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Initial commit
This commit is contained in:
Bahadir Balban
184
src/api/syscall.c
Normal file
184
src/api/syscall.c
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@@ -0,0 +1,184 @@
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/*
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* System Calls
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*
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* Copyright (C) 2007 Bahadir Balban
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*/
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#include <l4/lib/mutex.h>
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#include <l4/lib/printk.h>
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#include <l4/generic/scheduler.h>
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#include <l4/generic/tcb.h>
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#include <l4/generic/pgalloc.h>
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#include <l4/generic/tcb.h>
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#include <l4/generic/space.h>
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#include <l4/api/space.h>
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#include <l4/api/ipc.h>
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#include <l4/api/kip.h>
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#include <l4/api/errno.h>
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#include INC_API(syscall.h)
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#include INC_ARCH(exception.h)
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int sys_exchange_registers(struct syscall_args *regs)
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{
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struct ktcb *task;
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unsigned int pc = regs->r0;
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unsigned int sp = regs->r1;
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unsigned int pagerid = regs->r2;
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l4id_t tid = regs->r3;
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/* Find tcb from its hash list */
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if ((task = find_task(tid)))
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goto found;
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/* FIXME: Whatif not found??? Recover gracefully. */
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BUG();
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found:
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/* Set its registers */
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task->context.pc = pc;
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task->context.sp = sp;
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task->context.spsr = ARM_MODE_USR;
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/* Set its pager */
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task->pagerid = pagerid;
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return 0;
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}
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int sys_schedule(struct syscall_args *regs)
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{
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printk("(SVC) %s called. Tid (%d)\n", __FUNCTION__, current->tid);
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return 0;
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}
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#if 0
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/*
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* THIS CODE IS TO BE USED WHEN MODIFYING PAGE TABLES FOR SHARED MEMORY!!!
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*/
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int do_shm_setup(struct shm_kdata *kdata)
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{
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struct ktcb *sender, *receiver;
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unsigned long sndphys, sndvirt, rcvvirt;
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if (!(sender = find_task(kdata->sender)))
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return -1;
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if (!(receiver = find_task(kdata->receiver)))
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return -1;
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/*
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* There's no guarantee that shared pages are contiguous in physical,
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* therefore every virtual page in the sharer shall be converted for
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* its physical address, and each of those addresses are mapped.
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*/
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for (int i = 0; i < kdata->npages; i++) {
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/* The sender virtual address for each shared page */
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sndvirt = __pfn_to_addr(kdata->send_pfn) + (i * PAGE_SIZE);
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/* The corresponding receiver virtual address */
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rcvvirt = __pfn_to_addr(kdata->recv_pfn) + (i * PAGE_SIZE);
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/* Converted to physical, through the sharer's page table. */
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sndphys = __pte_to_addr(virt_to_pte_from_pgd(sndvirt,
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sender->pgd));
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/*
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* Mapped to virtual in the sharee's address space. Note this
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* is mapped as uncached, in order to avoid cache aliasing
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* issues in ARM v5, which is VIVT. A possible optimisation for
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* the future is to make it cached and restrict the shm
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* address range.
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*/
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add_mapping_pgd(sndphys, rcvvirt, PAGE_SIZE, MAP_SVC_IO_FLAGS,
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receiver->pgd);
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}
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return 0;
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}
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/* Modifies an address space */
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int sys_space_control(struct syscall_args *regs)
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{
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unsigned int operation = regs->r0;
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int err = 0;
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if (current->tid != PAGER_TID) {
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printk("%s: Priveledged call, only task id %d can call it. (Current id: %d)\n",
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__FUNCTION__, current->tid, PAGER_TID);
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return -EPERM;
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}
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switch (operation) {
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case SPCCTRL_SHM:
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/* FIXME: Add an access check for user space structure */
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if ((err = do_shm_setup((struct shm_kdata *)®s->r1) < 0))
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printk("%s: Error setting up the shm area.\n", __FUNCTION__);
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break;
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default:
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printk("%s: Unsupported operation: %d\n", __FUNCTION__, operation);
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err = -ENOSYS;
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}
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printk("%s called. Tid (%d)\n", __FUNCTION__, current->tid);
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return err;
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}
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#endif
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int sys_space_control(struct syscall_args *regs)
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{
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return -ENOSYS;
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}
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int sys_getid(struct syscall_args *regs)
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{
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struct task_ids *ids = (struct task_ids *)regs->r0;
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struct ktcb *this = current;
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ids->tid = this->tid;
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ids->spid = this->spid;
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return 0;
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}
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/*
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* Granted pages *must* be outside of the pages that are already owned and used
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* by the kernel, otherwise a hostile/buggy pager can attack kernel addresses by
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* fooling it to use them as freshly granted pages. Kernel owned pages are
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* defined as, "any page that has been used by the kernel prior to all free
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* physical memory is taken by a pager, and any other page that has been granted
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* so far by any such pager."
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*/
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int validate_granted_pages(unsigned long pfn, int npages)
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{
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/* FIXME: Fill this in */
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return 0;
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}
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/*
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* Used by a pager to grant memory to kernel for its own use. Generally
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* this memory is used for thread creation and memory mapping, (e.g. new
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* page tables, page middle directories, per-task kernel stack etc.)
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*/
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int sys_kmem_grant(struct syscall_args *regs)
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{
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unsigned long pfn = (unsigned long)regs->r0;
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int npages = (int)regs->r1;
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/*
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* Check if given set of pages are outside the pages already
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* owned by the kernel.
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*/
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if (validate_granted_pages(pfn, npages) < 0)
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return -EINVAL;
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/* Add the granted pages to the allocator */
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if (pgalloc_add_new_grant(pfn, npages))
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BUG();
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return 0;
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}
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/* FIXME:
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* The pager reclaims memory from the kernel whenever it thinks this is just.
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*/
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int sys_kmem_reclaim(struct syscall_args *regs)
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{
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BUG();
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return 0;
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}
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