From 1b8ec454840ea02df83b79316e5701eefa55fa06 Mon Sep 17 00:00:00 2001 From: Brian Cain Date: Mon, 22 Jun 2026 15:28:50 -0700 Subject: [PATCH] target/hexagon: Add k0 {un,}lock Reviewed-by: Taylor Simpson Signed-off-by: Brian Cain --- target/hexagon/hex_mmu.c | 4 +- target/hexagon/op_helper.c | 119 ++++++++++++++++++++++++++++++++++++ target/hexagon/sys_macros.h | 3 + 3 files changed, 124 insertions(+), 2 deletions(-) diff --git a/target/hexagon/hex_mmu.c b/target/hexagon/hex_mmu.c index 1c8ccec69e..81d64a6146 100644 --- a/target/hexagon/hex_mmu.c +++ b/target/hexagon/hex_mmu.c @@ -206,8 +206,8 @@ void hex_tlb_unlock(CPUHexagonState *env) (env->tlb_lock_state != HEX_LOCK_OWNER)) { qemu_log_mask(LOG_GUEST_ERROR, "thread %" PRIu32 " attempted to tlbunlock" - " without having the lock, tlb_lock state = %d\n", - env->threadId, env->tlb_lock_state); + " without having the lock, tlb_lock state = %u\n", + env->threadId, (unsigned)env->tlb_lock_state); g_assert(env->tlb_lock_state != HEX_LOCK_WAITING); return; } diff --git a/target/hexagon/op_helper.c b/target/hexagon/op_helper.c index 9fbcd79c9d..b82713bd1c 100644 --- a/target/hexagon/op_helper.c +++ b/target/hexagon/op_helper.c @@ -37,6 +37,9 @@ #include "cpu_helper.h" #include "translate.h" #ifndef CONFIG_USER_ONLY +#include "hw/hexagon/hexagon_globalreg.h" +#include "hex_mmu.h" +#include "hw/hexagon/hexagon_tlb.h" #include "hex_interrupts.h" #include "hexswi.h" #endif @@ -1233,6 +1236,122 @@ void HELPER(modify_ssr)(CPUHexagonState *env, uint32_t new, uint32_t old) BQL_LOCK_GUARD(); hexagon_modify_ssr(env, new, old); } + +static void hex_k0_lock(CPUHexagonState *env) +{ + HexagonCPU *cpu = env_archcpu(env); + CPUState *cs = env_cpu(env); + target_ulong syscfg; + + BQL_LOCK_GUARD(); + g_assert((env->k0_lock_count == 0) || (env->k0_lock_count == 1)); + + syscfg = cpu->globalregs ? + hexagon_globalreg_read(cpu->globalregs, HEX_SREG_SYSCFG, + env->threadId) : 0; + if (GET_SYSCFG_FIELD(SYSCFG_K0LOCK, syscfg)) { + if (env->k0_lock_state == HEX_LOCK_QUEUED) { + env->next_PC += 4; + env->k0_lock_count++; + env->k0_lock_state = HEX_LOCK_OWNER; + SET_SYSCFG_FIELD(env, SYSCFG_K0LOCK, 1); + return; + } + if (env->k0_lock_state == HEX_LOCK_OWNER) { + qemu_log_mask(LOG_GUEST_ERROR, + "Double k0lock at PC: 0x%" PRIx32 + ", thread may hang\n", + env->next_PC); + env->next_PC += 4; + cpu_interrupt(cs, CPU_INTERRUPT_HALT); + cpu_loop_exit(cs); + return; + } + env->k0_lock_state = HEX_LOCK_WAITING; + cpu_interrupt(cs, CPU_INTERRUPT_HALT); + cpu_loop_exit(cs); + } else { + env->next_PC += 4; + env->k0_lock_count++; + env->k0_lock_state = HEX_LOCK_OWNER; + SET_SYSCFG_FIELD(env, SYSCFG_K0LOCK, 1); + } +} + +static void hex_k0_unlock(CPUHexagonState *env) +{ + HexagonCPU *cpu = env_archcpu(env); + unsigned int this_threadId = env->threadId; + CPUHexagonState *unlock_thread = NULL; + CPUState *cs; + target_ulong syscfg; + + BQL_LOCK_GUARD(); + g_assert((env->k0_lock_count == 0) || (env->k0_lock_count == 1)); + + /* Nothing to do if the k0 isn't locked by this thread */ + syscfg = cpu->globalregs ? + hexagon_globalreg_read(cpu->globalregs, HEX_SREG_SYSCFG, + env->threadId) : 0; + if ((GET_SYSCFG_FIELD(SYSCFG_K0LOCK, syscfg) == 0) || + (env->k0_lock_state != HEX_LOCK_OWNER)) { + qemu_log_mask(LOG_GUEST_ERROR, + "thread %" PRIu32 " attempted to unlock k0 without" + " having the lock, k0_lock state = %u," + " syscfg:k0 = %" PRIu32 "\n", + env->threadId, (unsigned)env->k0_lock_state, + (uint32_t)GET_SYSCFG_FIELD(SYSCFG_K0LOCK, syscfg)); + g_assert(env->k0_lock_state != HEX_LOCK_WAITING); + return; + } + + env->k0_lock_count--; + env->k0_lock_state = HEX_LOCK_UNLOCKED; + SET_SYSCFG_FIELD(env, SYSCFG_K0LOCK, 0); + + /* Look for a thread to unlock */ + CPU_FOREACH(cs) { + CPUHexagonState *thread = cpu_env(cs); + + /* + * The hardware implements round-robin fairness, so we look for threads + * starting at env->threadId + 1 and incrementing modulo the number of + * threads. + * + * To implement this, we check if thread is a earlier in the modulo + * sequence than unlock_thread. + * if unlock thread is higher than this thread + * thread must be between this thread and unlock_thread + * else + * thread higher than this thread is ahead of unlock_thread + * thread must be lower then unlock thread + */ + if (thread->k0_lock_state == HEX_LOCK_WAITING) { + if (!unlock_thread) { + unlock_thread = thread; + } else if (unlock_thread->threadId > this_threadId) { + if (this_threadId < thread->threadId && + thread->threadId < unlock_thread->threadId) { + unlock_thread = thread; + } + } else { + if (thread->threadId > this_threadId) { + unlock_thread = thread; + } + if (thread->threadId < unlock_thread->threadId) { + unlock_thread = thread; + } + } + } + } + if (unlock_thread) { + cs = env_cpu(unlock_thread); + unlock_thread->k0_lock_state = HEX_LOCK_QUEUED; + SET_SYSCFG_FIELD(unlock_thread, SYSCFG_K0LOCK, 1); + cpu_interrupt(cs, CPU_INTERRUPT_K0_UNLOCK); + } + +} #endif diff --git a/target/hexagon/sys_macros.h b/target/hexagon/sys_macros.h index 707afc53e1..a49c72715d 100644 --- a/target/hexagon/sys_macros.h +++ b/target/hexagon/sys_macros.h @@ -148,6 +148,9 @@ #define fSET_TLB_LOCK() hex_tlb_lock(env); #define fCLEAR_TLB_LOCK() hex_tlb_unlock(env); +#define fSET_K0_LOCK() hex_k0_lock(env); +#define fCLEAR_K0_LOCK() hex_k0_unlock(env); + #define fTLB_IDXMASK(INDEX) \ ((INDEX) & (fPOW2_ROUNDUP( \ fCAST4u(hexagon_tlb_get_num_entries(env_archcpu(env)->tlb))) - 1))