blob: 113edcffe35080e5bc8ae4f23782dc44cb263824 [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/cpu_ldst.h"
#include "exec/plugin-gen.h"
#include "exec/cpu_ldst.h"
#include "tcg/tcg-op-common.h"
#include "internal-target.h"
#include "disas/disas.h"
static void set_can_do_io(DisasContextBase *db, bool val)
{
QEMU_BUILD_BUG_ON(sizeof_field(CPUState, neg.can_do_io) != 1);
tcg_gen_st8_i32(tcg_constant_i32(val), tcg_env,
offsetof(ArchCPU, parent_obj.neg.can_do_io) -
offsetof(ArchCPU, env));
}
bool translator_io_start(DisasContextBase *db)
{
/*
* 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(DisasContextBase *db, uint32_t cflags)
{
TCGv_i32 count = NULL;
TCGOp *icount_start_insn = NULL;
if ((cflags & CF_USE_ICOUNT) || !(cflags & CF_NOIRQ)) {
count = tcg_temp_new_i32();
tcg_gen_ld_i32(count, tcg_env,
offsetof(ArchCPU, parent_obj.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, tcg_env,
offsetof(ArchCPU, parent_obj.neg.icount_decr.u16.low)
- 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, vaddr 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,
vaddr pc, void *host_pc, const TranslatorOps *ops,
DisasContextBase *db)
{
uint32_t cflags = tb_cflags(tb);
TCGOp *icount_start_insn;
TCGOp *first_insn_start = NULL;
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->insn_start = NULL;
db->fake_insn = false;
db->host_addr[0] = host_pc;
db->host_addr[1] = NULL;
db->record_start = 0;
db->record_len = 0;
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(db, 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);
db->plugin_enabled = plugin_enabled;
while (true) {
*max_insns = ++db->num_insns;
ops->insn_start(db, cpu);
db->insn_start = tcg_last_op();
if (first_insn_start == NULL) {
first_insn_start = db->insn_start;
}
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.
*/
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);
/*
* Manage can_do_io for the translation block: set to false before
* the first insn and set to true before the last insn.
*/
if (db->num_insns == 1) {
tcg_debug_assert(first_insn_start == db->insn_start);
} else {
tcg_debug_assert(first_insn_start != db->insn_start);
tcg_ctx->emit_before_op = first_insn_start;
set_can_do_io(db, false);
}
tcg_ctx->emit_before_op = db->insn_start;
set_can_do_io(db, true);
tcg_ctx->emit_before_op = NULL;
/* May be used by disas_log or plugin callbacks. */
tb->size = db->pc_next - db->pc_first;
tb->icount = db->num_insns;
if (plugin_enabled) {
plugin_gen_tb_end(cpu, 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");
if (!ops->disas_log ||
!ops->disas_log(db, cpu, logfile)) {
fprintf(logfile, "IN: %s\n", lookup_symbol(db->pc_first));
target_disas(logfile, cpu, db);
}
fprintf(logfile, "\n");
qemu_log_unlock(logfile);
}
}
}
static bool translator_ld(CPUArchState *env, DisasContextBase *db,
void *dest, vaddr pc, size_t len)
{
TranslationBlock *tb = db->tb;
vaddr last = pc + len - 1;
void *host;
vaddr base;
/* Use slow path if first page is MMIO. */
if (unlikely(tb_page_addr0(tb) == -1)) {
/* We capped translation with first page MMIO in tb_gen_code. */
tcg_debug_assert(db->max_insns == 1);
return false;
}
host = db->host_addr[0];
base = db->pc_first;
if (likely(((base ^ last) & TARGET_PAGE_MASK) == 0)) {
/* Entire read is from the first page. */
memcpy(dest, host + (pc - base), len);
return true;
}
if (unlikely(((base ^ pc) & TARGET_PAGE_MASK) == 0)) {
/* Read begins on the first page and extends to the second. */
size_t len0 = -(pc | TARGET_PAGE_MASK);
memcpy(dest, host + (pc - base), len0);
pc += len0;
dest += len0;
len -= len0;
}
/*
* The read must conclude on the second page and not extend to a third.
*
* TODO: We could allow the two pages to be virtually discontiguous,
* since we already allow the two pages to be physically discontiguous.
* The only reasonable use case would be executing an insn at the end
* of the address space wrapping around to the beginning. For that,
* we would need to know the current width of the address space.
* In the meantime, assert.
*/
base = (base & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
assert(((base ^ pc) & TARGET_PAGE_MASK) == 0);
assert(((base ^ last) & TARGET_PAGE_MASK) == 0);
host = db->host_addr[1];
if (host == NULL) {
tb_page_addr_t page0, old_page1, new_page1;
new_page1 = 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(new_page1 == -1)) {
tb_unlock_pages(tb);
tb_set_page_addr0(tb, -1);
/* Require that this be the final insn. */
db->max_insns = db->num_insns;
return false;
}
/*
* If this is not the first time around, and page1 matches,
* then we already have the page locked. Alternately, we're
* not doing anything to prevent the PTE from changing, so
* we might wind up with a different page, requiring us to
* re-do the locking.
*/
old_page1 = tb_page_addr1(tb);
if (likely(new_page1 != old_page1)) {
page0 = tb_page_addr0(tb);
if (unlikely(old_page1 != -1)) {
tb_unlock_page1(page0, old_page1);
}
tb_set_page_addr1(tb, new_page1);
tb_lock_page1(page0, new_page1);
}
host = db->host_addr[1];
}
memcpy(dest, host + (pc - base), len);
return true;
}
static void record_save(DisasContextBase *db, vaddr pc,
const void *from, int size)
{
int offset;
/* Do not record probes before the start of TB. */
if (pc < db->pc_first) {
return;
}
/*
* In translator_access, we verified that pc is within 2 pages
* of pc_first, thus this will never overflow.
*/
offset = pc - db->pc_first;
/*
* Either the first or second page may be I/O. If it is the second,
* then the first byte we need to record will be at a non-zero offset.
* In either case, we should not need to record but a single insn.
*/
if (db->record_len == 0) {
db->record_start = offset;
db->record_len = size;
} else {
assert(offset == db->record_start + db->record_len);
assert(db->record_len + size <= sizeof(db->record));
db->record_len += size;
}
memcpy(db->record + (offset - db->record_start), from, size);
}
size_t translator_st_len(const DisasContextBase *db)
{
return db->fake_insn ? db->record_len : db->tb->size;
}
bool translator_st(const DisasContextBase *db, void *dest,
vaddr addr, size_t len)
{
size_t offset, offset_end;
if (addr < db->pc_first) {
return false;
}
offset = addr - db->pc_first;
offset_end = offset + len;
if (offset_end > translator_st_len(db)) {
return false;
}
if (!db->fake_insn) {
size_t offset_page1 = -(db->pc_first | TARGET_PAGE_MASK);
/* Get all the bytes from the first page. */
if (db->host_addr[0]) {
if (offset_end <= offset_page1) {
memcpy(dest, db->host_addr[0] + offset, len);
return true;
}
if (offset < offset_page1) {
size_t len0 = offset_page1 - offset;
memcpy(dest, db->host_addr[0] + offset, len0);
offset += len0;
dest += len0;
}
}
/* Get any bytes from the second page. */
if (db->host_addr[1] && offset >= offset_page1) {
memcpy(dest, db->host_addr[1] + (offset - offset_page1),
offset_end - offset);
return true;
}
}
/* Else get recorded bytes. */
if (db->record_len != 0 &&
offset >= db->record_start &&
offset_end <= db->record_start + db->record_len) {
memcpy(dest, db->record + (offset - db->record_start),
offset_end - offset);
return true;
}
return false;
}
uint8_t translator_ldub(CPUArchState *env, DisasContextBase *db, vaddr pc)
{
uint8_t raw;
if (!translator_ld(env, db, &raw, pc, sizeof(raw))) {
raw = cpu_ldub_code(env, pc);
record_save(db, pc, &raw, sizeof(raw));
}
return raw;
}
uint16_t translator_lduw(CPUArchState *env, DisasContextBase *db, vaddr pc)
{
uint16_t raw, tgt;
if (translator_ld(env, db, &raw, pc, sizeof(raw))) {
tgt = tswap16(raw);
} else {
tgt = cpu_lduw_code(env, pc);
raw = tswap16(tgt);
record_save(db, pc, &raw, sizeof(raw));
}
return tgt;
}
uint32_t translator_ldl(CPUArchState *env, DisasContextBase *db, vaddr pc)
{
uint32_t raw, tgt;
if (translator_ld(env, db, &raw, pc, sizeof(raw))) {
tgt = tswap32(raw);
} else {
tgt = cpu_ldl_code(env, pc);
raw = tswap32(tgt);
record_save(db, pc, &raw, sizeof(raw));
}
return tgt;
}
uint64_t translator_ldq(CPUArchState *env, DisasContextBase *db, vaddr pc)
{
uint64_t raw, tgt;
if (translator_ld(env, db, &raw, pc, sizeof(raw))) {
tgt = tswap64(raw);
} else {
tgt = cpu_ldq_code(env, pc);
raw = tswap64(tgt);
record_save(db, pc, &raw, sizeof(raw));
}
return tgt;
}
void translator_fake_ld(DisasContextBase *db, const void *data, size_t len)
{
db->fake_insn = true;
record_save(db, db->pc_first, data, len);
}