From f1484f148e383be3404e7f6456079abfb806fa30 Mon Sep 17 00:00:00 2001 From: Your Name Date: Wed, 28 Jun 2023 08:37:21 +0000 Subject: 更多注释 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- arch/x86/kernel/uintr_core.c | 68 +++++++++++++++++++++++--------------------- 1 file changed, 36 insertions(+), 32 deletions(-) diff --git a/arch/x86/kernel/uintr_core.c b/arch/x86/kernel/uintr_core.c index 607f9df83049..06640d5c9e80 100644 --- a/arch/x86/kernel/uintr_core.c +++ b/arch/x86/kernel/uintr_core.c @@ -309,16 +309,16 @@ static void teardown_uitt(void) if (fpregs_state_valid(fpu, smp_processor_id())) { /* Modify only the relevant bits of the MISC MSR */ - rdmsrl(MSR_IA32_UINTR_MISC, msr64); // - msr64 &= GENMASK_ULL(63, 32); - wrmsrl(MSR_IA32_UINTR_MISC, msr64); - wrmsrl(MSR_IA32_UINTR_TT, 0ULL); + rdmsrl(MSR_IA32_UINTR_MISC, msr64); // 读取 MSR_IA32_UINTR_MISC + msr64 &= GENMASK_ULL(63, 32);// 31-0 位清零, uitt_size = 0 了 + wrmsrl(MSR_IA32_UINTR_MISC, msr64); // 写入 MSR_IA32_UINTR_MISC + wrmsrl(MSR_IA32_UINTR_TT, 0ULL); // 全0 相当于 UITTADDR=0, 也没有 SENDUIPI 了 } else {// 若浮点寄存器无效 struct uintr_state *p; p = get_xsave_addr(&fpu->state.xsave, XFEATURE_UINTR); if (p) { - p->uitt_size = 0; + p->uitt_size = 0; // 同上 p->uitt_addr = 0; } } @@ -348,12 +348,12 @@ static int init_uitt(void) fpregs_lock(); // if (fpregs_state_valid(fpu, smp_processor_id())) { // 浮点寄存器有效 - wrmsrl(MSR_IA32_UINTR_TT, (u64)ui_send->uitt_ctx->uitt | 1); - /* Modify only the relevant bits of the MISC MSR */ - rdmsrl(MSR_IA32_UINTR_MISC, msr64); - msr64 &= GENMASK_ULL(63, 32); - msr64 |= UINTR_MAX_UITT_NR; - wrmsrl(MSR_IA32_UINTR_MISC, msr64); + wrmsrl(MSR_IA32_UINTR_TT, (u64)ui_send->uitt_ctx->uitt | 1); // UITTADDR + /* Modify only the relevant bits of the MISC MSR *///只改相关位 + rdmsrl(MSR_IA32_UINTR_MISC, msr64); // 映射 MSR_IA32_UINTR_MISC 到 msr64 + msr64 &= GENMASK_ULL(63, 32); // 前 32 位清零(UITTSZ = 0), 其他位置数据不变. + msr64 |= UINTR_MAX_UITT_NR; // + wrmsrl(MSR_IA32_UINTR_MISC, msr64); // 写入 MSR_IA32_UINTR_MISC } else { // 浮点寄存器无效,写入 xsave struct xregs_state *xsave; struct uintr_state *p; @@ -362,8 +362,8 @@ static int init_uitt(void) xsave->header.xfeatures |= XFEATURE_MASK_UINTR; p = get_xsave_addr(&fpu->state.xsave, XFEATURE_UINTR); if (p) { - p->uitt_size = UINTR_MAX_UITT_NR; - p->uitt_addr = (u64)ui_send->uitt_ctx->uitt | 1; + p->uitt_size = UINTR_MAX_UITT_NR; // 设置 UITTSZ 大小 + p->uitt_addr = (u64)ui_send->uitt_ctx->uitt | 1; // 设置 UITTADDR } } @@ -510,7 +510,7 @@ int uintr_receiver_wait(void) return -EOPNOTSUPP; upid_ctx = current->thread.ui_recv->upid_ctx; // 取出当前进程的 upid_ctx - upid_ctx->upid->nc.nv = UINTR_KERNEL_VECTOR; + upid_ctx->upid->nc.nv = UINTR_KERNEL_VECTOR; // 设置 upid_ctx 的 upid->nc.nv 为内核向量 upid_ctx->waiting = true; // 标记为 等待中 spin_lock_irqsave(&uintr_wait_lock, flags); // 锁 list_add(&upid_ctx->node, &uintr_wait_list); // 加入到等待队列 @@ -591,9 +591,9 @@ int do_uintr_unregister_handler(void) // 仅清除接收者相关的状态 发送者相关的状态不会被修改 if (fpregs_state_valid(fpu, smp_processor_id())) { // 浮点寄存器状态有效 /* Modify only the relevant bits of the MISC MSR */ - rdmsrl(MSR_IA32_UINTR_MISC, msr64); + rdmsrl(MSR_IA32_UINTR_MISC, msr64); // msr64 &= ~GENMASK_ULL(39, 32); - wrmsrl(MSR_IA32_UINTR_MISC, msr64); + wrmsrl(MSR_IA32_UINTR_MISC, msr64); // wrmsrl(MSR_IA32_UINTR_PD, 0ULL); wrmsrl(MSR_IA32_UINTR_RR, 0ULL); wrmsrl(MSR_IA32_UINTR_STACKADJUST, 0ULL); @@ -621,7 +621,7 @@ int do_uintr_unregister_handler(void) // 抑制通知，以便不再基于此 UPID 生成进一步的中断 set_bit(UPID_SN, (unsigned long *)&ui_recv->upid_ctx->upid->nc.status); //关掉 UPID status 使能 uintr_remove_task_wait(t); // 从等待列表中移除当前进程 - put_upid_ref(ui_recv->upid_ctx); // upid_ctx->refs - 1, 且应用技术为 0 时释放 upid_ctx + put_upid_ref(ui_recv->upid_ctx); // upid_ctx->refs - 1, 且计数为 0 时释放 upid_ctx kfree(ui_recv); // 释放 ui_recv t->thread.ui_recv = NULL; // 置空 @@ -680,16 +680,16 @@ int do_uintr_register_handler(u64 handler) if (fpregs_state_valid(fpu, cpu)) { //如果当前进程的浮点寄存器有效 //都是新增加的硬件寄存器,归硬件直接操作. - wrmsrl(MSR_IA32_UINTR_HANDLER, handler); // handler 放到 MSR_IA32_UINTR_HANDLER 寄存器 - wrmsrl(MSR_IA32_UINTR_PD, (u64)ui_recv->upid_ctx->upid); // upid 放到 MSR_IA32_UINTR_PD 寄存器 + wrmsrl(MSR_IA32_UINTR_HANDLER, handler); // handler 内存地址 放到 MSR_IA32_UINTR_HANDLER 寄存器 + wrmsrl(MSR_IA32_UINTR_PD, (u64)ui_recv->upid_ctx->upid); // upid 地址 放到 MSR_IA32_UINTR_PD 寄存器 /* Set value as size of ABI redzone */ - wrmsrl(MSR_IA32_UINTR_STACKADJUST, 128); + wrmsrl(MSR_IA32_UINTR_STACKADJUST, 128); // 用户中断堆栈的调整值?? - /* Modify only the relevant bits of the MISC MSR */ - rdmsrl(MSR_IA32_UINTR_MISC, misc_msr); - misc_msr |= (u64)UINTR_NOTIFICATION_VECTOR << 32; - wrmsrl(MSR_IA32_UINTR_MISC, misc_msr); + /* Modify only the relevant bits of the MISC MSR */ //更新 UINV + rdmsrl(MSR_IA32_UINTR_MISC, misc_msr); // 读取 MSR_IA32_UINTR_MISC 寄存器的值 + misc_msr |= (u64)UINTR_NOTIFICATION_VECTOR << 32; // UINTR_NOTIFICATION_VECTOR 的值换入 63:32 的位置 其实是 UINV 了.或者说是 中断编号 + wrmsrl(MSR_IA32_UINTR_MISC, misc_msr); // 回写 } else { // 当前进程的浮点寄存器无效 struct xregs_state *xsave; struct uintr_state *p; @@ -699,10 +699,10 @@ int do_uintr_register_handler(u64 handler) p = get_xsave_addr(&fpu->state.xsave, XFEATURE_UINTR); printk("----uintr xsave addr is %px\n",p); if (p) { - p->handler = handler; - p->upid_addr = (u64)ui_recv->upid_ctx->upid; - p->stack_adjust = 128; - p->uinv = UINTR_NOTIFICATION_VECTOR; + p->handler = handler; // 中断处理函数地址 + p->upid_addr = (u64)ui_recv->upid_ctx->upid; // upid 地址 + p->stack_adjust = 128; // 用户中断堆栈的调整值?? + p->uinv = UINTR_NOTIFICATION_VECTOR; // 中断编号 printk("the xsave addr is %p\n handler: 0x%llx | upid_addr: 0x%llx | uif: %d\n", p, handler,p->upid_addr,p->uif_pad3); } } @@ -764,13 +764,15 @@ int do_uintr_register_vector(struct uintr_receiver_info *r_info) } /* Suppress notifications since this task is being context switched out */ +// 线程切出时调用, 线程不在前台就不再允许接收通知. void switch_uintr_prepare(struct task_struct *prev) { struct uintr_upid *upid; if (is_uintr_receiver(prev) && !is_uintr_waiting(prev)) { + printk("receiver task %d blocking \n",prev->pid); upid = prev->thread.ui_recv->upid_ctx->upid; - set_bit(UPID_SN, (unsigned long *)&upid->nc.status); + set_bit(UPID_SN, (unsigned long *)&upid->nc.status); // 禁用通知 } } @@ -779,6 +781,7 @@ void switch_uintr_prepare(struct task_struct *prev) * reloaded i.e. TIF_NEED_FPU_LOAD is clear. * Called from arch_exit_to_user_mode_prepare() with interrupts disabled. */ +// 线程切入时调用, 恢复寄存器状态 void switch_uintr_return(void) { struct uintr_upid *upid; @@ -806,8 +809,8 @@ void switch_uintr_return(void) /* Modify only the relevant bits of the MISC MSR */ rdmsrl(MSR_IA32_UINTR_MISC, misc_msr); - if (!(misc_msr & GENMASK_ULL(39, 32))) { - misc_msr |= (u64)UINTR_NOTIFICATION_VECTOR << 32; + if (!(misc_msr & GENMASK_ULL(39, 32))) { // 如果 UINV 位没有设置 + misc_msr |= (u64)UINTR_NOTIFICATION_VECTOR << 32; // 恢复 UINV 位为 UINTR_NOTIFICATION_VECTOR|中断编号 wrmsrl(MSR_IA32_UINTR_MISC, misc_msr); } @@ -835,8 +838,9 @@ void switch_uintr_return(void) */ if (READ_ONCE(upid->puir)){ // 有未处理的用户中断请求 + printk("receiver task %d resuming \n",current->pid); printk("sending self ipi\n"); - apic->send_IPI_self(UINTR_NOTIFICATION_VECTOR); + apic->send_IPI_self(UINTR_NOTIFICATION_VECTOR); // 发送自己的中断,进入 UINTR_NOTIFICATION_VECTOR 对应中断 } } } -- cgit v1.2.3