Add support for loadable kernel modules.
Submitted by: Yukishige Shibata <y-shibat@mtd.biglobe.ne.jp>
This commit is contained in:
Ruslan Bukin
parent
e6023d7095
commit
99ea4d4733
@ -23,7 +23,9 @@ ident GENERIC
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makeoptions DEBUG=-g # Build kernel with gdb(1) debug symbols
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# makeoptions WITH_CTF=1 # Run ctfconvert(1) for DTrace support
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makeoptions NO_MODULES=1 # We don't yet support modules on RISC-V
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# FIXME: linker error. "--relax and -r may not be used together"
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makeoptions WITHOUT_MODULES="usb otusfw mwlfw ispfw mwlfw ralfw rtwnfw urtwnfw"
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options SCHED_ULE # ULE scheduler
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options PREEMPTION # Enable kernel thread preemption
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@ -1,6 +1,7 @@
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/*-
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* Copyright 1996-1998 John D. Polstra.
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* Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
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* Copyright (c) 2016 Yukishige SHibata <y-shibat@mtd.biglobe.ne.jp>
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* All rights reserved.
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*
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* Portions of this software were developed by SRI International and the
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@ -43,6 +44,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/imgact.h>
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#include <sys/linker.h>
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#include <sys/proc.h>
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#include <sys/sysctl.h>
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#include <sys/sysent.h>
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#include <sys/imgact_elf.h>
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#include <sys/syscall.h>
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@ -123,19 +125,380 @@ SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
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(sysinit_cfunc_t) elf64_insert_brand_entry,
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&freebsd_brand_oinfo);
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static int debug_kld;
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SYSCTL_INT(_kern, OID_AUTO, debug_kld,
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CTLFLAG_RW, &debug_kld, 0,
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"Activate debug prints in elf_reloc_internal()");
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struct type2str_ent {
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int type;
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const char* str;
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};
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void
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elf64_dump_thread(struct thread *td, void *dst, size_t *off)
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{
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}
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/* Process one elf relocation with addend. */
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/*
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* Following 4 functions are used to manupilate bits on 32bit interger value.
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* FIXME: I implemetend for ease-to-understand rather than for well-optimized.
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*/
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static uint32_t
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gen_bitmask(int msb, int lsb)
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{
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uint32_t mask;
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if (msb == sizeof(mask) * 8 - 1)
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mask = ~0;
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else
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mask = (1U << (msb + 1)) - 1;
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if (lsb > 0)
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mask &= ~((1U << lsb) - 1);
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return (mask);
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}
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static uint32_t
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extract_bits(uint32_t x, int msb, int lsb)
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{
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uint32_t mask;
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mask = gen_bitmask(msb, lsb);
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x &= mask;
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x >>= lsb;
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return (x);
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}
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static uint32_t
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insert_bits(uint32_t d, uint32_t s, int msb, int lsb)
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{
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uint32_t mask;
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mask = gen_bitmask(msb, lsb);
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d &= ~mask;
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s <<= lsb;
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s &= mask;
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return (d | s);
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}
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static uint32_t
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insert_imm(uint32_t insn, uint32_t imm, int imm_msb, int imm_lsb,
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int insn_lsb)
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{
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int insn_msb;
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uint32_t v;
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v = extract_bits(imm, imm_msb, imm_lsb);
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insn_msb = (imm_msb - imm_lsb) + insn_lsb;
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return (insert_bits(insn, v, insn_msb, insn_lsb));
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}
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/*
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* The RISCV ISA is designed so that all of immediate value is
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* sign-extened.
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* An immediate value is sometimes generated at runtime by adding
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* 12bit sign integer and 20bit signed integer. This requests 20bit
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* immediate value to be ajusted if the MSB of the 12bit immediate
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* value is asserted (sign extened value is treated as negative value).
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*
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* For example, 0x123800 can be calculated by adding upper 20 bit of
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* 0x124000 and signed-extended 12bit immediate whose bit pattern is
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* 0x800 as follows;
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* 0x123800
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* = 0x123000 + 0x800
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* = (0x123000 + 0x1000) + (-0x1000 + 0x800)
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* = (0x123000 + 0x1000) + (0xff...ff800)
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* = 0x124000 + sign-exntend(0x800)
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*/
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static uint32_t
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calc_hi20_imm(uint32_t value)
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{
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/*
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* There is the arithmetical hack that can remove conditional
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* statement. But I implement it in straghtforward way.
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*/
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if ((value & 0x800) != 0)
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value += 0x1000;
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return (value & ~0xfff);
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}
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static const struct type2str_ent t2s[] = {
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{ R_RISCV_NONE, "R_RISCV_NONE" },
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{ R_RISCV_64, "R_RISCV_64" },
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{ R_RISCV_JUMP_SLOT, "R_RISCV_JUMP_SLOT" },
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{ R_RISCV_RELATIVE, "R_RISCV_RELATIVE" },
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{ R_RISCV_JAL, "R_RISCV_JAL" },
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{ R_RISCV_CALL, "R_RISCV_CALL" },
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{ R_RISCV_PCREL_HI20, "R_RISCV_PCREL_HI20" },
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{ R_RISCV_PCREL_LO12_I, "R_RISCV_PCREL_LO12_I" },
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{ R_RISCV_PCREL_LO12_S, "R_RISCV_PCREL_LO12_S" },
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{ R_RISCV_HI20, "R_RISCV_HI20" },
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{ R_RISCV_LO12_I, "R_RISCV_LO12_I" },
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{ R_RISCV_LO12_S, "R_RISCV_LO12_S" },
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};
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static const char*
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reloctype_to_str(int type)
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{
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int i;
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for (i = 0; i < sizeof(t2s) / sizeof(t2s[0]); ++i) {
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if (type == t2s[i].type)
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return t2s[i].str;
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}
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return "*unknown*";
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}
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/*
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* Currently kernel loadable module for RISCV is compiled with -fPIC option.
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* (see also additional CFLAGS definition for RISCV in sys/conf/kmod.mk)
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* Only R_RISCV_64, R_RISCV_JUMP_SLOT and RISCV_RELATIVE are emitted in
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* the module. Other relocations will be processed when kernel loadable
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* modules are built in non-PIC.
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*
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* FIXME: only RISCV64 is supported.
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*/
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static int
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elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
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int type, int local, elf_lookup_fn lookup)
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{
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Elf_Size rtype, symidx;
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const Elf_Rela *rela;
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Elf_Addr val, addr;
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Elf64_Addr *where;
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Elf_Addr addend;
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uint32_t before32_1;
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uint32_t before32;
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uint64_t before64;
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uint32_t* insn32p;
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uint32_t imm20;
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int error;
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panic("elf_reloc_internal");
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switch (type) {
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case ELF_RELOC_RELA:
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rela = (const Elf_Rela *)data;
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where = (Elf_Addr *)(relocbase + rela->r_offset);
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insn32p = (uint32_t*)where;
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addend = rela->r_addend;
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rtype = ELF_R_TYPE(rela->r_info);
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symidx = ELF_R_SYM(rela->r_info);
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break;
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default:
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printf("%s:%d unknown reloc type %d\n",
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__FUNCTION__, __LINE__, type);
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return -1;
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}
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switch (rtype) {
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case R_RISCV_NONE:
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break;
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case R_RISCV_64:
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case R_RISCV_JUMP_SLOT:
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error = lookup(lf, symidx, 1, &addr);
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if (error != 0)
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return -1;
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val = addr;
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before64 = *where;
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if (*where != val)
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*where = val;
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if (debug_kld)
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printf("%p %c %-24s %016lx -> %016lx\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before64, *where);
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break;
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case R_RISCV_RELATIVE:
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val = relocbase + addend;
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before64 = *where;
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if (*where != val)
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*where = val;
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if (debug_kld)
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printf("%p %c %-24s %016lx -> %016lx\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before64, *where);
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break;
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case R_RISCV_JAL:
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error = lookup(lf, symidx, 1, &addr);
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if (error != 0)
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return -1;
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val = addr - (Elf_Addr)where;
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if ((val <= -(1UL << 20) || (1UL << 20) <= val)) {
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printf("kldload: huge offset against R_RISCV_JAL\n");
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return -1;
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}
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before32 = *insn32p;
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*insn32p = insert_imm(*insn32p, val, 20, 20, 31);
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*insn32p = insert_imm(*insn32p, val, 10, 1, 21);
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*insn32p = insert_imm(*insn32p, val, 11, 11, 20);
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*insn32p = insert_imm(*insn32p, val, 19, 12, 12);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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case R_RISCV_CALL:
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/*
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* R_RISCV_CALL relocates 8-byte region that consists
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* of the sequence of AUIPC and JALR.
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*/
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/* calculate and check the pc relative offset. */
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error = lookup(lf, symidx, 1, &addr);
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if (error != 0)
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return -1;
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val = addr - (Elf_Addr)where;
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if ((val <= -(1UL << 32) || (1UL << 32) <= val)) {
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printf("kldload:%s: huge offset against R_RISCV_CALL\n");
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return -1;
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}
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/* Relocate AUIPC. */
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before32 = insn32p[0];
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imm20 = calc_hi20_imm(val);
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insn32p[0] = insert_imm(insn32p[0], imm20, 31, 12, 12);
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/* Relocate JALR. */
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before32_1 = insn32p[1];
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insn32p[1] = insert_imm(insn32p[1], val, 11, 0, 20);
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if (debug_kld)
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printf("%p %c %-24s %08x %08x -> %08x %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, insn32p[0],
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before32_1, insn32p[1]);
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break;
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case R_RISCV_PCREL_HI20:
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val = addr - (Elf_Addr)where;
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insn32p = (uint32_t*)where;
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before32 = *insn32p;
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imm20 = calc_hi20_imm(val);
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*insn32p = insert_imm(*insn32p, imm20, 31, 12, 12);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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case R_RISCV_PCREL_LO12_I:
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val = addr - (Elf_Addr)where;
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insn32p = (uint32_t*)where;
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before32 = *insn32p;
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*insn32p = insert_imm(*insn32p, addr, 11, 0, 20);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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case R_RISCV_PCREL_LO12_S:
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val = addr - (Elf_Addr)where;
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insn32p = (uint32_t*)where;
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before32 = *insn32p;
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*insn32p = insert_imm(*insn32p, addr, 11, 5, 25);
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*insn32p = insert_imm(*insn32p, addr, 4, 0, 7);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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case R_RISCV_HI20:
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error = lookup(lf, symidx, 1, &addr);
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if (error != 0)
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return -1;
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insn32p = (uint32_t*)where;
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before32 = *insn32p;
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imm20 = calc_hi20_imm(val);
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*insn32p = insert_imm(*insn32p, imm20, 31, 12, 12);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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case R_RISCV_LO12_I:
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error = lookup(lf, symidx, 1, &addr);
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if (error != 0)
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return -1;
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val = addr;
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insn32p = (uint32_t*)where;
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before32 = *insn32p;
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*insn32p = insert_imm(*insn32p, addr, 11, 0, 20);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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case R_RISCV_LO12_S:
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error = lookup(lf, symidx, 1, &addr);
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if (error != 0)
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return -1;
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val = addr;
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insn32p = (uint32_t*)where;
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before32 = *insn32p;
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*insn32p = insert_imm(*insn32p, addr, 11, 5, 25);
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*insn32p = insert_imm(*insn32p, addr, 4, 0, 7);
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if (debug_kld)
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printf("%p %c %-24s %08x -> %08x\n",
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where,
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(local? 'l': 'g'),
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reloctype_to_str(rtype),
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before32, *insn32p);
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break;
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default:
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printf("kldload: unexpected relocation type %ld\n", rtype);
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return (-1);
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}
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return (0);
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}
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int
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