GDB's remote protocol requires M-profile cores to use the feature name 'org.gnu.gdb.arm.m-profile' instead of the 'org.gnu.gdb.arm.core' feature used for A- and R-profile cores. We weren't doing this, which meant GDB treated our M-profile cores like A-profile ones. This mostly doesn't matter, but for instance means that it doesn't correctly handle backtraces where an M-profile exception frame is involved. Ship a copy of GDB's arm-m-profile.xml and use it on the M-profile cores. The integer registers have the same offsets as the arm-core.xml, but register 25 is the M-profile XPSR rather than the A-profile CPSR, so we need to update arm_cpu_gdb_read_register() and arm_cpu_gdb_write_register() to handle XSPR reads and writes. Fixes: https://bugs.launchpad.net/qemu/+bug/1877136 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20200507134755.13997-1-peter.maydell@linaro.org
		
			
				
	
	
		
			335 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			335 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * ARM gdb server stub
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 *
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 * Copyright (c) 2003-2005 Fabrice Bellard
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 * Copyright (c) 2013 SUSE LINUX Products GmbH
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
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 */
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include "exec/gdbstub.h"
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typedef struct RegisterSysregXmlParam {
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    CPUState *cs;
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    GString *s;
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    int n;
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} RegisterSysregXmlParam;
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/* Old gdb always expect FPA registers.  Newer (xml-aware) gdb only expect
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   whatever the target description contains.  Due to a historical mishap
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   the FPA registers appear in between core integer regs and the CPSR.
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   We hack round this by giving the FPA regs zero size when talking to a
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   newer gdb.  */
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int arm_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
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{
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    ARMCPU *cpu = ARM_CPU(cs);
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    CPUARMState *env = &cpu->env;
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    if (n < 16) {
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        /* Core integer register.  */
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        return gdb_get_reg32(mem_buf, env->regs[n]);
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    }
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    if (n < 24) {
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        /* FPA registers.  */
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        if (gdb_has_xml) {
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            return 0;
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        }
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        return gdb_get_zeroes(mem_buf, 12);
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    }
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    switch (n) {
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    case 24:
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        /* FPA status register.  */
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        if (gdb_has_xml) {
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            return 0;
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        }
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        return gdb_get_reg32(mem_buf, 0);
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    case 25:
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        /* CPSR, or XPSR for M-profile */
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        if (arm_feature(env, ARM_FEATURE_M)) {
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            return gdb_get_reg32(mem_buf, xpsr_read(env));
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        } else {
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            return gdb_get_reg32(mem_buf, cpsr_read(env));
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        }
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    }
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    /* Unknown register.  */
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    return 0;
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}
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int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
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{
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    ARMCPU *cpu = ARM_CPU(cs);
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    CPUARMState *env = &cpu->env;
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    uint32_t tmp;
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    tmp = ldl_p(mem_buf);
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    /* Mask out low bit of PC to workaround gdb bugs.  This will probably
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       cause problems if we ever implement the Jazelle DBX extensions.  */
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    if (n == 15) {
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        tmp &= ~1;
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    }
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    if (n < 16) {
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        /* Core integer register.  */
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        env->regs[n] = tmp;
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        return 4;
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    }
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    if (n < 24) { /* 16-23 */
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        /* FPA registers (ignored).  */
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        if (gdb_has_xml) {
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            return 0;
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        }
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        return 12;
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    }
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    switch (n) {
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    case 24:
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        /* FPA status register (ignored).  */
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        if (gdb_has_xml) {
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            return 0;
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        }
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        return 4;
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    case 25:
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        /* CPSR, or XPSR for M-profile */
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        if (arm_feature(env, ARM_FEATURE_M)) {
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            /*
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             * Don't allow writing to XPSR.Exception as it can cause
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             * a transition into or out of handler mode (it's not
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             * writeable via the MSR insn so this is a reasonable
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             * restriction). Other fields are safe to update.
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             */
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            xpsr_write(env, tmp, ~XPSR_EXCP);
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        } else {
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            cpsr_write(env, tmp, 0xffffffff, CPSRWriteByGDBStub);
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        }
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        return 4;
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    }
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    /* Unknown register.  */
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    return 0;
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}
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static void arm_gen_one_xml_sysreg_tag(GString *s, DynamicGDBXMLInfo *dyn_xml,
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                                       ARMCPRegInfo *ri, uint32_t ri_key,
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                                       int bitsize, int regnum)
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{
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    g_string_append_printf(s, "<reg name=\"%s\"", ri->name);
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    g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
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    g_string_append_printf(s, " regnum=\"%d\"", regnum);
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    g_string_append_printf(s, " group=\"cp_regs\"/>");
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    dyn_xml->data.cpregs.keys[dyn_xml->num] = ri_key;
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    dyn_xml->num++;
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}
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static void arm_register_sysreg_for_xml(gpointer key, gpointer value,
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                                        gpointer p)
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{
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    uint32_t ri_key = *(uint32_t *)key;
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    ARMCPRegInfo *ri = value;
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    RegisterSysregXmlParam *param = (RegisterSysregXmlParam *)p;
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    GString *s = param->s;
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    ARMCPU *cpu = ARM_CPU(param->cs);
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    CPUARMState *env = &cpu->env;
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    DynamicGDBXMLInfo *dyn_xml = &cpu->dyn_sysreg_xml;
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    if (!(ri->type & (ARM_CP_NO_RAW | ARM_CP_NO_GDB))) {
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        if (arm_feature(env, ARM_FEATURE_AARCH64)) {
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            if (ri->state == ARM_CP_STATE_AA64) {
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                arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
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                                           param->n++);
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            }
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        } else {
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            if (ri->state == ARM_CP_STATE_AA32) {
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                if (!arm_feature(env, ARM_FEATURE_EL3) &&
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                    (ri->secure & ARM_CP_SECSTATE_S)) {
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                    return;
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                }
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                if (ri->type & ARM_CP_64BIT) {
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                    arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 64,
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                                               param->n++);
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                } else {
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                    arm_gen_one_xml_sysreg_tag(s , dyn_xml, ri, ri_key, 32,
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                                               param->n++);
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                }
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            }
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        }
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    }
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}
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int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
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{
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    ARMCPU *cpu = ARM_CPU(cs);
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    GString *s = g_string_new(NULL);
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    RegisterSysregXmlParam param = {cs, s, base_reg};
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    cpu->dyn_sysreg_xml.num = 0;
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    cpu->dyn_sysreg_xml.data.cpregs.keys = g_new(uint32_t, g_hash_table_size(cpu->cp_regs));
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    g_string_printf(s, "<?xml version=\"1.0\"?>");
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    g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
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    g_string_append_printf(s, "<feature name=\"org.qemu.gdb.arm.sys.regs\">");
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    g_hash_table_foreach(cpu->cp_regs, arm_register_sysreg_for_xml, ¶m);
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    g_string_append_printf(s, "</feature>");
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    cpu->dyn_sysreg_xml.desc = g_string_free(s, false);
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    return cpu->dyn_sysreg_xml.num;
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}
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struct TypeSize {
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    const char *gdb_type;
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    int  size;
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    const char sz, suffix;
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};
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static const struct TypeSize vec_lanes[] = {
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    /* quads */
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    { "uint128", 128, 'q', 'u' },
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    { "int128", 128, 'q', 's' },
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    /* 64 bit */
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    { "uint64", 64, 'd', 'u' },
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    { "int64", 64, 'd', 's' },
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    { "ieee_double", 64, 'd', 'f' },
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    /* 32 bit */
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    { "uint32", 32, 's', 'u' },
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    { "int32", 32, 's', 's' },
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    { "ieee_single", 32, 's', 'f' },
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    /* 16 bit */
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    { "uint16", 16, 'h', 'u' },
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    { "int16", 16, 'h', 's' },
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    /*
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     * TODO: currently there is no reliable way of telling
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     * if the remote gdb actually understands ieee_half so
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     * we don't expose it in the target description for now.
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     * { "ieee_half", 16, 'h', 'f' },
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     */
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    /* bytes */
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    { "uint8", 8, 'b', 'u' },
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    { "int8", 8, 'b', 's' },
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};
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int arm_gen_dynamic_svereg_xml(CPUState *cs, int base_reg)
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{
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    ARMCPU *cpu = ARM_CPU(cs);
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    GString *s = g_string_new(NULL);
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    DynamicGDBXMLInfo *info = &cpu->dyn_svereg_xml;
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    g_autoptr(GString) ts = g_string_new("");
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    int i, bits, reg_width = (cpu->sve_max_vq * 128);
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    info->num = 0;
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    g_string_printf(s, "<?xml version=\"1.0\"?>");
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    g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
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    g_string_append_printf(s, "<feature name=\"org.qemu.gdb.aarch64.sve\">");
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    /* First define types and totals in a whole VL */
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    for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
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        int count = reg_width / vec_lanes[i].size;
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        g_string_printf(ts, "vq%d%c%c", count,
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                        vec_lanes[i].sz, vec_lanes[i].suffix);
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        g_string_append_printf(s,
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                               "<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
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                               ts->str, vec_lanes[i].gdb_type, count);
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    }
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    /*
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     * Now define a union for each size group containing unsigned and
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     * signed and potentially float versions of each size from 128 to
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     * 8 bits.
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     */
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    for (bits = 128; bits >= 8; bits /= 2) {
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        int count = reg_width / bits;
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        g_string_append_printf(s, "<union id=\"vq%dn\">", count);
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        for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
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            if (vec_lanes[i].size == bits) {
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                g_string_append_printf(s, "<field name=\"%c\" type=\"vq%d%c%c\"/>",
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                                       vec_lanes[i].suffix,
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                                       count,
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                                       vec_lanes[i].sz, vec_lanes[i].suffix);
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            }
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        }
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        g_string_append(s, "</union>");
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    }
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    /* And now the final union of unions */
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    g_string_append(s, "<union id=\"vq\">");
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    for (bits = 128; bits >= 8; bits /= 2) {
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        int count = reg_width / bits;
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        for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
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            if (vec_lanes[i].size == bits) {
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                g_string_append_printf(s, "<field name=\"%c\" type=\"vq%dn\"/>",
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                                       vec_lanes[i].sz, count);
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                break;
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            }
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        }
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    }
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    g_string_append(s, "</union>");
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    /* Then define each register in parts for each vq */
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    for (i = 0; i < 32; i++) {
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        g_string_append_printf(s,
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                               "<reg name=\"z%d\" bitsize=\"%d\""
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                               " regnum=\"%d\" group=\"vector\""
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                               " type=\"vq\"/>",
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                               i, reg_width, base_reg++);
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        info->num++;
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    }
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    /* fpscr & status registers */
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    g_string_append_printf(s, "<reg name=\"fpsr\" bitsize=\"32\""
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                           " regnum=\"%d\" group=\"float\""
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                           " type=\"int\"/>", base_reg++);
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    g_string_append_printf(s, "<reg name=\"fpcr\" bitsize=\"32\""
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                           " regnum=\"%d\" group=\"float\""
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                           " type=\"int\"/>", base_reg++);
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    info->num += 2;
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    /*
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     * Predicate registers aren't so big they are worth splitting up
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     * but we do need to define a type to hold the array of quad
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     * references.
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     */
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    g_string_append_printf(s,
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                           "<vector id=\"vqp\" type=\"uint16\" count=\"%d\"/>",
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                           cpu->sve_max_vq);
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    for (i = 0; i < 16; i++) {
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        g_string_append_printf(s,
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                               "<reg name=\"p%d\" bitsize=\"%d\""
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                               " regnum=\"%d\" group=\"vector\""
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                               " type=\"vqp\"/>",
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                               i, cpu->sve_max_vq * 16, base_reg++);
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        info->num++;
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    }
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    g_string_append_printf(s,
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                           "<reg name=\"ffr\" bitsize=\"%d\""
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                           " regnum=\"%d\" group=\"vector\""
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                           " type=\"vqp\"/>",
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                           cpu->sve_max_vq * 16, base_reg++);
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    g_string_append_printf(s,
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                           "<reg name=\"vg\" bitsize=\"64\""
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                           " regnum=\"%d\" group=\"vector\""
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                           " type=\"uint32\"/>",
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                           base_reg++);
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    info->num += 2;
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    g_string_append_printf(s, "</feature>");
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    cpu->dyn_svereg_xml.desc = g_string_free(s, false);
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    return cpu->dyn_svereg_xml.num;
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}
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const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
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{
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    ARMCPU *cpu = ARM_CPU(cs);
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    if (strcmp(xmlname, "system-registers.xml") == 0) {
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        return cpu->dyn_sysreg_xml.desc;
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    } else if (strcmp(xmlname, "sve-registers.xml") == 0) {
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        return cpu->dyn_svereg_xml.desc;
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    }
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    return NULL;
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}
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