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qemu/target/arm/gdbstub.c
Peter Maydell dbd9e08476 target/arm: Advertise MVE to gdb when present 
Cortex-M CPUs with MVE should advertise this fact to gdb, using the
org.gnu.gdb.arm.m-profile-mve XML feature, which defines the VPR
register.  Presence of this feature also tells gdb to create
pseudo-registers Q0..Q7, so we do not need to tell gdb about them
separately.

Note that unless you have a very recent GDB that includes this fix:
http://patches-tcwg.linaro.org/patch/58133/ gdb will mis-print the
individual fields of the VPR register as zero (but showing the whole
thing as hex, eg with "print /x $vpr" will give the correct value).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20211101160814.5103-1-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-11-02 14:14:55 -04:00

501 lines
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/*
* ARM gdb server stub
*
* Copyright (c) 2003-2005 Fabrice Bellard
* Copyright (c) 2013 SUSE LINUX Products GmbH
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "internals.h"
#include "exec/gdbstub.h"
typedef struct RegisterSysregXmlParam {
CPUState *cs;
GString *s;
int n;
} RegisterSysregXmlParam;
/* Old gdb always expect FPA registers. Newer (xml-aware) gdb only expect
whatever the target description contains. Due to a historical mishap
the FPA registers appear in between core integer regs and the CPSR.
We hack round this by giving the FPA regs zero size when talking to a
newer gdb. */
int arm_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
if (n < 16) {
/* Core integer register. */
return gdb_get_reg32(mem_buf, env->regs[n]);
}
if (n < 24) {
/* FPA registers. */
if (gdb_has_xml) {
return 0;
}
return gdb_get_zeroes(mem_buf, 12);
}
switch (n) {
case 24:
/* FPA status register. */
if (gdb_has_xml) {
return 0;
}
return gdb_get_reg32(mem_buf, 0);
case 25:
/* CPSR, or XPSR for M-profile */
if (arm_feature(env, ARM_FEATURE_M)) {
return gdb_get_reg32(mem_buf, xpsr_read(env));
} else {
return gdb_get_reg32(mem_buf, cpsr_read(env));
}
}
/* Unknown register. */
return 0;
}
int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
uint32_t tmp;
tmp = ldl_p(mem_buf);
/* Mask out low bit of PC to workaround gdb bugs. This will probably
cause problems if we ever implement the Jazelle DBX extensions. */
if (n == 15) {
tmp &= ~1;
}
if (n < 16) {
/* Core integer register. */
if (n == 13 && arm_feature(env, ARM_FEATURE_M)) {
/* M profile SP low bits are always 0 */
tmp &= ~3;
}
env->regs[n] = tmp;
return 4;
}
if (n < 24) { /* 16-23 */
/* FPA registers (ignored). */
if (gdb_has_xml) {
return 0;
}
return 12;
}
switch (n) {
case 24:
/* FPA status register (ignored). */
if (gdb_has_xml) {
return 0;
}
return 4;
case 25:
/* CPSR, or XPSR for M-profile */
if (arm_feature(env, ARM_FEATURE_M)) {
/*
* Don't allow writing to XPSR.Exception as it can cause
* a transition into or out of handler mode (it's not
* writeable via the MSR insn so this is a reasonable
* restriction). Other fields are safe to update.
*/
xpsr_write(env, tmp, ~XPSR_EXCP);
} else {
cpsr_write(env, tmp, 0xffffffff, CPSRWriteByGDBStub);
}
return 4;
}
/* Unknown register. */
return 0;
}
static int vfp_gdb_get_reg(CPUARMState *env, GByteArray *buf, int reg)
{
ARMCPU *cpu = env_archcpu(env);
int nregs = cpu_isar_feature(aa32_simd_r32, cpu) ? 32 : 16;
/* VFP data registers are always little-endian. */
if (reg < nregs) {
return gdb_get_reg64(buf, *aa32_vfp_dreg(env, reg));
}
if (arm_feature(env, ARM_FEATURE_NEON)) {
/* Aliases for Q regs. */
nregs += 16;
if (reg < nregs) {
uint64_t *q = aa32_vfp_qreg(env, reg - 32);
return gdb_get_reg128(buf, q[0], q[1]);
}
}
switch (reg - nregs) {
case 0:
return gdb_get_reg32(buf, vfp_get_fpscr(env));
}
return 0;
}
static int vfp_gdb_set_reg(CPUARMState *env, uint8_t *buf, int reg)
{
ARMCPU *cpu = env_archcpu(env);
int nregs = cpu_isar_feature(aa32_simd_r32, cpu) ? 32 : 16;
if (reg < nregs) {
*aa32_vfp_dreg(env, reg) = ldq_le_p(buf);
return 8;
}
if (arm_feature(env, ARM_FEATURE_NEON)) {
nregs += 16;
if (reg < nregs) {
uint64_t *q = aa32_vfp_qreg(env, reg - 32);
q[0] = ldq_le_p(buf);
q[1] = ldq_le_p(buf + 8);
return 16;
}
}
switch (reg - nregs) {
case 0:
vfp_set_fpscr(env, ldl_p(buf));
return 4;
}
return 0;
}
static int vfp_gdb_get_sysreg(CPUARMState *env, GByteArray *buf, int reg)
{
switch (reg) {
case 0:
return gdb_get_reg32(buf, env->vfp.xregs[ARM_VFP_FPSID]);
case 1:
return gdb_get_reg32(buf, env->vfp.xregs[ARM_VFP_FPEXC]);
}
return 0;
}
static int vfp_gdb_set_sysreg(CPUARMState *env, uint8_t *buf, int reg)
{
switch (reg) {
case 0:
env->vfp.xregs[ARM_VFP_FPSID] = ldl_p(buf);
return 4;
case 1:
env->vfp.xregs[ARM_VFP_FPEXC] = ldl_p(buf) & (1 << 30);
return 4;
}
return 0;
}
static int mve_gdb_get_reg(CPUARMState *env, GByteArray *buf, int reg)
{
switch (reg) {
case 0:
return gdb_get_reg32(buf, env->v7m.vpr);
default:
return 0;
}
}
static int mve_gdb_set_reg(CPUARMState *env, uint8_t *buf, int reg)
{
switch (reg) {
case 0:
env->v7m.vpr = ldl_p(buf);
return 4;
default:
return 0;
}
}
/**
* arm_get/set_gdb_*: get/set a gdb register
* @env: the CPU state
* @buf: a buffer to copy to/from
* @reg: register number (offset from start of group)
*
* We return the number of bytes copied
*/
static int arm_gdb_get_sysreg(CPUARMState *env, GByteArray *buf, int reg)
{
ARMCPU *cpu = env_archcpu(env);
const ARMCPRegInfo *ri;
uint32_t key;
key = cpu->dyn_sysreg_xml.data.cpregs.keys[reg];
ri = get_arm_cp_reginfo(cpu->cp_regs, key);
if (ri) {
if (cpreg_field_is_64bit(ri)) {
return gdb_get_reg64(buf, (uint64_t)read_raw_cp_reg(env, ri));
} else {
return gdb_get_reg32(buf, (uint32_t)read_raw_cp_reg(env, ri));
}
}
return 0;
}
static int arm_gdb_set_sysreg(CPUARMState *env, uint8_t *buf, int reg)
{
return 0;
}
static void arm_gen_one_xml_sysreg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
ARMCPRegInfo *ri, uint32_t ri_key,
int bitsize, int regnum)
{
g_string_append_printf(s, "<reg name=\"%s\"", ri->name);
g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
g_string_append_printf(s, " regnum=\"%d\"", regnum);
g_string_append_printf(s, " group=\"cp_regs\"/>");
dyn_xml->data.cpregs.keys[dyn_xml->num] = ri_key;
dyn_xml->num++;
}
static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
gpointer p)
{
uint32_t ri_key = *(uint32_t *)key;
ARMCPRegInfo *ri = value;
RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
GString *s = param->s;
ARMCPU *cpu = ARM_CPU(param->cs);
CPUARMState *env = &cpu->env;
DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_sysreg_xml;
if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
if (arm_feature(env, ARM_FEATURE_AARCH64)) {
if (ri->state == ARM_CP_STATE_AA64) {
arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
param->n++);
}
} else {
if (ri->state == ARM_CP_STATE_AA32) {
if (!arm_feature(env, ARM_FEATURE_EL3) &&
(ri->secure & ARM_CP_SECSTATE_S)) {
return;
}
if (ri->type & ARM_CP_64BIT) {
arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
param->n++);
} else {
arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 32,
param->n++);
}
}
}
}
}
int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
{
ARMCPU *cpu = ARM_CPU(cs);
GString *s = g_string_new(NULL);
RegisterSysregXmlParam param = {cs, s, base_reg};
cpu->dyn_sysreg_xml.num = 0;
cpu->dyn_sysreg_xml.data.cpregs.keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
g_string_printf(s, "<?xml version=\"1.0\"?>");
g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, &param);
g_string_append_printf(s, "</feature>");
cpu->dyn_sysreg_xml.desc = g_string_free(s, false);
return cpu->dyn_sysreg_xml.num;
}
struct TypeSize {
const char *gdb_type;
int size;
const char sz, suffix;
};
static const struct TypeSize vec_lanes[] = {
/* quads */
{ "uint128", 128, 'q', 'u' },
{ "int128", 128, 'q', 's' },
/* 64 bit */
{ "ieee_double", 64, 'd', 'f' },
{ "uint64", 64, 'd', 'u' },
{ "int64", 64, 'd', 's' },
/* 32 bit */
{ "ieee_single", 32, 's', 'f' },
{ "uint32", 32, 's', 'u' },
{ "int32", 32, 's', 's' },
/* 16 bit */
{ "ieee_half", 16, 'h', 'f' },
{ "uint16", 16, 'h', 'u' },
{ "int16", 16, 'h', 's' },
/* bytes */
{ "uint8", 8, 'b', 'u' },
{ "int8", 8, 'b', 's' },
};
int arm_gen_dynamic_svereg_xml(CPUState *cs, int base_reg)
{
ARMCPU *cpu = ARM_CPU(cs);
GString *s = g_string_new(NULL);
DynamicGDBXMLInfo *info = &cpu->dyn_svereg_xml;
g_autoptr(GString) ts = g_string_new("");
int i, j, bits, reg_width = (cpu->sve_max_vq * 128);
info->num = 0;
g_string_printf(s, "<?xml version=\"1.0\"?>");
g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
g_string_append_printf(s, "<feature name=\"org.gnu.gdb.aarch64.sve\">");
/* First define types and totals in a whole VL */
for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
int count = reg_width / vec_lanes[i].size;
g_string_printf(ts, "svev%c%c", vec_lanes[i].sz, vec_lanes[i].suffix);
g_string_append_printf(s,
"<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
ts->str, vec_lanes[i].gdb_type, count);
}
/*
* Now define a union for each size group containing unsigned and
* signed and potentially float versions of each size from 128 to
* 8 bits.
*/
for (bits = 128, i = 0; bits >= 8; bits /= 2, i++) {
const char suf[] = { 'q', 'd', 's', 'h', 'b' };
g_string_append_printf(s, "<union id=\"svevn%c\">", suf[i]);
for (j = 0; j < ARRAY_SIZE(vec_lanes); j++) {
if (vec_lanes[j].size == bits) {
g_string_append_printf(s, "<field name=\"%c\" type=\"svev%c%c\"/>",
vec_lanes[j].suffix,
vec_lanes[j].sz, vec_lanes[j].suffix);
}
}
g_string_append(s, "</union>");
}
/* And now the final union of unions */
g_string_append(s, "<union id=\"svev\">");
for (bits = 128, i = 0; bits >= 8; bits /= 2, i++) {
const char suf[] = { 'q', 'd', 's', 'h', 'b' };
g_string_append_printf(s, "<field name=\"%c\" type=\"svevn%c\"/>",
suf[i], suf[i]);
}
g_string_append(s, "</union>");
/* Finally the sve prefix type */
g_string_append_printf(s,
"<vector id=\"svep\" type=\"uint8\" count=\"%d\"/>",
reg_width / 8);
/* Then define each register in parts for each vq */
for (i = 0; i < 32; i++) {
g_string_append_printf(s,
"<reg name=\"z%d\" bitsize=\"%d\""
" regnum=\"%d\" type=\"svev\"/>",
i, reg_width, base_reg++);
info->num++;
}
/* fpscr & status registers */
g_string_append_printf(s, "<reg name=\"fpsr\" bitsize=\"32\""
" regnum=\"%d\" group=\"float\""
" type=\"int\"/>", base_reg++);
g_string_append_printf(s, "<reg name=\"fpcr\" bitsize=\"32\""
" regnum=\"%d\" group=\"float\""
" type=\"int\"/>", base_reg++);
info->num += 2;
for (i = 0; i < 16; i++) {
g_string_append_printf(s,
"<reg name=\"p%d\" bitsize=\"%d\""
" regnum=\"%d\" type=\"svep\"/>",
i, cpu->sve_max_vq * 16, base_reg++);
info->num++;
}
g_string_append_printf(s,
"<reg name=\"ffr\" bitsize=\"%d\""
" regnum=\"%d\" group=\"vector\""
" type=\"svep\"/>",
cpu->sve_max_vq * 16, base_reg++);
g_string_append_printf(s,
"<reg name=\"vg\" bitsize=\"64\""
" regnum=\"%d\" type=\"int\"/>",
base_reg++);
info->num += 2;
g_string_append_printf(s, "</feature>");
cpu->dyn_svereg_xml.desc = g_string_free(s, false);
return cpu->dyn_svereg_xml.num;
}
const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
{
ARMCPU *cpu = ARM_CPU(cs);
if (strcmp(xmlname, "system-registers.xml") == 0) {
return cpu->dyn_sysreg_xml.desc;
} else if (strcmp(xmlname, "sve-registers.xml") == 0) {
return cpu->dyn_svereg_xml.desc;
}
return NULL;
}
void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)
{
CPUState *cs = CPU(cpu);
CPUARMState *env = &cpu->env;
if (arm_feature(env, ARM_FEATURE_AARCH64)) {
/*
* The lower part of each SVE register aliases to the FPU
* registers so we don't need to include both.
*/
#ifdef TARGET_AARCH64
if (isar_feature_aa64_sve(&cpu->isar)) {
gdb_register_coprocessor(cs, arm_gdb_get_svereg, arm_gdb_set_svereg,
arm_gen_dynamic_svereg_xml(cs, cs->gdb_num_regs),
"sve-registers.xml", 0);
} else {
gdb_register_coprocessor(cs, aarch64_fpu_gdb_get_reg,
aarch64_fpu_gdb_set_reg,
34, "aarch64-fpu.xml", 0);
}
#endif
} else {
if (arm_feature(env, ARM_FEATURE_NEON)) {
gdb_register_coprocessor(cs, vfp_gdb_get_reg, vfp_gdb_set_reg,
49, "arm-neon.xml", 0);
} else if (cpu_isar_feature(aa32_simd_r32, cpu)) {
gdb_register_coprocessor(cs, vfp_gdb_get_reg, vfp_gdb_set_reg,
33, "arm-vfp3.xml", 0);
} else if (cpu_isar_feature(aa32_vfp_simd, cpu)) {
gdb_register_coprocessor(cs, vfp_gdb_get_reg, vfp_gdb_set_reg,
17, "arm-vfp.xml", 0);
}
if (!arm_feature(env, ARM_FEATURE_M)) {
/*
* A and R profile have FP sysregs FPEXC and FPSID that we
* expose to gdb.
*/
gdb_register_coprocessor(cs, vfp_gdb_get_sysreg, vfp_gdb_set_sysreg,
2, "arm-vfp-sysregs.xml", 0);
}
}
if (cpu_isar_feature(aa32_mve, cpu)) {
gdb_register_coprocessor(cs, mve_gdb_get_reg, mve_gdb_set_reg,
1, "arm-m-profile-mve.xml", 0);
}
gdb_register_coprocessor(cs, arm_gdb_get_sysreg, arm_gdb_set_sysreg,
arm_gen_dynamic_sysreg_xml(cs, cs->gdb_num_regs),
"system-registers.xml", 0);
}
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