rename of mode/context switching functions
- this patch only renames schedcheck() to switch_to_user(), cycles_accounting_stop() to context_stop() and restart() to +restore_user_context() - the motivation is that since the introduction of schedcheck() it has been abused for many things. It deserves a better name. It should express the fact that from the moment we call the function we are in the process of switching to user. - cycles_accounting_stop() was originally a single purpose function. As this function is called at were convenient places it is used in for other things too, e.g. (un)locking the kernel. Thus it deserves a better name too. - using the old name, restart() does not call schedcheck(), however calls to restart are replaced by calls to schedcheck() [switch_to_user] and it calls restart() [restore_user_context]
This commit is contained in:
Tomas Hruby
parent
9ba65d2ea8
commit
b90c2d7026
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@ -38,15 +38,15 @@
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\
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SAVE_PROCESS_CTX(0) ;\
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push %ebp ;\
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call cycles_accounting_stop ;\
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call context_stop ;\
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add $4, %esp ;\
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movl $0, %ebp /* for stack trace */ ;\
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APIC_IRQ_HANDLER(irq) ;\
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jmp restart ;\
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jmp switch_to_user ;\
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\
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0: \
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pusha ;\
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call cycles_accounting_stop_idle ;\
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call context_stop_idle ;\
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APIC_IRQ_HANDLER(irq) ;\
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CLEAR_IF(10*4(%esp)) ;\
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popa ;\
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@ -149,15 +149,15 @@ apic_hwint15:
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\
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SAVE_PROCESS_CTX(0) ;\
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push %ebp ;\
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call cycles_accounting_stop ;\
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call context_stop ;\
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add $4, %esp ;\
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movl $0, %ebp /* for stack trace */ ;\
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LAPIC_INTR_HANDLER(func) ;\
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jmp restart ;\
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jmp switch_to_user ;\
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\
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0: \
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pusha ;\
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call cycles_accounting_stop_idle ;\
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call context_stop_idle ;\
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LAPIC_INTR_HANDLER(func) ;\
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CLEAR_IF(10*4(%esp)) ;\
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popa ;\
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@ -131,7 +131,7 @@ PUBLIC void cycles_accounting_init(void)
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read_tsc_64(&tsc_ctr_switch);
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}
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PUBLIC void cycles_accounting_stop(struct proc * p)
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PUBLIC void context_stop(struct proc * p)
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{
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u64_t tsc;
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@ -140,7 +140,7 @@ PUBLIC void cycles_accounting_stop(struct proc * p)
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tsc_ctr_switch = tsc;
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}
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PUBLIC void cycles_accounting_stop_idle(void)
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PUBLIC void context_stop_idle(void)
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{
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cycles_accounting_stop(proc_addr(IDLE));
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context_stop(proc_addr(IDLE));
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}
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@ -423,7 +423,7 @@ PUBLIC void arch_do_syscall(struct proc *proc)
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do_ipc(proc->p_reg.cx, proc->p_reg.retreg, proc->p_reg.bx);
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}
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PUBLIC struct proc * arch_finish_schedcheck(void)
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PUBLIC struct proc * arch_finish_switch_to_user(void)
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{
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char * stk;
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stk = (char *)tss.sp0;
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@ -5,29 +5,12 @@
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* interrupt handlers. It cooperates with the code in "start.c" to set up a
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* good environment for main().
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*
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* Every transition to the kernel goes through this file. Transitions to the
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* kernel may be nested. The initial entry may be with a system call (i.e.,
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* send or receive a message), an exception or a hardware interrupt; kernel
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* reentries may only be made by hardware interrupts. The count of reentries
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* is kept in "k_reenter". It is important for deciding whether to switch to
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* the kernel stack and for protecting the message passing code in "proc.c".
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*
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* For the message passing trap, most of the machine state is saved in the
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* proc table. (Some of the registers need not be saved.) Then the stack is
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* switched to "k_stack", and interrupts are reenabled. Finally, the system
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* call handler (in C) is called. When it returns, interrupts are disabled
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* again and the code falls into the restart routine, to finish off held-up
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* interrupts and run the process or task whose pointer is in "proc_ptr".
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*
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* Hardware interrupt handlers do the same, except (1) The entire state must
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* be saved. (2) There are too many handlers to do this inline, so the save
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* routine is called. A few cycles are saved by pushing the address of the
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* appropiate restart routine for a return later. (3) A stack switch is
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* avoided when the stack is already switched. (4) The (master) 8259 interrupt
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* controller is reenabled centrally in save(). (5) Each interrupt handler
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* masks its interrupt line using the 8259 before enabling (other unmasked)
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* interrupts, and unmasks it after servicing the interrupt. This limits the
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* nest level to the number of lines and protects the handler from itself.
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* Kernel is entered either because of kernel-calls, ipc-calls, interrupts or
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* exceptions. TSS is set so that the kernel stack is loaded. The user cotext is
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* saved to the proc table and the handler of the event is called. Once the
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* handler is done, switch_to_user() function is called to pick a new process,
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* finish what needs to be done for the next process to run, sets its context
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* and switch to userspace.
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*
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* For communication with the boot monitor at startup time some constant
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* data are compiled into the beginning of the text segment. This facilitates
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@ -81,7 +64,7 @@ begbss:
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* the entity.
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*/
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.globl restart
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.globl restore_user_context
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.globl reload_cr3
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.globl divide_error
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@ -106,7 +89,7 @@ begbss:
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.globl params_size
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.globl params_offset
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.globl mon_ds
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.globl schedcheck
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.globl switch_to_user
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.globl lazy_fpu
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.globl hwint00 /* handlers for hardware interrupts */
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@ -250,17 +233,17 @@ csinit:
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\
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SAVE_PROCESS_CTX(0) ;\
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push %ebp ;\
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call cycles_accounting_stop ;\
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call context_stop ;\
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add $4, %esp ;\
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movl $0, %ebp /* for stack trace */ ;\
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PIC_IRQ_HANDLER(irq) ;\
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movb $END_OF_INT, %al ;\
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outb $INT_CTL /* reenable interrupts in master pic */ ;\
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jmp restart ;\
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jmp switch_to_user ;\
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\
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0: \
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pusha ;\
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call cycles_accounting_stop_idle ;\
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call context_stop_idle ;\
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PIC_IRQ_HANDLER(irq) ;\
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movb $END_OF_INT, %al ;\
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outb $INT_CTL /* reenable interrupts in master pic */ ;\
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@ -318,18 +301,18 @@ hwint07:
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\
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SAVE_PROCESS_CTX(0) ;\
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push %ebp ;\
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call cycles_accounting_stop ;\
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call context_stop ;\
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add $4, %esp ;\
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movl $0, %ebp /* for stack trace */ ;\
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PIC_IRQ_HANDLER(irq) ;\
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movb $END_OF_INT, %al ;\
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outb $INT_CTL /* reenable interrupts in master pic */ ;\
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outb $INT2_CTL /* reenable slave 8259 */ ;\
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jmp restart ;\
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jmp switch_to_user ;\
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\
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0: \
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pusha ;\
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call cycles_accounting_stop_idle ;\
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call context_stop_idle ;\
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PIC_IRQ_HANDLER(irq) ;\
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movb $END_OF_INT, %al ;\
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outb $INT_CTL /* reenable interrupts in master pic */ ;\
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@ -402,7 +385,7 @@ ipc_entry:
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/* stop user process cycles */
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push %ebp
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call cycles_accounting_stop
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call context_stop
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add $4, %esp
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/* for stack trace */
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@ -415,7 +398,7 @@ ipc_entry:
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pop %esi
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mov %eax, AXREG(%esi)
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jmp restart
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jmp switch_to_user
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/*
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@ -439,7 +422,7 @@ kernel_call_entry:
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/* stop user process cycles */
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push %ebp
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call cycles_accounting_stop
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call context_stop
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add $4, %esp
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/* for stack trace */
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@ -450,7 +433,7 @@ kernel_call_entry:
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/* restore the current process pointer and save the return value */
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add $8, %esp
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jmp restart
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jmp switch_to_user
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.balign 16
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@ -472,7 +455,7 @@ exception_entry_from_user:
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/* stop user process cycles */
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push %ebp
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call cycles_accounting_stop
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call context_stop
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add $4, %esp
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/* for stack trace clear %ebp */
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@ -487,7 +470,7 @@ exception_entry_from_user:
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push $0 /* it's not a nested exception */
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call exception_handler
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jmp restart
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jmp switch_to_user
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exception_entry_nested:
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@ -508,11 +491,8 @@ exception_entry_nested:
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/*===========================================================================*/
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/* restart */
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/*===========================================================================*/
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restart:
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call schedcheck
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/* %eax is set by schedcheck() to the process to run */
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mov %eax, %ebp /* will assume P_STACKBASE == 0 */
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restore_user_context:
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mov 4(%esp), %ebp /* will assume P_STACKBASE == 0 */
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/* reconstruct the stack for iret */
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movl SSREG(%ebp), %eax
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@ -617,7 +597,7 @@ copr_not_available:
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SAVE_PROCESS_CTX_NON_LAZY(0)
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/* stop user process cycles */
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push %ebp
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call cycles_accounting_stop
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call context_stop
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pop %ebp
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lea P_MISC_FLAGS(%ebp), %ebx
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movw (%ebx), %cx
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@ -639,7 +619,7 @@ fp_l_no_fxsr:
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frstor (%eax)
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copr_return:
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orw $MF_USED_FPU, (%ebx) /* fpu was used during last execution */
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jmp restart
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jmp switch_to_user
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copr_not_available_in_kernel:
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movl $0, (%esp)
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@ -257,7 +257,7 @@ PUBLIC void main(void)
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assert(runqueues_ok());
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restart();
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switch_to_user();
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NOT_REACHABLE;
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}
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@ -89,7 +89,7 @@ PRIVATE void idle(void)
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*/
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/* start accounting for the idle time */
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cycles_accounting_stop(proc_addr(KERNEL));
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context_stop(proc_addr(KERNEL));
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halt_cpu();
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/*
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* end of accounting for the idle task does not happen here, the kernel
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@ -98,9 +98,9 @@ PRIVATE void idle(void)
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}
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/*===========================================================================*
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* schedcheck *
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* switch_to_user *
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*===========================================================================*/
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PUBLIC struct proc * schedcheck(void)
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PUBLIC void switch_to_user(void)
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{
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/* This function is called an instant before proc_ptr is
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* to be scheduled again.
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@ -232,12 +232,17 @@ check_misc_flags:
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#endif
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proc_ptr = arch_finish_schedcheck();
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proc_ptr = arch_finish_switch_to_user();
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assert(proc_ptr->p_ticks_left > 0);
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cycles_accounting_stop(proc_addr(KERNEL));
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context_stop(proc_addr(KERNEL));
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return proc_ptr;
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/*
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* restore_user_context() carries out the actual mode switch from kernel
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* to userspace. This function does not return
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*/
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restore_user_context(proc_ptr);
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NOT_REACHABLE;
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}
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/*
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@ -1398,7 +1403,7 @@ PRIVATE void notify_scheduler(struct proc *p)
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/*
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* If a scheduler is scheduling itself or has no scheduler, and
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* runs out of quantum, we don't send a message. The
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* RTS_NO_QUANTUM flag will be removed by schedcheck in proc.c.
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* RTS_NO_QUANTUM flag will be removed in switch_to_user.
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*/
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}
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else {
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@ -25,9 +25,9 @@ _PROTOTYPE( void cycles_accounting_init, (void) );
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* possible before returning to userspace. These function is architecture
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* dependent
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*/
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_PROTOTYPE( void cycles_accounting_stop, (struct proc * p) );
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_PROTOTYPE( void context_stop, (struct proc * p) );
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/* this is a wrapper to make calling it from assembly easier */
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_PROTOTYPE( void cycles_accounting_stop_idle, (void) );
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_PROTOTYPE( void context_stop_idle, (void) );
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/* main.c */
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_PROTOTYPE( void main, (void) );
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@ -40,8 +40,8 @@ _PROTOTYPE( int do_ipc, (reg_t r1, reg_t r2, reg_t r3) );
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_PROTOTYPE( int mini_notify, (const struct proc *src, endpoint_t dst) );
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_PROTOTYPE( void enqueue, (struct proc *rp) );
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_PROTOTYPE( void dequeue, (const struct proc *rp) );
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_PROTOTYPE( struct proc * schedcheck, (void) );
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_PROTOTYPE( struct proc * arch_finish_schedcheck, (void) );
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_PROTOTYPE( void switch_to_user, (void) );
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_PROTOTYPE( struct proc * arch_finish_switch_to_user, (void) );
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_PROTOTYPE( struct proc *endpoint_lookup, (endpoint_t ep) );
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#if DEBUG_ENABLE_IPC_WARNINGS
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_PROTOTYPE( int isokendpt_f, (const char *file, int line, endpoint_t e, int *p, int f));
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@ -155,7 +155,7 @@ _PROTOTYPE( void ser_putc, (char) );
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_PROTOTYPE( void arch_shutdown, (int) );
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_PROTOTYPE( void arch_monitor, (void) );
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_PROTOTYPE( void arch_get_aout_headers, (int i, struct exec *h) );
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_PROTOTYPE( void restart, (void) );
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_PROTOTYPE( void restore_user_context, (struct proc * p) );
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_PROTOTYPE( void read_tsc, (unsigned long *high, unsigned long *low) );
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_PROTOTYPE( int arch_init_profile_clock, (u32_t freq) );
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_PROTOTYPE( void arch_stop_profile_clock, (void) );
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@ -130,7 +130,7 @@ PUBLIC void kernel_call(message *m_user, struct proc * caller)
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caller->p_delivermsg_vir = (vir_bytes) m_user;
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/*
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* the ldt and cr3 of the caller process is loaded because it just've trapped
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* into the kernel or was already set in schedcheck() before we resume
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* into the kernel or was already set in switch_to_user() before we resume
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* execution of an interrupted kernel call
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*/
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if (copy_msg_from_user(caller, m_user, &msg) == 0) {
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