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trampin -> uservec

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trampout -> userret
This commit is contained in:
Robert Morris 2019-07-26 04:53:46 -04:00
parent 4e62de64cd
commit ea95a6654c
6 changed files with 18 additions and 17 deletions
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2
kernel/kernel.ld
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@ -12,7 +12,7 @@ SECTIONS
{ {
*(.text) *(.text)
. = ALIGN(0x1000); . = ALIGN(0x1000);
*(trampoline) *(trampsec)
} }
. = ALIGN(0x1000); . = ALIGN(0x1000);

4
kernel/proc.c
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@ -18,7 +18,7 @@ struct spinlock pid_lock;
extern void forkret(void); extern void forkret(void);
static void wakeup1(struct proc *chan); static void wakeup1(struct proc *chan);
extern char trampout[]; // trampoline.S extern char trampoline[]; // trampoline.S
void void
procinit(void) procinit(void)
@ -159,7 +159,7 @@ proc_pagetable(struct proc *p)
// only the supervisor uses it, on the way // only the supervisor uses it, on the way
// to/from user space, so not PTE_U. // to/from user space, so not PTE_U.
mappages(pagetable, TRAMPOLINE, PGSIZE, mappages(pagetable, TRAMPOLINE, PGSIZE,
(uint64)trampout, PTE_R | PTE_X); (uint64)trampoline, PTE_R | PTE_X);
// map the trapframe just below TRAMPOLINE, for trampoline.S. // map the trapframe just below TRAMPOLINE, for trampoline.S.
mappages(pagetable, TRAPFRAME, PGSIZE, mappages(pagetable, TRAPFRAME, PGSIZE,

4
kernel/proc.h
View file

@ -32,10 +32,10 @@ extern struct cpu cpus[NCPU];
// sits in a page by itself just under the trampoline page in the // sits in a page by itself just under the trampoline page in the
// user page table. not specially mapped in the kernel page table. // user page table. not specially mapped in the kernel page table.
// the sscratch register points here. // the sscratch register points here.
// trampin in trampoline.S saves user registers in the trapframe, // uservec in trampoline.S saves user registers in the trapframe,
// then initializes registers from the trapframe's // then initializes registers from the trapframe's
// kernel_sp, kernel_hartid, kernel_satp, and jumps to kernel_trap. // kernel_sp, kernel_hartid, kernel_satp, and jumps to kernel_trap.
// usertrapret() and trampout in trampoline.S set up // usertrapret() and userret in trampoline.S set up
// the trapframe's kernel_*, restore user registers from the // the trapframe's kernel_*, restore user registers from the
// trapframe, switch to the user page table, and enter user space. // trapframe, switch to the user page table, and enter user space.
// the trapframe includes callee-saved user registers like s0-s11 because the // the trapframe includes callee-saved user registers like s0-s11 because the

17
kernel/trampoline.S
View file

@ -5,14 +5,15 @@
# in user and kernel space so that it continues # in user and kernel space so that it continues
# to work when it switches page tables. # to work when it switches page tables.
# #
# kernel.ld causes trampout to be aligned # kernel.ld causes userret to be aligned
# to a page boundary. # to a page boundary.
# #
.globl usertrap .section trampsec
.section trampoline .globl trampoline
.globl trampout trampoline:
trampout: .globl userret
# trampout(trapframe, pagetable) userret:
# userret(trapframe, pagetable)
# switch from kernel to user. # switch from kernel to user.
# usertrapret() calls here. # usertrapret() calls here.
# a0: p->tf in user page table # a0: p->tf in user page table
@ -67,8 +68,8 @@ trampout:
sret sret
.align 4 .align 4
.globl trampin .globl uservec
trampin: uservec:
# #
# trap.c set stvec to point here, so # trap.c set stvec to point here, so
# user interrupts and exceptions start here, # user interrupts and exceptions start here,

4
kernel/trap.c
View file

@ -9,7 +9,7 @@
struct spinlock tickslock; struct spinlock tickslock;
uint ticks; uint ticks;
extern char trampout[], trampin[]; extern char trampoline[], uservec[];
// in kernelvec.S, calls kerneltrap(). // in kernelvec.S, calls kerneltrap().
void kernelvec(); void kernelvec();
@ -96,7 +96,7 @@ usertrapret(void)
intr_off(); intr_off();
// send interrupts and exceptions to trampoline.S // send interrupts and exceptions to trampoline.S
w_stvec(TRAMPOLINE + (trampin - trampout)); w_stvec(TRAMPOLINE + (uservec - trampoline));
// set up values that trampoline.S will need when // set up values that trampoline.S will need when
// the process next re-enters the kernel. // the process next re-enters the kernel.

4
kernel/vm.c
View file

@ -13,7 +13,7 @@ pagetable_t kernel_pagetable;
extern char etext[]; // kernel.ld sets this to end of kernel code. extern char etext[]; // kernel.ld sets this to end of kernel code.
extern char trampout[]; // trampoline.S extern char trampoline[]; // trampoline.S
/* /*
* create a direct-map page table for the kernel and * create a direct-map page table for the kernel and
@ -46,7 +46,7 @@ kvminit()
// map the trampoline for trap entry/exit to // map the trampoline for trap entry/exit to
// the highest virtual address in the kernel. // the highest virtual address in the kernel.
kvmmap(TRAMPOLINE, (uint64)trampout, PGSIZE, PTE_R | PTE_X); kvmmap(TRAMPOLINE, (uint64)trampoline, PGSIZE, PTE_R | PTE_X);
} }
// Switch h/w page table register to the kernel's page table, // Switch h/w page table register to the kernel's page table,