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s390/bpf: Get rid of get_probe_mem_regno()

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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 <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240701234304.14336-4-iii@linux.ibm.com
This commit is contained in:
Ilya Leoshkevich 2024-07-02 01:40:21 +02:00 committed by Daniel Borkmann
parent d0736d8c49
commit 9a04858726
1 changed files with 7 additions and 26 deletions
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33
arch/s390/net/bpf_jit_comp.c
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@ -667,25 +667,6 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
jit->prg += sizeof(struct bpf_plt); 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) bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs)
{ {
regs->psw.addr = extable_fixup(x); 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 { struct bpf_jit_probe {
int prg; /* JITed instruction offset */ int prg; /* JITed instruction offset */
int nop_prg; /* JITed nop 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) static void bpf_jit_probe_init(struct bpf_jit_probe *probe)
{ {
probe->prg = -1; probe->prg = -1;
probe->nop_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 bpf_jit_probe *probe)
{ {
struct exception_table_entry *ex; struct exception_table_entry *ex;
int i, prg, reg; int i, prg;
s64 delta; s64 delta;
u8 *insn; 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. */ /* Do nothing during early JIT passes. */
return 0; return 0;
insn = jit->prg_buf + probe->prg; 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)) if (WARN_ON_ONCE(probe->prg + insn_length(*insn) != probe->nop_prg))
/* JIT bug - gap between probe and nop instructions. */ /* JIT bug - gap between probe and nop instructions. */
return -1; return -1;
@ -763,7 +742,7 @@ static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp,
return -1; return -1;
ex->fixup = delta; ex->fixup = delta;
ex->type = EX_TYPE_BPF; ex->type = EX_TYPE_BPF;
ex->data = reg; ex->data = probe->reg;
jit->excnt++; jit->excnt++;
} }
return 0; 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); bpf_jit_probe_init(&probe);
if (BPF_CLASS(insn->code) == BPF_LDX && if (BPF_CLASS(insn->code) == BPF_LDX &&
(BPF_MODE(insn->code) == BPF_PROBE_MEM || (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.prg = jit->prg;
probe.reg = reg2hex[dst_reg];
}
switch (insn->code) { switch (insn->code) {
/* /*