From 54178ad94d758e557bfa369b7f137e2844e030e1 Mon Sep 17 00:00:00 2001 From: Robert Morris Date: Tue, 23 Jul 2019 12:17:17 -0400 Subject: simplify kernel mapping calls --- kernel/proc.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index cebef1a..5ce31c7 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -28,12 +28,18 @@ procinit(void) initlock(&pid_lock, "nextpid"); for(p = proc; p < &proc[NPROC]; p++) { initlock(&p->lock, "proc"); - // Allocate a page for the kernel stack. - uint64 kstack = KSTACK((int) (p - proc)); - if((p->kstack = mapkstack(kstack)) == 0) { - panic("procinit"); - } + + // Allocate a page for the process's kernel stack. + // Map it high in memory, followed by an invalid + // guard page. + char *pa = kalloc(); + if(pa == 0) + panic("kalloc"); + uint64 va = KSTACK((int) (p - proc)); + kmap(va, (uint64)pa, PGSIZE, PTE_R | PTE_W); + p->kstack = va; } + kvminithart(); } // Must be called with interrupts disabled, @@ -113,7 +119,7 @@ found: // which returns to user space. memset(&p->context, 0, sizeof p->context); p->context.ra = (uint64)forkret; - p->context.sp = (uint64)p->kstack + PGSIZE; + p->context.sp = p->kstack + PGSIZE; return p; } -- cgit v1.2.3