reg_high(b) << 16 | rel >> 16, rel & 0xffff); \ + REG_SET_SEEN(b); \ +}) + +#define EMIT6_PCREL_RIL(op, target) \ +({ \ + int rel = (target - jit->prg) / 2; \ + _EMIT6(op | rel >> 16, rel & 0xffff); \ +}) + #define _EMIT6_IMM(op, imm) \ ({ \ unsigned int __imm = (imm); \ @@ -469,8 +486,45 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth) EMIT4(0xb9040000, REG_2, BPF_REG_0); /* Restore registers */ save_restore_regs(jit, REGS_RESTORE, stack_depth); + if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable) { + jit->r14_thunk_ip = jit->prg; + /* Generate __s390_indirect_jump_r14 thunk */ + if (test_facility(35)) { + /* exrl %r0,.+10 */ + EMIT6_PCREL_RIL(0xc6000000, jit->prg + 10); + } else { + /* larl %r1,.+14 */ + EMIT6_PCREL_RILB(0xc0000000, REG_1, jit->prg + 14); + /* ex 0,0(%r1) */ + EMIT4_DISP(0x44000000, REG_0, REG_1, 0); + } + /* j . */ + EMIT4_PCREL(0xa7f40000, 0); + } /* br %r14 */ _EMIT2(0x07fe); + + if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable && + (jit->seen & SEEN_FUNC)) { + jit->r1_thunk_ip = jit->prg; + /* Generate __s390_indirect_jump_r1 thunk */ + if (test_facility(35)) { + /* exrl %r0,.+10 */ + EMIT6_PCREL_RIL(0xc6000000, jit->prg + 10); + /* j . */ + EMIT4_PCREL(0xa7f40000, 0); + /* br %r1 */ + _EMIT2(0x07f1); + } else { + /* larl %r1,.+14 */ + EMIT6_PCREL_RILB(0xc0000000, REG_1, jit->prg + 14); + /* ex 0,S390_lowcore.br_r1_tampoline */ + EMIT4_DISP(0x44000000, REG_0, REG_0, + offsetof(struct lowcore, br_r1_trampoline)); + /* j . */ + EMIT4_PCREL(0xa7f40000, 0); + } + } } /* @@ -966,8 +1020,13 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i /* lg %w1,<d(imm)>(%l) */ EMIT6_DISP_LH(0xe3000000, 0x0004, REG_W1, REG_0, REG_L, EMIT_CONST_U64(func)); - /* basr %r14,%w1 */ - EMIT2(0x0d00, REG_14, REG_W1); + if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable) { + /* brasl %r14,__s390_indirect_jump_r1 */ + EMIT6_PCREL_RILB(0xc0050000, REG_14, jit->r1_thunk_ip); + } else { + /* basr %r14,%w1 */ + EMIT2(0x0d00, REG_14, REG_W1); + } /* lgr %b0,%r2: load return value into %b0 */ EMIT4(0xb9040000, BPF_REG_0, REG_2); if ((jit->seen & SEEN_SKB) && |