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qemu/target/arm/debug_helper.c
Alex Bennée f654387b81 target/arm: hide all versions of DBGD[RS]AR from gdbstub 
This avoids two duplicates being presented to gdbstub. As the
registers are RAZ anyway it is unlikely their value would be of use to
someone using gdbstub anyway.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231106185112.2755262-5-alex.bennee@linaro.org>
2023-11-08 15:15:23 +00:00

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/*
* ARM debug helpers.
*
* This code is licensed under the GNU GPL v2 or later.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "cpu.h"
#include "internals.h"
#include "cpu-features.h"
#include "cpregs.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include "sysemu/tcg.h"
#ifdef CONFIG_TCG
/* Return the Exception Level targeted by debug exceptions. */
static int arm_debug_target_el(CPUARMState *env)
{
bool secure = arm_is_secure(env);
bool route_to_el2 = false;
if (arm_feature(env, ARM_FEATURE_M)) {
return 1;
}
if (arm_is_el2_enabled(env)) {
route_to_el2 = env->cp15.hcr_el2 & HCR_TGE ||
env->cp15.mdcr_el2 & MDCR_TDE;
}
if (route_to_el2) {
return 2;
} else if (arm_feature(env, ARM_FEATURE_EL3) &&
!arm_el_is_aa64(env, 3) && secure) {
return 3;
} else {
return 1;
}
}
/*
* Raise an exception to the debug target el.
* Modify syndrome to indicate when origin and target EL are the same.
*/
G_NORETURN static void
raise_exception_debug(CPUARMState *env, uint32_t excp, uint32_t syndrome)
{
int debug_el = arm_debug_target_el(env);
int cur_el = arm_current_el(env);
/*
* If singlestep is targeting a lower EL than the current one, then
* DisasContext.ss_active must be false and we can never get here.
* Similarly for watchpoint and breakpoint matches.
*/
assert(debug_el >= cur_el);
syndrome |= (debug_el == cur_el) << ARM_EL_EC_SHIFT;
raise_exception(env, excp, syndrome, debug_el);
}
/* See AArch64.GenerateDebugExceptionsFrom() in ARM ARM pseudocode */
static bool aa64_generate_debug_exceptions(CPUARMState *env)
{
int cur_el = arm_current_el(env);
int debug_el;
if (cur_el == 3) {
return false;
}
/* MDCR_EL3.SDD disables debug events from Secure state */
if (arm_is_secure_below_el3(env)
&& extract32(env->cp15.mdcr_el3, 16, 1)) {
return false;
}
/*
* Same EL to same EL debug exceptions need MDSCR_KDE enabled
* while not masking the (D)ebug bit in DAIF.
*/
debug_el = arm_debug_target_el(env);
if (cur_el == debug_el) {
return extract32(env->cp15.mdscr_el1, 13, 1)
&& !(env->daif & PSTATE_D);
}
/* Otherwise the debug target needs to be a higher EL */
return debug_el > cur_el;
}
static bool aa32_generate_debug_exceptions(CPUARMState *env)
{
int el = arm_current_el(env);
if (el == 0 && arm_el_is_aa64(env, 1)) {
return aa64_generate_debug_exceptions(env);
}
if (arm_is_secure(env)) {
int spd;
if (el == 0 && (env->cp15.sder & 1)) {
/*
* SDER.SUIDEN means debug exceptions from Secure EL0
* are always enabled. Otherwise they are controlled by
* SDCR.SPD like those from other Secure ELs.
*/
return true;
}
spd = extract32(env->cp15.mdcr_el3, 14, 2);
switch (spd) {
case 1:
/* SPD == 0b01 is reserved, but behaves as 0b00. */
case 0:
/*
* For 0b00 we return true if external secure invasive debug
* is enabled. On real hardware this is controlled by external
* signals to the core. QEMU always permits debug, and behaves
* as if DBGEN, SPIDEN, NIDEN and SPNIDEN are all tied high.
*/
return true;
case 2:
return false;
case 3:
return true;
}
}
return el != 2;
}
/*
* Return true if debugging exceptions are currently enabled.
* This corresponds to what in ARM ARM pseudocode would be
* if UsingAArch32() then
* return AArch32.GenerateDebugExceptions()
* else
* return AArch64.GenerateDebugExceptions()
* We choose to push the if() down into this function for clarity,
* since the pseudocode has it at all callsites except for the one in
* CheckSoftwareStep(), where it is elided because both branches would
* always return the same value.
*/
bool arm_generate_debug_exceptions(CPUARMState *env)
{
if ((env->cp15.oslsr_el1 & 1) || (env->cp15.osdlr_el1 & 1)) {
return false;
}
if (is_a64(env)) {
return aa64_generate_debug_exceptions(env);
} else {
return aa32_generate_debug_exceptions(env);
}
}
/*
* Is single-stepping active? (Note that the "is EL_D AArch64?" check
* implicitly means this always returns false in pre-v8 CPUs.)
*/
bool arm_singlestep_active(CPUARMState *env)
{
return extract32(env->cp15.mdscr_el1, 0, 1)
&& arm_el_is_aa64(env, arm_debug_target_el(env))
&& arm_generate_debug_exceptions(env);
}
/* Return true if the linked breakpoint entry lbn passes its checks */
static bool linked_bp_matches(ARMCPU *cpu, int lbn)
{
CPUARMState *env = &cpu->env;
uint64_t bcr = env->cp15.dbgbcr[lbn];
int brps = arm_num_brps(cpu);
int ctx_cmps = arm_num_ctx_cmps(cpu);
int bt;
uint32_t contextidr;
uint64_t hcr_el2;
/*
* Links to unimplemented or non-context aware breakpoints are
* CONSTRAINED UNPREDICTABLE: either behave as if disabled, or
* as if linked to an UNKNOWN context-aware breakpoint (in which
* case DBGWCR<n>_EL1.LBN must indicate that breakpoint).
* We choose the former.
*/
if (lbn >= brps || lbn < (brps - ctx_cmps)) {
return false;
}
bcr = env->cp15.dbgbcr[lbn];
if (extract64(bcr, 0, 1) == 0) {
/* Linked breakpoint disabled : generate no events */
return false;
}
bt = extract64(bcr, 20, 4);
hcr_el2 = arm_hcr_el2_eff(env);
switch (bt) {
case 3: /* linked context ID match */
switch (arm_current_el(env)) {
default:
/* Context matches never fire in AArch64 EL3 */
return false;
case 2:
if (!(hcr_el2 & HCR_E2H)) {
/* Context matches never fire in EL2 without E2H enabled. */
return false;
}
contextidr = env->cp15.contextidr_el[2];
break;
case 1:
contextidr = env->cp15.contextidr_el[1];
break;
case 0:
if ((hcr_el2 & (HCR_E2H | HCR_TGE)) == (HCR_E2H | HCR_TGE)) {
contextidr = env->cp15.contextidr_el[2];
} else {
contextidr = env->cp15.contextidr_el[1];
}
break;
}
break;
case 7: /* linked contextidr_el1 match */
contextidr = env->cp15.contextidr_el[1];
break;
case 13: /* linked contextidr_el2 match */
contextidr = env->cp15.contextidr_el[2];
break;
case 9: /* linked VMID match (reserved if no EL2) */
case 11: /* linked context ID and VMID match (reserved if no EL2) */
case 15: /* linked full context ID match */
default:
/*
* Links to Unlinked context breakpoints must generate no
* events; we choose to do the same for reserved values too.
*/
return false;
}
/*
* We match the whole register even if this is AArch32 using the
* short descriptor format (in which case it holds both PROCID and ASID),
* since we don't implement the optional v7 context ID masking.
*/
return contextidr == (uint32_t)env->cp15.dbgbvr[lbn];
}
static bool bp_wp_matches(ARMCPU *cpu, int n, bool is_wp)
{
CPUARMState *env = &cpu->env;
uint64_t cr;
int pac, hmc, ssc, wt, lbn;
/*
* Note that for watchpoints the check is against the CPU security
* state, not the S/NS attribute on the offending data access.
*/
bool is_secure = arm_is_secure(env);
int access_el = arm_current_el(env);
if (is_wp) {
CPUWatchpoint *wp = env->cpu_watchpoint[n];
if (!wp || !(wp->flags & BP_WATCHPOINT_HIT)) {
return false;
}
cr = env->cp15.dbgwcr[n];
if (wp->hitattrs.user) {
/*
* The LDRT/STRT/LDT/STT "unprivileged access" instructions should
* match watchpoints as if they were accesses done at EL0, even if
* the CPU is at EL1 or higher.
*/
access_el = 0;
}
} else {
uint64_t pc = is_a64(env) ? env->pc : env->regs[15];
if (!env->cpu_breakpoint[n] || env->cpu_breakpoint[n]->pc != pc) {
return false;
}
cr = env->cp15.dbgbcr[n];
}
/*
* The WATCHPOINT_HIT flag guarantees us that the watchpoint is
* enabled and that the address and access type match; for breakpoints
* we know the address matched; check the remaining fields, including
* linked breakpoints. We rely on WCR and BCR having the same layout
* for the LBN, SSC, HMC, PAC/PMC and is-linked fields.
* Note that some combinations of {PAC, HMC, SSC} are reserved and
* must act either like some valid combination or as if the watchpoint
* were disabled. We choose the former, and use this together with
* the fact that EL3 must always be Secure and EL2 must always be
* Non-Secure to simplify the code slightly compared to the full
* table in the ARM ARM.
*/
pac = FIELD_EX64(cr, DBGWCR, PAC);
hmc = FIELD_EX64(cr, DBGWCR, HMC);
ssc = FIELD_EX64(cr, DBGWCR, SSC);
switch (ssc) {
case 0:
break;
case 1:
case 3:
if (is_secure) {
return false;
}
break;
case 2:
if (!is_secure) {
return false;
}
break;
}
switch (access_el) {
case 3:
case 2:
if (!hmc) {
return false;
}
break;
case 1:
if (extract32(pac, 0, 1) == 0) {
return false;
}
break;
case 0:
if (extract32(pac, 1, 1) == 0) {
return false;
}
break;
default:
g_assert_not_reached();
}
wt = FIELD_EX64(cr, DBGWCR, WT);
lbn = FIELD_EX64(cr, DBGWCR, LBN);
if (wt && !linked_bp_matches(cpu, lbn)) {
return false;
}
return true;
}
static bool check_watchpoints(ARMCPU *cpu)
{
CPUARMState *env = &cpu->env;
int n;
/*
* If watchpoints are disabled globally or we can't take debug
* exceptions here then watchpoint firings are ignored.
*/
if (extract32(env->cp15.mdscr_el1, 15, 1) == 0
|| !arm_generate_debug_exceptions(env)) {
return false;
}
for (n = 0; n < ARRAY_SIZE(env->cpu_watchpoint); n++) {
if (bp_wp_matches(cpu, n, true)) {
return true;
}
}
return false;
}
bool arm_debug_check_breakpoint(CPUState *cs)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
target_ulong pc;
int n;
/*
* If breakpoints are disabled globally or we can't take debug
* exceptions here then breakpoint firings are ignored.
*/
if (extract32(env->cp15.mdscr_el1, 15, 1) == 0
|| !arm_generate_debug_exceptions(env)) {
return false;
}
/*
* Single-step exceptions have priority over breakpoint exceptions.
* If single-step state is active-pending, suppress the bp.
*/
if (arm_singlestep_active(env) && !(env->pstate & PSTATE_SS)) {
return false;
}
/*
* PC alignment faults have priority over breakpoint exceptions.
*/
pc = is_a64(env) ? env->pc : env->regs[15];
if ((is_a64(env) || !env->thumb) && (pc & 3) != 0) {
return false;
}
/*
* Instruction aborts have priority over breakpoint exceptions.
* TODO: We would need to look up the page for PC and verify that
* it is present and executable.
*/
for (n = 0; n < ARRAY_SIZE(env->cpu_breakpoint); n++) {
if (bp_wp_matches(cpu, n, false)) {
return true;
}
}
return false;
}
bool arm_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp)
{
/*
* Called by core code when a CPU watchpoint fires; need to check if this
* is also an architectural watchpoint match.
*/
ARMCPU *cpu = ARM_CPU(cs);
return check_watchpoints(cpu);
}
/*
* Return the FSR value for a debug exception (watchpoint, hardware
* breakpoint or BKPT insn) targeting the specified exception level.
*/
static uint32_t arm_debug_exception_fsr(CPUARMState *env)
{
ARMMMUFaultInfo fi = { .type = ARMFault_Debug };
int target_el = arm_debug_target_el(env);
bool using_lpae;
if (arm_feature(env, ARM_FEATURE_M)) {
using_lpae = false;
} else if (target_el == 2 || arm_el_is_aa64(env, target_el)) {
using_lpae = true;
} else if (arm_feature(env, ARM_FEATURE_PMSA) &&
arm_feature(env, ARM_FEATURE_V8)) {
using_lpae = true;
} else if (arm_feature(env, ARM_FEATURE_LPAE) &&
(env->cp15.tcr_el[target_el] & TTBCR_EAE)) {
using_lpae = true;
} else {
using_lpae = false;
}
if (using_lpae) {
return arm_fi_to_lfsc(&fi);
} else {
return arm_fi_to_sfsc(&fi);
}
}
void arm_debug_excp_handler(CPUState *cs)
{
/*
* Called by core code when a watchpoint or breakpoint fires;
* need to check which one and raise the appropriate exception.
*/
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
CPUWatchpoint *wp_hit = cs->watchpoint_hit;
if (wp_hit) {
if (wp_hit->flags & BP_CPU) {
bool wnr = (wp_hit->flags & BP_WATCHPOINT_HIT_WRITE) != 0;
cs->watchpoint_hit = NULL;
env->exception.fsr = arm_debug_exception_fsr(env);
env->exception.vaddress = wp_hit->hitaddr;
raise_exception_debug(env, EXCP_DATA_ABORT,
syn_watchpoint(0, 0, wnr));
}
} else {
uint64_t pc = is_a64(env) ? env->pc : env->regs[15];
/*
* (1) GDB breakpoints should be handled first.
* (2) Do not raise a CPU exception if no CPU breakpoint has fired,
* since singlestep is also done by generating a debug internal
* exception.
*/
if (cpu_breakpoint_test(cs, pc, BP_GDB)
|| !cpu_breakpoint_test(cs, pc, BP_CPU)) {
return;
}
env->exception.fsr = arm_debug_exception_fsr(env);
/*
* FAR is UNKNOWN: clear vaddress to avoid potentially exposing
* values to the guest that it shouldn't be able to see at its
* exception/security level.
*/
env->exception.vaddress = 0;
raise_exception_debug(env, EXCP_PREFETCH_ABORT, syn_breakpoint(0));
}
}
/*
* Raise an EXCP_BKPT with the specified syndrome register value,
* targeting the correct exception level for debug exceptions.
*/
void HELPER(exception_bkpt_insn)(CPUARMState *env, uint32_t syndrome)
{
int debug_el = arm_debug_target_el(env);
int cur_el = arm_current_el(env);
/* FSR will only be used if the debug target EL is AArch32. */
env->exception.fsr = arm_debug_exception_fsr(env);
/*
* FAR is UNKNOWN: clear vaddress to avoid potentially exposing
* values to the guest that it shouldn't be able to see at its
* exception/security level.
*/
env->exception.vaddress = 0;
/*
* Other kinds of architectural debug exception are ignored if
* they target an exception level below the current one (in QEMU
* this is checked by arm_generate_debug_exceptions()). Breakpoint
* instructions are special because they always generate an exception
* to somewhere: if they can't go to the configured debug exception
* level they are taken to the current exception level.
*/
if (debug_el < cur_el) {
debug_el = cur_el;
}
raise_exception(env, EXCP_BKPT, syndrome, debug_el);
}
void HELPER(exception_swstep)(CPUARMState *env, uint32_t syndrome)
{
raise_exception_debug(env, EXCP_UDEF, syndrome);
}
void hw_watchpoint_update(ARMCPU *cpu, int n)
{
CPUARMState *env = &cpu->env;
vaddr len = 0;
vaddr wvr = env->cp15.dbgwvr[n];
uint64_t wcr = env->cp15.dbgwcr[n];
int mask;
int flags = BP_CPU | BP_STOP_BEFORE_ACCESS;
if (env->cpu_watchpoint[n]) {
cpu_watchpoint_remove_by_ref(CPU(cpu), env->cpu_watchpoint[n]);
env->cpu_watchpoint[n] = NULL;
}
if (!FIELD_EX64(wcr, DBGWCR, E)) {
/* E bit clear : watchpoint disabled */
return;
}
switch (FIELD_EX64(wcr, DBGWCR, LSC)) {
case 0:
/* LSC 00 is reserved and must behave as if the wp is disabled */
return;
case 1:
flags |= BP_MEM_READ;
break;
case 2:
flags |= BP_MEM_WRITE;
break;
case 3:
flags |= BP_MEM_ACCESS;
break;
}
/*
* Attempts to use both MASK and BAS fields simultaneously are
* CONSTRAINED UNPREDICTABLE; we opt to ignore BAS in this case,
* thus generating a watchpoint for every byte in the masked region.
*/
mask = FIELD_EX64(wcr, DBGWCR, MASK);
if (mask == 1 || mask == 2) {
/*
* Reserved values of MASK; we must act as if the mask value was
* some non-reserved value, or as if the watchpoint were disabled.
* We choose the latter.
*/
return;
} else if (mask) {
/* Watchpoint covers an aligned area up to 2GB in size */
len = 1ULL << mask;
/*
* If masked bits in WVR are not zero it's CONSTRAINED UNPREDICTABLE
* whether the watchpoint fires when the unmasked bits match; we opt
* to generate the exceptions.
*/
wvr &= ~(len - 1);
} else {
/* Watchpoint covers bytes defined by the byte address select bits */
int bas = FIELD_EX64(wcr, DBGWCR, BAS);
int basstart;
if (extract64(wvr, 2, 1)) {
/*
* Deprecated case of an only 4-aligned address. BAS[7:4] are
* ignored, and BAS[3:0] define which bytes to watch.
*/
bas &= 0xf;
}
if (bas == 0) {
/* This must act as if the watchpoint is disabled */
return;
}
/*
* The BAS bits are supposed to be programmed to indicate a contiguous
* range of bytes. Otherwise it is CONSTRAINED UNPREDICTABLE whether
* we fire for each byte in the word/doubleword addressed by the WVR.
* We choose to ignore any non-zero bits after the first range of 1s.
*/
basstart = ctz32(bas);
len = cto32(bas >> basstart);
wvr += basstart;
}
cpu_watchpoint_insert(CPU(cpu), wvr, len, flags,
&env->cpu_watchpoint[n]);
}
void hw_watchpoint_update_all(ARMCPU *cpu)
{
int i;
CPUARMState *env = &cpu->env;
/*
* Completely clear out existing QEMU watchpoints and our array, to
* avoid possible stale entries following migration load.
*/
cpu_watchpoint_remove_all(CPU(cpu), BP_CPU);
memset(env->cpu_watchpoint, 0, sizeof(env->cpu_watchpoint));
for (i = 0; i < ARRAY_SIZE(cpu->env.cpu_watchpoint); i++) {
hw_watchpoint_update(cpu, i);
}
}
void hw_breakpoint_update(ARMCPU *cpu, int n)
{
CPUARMState *env = &cpu->env;
uint64_t bvr = env->cp15.dbgbvr[n];
uint64_t bcr = env->cp15.dbgbcr[n];
vaddr addr;
int bt;
int flags = BP_CPU;
if (env->cpu_breakpoint[n]) {
cpu_breakpoint_remove_by_ref(CPU(cpu), env->cpu_breakpoint[n]);
env->cpu_breakpoint[n] = NULL;
}
if (!extract64(bcr, 0, 1)) {
/* E bit clear : watchpoint disabled */
return;
}
bt = extract64(bcr, 20, 4);
switch (bt) {
case 4: /* unlinked address mismatch (reserved if AArch64) */
case 5: /* linked address mismatch (reserved if AArch64) */
qemu_log_mask(LOG_UNIMP,
"arm: address mismatch breakpoint types not implemented\n");
return;
case 0: /* unlinked address match */
case 1: /* linked address match */
{
/*
* Bits [1:0] are RES0.
*
* It is IMPLEMENTATION DEFINED whether bits [63:49]
* ([63:53] for FEAT_LVA) are hardwired to a copy of the sign bit
* of the VA field ([48] or [52] for FEAT_LVA), or whether the
* value is read as written. It is CONSTRAINED UNPREDICTABLE
* whether the RESS bits are ignored when comparing an address.
* Therefore we are allowed to compare the entire register, which
* lets us avoid considering whether FEAT_LVA is actually enabled.
*
* The BAS field is used to allow setting breakpoints on 16-bit
* wide instructions; it is CONSTRAINED UNPREDICTABLE whether
* a bp will fire if the addresses covered by the bp and the addresses
* covered by the insn overlap but the insn doesn't start at the
* start of the bp address range. We choose to require the insn and
* the bp to have the same address. The constraints on writing to
* BAS enforced in dbgbcr_write mean we have only four cases:
* 0b0000 => no breakpoint
* 0b0011 => breakpoint on addr
* 0b1100 => breakpoint on addr + 2
* 0b1111 => breakpoint on addr
* See also figure D2-3 in the v8 ARM ARM (DDI0487A.c).
*/
int bas = extract64(bcr, 5, 4);
addr = bvr & ~3ULL;
if (bas == 0) {
return;
}
if (bas == 0xc) {
addr += 2;
}
break;
}
case 2: /* unlinked context ID match */
case 8: /* unlinked VMID match (reserved if no EL2) */
case 10: /* unlinked context ID and VMID match (reserved if no EL2) */
qemu_log_mask(LOG_UNIMP,
"arm: unlinked context breakpoint types not implemented\n");
return;
case 9: /* linked VMID match (reserved if no EL2) */
case 11: /* linked context ID and VMID match (reserved if no EL2) */
case 3: /* linked context ID match */
default:
/*
* We must generate no events for Linked context matches (unless
* they are linked to by some other bp/wp, which is handled in
* updates for the linking bp/wp). We choose to also generate no events
* for reserved values.
*/
return;
}
cpu_breakpoint_insert(CPU(cpu), addr, flags, &env->cpu_breakpoint[n]);
}
void hw_breakpoint_update_all(ARMCPU *cpu)
{
int i;
CPUARMState *env = &cpu->env;
/*
* Completely clear out existing QEMU breakpoints and our array, to
* avoid possible stale entries following migration load.
*/
cpu_breakpoint_remove_all(CPU(cpu), BP_CPU);
memset(env->cpu_breakpoint, 0, sizeof(env->cpu_breakpoint));
for (i = 0; i < ARRAY_SIZE(cpu->env.cpu_breakpoint); i++) {
hw_breakpoint_update(cpu, i);
}
}
#if !defined(CONFIG_USER_ONLY)
vaddr arm_adjust_watchpoint_address(CPUState *cs, vaddr addr, int len)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
/*
* In BE32 system mode, target memory is stored byteswapped (on a
* little-endian host system), and by the time we reach here (via an
* opcode helper) the addresses of subword accesses have been adjusted
* to account for that, which means that watchpoints will not match.
* Undo the adjustment here.
*/
if (arm_sctlr_b(env)) {
if (len == 1) {
addr ^= 3;
} else if (len == 2) {
addr ^= 2;
}
}
return addr;
}
#endif /* !CONFIG_USER_ONLY */
#endif /* CONFIG_TCG */
/*
* Check for traps to "powerdown debug" registers, which are controlled
* by MDCR.TDOSA
*/
static CPAccessResult access_tdosa(CPUARMState *env, const ARMCPRegInfo *ri,
bool isread)
{
int el = arm_current_el(env);
uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
bool mdcr_el2_tdosa = (mdcr_el2 & MDCR_TDOSA) || (mdcr_el2 & MDCR_TDE) ||
(arm_hcr_el2_eff(env) & HCR_TGE);
if (el < 2 && mdcr_el2_tdosa) {
return CP_ACCESS_TRAP_EL2;
}
if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDOSA)) {
return CP_ACCESS_TRAP_EL3;
}
return CP_ACCESS_OK;
}
/*
* Check for traps to "debug ROM" registers, which are controlled
* by MDCR_EL2.TDRA for EL2 but by the more general MDCR_EL3.TDA for EL3.
*/
static CPAccessResult access_tdra(CPUARMState *env, const ARMCPRegInfo *ri,
bool isread)
{
int el = arm_current_el(env);
uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
bool mdcr_el2_tdra = (mdcr_el2 & MDCR_TDRA) || (mdcr_el2 & MDCR_TDE) ||
(arm_hcr_el2_eff(env) & HCR_TGE);
if (el < 2 && mdcr_el2_tdra) {
return CP_ACCESS_TRAP_EL2;
}
if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDA)) {
return CP_ACCESS_TRAP_EL3;
}
return CP_ACCESS_OK;
}
/*
* Check for traps to general debug registers, which are controlled
* by MDCR_EL2.TDA for EL2 and MDCR_EL3.TDA for EL3.
*/
static CPAccessResult access_tda(CPUARMState *env, const ARMCPRegInfo *ri,
bool isread)
{
int el = arm_current_el(env);
uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
bool mdcr_el2_tda = (mdcr_el2 & MDCR_TDA) || (mdcr_el2 & MDCR_TDE) ||
(arm_hcr_el2_eff(env) & HCR_TGE);
if (el < 2 && mdcr_el2_tda) {
return CP_ACCESS_TRAP_EL2;
}
if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDA)) {
return CP_ACCESS_TRAP_EL3;
}
return CP_ACCESS_OK;
}
/*
* Check for traps to Debug Comms Channel registers. If FEAT_FGT
* is implemented then these are controlled by MDCR_EL2.TDCC for
* EL2 and MDCR_EL3.TDCC for EL3. They are also controlled by
* the general debug access trap bits MDCR_EL2.TDA and MDCR_EL3.TDA.
* For EL0, they are also controlled by MDSCR_EL1.TDCC.
*/
static CPAccessResult access_tdcc(CPUARMState *env, const ARMCPRegInfo *ri,
bool isread)
{
int el = arm_current_el(env);
uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
bool mdscr_el1_tdcc = extract32(env->cp15.mdscr_el1, 12, 1);
bool mdcr_el2_tda = (mdcr_el2 & MDCR_TDA) || (mdcr_el2 & MDCR_TDE) ||
(arm_hcr_el2_eff(env) & HCR_TGE);
bool mdcr_el2_tdcc = cpu_isar_feature(aa64_fgt, env_archcpu(env)) &&
(mdcr_el2 & MDCR_TDCC);
bool mdcr_el3_tdcc = cpu_isar_feature(aa64_fgt, env_archcpu(env)) &&
(env->cp15.mdcr_el3 & MDCR_TDCC);
if (el < 1 && mdscr_el1_tdcc) {
return CP_ACCESS_TRAP;
}
if (el < 2 && (mdcr_el2_tda || mdcr_el2_tdcc)) {
return CP_ACCESS_TRAP_EL2;
}
if (el < 3 && ((env->cp15.mdcr_el3 & MDCR_TDA) || mdcr_el3_tdcc)) {
return CP_ACCESS_TRAP_EL3;
}
return CP_ACCESS_OK;
}
static void oslar_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
/*
* Writes to OSLAR_EL1 may update the OS lock status, which can be
* read via a bit in OSLSR_EL1.
*/
int oslock;
if (ri->state == ARM_CP_STATE_AA32) {
oslock = (value == 0xC5ACCE55);
} else {
oslock = value & 1;
}
env->cp15.oslsr_el1 = deposit32(env->cp15.oslsr_el1, 1, 1, oslock);
}
static void osdlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
ARMCPU *cpu = env_archcpu(env);
/*
* Only defined bit is bit 0 (DLK); if Feat_DoubleLock is not
* implemented this is RAZ/WI.
*/
if(arm_feature(env, ARM_FEATURE_AARCH64)
? cpu_isar_feature(aa64_doublelock, cpu)
: cpu_isar_feature(aa32_doublelock, cpu)) {
env->cp15.osdlr_el1 = value & 1;
}
}
static void dbgclaimset_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
env->cp15.dbgclaim |= (value & 0xFF);
}
static uint64_t dbgclaimset_read(CPUARMState *env, const ARMCPRegInfo *ri)
{
/* CLAIM bits are RAO */
return 0xFF;
}
static void dbgclaimclr_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
env->cp15.dbgclaim &= ~(value & 0xFF);
}
static const ARMCPRegInfo debug_cp_reginfo[] = {
/*
* DBGDRAR, DBGDSAR: always RAZ since we don't implement memory mapped
* debug components. The AArch64 version of DBGDRAR is named MDRAR_EL1;
* unlike DBGDRAR it is never accessible from EL0.
* DBGDSAR is deprecated and must RAZ from v8 anyway, so it has no AArch64
* accessor.
*/
{ .name = "DBGDRAR", .cp = 14, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
.access = PL0_R, .accessfn = access_tdra,
.type = ARM_CP_CONST | ARM_CP_NO_GDB, .resetvalue = 0 },
{ .name = "MDRAR_EL1", .state = ARM_CP_STATE_AA64,
.opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 0,
.access = PL1_R, .accessfn = access_tdra,
.type = ARM_CP_CONST, .resetvalue = 0 },
{ .name = "DBGDSAR", .cp = 14, .crn = 2, .crm = 0, .opc1 = 0, .opc2 = 0,
.access = PL0_R, .accessfn = access_tdra,
.type = ARM_CP_CONST | ARM_CP_NO_GDB, .resetvalue = 0 },
/* Monitor debug system control register; the 32-bit alias is DBGDSCRext. */
{ .name = "MDSCR_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_MDSCR_EL1,
.fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1),
.resetvalue = 0 },
/*
* MDCCSR_EL0[30:29] map to EDSCR[30:29]. Simply RAZ as the external
* Debug Communication Channel is not implemented.
*/
{ .name = "MDCCSR_EL0", .state = ARM_CP_STATE_AA64,
.opc0 = 2, .opc1 = 3, .crn = 0, .crm = 1, .opc2 = 0,
.access = PL0_R, .accessfn = access_tdcc,
.type = ARM_CP_CONST, .resetvalue = 0 },
/*
* These registers belong to the Debug Communications Channel,
* which is not implemented. However we implement RAZ/WI behaviour
* with trapping to prevent spurious SIGILLs if the guest OS does
* access them as the support cannot be probed for.
*/
{ .name = "OSDTRRX_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14,
.opc0 = 2, .opc1 = 0, .crn = 0, .crm = 0, .opc2 = 2,
.access = PL1_RW, .accessfn = access_tdcc,
.type = ARM_CP_CONST, .resetvalue = 0 },
{ .name = "OSDTRTX_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14,
.opc0 = 2, .opc1 = 0, .crn = 0, .crm = 3, .opc2 = 2,
.access = PL1_RW, .accessfn = access_tdcc,
.type = ARM_CP_CONST, .resetvalue = 0 },
/* DBGDTRTX_EL0/DBGDTRRX_EL0 depend on direction */
{ .name = "DBGDTR_EL0", .state = ARM_CP_STATE_BOTH, .cp = 14,
.opc0 = 2, .opc1 = 3, .crn = 0, .crm = 5, .opc2 = 0,
.access = PL0_RW, .accessfn = access_tdcc,
.type = ARM_CP_CONST, .resetvalue = 0 },
/*
* OSECCR_EL1 provides a mechanism for an operating system
* to access the contents of EDECCR. EDECCR is not implemented though,
* as is the rest of external device mechanism.
*/
{ .name = "OSECCR_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14,
.opc0 = 2, .opc1 = 0, .crn = 0, .crm = 6, .opc2 = 2,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_OSECCR_EL1,
.type = ARM_CP_CONST, .resetvalue = 0 },
/*
* DBGDSCRint[15,12,5:2] map to MDSCR_EL1[15,12,5:2]. Map all bits as
* it is unlikely a guest will care.
* We don't implement the configurable EL0 access.
*/
{ .name = "DBGDSCRint", .state = ARM_CP_STATE_AA32,
.cp = 14, .opc1 = 0, .crn = 0, .crm = 1, .opc2 = 0,
.type = ARM_CP_ALIAS,
.access = PL1_R, .accessfn = access_tda,
.fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1), },
{ .name = "OSLAR_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
.access = PL1_W, .type = ARM_CP_NO_RAW,
.accessfn = access_tdosa,
.fgt = FGT_OSLAR_EL1,
.writefn = oslar_write },
{ .name = "OSLSR_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 4,
.access = PL1_R, .resetvalue = 10,
.accessfn = access_tdosa,
.fgt = FGT_OSLSR_EL1,
.fieldoffset = offsetof(CPUARMState, cp15.oslsr_el1) },
/* Dummy OSDLR_EL1: 32-bit Linux will read this */
{ .name = "OSDLR_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 3, .opc2 = 4,
.access = PL1_RW, .accessfn = access_tdosa,
.fgt = FGT_OSDLR_EL1,
.writefn = osdlr_write,
.fieldoffset = offsetof(CPUARMState, cp15.osdlr_el1) },
/*
* Dummy DBGVCR: Linux wants to clear this on startup, but we don't
* implement vector catch debug events yet.
*/
{ .name = "DBGVCR",
.cp = 14, .opc1 = 0, .crn = 0, .crm = 7, .opc2 = 0,
.access = PL1_RW, .accessfn = access_tda,
.type = ARM_CP_NOP },
/*
* Dummy DBGVCR32_EL2 (which is only for a 64-bit hypervisor
* to save and restore a 32-bit guest's DBGVCR)
*/
{ .name = "DBGVCR32_EL2", .state = ARM_CP_STATE_AA64,
.opc0 = 2, .opc1 = 4, .crn = 0, .crm = 7, .opc2 = 0,
.access = PL2_RW, .accessfn = access_tda,
.type = ARM_CP_NOP | ARM_CP_EL3_NO_EL2_KEEP },
/*
* Dummy MDCCINT_EL1, since we don't implement the Debug Communications
* Channel but Linux may try to access this register. The 32-bit
* alias is DBGDCCINT.
*/
{ .name = "MDCCINT_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 0,
.access = PL1_RW, .accessfn = access_tdcc,
.type = ARM_CP_NOP },
/*
* Dummy DBGCLAIM registers.
* "The architecture does not define any functionality for the CLAIM tag bits.",
* so we only keep the raw bits
*/
{ .name = "DBGCLAIMSET_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 7, .crm = 8, .opc2 = 6,
.type = ARM_CP_ALIAS,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_DBGCLAIM,
.writefn = dbgclaimset_write, .readfn = dbgclaimset_read },
{ .name = "DBGCLAIMCLR_EL1", .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 7, .crm = 9, .opc2 = 6,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_DBGCLAIM,
.writefn = dbgclaimclr_write, .raw_writefn = raw_write,
.fieldoffset = offsetof(CPUARMState, cp15.dbgclaim) },
};
static const ARMCPRegInfo debug_lpae_cp_reginfo[] = {
/* 64 bit access versions of the (dummy) debug registers */
{ .name = "DBGDRAR", .cp = 14, .crm = 1, .opc1 = 0,
.access = PL0_R, .type = ARM_CP_CONST | ARM_CP_64BIT | ARM_CP_NO_GDB,
.resetvalue = 0 },
{ .name = "DBGDSAR", .cp = 14, .crm = 2, .opc1 = 0,
.access = PL0_R, .type = ARM_CP_CONST | ARM_CP_64BIT | ARM_CP_NO_GDB,
.resetvalue = 0 },
};
static void dbgwvr_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
ARMCPU *cpu = env_archcpu(env);
int i = ri->crm;
/*
* Bits [1:0] are RES0.
*
* It is IMPLEMENTATION DEFINED whether [63:49] ([63:53] with FEAT_LVA)
* are hardwired to the value of bit [48] ([52] with FEAT_LVA), or if
* they contain the value written. It is CONSTRAINED UNPREDICTABLE
* whether the RESS bits are ignored when comparing an address.
*
* Therefore we are allowed to compare the entire register, which lets
* us avoid considering whether or not FEAT_LVA is actually enabled.
*/
value &= ~3ULL;
raw_write(env, ri, value);
if (tcg_enabled()) {
hw_watchpoint_update(cpu, i);
}
}
static void dbgwcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
ARMCPU *cpu = env_archcpu(env);
int i = ri->crm;
raw_write(env, ri, value);
if (tcg_enabled()) {
hw_watchpoint_update(cpu, i);
}
}
static void dbgbvr_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
ARMCPU *cpu = env_archcpu(env);
int i = ri->crm;
raw_write(env, ri, value);
if (tcg_enabled()) {
hw_breakpoint_update(cpu, i);
}
}
static void dbgbcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
uint64_t value)
{
ARMCPU *cpu = env_archcpu(env);
int i = ri->crm;
/*
* BAS[3] is a read-only copy of BAS[2], and BAS[1] a read-only
* copy of BAS[0].
*/
value = deposit64(value, 6, 1, extract64(value, 5, 1));
value = deposit64(value, 8, 1, extract64(value, 7, 1));
raw_write(env, ri, value);
if (tcg_enabled()) {
hw_breakpoint_update(cpu, i);
}
}
void define_debug_regs(ARMCPU *cpu)
{
/*
* Define v7 and v8 architectural debug registers.
* These are just dummy implementations for now.
*/
int i;
int wrps, brps, ctx_cmps;
/*
* The Arm ARM says DBGDIDR is optional and deprecated if EL1 cannot
* use AArch32. Given that bit 15 is RES1, if the value is 0 then
* the register must not exist for this cpu.
*/
if (cpu->isar.dbgdidr != 0) {
ARMCPRegInfo dbgdidr = {
.name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0,
.opc1 = 0, .opc2 = 0,
.access = PL0_R, .accessfn = access_tda,
.type = ARM_CP_CONST, .resetvalue = cpu->isar.dbgdidr,
};
define_one_arm_cp_reg(cpu, &dbgdidr);
}
/*
* DBGDEVID is present in the v7 debug architecture if
* DBGDIDR.DEVID_imp is 1 (bit 15); from v7.1 and on it is
* mandatory (and bit 15 is RES1). DBGDEVID1 and DBGDEVID2 exist
* from v7.1 of the debug architecture. Because no fields have yet
* been defined in DBGDEVID2 (and quite possibly none will ever
* be) we don't define an ARMISARegisters field for it.
* These registers exist only if EL1 can use AArch32, but that
* happens naturally because they are only PL1 accessible anyway.
*/
if (extract32(cpu->isar.dbgdidr, 15, 1)) {
ARMCPRegInfo dbgdevid = {
.name = "DBGDEVID",
.cp = 14, .opc1 = 0, .crn = 7, .opc2 = 2, .crn = 7,
.access = PL1_R, .accessfn = access_tda,
.type = ARM_CP_CONST, .resetvalue = cpu->isar.dbgdevid,
};
define_one_arm_cp_reg(cpu, &dbgdevid);
}
if (cpu_isar_feature(aa32_debugv7p1, cpu)) {
ARMCPRegInfo dbgdevid12[] = {
{
.name = "DBGDEVID1",
.cp = 14, .opc1 = 0, .crn = 7, .opc2 = 1, .crn = 7,
.access = PL1_R, .accessfn = access_tda,
.type = ARM_CP_CONST, .resetvalue = cpu->isar.dbgdevid1,
}, {
.name = "DBGDEVID2",
.cp = 14, .opc1 = 0, .crn = 7, .opc2 = 0, .crn = 7,
.access = PL1_R, .accessfn = access_tda,
.type = ARM_CP_CONST, .resetvalue = 0,
},
};
define_arm_cp_regs(cpu, dbgdevid12);
}
brps = arm_num_brps(cpu);
wrps = arm_num_wrps(cpu);
ctx_cmps = arm_num_ctx_cmps(cpu);
assert(ctx_cmps <= brps);
define_arm_cp_regs(cpu, debug_cp_reginfo);
if (arm_feature(&cpu->env, ARM_FEATURE_LPAE)) {
define_arm_cp_regs(cpu, debug_lpae_cp_reginfo);
}
for (i = 0; i < brps; i++) {
char *dbgbvr_el1_name = g_strdup_printf("DBGBVR%d_EL1", i);
char *dbgbcr_el1_name = g_strdup_printf("DBGBCR%d_EL1", i);
ARMCPRegInfo dbgregs[] = {
{ .name = dbgbvr_el1_name, .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 4,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_DBGBVRN_EL1,
.fieldoffset = offsetof(CPUARMState, cp15.dbgbvr[i]),
.writefn = dbgbvr_write, .raw_writefn = raw_write
},
{ .name = dbgbcr_el1_name, .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 5,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_DBGBCRN_EL1,
.fieldoffset = offsetof(CPUARMState, cp15.dbgbcr[i]),
.writefn = dbgbcr_write, .raw_writefn = raw_write
},
};
define_arm_cp_regs(cpu, dbgregs);
g_free(dbgbvr_el1_name);
g_free(dbgbcr_el1_name);
}
for (i = 0; i < wrps; i++) {
char *dbgwvr_el1_name = g_strdup_printf("DBGWVR%d_EL1", i);
char *dbgwcr_el1_name = g_strdup_printf("DBGWCR%d_EL1", i);
ARMCPRegInfo dbgregs[] = {
{ .name = dbgwvr_el1_name, .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 6,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_DBGWVRN_EL1,
.fieldoffset = offsetof(CPUARMState, cp15.dbgwvr[i]),
.writefn = dbgwvr_write, .raw_writefn = raw_write
},
{ .name = dbgwcr_el1_name, .state = ARM_CP_STATE_BOTH,
.cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 7,
.access = PL1_RW, .accessfn = access_tda,
.fgt = FGT_DBGWCRN_EL1,
.fieldoffset = offsetof(CPUARMState, cp15.dbgwcr[i]),
.writefn = dbgwcr_write, .raw_writefn = raw_write
},
};
define_arm_cp_regs(cpu, dbgregs);
g_free(dbgwvr_el1_name);
g_free(dbgwcr_el1_name);
}
}
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