Commit 7bea97639e for qemu.org

commit 7bea97639e0505e911a639e8b7f12e2ddf2cabb0
Author: Peter Maydell <peter.maydell@linaro.org>
Date:   Wed Feb 18 20:01:37 2026 -0800

    target/arm: Move TCG-specific code out of debug_helper.c

    The target/arm/debug_helper.c file has some code which we need
    for non-TCG accelerators, but quite a lot which is guarded by
    a CONFIG_TCG ifdef. Move all this TCG-only code out to a
    new file target/arm/tcg/debug.c.

    In particular all the code requiring access to the TCG
    helper function prototypes is in the moved code, so we can
    drop the use of tcg/helper.h from debug_helper.c.

    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
    Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
    Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
    Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
    Message-id: 20260219040150.2098396-2-pierrick.bouvier@linaro.org
    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/debug_helper.c b/target/arm/debug_helper.c
index 579516e154..352c8e5c8e 100644
--- a/target/arm/debug_helper.c
+++ b/target/arm/debug_helper.c
@@ -14,775 +14,6 @@
 #include "exec/watchpoint.h"
 #include "system/tcg.h"

-#define HELPER_H "tcg/helper.h"
-#include "exec/helper-proto.h.inc"
-
-#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;
-    vaddr 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
diff --git a/target/arm/tcg/debug.c b/target/arm/tcg/debug.c
new file mode 100644
index 0000000000..7dfb291a9b
--- /dev/null
+++ b/target/arm/tcg/debug.c
@@ -0,0 +1,782 @@
+/*
+ * ARM debug helpers used by TCG
+ *
+ * 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/watchpoint.h"
+#include "system/tcg.h"
+
+#define HELPER_H "tcg/helper.h"
+#include "exec/helper-proto.h.inc"
+
+/* 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.
+ */
+static G_NORETURN 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;
+    vaddr 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 */
diff --git a/target/arm/tcg/meson.build b/target/arm/tcg/meson.build
index 1b115656c4..6e9aed3e5d 100644
--- a/target/arm/tcg/meson.build
+++ b/target/arm/tcg/meson.build
@@ -65,6 +65,7 @@ arm_common_ss.add(files(

 arm_common_system_ss.add(files(
   'cpregs-at.c',
+  'debug.c',
   'hflags.c',
   'neon_helper.c',
   'tlb_helper.c',
@@ -72,6 +73,7 @@ arm_common_system_ss.add(files(
   'vfp_helper.c',
 ))
 arm_user_ss.add(files(
+  'debug.c',
   'hflags.c',
   'neon_helper.c',
   'tlb_helper.c',