blob: 918a455e732848efcaf2eeb9e3cacb1456ee2101 [file] [log] [blame]
/*
* Generic intermediate code generation.
*
* Copyright (C) 2016-2017 LluĂ­s Vilanova <vilanova@ac.upc.edu>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu/error-report.h"
#include "exec/exec-all.h"
#include "exec/translator.h"
#include "exec/translate-all.h"
#include "exec/plugin-gen.h"
#include "tcg/tcg-op-common.h"
static void gen_io_start(void)
{
tcg_gen_st_i32(tcg_constant_i32(1), cpu_env,
offsetof(ArchCPU, parent_obj.can_do_io) -
offsetof(ArchCPU, env));
}
bool translator_io_start(DisasContextBase *db)
{
uint32_t cflags = tb_cflags(db->tb);
if (!(cflags & CF_USE_ICOUNT)) {
return false;
}
if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
/* Already started in translator_loop. */
return true;
}
gen_io_start();
/*
* Ensure that this instruction will be the last in the TB.
* The target may override this to something more forceful.
*/
if (db->is_jmp == DISAS_NEXT) {
db->is_jmp = DISAS_TOO_MANY;
}
return true;
}
static TCGOp *gen_tb_start(uint32_t cflags)
{
TCGv_i32 count = tcg_temp_new_i32();
TCGOp *icount_start_insn = NULL;
tcg_gen_ld_i32(count, cpu_env,
offsetof(ArchCPU, neg.icount_decr.u32) -
offsetof(ArchCPU, env));
if (cflags & CF_USE_ICOUNT) {
/*
* We emit a sub with a dummy immediate argument. Keep the insn index
* of the sub so that we later (when we know the actual insn count)
* can update the argument with the actual insn count.
*/
tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
icount_start_insn = tcg_last_op();
}
/*
* Emit the check against icount_decr.u32 to see if we should exit
* unless we suppress the check with CF_NOIRQ. If we are using
* icount and have suppressed interruption the higher level code
* should have ensured we don't run more instructions than the
* budget.
*/
if (cflags & CF_NOIRQ) {
tcg_ctx->exitreq_label = NULL;
} else {
tcg_ctx->exitreq_label = gen_new_label();
tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
}
if (cflags & CF_USE_ICOUNT) {
tcg_gen_st16_i32(count, cpu_env,
offsetof(ArchCPU, neg.icount_decr.u16.low) -
offsetof(ArchCPU, env));
/*
* cpu->can_do_io is cleared automatically here at the beginning of
* each translation block. The cost is minimal and only paid for
* -icount, plus it would be very easy to forget doing it in the
* translator. Doing it here means we don't need a gen_io_end() to
* go with gen_io_start().
*/
tcg_gen_st_i32(tcg_constant_i32(0), cpu_env,
offsetof(ArchCPU, parent_obj.can_do_io) -
offsetof(ArchCPU, env));
}
return icount_start_insn;
}
static void gen_tb_end(const TranslationBlock *tb, uint32_t cflags,
TCGOp *icount_start_insn, int num_insns)
{
if (cflags & CF_USE_ICOUNT) {
/*
* Update the num_insn immediate parameter now that we know
* the actual insn count.
*/
tcg_set_insn_param(icount_start_insn, 2,
tcgv_i32_arg(tcg_constant_i32(num_insns)));
}
if (tcg_ctx->exitreq_label) {
gen_set_label(tcg_ctx->exitreq_label);
tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
}
}
bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
{
/* Suppress goto_tb if requested. */
if (tb_cflags(db->tb) & CF_NO_GOTO_TB) {
return false;
}
/* Check for the dest on the same page as the start of the TB. */
return ((db->pc_first ^ dest) & TARGET_PAGE_MASK) == 0;
}
void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
target_ulong pc, void *host_pc,
const TranslatorOps *ops, DisasContextBase *db)
{
uint32_t cflags = tb_cflags(tb);
TCGOp *icount_start_insn;
bool plugin_enabled;
/* Initialize DisasContext */
db->tb = tb;
db->pc_first = pc;
db->pc_next = pc;
db->is_jmp = DISAS_NEXT;
db->num_insns = 0;
db->max_insns = *max_insns;
db->singlestep_enabled = cflags & CF_SINGLE_STEP;
db->host_addr[0] = host_pc;
db->host_addr[1] = NULL;
#ifdef CONFIG_USER_ONLY
page_protect(pc);
#endif
ops->init_disas_context(db, cpu);
tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
/* Start translating. */
icount_start_insn = gen_tb_start(cflags);
ops->tb_start(db, cpu);
tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
plugin_enabled = plugin_gen_tb_start(cpu, db, cflags & CF_MEMI_ONLY);
while (true) {
*max_insns = ++db->num_insns;
ops->insn_start(db, cpu);
tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
if (plugin_enabled) {
plugin_gen_insn_start(cpu, db);
}
/* Disassemble one instruction. The translate_insn hook should
update db->pc_next and db->is_jmp to indicate what should be
done next -- either exiting this loop or locate the start of
the next instruction. */
if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
/* Accept I/O on the last instruction. */
gen_io_start();
ops->translate_insn(db, cpu);
} else {
/* we should only see CF_MEMI_ONLY for io_recompile */
tcg_debug_assert(!(cflags & CF_MEMI_ONLY));
ops->translate_insn(db, cpu);
}
/*
* We can't instrument after instructions that change control
* flow although this only really affects post-load operations.
*
* Calling plugin_gen_insn_end() before we possibly stop translation
* is important. Even if this ends up as dead code, plugin generation
* needs to see a matching plugin_gen_insn_{start,end}() pair in order
* to accurately track instrumented helpers that might access memory.
*/
if (plugin_enabled) {
plugin_gen_insn_end();
}
/* Stop translation if translate_insn so indicated. */
if (db->is_jmp != DISAS_NEXT) {
break;
}
/* Stop translation if the output buffer is full,
or we have executed all of the allowed instructions. */
if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
db->is_jmp = DISAS_TOO_MANY;
break;
}
}
/* Emit code to exit the TB, as indicated by db->is_jmp. */
ops->tb_stop(db, cpu);
gen_tb_end(tb, cflags, icount_start_insn, db->num_insns);
if (plugin_enabled) {
plugin_gen_tb_end(cpu);
}
/* The disas_log hook may use these values rather than recompute. */
tb->size = db->pc_next - db->pc_first;
tb->icount = db->num_insns;
if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
&& qemu_log_in_addr_range(db->pc_first)) {
FILE *logfile = qemu_log_trylock();
if (logfile) {
fprintf(logfile, "----------------\n");
ops->disas_log(db, cpu, logfile);
fprintf(logfile, "\n");
qemu_log_unlock(logfile);
}
}
}
static void *translator_access(CPUArchState *env, DisasContextBase *db,
target_ulong pc, size_t len)
{
void *host;
target_ulong base, end;
TranslationBlock *tb;
tb = db->tb;
/* Use slow path if first page is MMIO. */
if (unlikely(tb_page_addr0(tb) == -1)) {
return NULL;
}
end = pc + len - 1;
if (likely(is_same_page(db, end))) {
host = db->host_addr[0];
base = db->pc_first;
} else {
host = db->host_addr[1];
base = TARGET_PAGE_ALIGN(db->pc_first);
if (host == NULL) {
tb_page_addr_t phys_page =
get_page_addr_code_hostp(env, base, &db->host_addr[1]);
/*
* If the second page is MMIO, treat as if the first page
* was MMIO as well, so that we do not cache the TB.
*/
if (unlikely(phys_page == -1)) {
tb_set_page_addr0(tb, -1);
return NULL;
}
tb_set_page_addr1(tb, phys_page);
#ifdef CONFIG_USER_ONLY
page_protect(end);
#endif
host = db->host_addr[1];
}
/* Use slow path when crossing pages. */
if (is_same_page(db, pc)) {
return NULL;
}
}
tcg_debug_assert(pc >= base);
return host + (pc - base);
}
static void plugin_insn_append(abi_ptr pc, const void *from, size_t size)
{
#ifdef CONFIG_PLUGIN
struct qemu_plugin_insn *insn = tcg_ctx->plugin_insn;
abi_ptr off;
if (insn == NULL) {
return;
}
off = pc - insn->vaddr;
if (off < insn->data->len) {
g_byte_array_set_size(insn->data, off);
} else if (off > insn->data->len) {
/* we have an unexpected gap */
g_assert_not_reached();
}
insn->data = g_byte_array_append(insn->data, from, size);
#endif
}
uint8_t translator_ldub(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
{
uint8_t ret;
void *p = translator_access(env, db, pc, sizeof(ret));
if (p) {
plugin_insn_append(pc, p, sizeof(ret));
return ldub_p(p);
}
ret = cpu_ldub_code(env, pc);
plugin_insn_append(pc, &ret, sizeof(ret));
return ret;
}
uint16_t translator_lduw(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
{
uint16_t ret, plug;
void *p = translator_access(env, db, pc, sizeof(ret));
if (p) {
plugin_insn_append(pc, p, sizeof(ret));
return lduw_p(p);
}
ret = cpu_lduw_code(env, pc);
plug = tswap16(ret);
plugin_insn_append(pc, &plug, sizeof(ret));
return ret;
}
uint32_t translator_ldl(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
{
uint32_t ret, plug;
void *p = translator_access(env, db, pc, sizeof(ret));
if (p) {
plugin_insn_append(pc, p, sizeof(ret));
return ldl_p(p);
}
ret = cpu_ldl_code(env, pc);
plug = tswap32(ret);
plugin_insn_append(pc, &plug, sizeof(ret));
return ret;
}
uint64_t translator_ldq(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
{
uint64_t ret, plug;
void *p = translator_access(env, db, pc, sizeof(ret));
if (p) {
plugin_insn_append(pc, p, sizeof(ret));
return ldq_p(p);
}
ret = cpu_ldq_code(env, pc);
plug = tswap64(ret);
plugin_insn_append(pc, &plug, sizeof(ret));
return ret;
}
void translator_fake_ldb(uint8_t insn8, abi_ptr pc)
{
plugin_insn_append(pc, &insn8, sizeof(insn8));
}