Author: br
Date: Wed Jun 1 14:12:31 2016
New Revision: 301126
URL: https://svnweb.freebsd.org/changeset/base/301126
Log:
Add support for loadable kernel modules.
Submitted by: Yukishige Shibata <y-shi...@mtd.biglobe.ne.jp>
Modified:
head/sys/riscv/conf/GENERIC
head/sys/riscv/riscv/elf_machdep.c
Modified: head/sys/riscv/conf/GENERIC
==============================================================================
--- head/sys/riscv/conf/GENERIC Wed Jun 1 14:11:40 2016 (r301125)
+++ head/sys/riscv/conf/GENERIC Wed Jun 1 14:12:31 2016 (r301126)
@@ -23,7 +23,9 @@ ident GENERIC
makeoptions DEBUG=-g # Build kernel with gdb(1) debug symbols
# makeoptions WITH_CTF=1 # Run ctfconvert(1) for DTrace support
-makeoptions NO_MODULES=1 # We don't yet support modules on RISC-V
+
+# FIXME: linker error. "--relax and -r may not be used together"
+makeoptions WITHOUT_MODULES="usb otusfw mwlfw ispfw mwlfw ralfw rtwnfw
urtwnfw"
options SCHED_ULE # ULE scheduler
options PREEMPTION # Enable kernel thread preemption
Modified: head/sys/riscv/riscv/elf_machdep.c
==============================================================================
--- head/sys/riscv/riscv/elf_machdep.c Wed Jun 1 14:11:40 2016
(r301125)
+++ head/sys/riscv/riscv/elf_machdep.c Wed Jun 1 14:12:31 2016
(r301126)
@@ -1,6 +1,7 @@
/*-
* Copyright 1996-1998 John D. Polstra.
* Copyright (c) 2015 Ruslan Bukin <b...@bsdpad.com>
+ * Copyright (c) 2016 Yukishige SHibata <y-shi...@mtd.biglobe.ne.jp>
* All rights reserved.
*
* Portions of this software were developed by SRI International and the
@@ -43,6 +44,7 @@ __FBSDID("$FreeBSD$");
#include <sys/imgact.h>
#include <sys/linker.h>
#include <sys/proc.h>
+#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/imgact_elf.h>
#include <sys/syscall.h>
@@ -123,19 +125,380 @@ SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_AN
(sysinit_cfunc_t) elf64_insert_brand_entry,
&freebsd_brand_oinfo);
+static int debug_kld;
+SYSCTL_INT(_kern, OID_AUTO, debug_kld,
+ CTLFLAG_RW, &debug_kld, 0,
+ "Activate debug prints in elf_reloc_internal()");
+
+struct type2str_ent {
+ int type;
+ const char* str;
+};
+
void
elf64_dump_thread(struct thread *td, void *dst, size_t *off)
{
}
-/* Process one elf relocation with addend. */
+/*
+ * Following 4 functions are used to manupilate bits on 32bit interger value.
+ * FIXME: I implemetend for ease-to-understand rather than for well-optimized.
+ */
+static uint32_t
+gen_bitmask(int msb, int lsb)
+{
+ uint32_t mask;
+
+ if (msb == sizeof(mask) * 8 - 1)
+ mask = ~0;
+ else
+ mask = (1U << (msb + 1)) - 1;
+
+ if (lsb > 0)
+ mask &= ~((1U << lsb) - 1);
+
+ return (mask);
+}
+
+static uint32_t
+extract_bits(uint32_t x, int msb, int lsb)
+{
+ uint32_t mask;
+
+ mask = gen_bitmask(msb, lsb);
+
+ x &= mask;
+ x >>= lsb;
+
+ return (x);
+}
+
+static uint32_t
+insert_bits(uint32_t d, uint32_t s, int msb, int lsb)
+{
+ uint32_t mask;
+
+ mask = gen_bitmask(msb, lsb);
+
+ d &= ~mask;
+
+ s <<= lsb;
+ s &= mask;
+
+ return (d | s);
+}
+
+static uint32_t
+insert_imm(uint32_t insn, uint32_t imm, int imm_msb, int imm_lsb,
+ int insn_lsb)
+{
+ int insn_msb;
+ uint32_t v;
+
+ v = extract_bits(imm, imm_msb, imm_lsb);
+ insn_msb = (imm_msb - imm_lsb) + insn_lsb;
+
+ return (insert_bits(insn, v, insn_msb, insn_lsb));
+}
+
+/*
+ * The RISCV ISA is designed so that all of immediate value is
+ * sign-extened.
+ * An immediate value is sometimes generated at runtime by adding
+ * 12bit sign integer and 20bit signed integer. This requests 20bit
+ * immediate value to be ajusted if the MSB of the 12bit immediate
+ * value is asserted (sign extened value is treated as negative value).
+ *
+ * For example, 0x123800 can be calculated by adding upper 20 bit of
+ * 0x124000 and signed-extended 12bit immediate whose bit pattern is
+ * 0x800 as follows;
+ * 0x123800
+ * = 0x123000 + 0x800
+ * = (0x123000 + 0x1000) + (-0x1000 + 0x800)
+ * = (0x123000 + 0x1000) + (0xff...ff800)
+ * = 0x124000 + sign-exntend(0x800)
+ */
+static uint32_t
+calc_hi20_imm(uint32_t value)
+{
+ /*
+ * There is the arithmetical hack that can remove conditional
+ * statement. But I implement it in straghtforward way.
+ */
+ if ((value & 0x800) != 0)
+ value += 0x1000;
+ return (value & ~0xfff);
+}
+
+static const struct type2str_ent t2s[] = {
+ { R_RISCV_NONE, "R_RISCV_NONE" },
+ { R_RISCV_64, "R_RISCV_64" },
+ { R_RISCV_JUMP_SLOT, "R_RISCV_JUMP_SLOT" },
+ { R_RISCV_RELATIVE, "R_RISCV_RELATIVE" },
+ { R_RISCV_JAL, "R_RISCV_JAL" },
+ { R_RISCV_CALL, "R_RISCV_CALL" },
+ { R_RISCV_PCREL_HI20, "R_RISCV_PCREL_HI20" },
+ { R_RISCV_PCREL_LO12_I, "R_RISCV_PCREL_LO12_I" },
+ { R_RISCV_PCREL_LO12_S, "R_RISCV_PCREL_LO12_S" },
+ { R_RISCV_HI20, "R_RISCV_HI20" },
+ { R_RISCV_LO12_I, "R_RISCV_LO12_I" },
+ { R_RISCV_LO12_S, "R_RISCV_LO12_S" },
+};
+
+static const char*
+reloctype_to_str(int type)
+{
+ int i;
+
+ for (i = 0; i < sizeof(t2s) / sizeof(t2s[0]); ++i) {
+ if (type == t2s[i].type)
+ return t2s[i].str;
+ }
+
+ return "*unknown*";
+}
+
+/*
+ * Currently kernel loadable module for RISCV is compiled with -fPIC option.
+ * (see also additional CFLAGS definition for RISCV in sys/conf/kmod.mk)
+ * Only R_RISCV_64, R_RISCV_JUMP_SLOT and RISCV_RELATIVE are emitted in
+ * the module. Other relocations will be processed when kernel loadable
+ * modules are built in non-PIC.
+ *
+ * FIXME: only RISCV64 is supported.
+ */
static int
elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
int type, int local, elf_lookup_fn lookup)
{
+ Elf_Size rtype, symidx;
+ const Elf_Rela *rela;
+ Elf_Addr val, addr;
+ Elf64_Addr *where;
+ Elf_Addr addend;
+ uint32_t before32_1;
+ uint32_t before32;
+ uint64_t before64;
+ uint32_t* insn32p;
+ uint32_t imm20;
+ int error;
+
+ switch (type) {
+ case ELF_RELOC_RELA:
+ rela = (const Elf_Rela *)data;
+ where = (Elf_Addr *)(relocbase + rela->r_offset);
+ insn32p = (uint32_t*)where;
+ addend = rela->r_addend;
+ rtype = ELF_R_TYPE(rela->r_info);
+ symidx = ELF_R_SYM(rela->r_info);
+ break;
+ default:
+ printf("%s:%d unknown reloc type %d\n",
+ __FUNCTION__, __LINE__, type);
+ return -1;
+ }
+
+ switch (rtype) {
+ case R_RISCV_NONE:
+ break;
+
+ case R_RISCV_64:
+ case R_RISCV_JUMP_SLOT:
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
+ return -1;
+
+ val = addr;
+ before64 = *where;
+ if (*where != val)
+ *where = val;
+
+ if (debug_kld)
+ printf("%p %c %-24s %016lx -> %016lx\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before64, *where);
+ break;
+
+ case R_RISCV_RELATIVE:
+ val = relocbase + addend;
+
+ before64 = *where;
+ if (*where != val)
+ *where = val;
+
+ if (debug_kld)
+ printf("%p %c %-24s %016lx -> %016lx\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before64, *where);
+ break;
+
+ case R_RISCV_JAL:
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
+ return -1;
+
+ val = addr - (Elf_Addr)where;
+ if ((val <= -(1UL << 20) || (1UL << 20) <= val)) {
+ printf("kldload: huge offset against R_RISCV_JAL\n");
+ return -1;
+ }
+
+ before32 = *insn32p;
+ *insn32p = insert_imm(*insn32p, val, 20, 20, 31);
+ *insn32p = insert_imm(*insn32p, val, 10, 1, 21);
+ *insn32p = insert_imm(*insn32p, val, 11, 11, 20);
+ *insn32p = insert_imm(*insn32p, val, 19, 12, 12);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ case R_RISCV_CALL:
+ /*
+ * R_RISCV_CALL relocates 8-byte region that consists
+ * of the sequence of AUIPC and JALR.
+ */
+ /* calculate and check the pc relative offset. */
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
+ return -1;
+ val = addr - (Elf_Addr)where;
+ if ((val <= -(1UL << 32) || (1UL << 32) <= val)) {
+ printf("kldload:%s: huge offset against
R_RISCV_CALL\n");
+ return -1;
+ }
+
+ /* Relocate AUIPC. */
+ before32 = insn32p[0];
+ imm20 = calc_hi20_imm(val);
+ insn32p[0] = insert_imm(insn32p[0], imm20, 31, 12, 12);
+
+ /* Relocate JALR. */
+ before32_1 = insn32p[1];
+ insn32p[1] = insert_imm(insn32p[1], val, 11, 0, 20);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x %08x -> %08x %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, insn32p[0],
+ before32_1, insn32p[1]);
+ break;
+
+ case R_RISCV_PCREL_HI20:
+ val = addr - (Elf_Addr)where;
+ insn32p = (uint32_t*)where;
+ before32 = *insn32p;
+ imm20 = calc_hi20_imm(val);
+ *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ case R_RISCV_PCREL_LO12_I:
+ val = addr - (Elf_Addr)where;
+ insn32p = (uint32_t*)where;
+ before32 = *insn32p;
+ *insn32p = insert_imm(*insn32p, addr, 11, 0, 20);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ case R_RISCV_PCREL_LO12_S:
+ val = addr - (Elf_Addr)where;
+ insn32p = (uint32_t*)where;
+ before32 = *insn32p;
+ *insn32p = insert_imm(*insn32p, addr, 11, 5, 25);
+ *insn32p = insert_imm(*insn32p, addr, 4, 0, 7);
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ case R_RISCV_HI20:
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
+ return -1;
+
+ insn32p = (uint32_t*)where;
+ before32 = *insn32p;
+ imm20 = calc_hi20_imm(val);
+ *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ case R_RISCV_LO12_I:
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
+ return -1;
+
+ val = addr;
+ insn32p = (uint32_t*)where;
+ before32 = *insn32p;
+ *insn32p = insert_imm(*insn32p, addr, 11, 0, 20);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ case R_RISCV_LO12_S:
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
+ return -1;
+
+ val = addr;
+ insn32p = (uint32_t*)where;
+ before32 = *insn32p;
+ *insn32p = insert_imm(*insn32p, addr, 11, 5, 25);
+ *insn32p = insert_imm(*insn32p, addr, 4, 0, 7);
+
+ if (debug_kld)
+ printf("%p %c %-24s %08x -> %08x\n",
+ where,
+ (local? 'l': 'g'),
+ reloctype_to_str(rtype),
+ before32, *insn32p);
+ break;
+
+ default:
+ printf("kldload: unexpected relocation type %ld\n", rtype);
+ return (-1);
+ }
- panic("elf_reloc_internal");
+ return (0);
}
int
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