github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc64 JIT

Browse Source 
emit_call_libgcc_ll() zero-extends the ALU32 operands and calls the
unsigned hppa_div64()/hppa_div64_rem() helpers regardless of the BPF
instruction's signedness, so the parisc64 JIT does not implement
signed BPF_SDIV and BPF_SMOD (off == 1). Signed ALU32 and ALU64
div/mod get an unsigned quotient and remainder rather than the
verifier's and the interpreter's signed result for negative operands.

Add hppa_sdiv64()/hppa_sdiv64_rem() wrapping div64_s64(), thread
is_signed = (insn->off == 1) through the div/mod emit sites, and on the
signed path sign-extend the ALU32 operands (and the immediate divisor)
instead of zero-extending them before calling the signed helpers.
bpf_do_misc_fixups() rewrites the zero-divisor and INT_MIN/-1 cases out
of the instruction stream before the JIT runs.

Signed-off-by: Nicholas Dudar <main.kalliope@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Helge Deller <deller@gmx.de>
Acked-by: Helge Deller <deller@gmx.de>
Link: https://lore.kernel.org/bpf/20260915022905.1535566-2-main.kalliope@gmail.com
This commit is contained in:
Nicholas Dudar 2026-09-14 22:29:04 -04:00 committed by Daniel Borkmann
parent 8715b13c1a
commit 32a7b17bc8
3 changed files with 42 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/parisc/net/bpf_jit.h
View File

@ -467,6 +467,8 @@ static inline u32 hppa_t21_insn(u8 opcode, u8 r2, u8 r1, u8 ext8, u8 t)
u64 hppa_div64(u64 div, u64 divisor);
u64 hppa_div64_rem(u64 div, u64 divisor);
u64 hppa_sdiv64(u64 div, u64 divisor);
u64 hppa_sdiv64_rem(u64 div, u64 divisor);
/* Helper functions that emit HPPA instructions when possible. */

35
arch/parisc/net/bpf_jit_comp64.c
View File

@ -502,14 +502,19 @@ static void emit_call(u64 addr, bool fixed, struct hppa_jit_context *ctx)
emit_hppa_copy(HPPA_REG_RET0, regmap[BPF_REG_0], ctx);
}
static void emit_call_libgcc_ll(void *func, const s8 arg0,
const s8 arg1, u8 opcode, struct hppa_jit_context *ctx)
static void emit_call_libgcc_ll(void *func, const s8 arg0, const s8 arg1,
u8 opcode, bool is_signed, struct hppa_jit_context *ctx)
{
u64 func_addr;
if (BPF_CLASS(opcode) == BPF_ALU) {
emit_hppa64_zext32(arg0, HPPA_REG_ARG0, ctx);
emit_hppa64_zext32(arg1, HPPA_REG_ARG1, ctx);
if (is_signed) {
emit_hppa64_sext32(arg0, HPPA_REG_ARG0, ctx);
emit_hppa64_sext32(arg1, HPPA_REG_ARG1, ctx);
} else {
emit_hppa64_zext32(arg0, HPPA_REG_ARG0, ctx);
emit_hppa64_zext32(arg1, HPPA_REG_ARG1, ctx);
}
} else {
emit_hppa_copy(arg0, HPPA_REG_ARG0, ctx);
emit_hppa_copy(arg1, HPPA_REG_ARG1, ctx);
@ -600,6 +605,8 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct hppa_jit_context *ctx,
u8 rd = -1, rs = -1, code = insn->code;
s16 off = insn->off;
s32 imm = insn->imm;
bool is_signed;
void *func;
init_regs(&rd, &rs, insn, ctx);
@ -656,29 +663,39 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct hppa_jit_context *ctx,
fallthrough;
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_X:
emit_call_libgcc_ll(__muldi3, rd, rs, code, ctx);
emit_call_libgcc_ll(__muldi3, rd, rs, code, false, ctx);
if (!is64 && !aux->verifier_zext)
emit_zext_32(rd, ctx);
break;
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
emit_imm(HPPA_REG_T1, is64 ? (s64)(s32)imm : (u32)imm, HPPA_REG_T2, ctx);
is_signed = (off == 1);
emit_imm(HPPA_REG_T1,
is64 || is_signed ? (s64)(s32)imm : (u32)imm,
HPPA_REG_T2, ctx);
rs = HPPA_REG_T1;
fallthrough;
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
emit_call_libgcc_ll(&hppa_div64, rd, rs, code, ctx);
is_signed = (off == 1);
func = is_signed ? &hppa_sdiv64 : &hppa_div64;
emit_call_libgcc_ll(func, rd, rs, code, is_signed, ctx);
if (!is64 && !aux->verifier_zext)
emit_zext_32(rd, ctx);
break;
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
emit_imm(HPPA_REG_T1, is64 ? (s64)(s32)imm : (u32)imm, HPPA_REG_T2, ctx);
is_signed = (off == 1);
emit_imm(HPPA_REG_T1,
is64 || is_signed ? (s64)(s32)imm : (u32)imm,
HPPA_REG_T2, ctx);
rs = HPPA_REG_T1;
fallthrough;
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_X:
emit_call_libgcc_ll(&hppa_div64_rem, rd, rs, code, ctx);
is_signed = (off == 1);
func = is_signed ? &hppa_sdiv64_rem : &hppa_div64_rem;
emit_call_libgcc_ll(func, rd, rs, code, is_signed, ctx);
if (!is64 && !aux->verifier_zext)
emit_zext_32(rd, ctx);
break;

14
arch/parisc/net/bpf_jit_core.c
View File

@ -190,3 +190,17 @@ u64 hppa_div64_rem(u64 div, u64 divisor)
div64_u64_rem(div, divisor, &rem);
return rem;
}
u64 hppa_sdiv64(u64 div, u64 divisor)
{
s64 sdiv = div64_s64((s64)div, (s64)divisor);
return (u64)sdiv;
}
u64 hppa_sdiv64_rem(u64 div, u64 divisor)
{
s64 sdiv = div64_s64((s64)div, (s64)divisor);
return (u64)((s64)div - sdiv * (s64)divisor);
}