diff options
| -rw-r--r-- | kernel/kernelvec.S | 4 | ||||
| -rw-r--r-- | kernel/riscv.h | 6 | ||||
| -rw-r--r-- | kernel/start.c | 15 | ||||
| -rw-r--r-- | kernel/trampoline.S | 16 | ||||
| -rw-r--r-- | kernel/trap.c | 10 |
5 files changed, 26 insertions, 25 deletions
diff --git a/kernel/kernelvec.S b/kernel/kernelvec.S index 222b172..5fce79a 100644 --- a/kernel/kernelvec.S +++ b/kernel/kernelvec.S @@ -88,9 +88,9 @@ kernelvec: # # machine-mode timer interrupt. # -.globl machinevec +.globl timervec .align 4 -machinevec: +timervec: # start.c has set up the memory that mscratch points to: # scratch[0,8,16] : register save area. # scratch[32] : address of CLINT's MTIMECMP register. diff --git a/kernel/riscv.h b/kernel/riscv.h index 63f71b4..0f83db6 100644 --- a/kernel/riscv.h +++ b/kernel/riscv.h @@ -257,7 +257,7 @@ r_time() return x; } -// enable interrupts +// enable device interrupts static inline void intr_on() { @@ -265,14 +265,14 @@ intr_on() w_sstatus(r_sstatus() | SSTATUS_SIE); } -// disable interrupts +// disable device interrupts static inline void intr_off() { w_sstatus(r_sstatus() & ~SSTATUS_SIE); } -// are interrupts enabled? +// are device interrupts enabled? static inline int intr_get() { diff --git a/kernel/start.c b/kernel/start.c index d1fc9c6..0f3453d 100644 --- a/kernel/start.c +++ b/kernel/start.c @@ -12,8 +12,8 @@ __attribute__ ((aligned (16))) char stack0[4096 * NCPU]; // scratch area for timer interrupt, one per CPU. uint64 mscratch0[NCPU * 32]; -// assembly code in kernelvec for machine-mode timer interrupt. -extern void machinevec(); +// assembly code in kernelvec.S for machine-mode timer interrupt. +extern void timervec(); // entry.S jumps here in machine mode on stack0. void @@ -36,16 +36,17 @@ start() w_medeleg(0xffff); w_mideleg(0xffff); + int id = r_mhartid(); + // set up to receive timer interrupts in machine mode, - // which arrive at machinevec in kernelvec.S, + // which arrive at timervec in kernelvec.S, // which turns them into software interrupts for // devintr() in trap.c. - int id = r_mhartid(); // ask the CLINT for a timer interrupt. int interval = 1000000; // cycles; about 1/10th second in qemu. *(uint64*)CLINT_MTIMECMP(id) = *(uint64*)CLINT_MTIME + interval; - // prepare information in scratch[] for machinevec. - // scratch[0..3] : space for machinevec to save registers. + // prepare information in scratch[] for timervec. + // scratch[0..3] : space for timervec to save registers. // scratch[4] : address of CLINT MTIMECMP register. // scratch[5] : desired interval (in cycles) between timer interrupts. uint64 *scratch = &mscratch0[32 * id]; @@ -53,7 +54,7 @@ start() scratch[5] = interval; w_mscratch((uint64)scratch); // set the machine-mode trap handler. - w_mtvec((uint64)machinevec); + w_mtvec((uint64)timervec); // enable machine-mode interrupts. w_mstatus(r_mstatus() | MSTATUS_MIE); // enable machine-mode timer interrupts. diff --git a/kernel/trampoline.S b/kernel/trampoline.S index 6e436d2..24499d9 100644 --- a/kernel/trampoline.S +++ b/kernel/trampoline.S @@ -25,10 +25,10 @@ uservec: # # swap a0 and sscratch - # so that a0 is p->tf + # so that a0 is TRAPFRAME csrrw a0, sscratch, a0 - # save the user registers in p->tf + # save the user registers in TRAPFRAME sd ra, 40(a0) sd sp, 48(a0) sd gp, 56(a0) @@ -86,22 +86,22 @@ uservec: .globl userret userret: - # userret(trapframe, pagetable) + # userret(TRAPFRAME, pagetable) # switch from kernel to user. # usertrapret() calls here. - # a0: p->tf in user page table - # a1: new value for satp, for user page table + # a0: TRAPFRAME, in user page table + # a1: user page table, for satp # switch to the user page table. sfence.vma zero, zero csrw satp, a1 # put the saved user a0 in sscratch, so we - # can swap it with our a0 (p->tf) in the last step. + # can swap it with our a0 (TRAPFRAME) in the last step. ld t0, 112(a0) csrw sscratch, t0 - # restore all but a0 from p->tf + # restore all but a0 from TRAPFRAME ld ra, 40(a0) ld sp, 48(a0) ld gp, 56(a0) @@ -133,7 +133,7 @@ userret: ld t5, 272(a0) ld t6, 280(a0) - # restore user a0, and save p->tf in sscratch + # restore user a0, and save TRAPFRAME in sscratch csrrw a0, sscratch, a0 # return to user mode and user pc. diff --git a/kernel/trap.c b/kernel/trap.c index ce7a65a..6d5e46b 100644 --- a/kernel/trap.c +++ b/kernel/trap.c @@ -98,12 +98,12 @@ usertrapret(void) // send interrupts and exceptions to trampoline.S w_stvec(TRAMPOLINE + (uservec - trampoline)); - // set up values that trampoline.S will need when + // set up values that uservec will need when // the process next re-enters the kernel. - p->tf->kernel_satp = r_satp(); - p->tf->kernel_sp = p->kstack + PGSIZE; + p->tf->kernel_satp = r_satp(); // kernel page table + p->tf->kernel_sp = p->kstack + PGSIZE; // process's kernel stack p->tf->kernel_trap = (uint64)usertrap; - p->tf->kernel_hartid = r_tp(); + p->tf->kernel_hartid = r_tp(); // hartid for cpuid() // set up the registers that trampoline.S's sret will use // to get to user space. @@ -193,7 +193,7 @@ devintr() return 1; } else if(scause == 0x8000000000000001){ // software interrupt from a machine-mode timer interrupt, - // forwarded by machinevec in kernelvec.S. + // forwarded by timervec in kernelvec.S. if(cpuid() == 0){ clockintr(); |