From 9a048587269174f218e8d8d737ebfa628589358f Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Tue, 2 Jul 2024 01:40:21 +0200 Subject: [PATCH] s390/bpf: Get rid of get_probe_mem_regno() Commit 7fc8c362e782 ("s390/bpf: encode register within extable entry") introduced explicit passing of the number of the register to be cleared to ex_handler_bpf(), which replaced deducing it from the respective native load instruction using get_probe_mem_regno(). Replace the second and last usage in the same manner, and remove this function. Signed-off-by: Ilya Leoshkevich Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240701234304.14336-4-iii@linux.ibm.com --- arch/s390/net/bpf_jit_comp.c | 33 +++++++-------------------------- 1 file changed, 7 insertions(+), 26 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 260e7009784b..d9d79aa2be1b 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -667,25 +667,6 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth) jit->prg += sizeof(struct bpf_plt); } -static int get_probe_mem_regno(const u8 *insn) -{ - /* - * insn must point to llgc, llgh, llgf, lg, lgb, lgh or lgf, which have - * destination register at the same position. - */ - if (insn[0] != 0xe3) /* common prefix */ - return -1; - if (insn[5] != 0x90 && /* llgc */ - insn[5] != 0x91 && /* llgh */ - insn[5] != 0x16 && /* llgf */ - insn[5] != 0x04 && /* lg */ - insn[5] != 0x77 && /* lgb */ - insn[5] != 0x15 && /* lgh */ - insn[5] != 0x14) /* lgf */ - return -1; - return insn[1] >> 4; -} - bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs) { regs->psw.addr = extable_fixup(x); @@ -699,12 +680,14 @@ bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs) struct bpf_jit_probe { int prg; /* JITed instruction offset */ int nop_prg; /* JITed nop offset */ + int reg; /* Register to clear on exception */ }; static void bpf_jit_probe_init(struct bpf_jit_probe *probe) { probe->prg = -1; probe->nop_prg = -1; + probe->reg = -1; } /* @@ -725,7 +708,7 @@ static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp, struct bpf_jit_probe *probe) { struct exception_table_entry *ex; - int i, prg, reg; + int i, prg; s64 delta; u8 *insn; @@ -734,10 +717,6 @@ static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp, /* Do nothing during early JIT passes. */ return 0; insn = jit->prg_buf + probe->prg; - reg = get_probe_mem_regno(insn); - if (WARN_ON_ONCE(reg < 0)) - /* JIT bug - unexpected probe instruction. */ - return -1; if (WARN_ON_ONCE(probe->prg + insn_length(*insn) != probe->nop_prg)) /* JIT bug - gap between probe and nop instructions. */ return -1; @@ -763,7 +742,7 @@ static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp, return -1; ex->fixup = delta; ex->type = EX_TYPE_BPF; - ex->data = reg; + ex->data = probe->reg; jit->excnt++; } return 0; @@ -821,8 +800,10 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, bpf_jit_probe_init(&probe); if (BPF_CLASS(insn->code) == BPF_LDX && (BPF_MODE(insn->code) == BPF_PROBE_MEM || - BPF_MODE(insn->code) == BPF_PROBE_MEMSX)) + BPF_MODE(insn->code) == BPF_PROBE_MEMSX)) { probe.prg = jit->prg; + probe.reg = reg2hex[dst_reg]; + } switch (insn->code) { /* -- 2.20.1