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qemu/target/arm/gdbstub.c
Peter Maydell 7bdd67a560 target/arm: Report pauth information to gdb as 'pauth_v2' 
So that we can avoid the "older gdb crashes" problem described in
commit 5787d17a42 and which caused us to disable reporting pauth
information via the gdbstub, newer gdb is going to implement support
for recognizing the pauth information via a new feature name:
 org.gnu.gdb.aarch64.pauth_v2

Older gdb won't recognize this feature name, so we can re-enable the
pauth support under the new name without risking them crashing.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230406150827.3322670-1-peter.maydell@linaro.org
2023-04-20 10:21:16 +01:00

579 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 "exec/gdbstub.h"
#include "gdbstub/helpers.h"
#include "sysemu/tcg.h"
#include "internals.h"
#include "cpregs.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 bits of PC to workaround gdb bugs.
* This avoids an assert in thumb_tr_translate_insn, because it is
* architecturally impossible to misalign the pc.
* 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
* writable 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 = (uintptr_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++);
}
}
}
}
}
static 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;
}
typedef enum {
M_SYSREG_MSP,
M_SYSREG_PSP,
M_SYSREG_PRIMASK,
M_SYSREG_CONTROL,
M_SYSREG_BASEPRI,
M_SYSREG_FAULTMASK,
M_SYSREG_MSPLIM,
M_SYSREG_PSPLIM,
} MProfileSysreg;
static const struct {
const char *name;
int feature;
} m_sysreg_def[] = {
[M_SYSREG_MSP] = { "msp", ARM_FEATURE_M },
[M_SYSREG_PSP] = { "psp", ARM_FEATURE_M },
[M_SYSREG_PRIMASK] = { "primask", ARM_FEATURE_M },
[M_SYSREG_CONTROL] = { "control", ARM_FEATURE_M },
[M_SYSREG_BASEPRI] = { "basepri", ARM_FEATURE_M_MAIN },
[M_SYSREG_FAULTMASK] = { "faultmask", ARM_FEATURE_M_MAIN },
[M_SYSREG_MSPLIM] = { "msplim", ARM_FEATURE_V8 },
[M_SYSREG_PSPLIM] = { "psplim", ARM_FEATURE_V8 },
};
static uint32_t *m_sysreg_ptr(CPUARMState *env, MProfileSysreg reg, bool sec)
{
uint32_t *ptr;
switch (reg) {
case M_SYSREG_MSP:
ptr = arm_v7m_get_sp_ptr(env, sec, false, true);
break;
case M_SYSREG_PSP:
ptr = arm_v7m_get_sp_ptr(env, sec, true, true);
break;
case M_SYSREG_MSPLIM:
ptr = &env->v7m.msplim[sec];
break;
case M_SYSREG_PSPLIM:
ptr = &env->v7m.psplim[sec];
break;
case M_SYSREG_PRIMASK:
ptr = &env->v7m.primask[sec];
break;
case M_SYSREG_BASEPRI:
ptr = &env->v7m.basepri[sec];
break;
case M_SYSREG_FAULTMASK:
ptr = &env->v7m.faultmask[sec];
break;
case M_SYSREG_CONTROL:
ptr = &env->v7m.control[sec];
break;
default:
return NULL;
}
return arm_feature(env, m_sysreg_def[reg].feature) ? ptr : NULL;
}
static int m_sysreg_get(CPUARMState *env, GByteArray *buf,
MProfileSysreg reg, bool secure)
{
uint32_t *ptr = m_sysreg_ptr(env, reg, secure);
if (ptr == NULL) {
return 0;
}
return gdb_get_reg32(buf, *ptr);
}
static int arm_gdb_get_m_systemreg(CPUARMState *env, GByteArray *buf, int reg)
{
/*
* Here, we emulate MRS instruction, where CONTROL has a mix of
* banked and non-banked bits.
*/
if (reg == M_SYSREG_CONTROL) {
return gdb_get_reg32(buf, arm_v7m_mrs_control(env, env->v7m.secure));
}
return m_sysreg_get(env, buf, reg, env->v7m.secure);
}
static int arm_gdb_set_m_systemreg(CPUARMState *env, uint8_t *buf, int reg)
{
return 0; /* TODO */
}
static int arm_gen_dynamic_m_systemreg_xml(CPUState *cs, int orig_base_reg)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
GString *s = g_string_new(NULL);
int base_reg = orig_base_reg;
int i;
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.arm.m-system\">\n");
for (i = 0; i < ARRAY_SIZE(m_sysreg_def); i++) {
if (arm_feature(env, m_sysreg_def[i].feature)) {
g_string_append_printf(s,
"<reg name=\"%s\" bitsize=\"32\" regnum=\"%d\"/>\n",
m_sysreg_def[i].name, base_reg++);
}
}
g_string_append_printf(s, "</feature>");
cpu->dyn_m_systemreg_xml.desc = g_string_free(s, false);
cpu->dyn_m_systemreg_xml.num = base_reg - orig_base_reg;
return cpu->dyn_m_systemreg_xml.num;
}
#ifndef CONFIG_USER_ONLY
/*
* For user-only, we see the non-secure registers via m_systemreg above.
* For secext, encode the non-secure view as even and secure view as odd.
*/
static int arm_gdb_get_m_secextreg(CPUARMState *env, GByteArray *buf, int reg)
{
return m_sysreg_get(env, buf, reg >> 1, reg & 1);
}
static int arm_gdb_set_m_secextreg(CPUARMState *env, uint8_t *buf, int reg)
{
return 0; /* TODO */
}
static int arm_gen_dynamic_m_secextreg_xml(CPUState *cs, int orig_base_reg)
{
ARMCPU *cpu = ARM_CPU(cs);
GString *s = g_string_new(NULL);
int base_reg = orig_base_reg;
int i;
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.arm.secext\">\n");
for (i = 0; i < ARRAY_SIZE(m_sysreg_def); i++) {
g_string_append_printf(s,
"<reg name=\"%s_ns\" bitsize=\"32\" regnum=\"%d\"/>\n",
m_sysreg_def[i].name, base_reg++);
g_string_append_printf(s,
"<reg name=\"%s_s\" bitsize=\"32\" regnum=\"%d\"/>\n",
m_sysreg_def[i].name, base_reg++);
}
g_string_append_printf(s, "</feature>");
cpu->dyn_m_secextreg_xml.desc = g_string_free(s, false);
cpu->dyn_m_secextreg_xml.num = base_reg - orig_base_reg;
return cpu->dyn_m_secextreg_xml.num;
}
#endif
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;
} else if (strcmp(xmlname, "arm-m-system.xml") == 0) {
return cpu->dyn_m_systemreg_xml.desc;
#ifndef CONFIG_USER_ONLY
} else if (strcmp(xmlname, "arm-m-secext.xml") == 0) {
return cpu->dyn_m_secextreg_xml.desc;
#endif
}
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)) {
int nreg = arm_gen_dynamic_svereg_xml(cs, cs->gdb_num_regs);
gdb_register_coprocessor(cs, aarch64_gdb_get_sve_reg,
aarch64_gdb_set_sve_reg, nreg,
"sve-registers.xml", 0);
} else {
gdb_register_coprocessor(cs, aarch64_gdb_get_fpu_reg,
aarch64_gdb_set_fpu_reg,
34, "aarch64-fpu.xml", 0);
}
/*
* Note that we report pauth information via the feature name
* org.gnu.gdb.aarch64.pauth_v2, not org.gnu.gdb.aarch64.pauth.
* GDB versions 9 through 12 have a bug where they will crash
* if they see the latter XML from QEMU.
*/
if (isar_feature_aa64_pauth(&cpu->isar)) {
gdb_register_coprocessor(cs, aarch64_gdb_get_pauth_reg,
aarch64_gdb_set_pauth_reg,
4, "aarch64-pauth.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) && tcg_enabled()) {
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);
if (arm_feature(env, ARM_FEATURE_M) && tcg_enabled()) {
gdb_register_coprocessor(cs,
arm_gdb_get_m_systemreg, arm_gdb_set_m_systemreg,
arm_gen_dynamic_m_systemreg_xml(cs, cs->gdb_num_regs),
"arm-m-system.xml", 0);
#ifndef CONFIG_USER_ONLY
if (arm_feature(env, ARM_FEATURE_M_SECURITY)) {
gdb_register_coprocessor(cs,
arm_gdb_get_m_secextreg, arm_gdb_set_m_secextreg,
arm_gen_dynamic_m_secextreg_xml(cs, cs->gdb_num_regs),
"arm-m-secext.xml", 0);
}
#endif
}
}
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