176 lines
3.7 KiB
C++
176 lines
3.7 KiB
C++
/*
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* \brief Pager support for Codezero
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* \author Norman Feske
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* \date 2010-02-16
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*/
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/*
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* Copyright (C) 2010-2012 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/* Genode includes */
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#include <base/ipc_pager.h>
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#include <base/printf.h>
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/* Codezero includes */
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#include <codezero/syscalls.h>
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using namespace Genode;
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using namespace Codezero;
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enum { verbose_page_faults = false };
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/************************
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** Page-fault utility **
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************************/
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class Fault
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{
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public:
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enum Type { READ, WRITE, EXEC, UNKNOWN };
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private:
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/**
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* Translate Codezero page-fault information to generic fault type
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*
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* \param sr status
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* \param pte page-table entry
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*/
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static Type _fault_type(umword_t sr, umword_t pte)
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{
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if (is_prefetch_abort(sr))
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return EXEC;
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if ((pte & PTE_PROT_MASK) == (__MAP_USR_RO & PTE_PROT_MASK))
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return WRITE;
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return READ;
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}
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Type _type;
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umword_t _addr;
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umword_t _ip;
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public:
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/**
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* Constructor
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*
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* \param kdata Codezero-specific page-fault information
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*/
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Fault(struct fault_kdata const &kdata)
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:
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_type(_fault_type(kdata.fsr, kdata.pte)),
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_addr(_type == EXEC ? kdata.faulty_pc : kdata.far),
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_ip(kdata.faulty_pc)
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{ }
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Type type() const { return _type; }
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umword_t addr() const { return _addr; }
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umword_t ip() const { return _ip; }
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};
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/**
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* Print page-fault information in a human-readable form
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*/
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inline void print_page_fault(Fault &fault, int from)
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{
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printf("page (%s%s%s) fault from %d at pf_addr=%lx, pf_ip=%lx\n",
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fault.type() == Fault::READ ? "r" : "-",
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fault.type() == Fault::WRITE ? "w" : "-",
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fault.type() == Fault::EXEC ? "x" : "-",
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from, fault.addr(), fault.ip());
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}
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/***************
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** IPC pager **
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***************/
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void Ipc_pager::wait_for_fault()
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{
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for (;;) {
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int ret = l4_receive(L4_ANYTHREAD);
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if (ret < 0) {
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PERR("pager: l4_received returned ret=%d", ret);
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continue;
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}
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umword_t tag = l4_get_tag();
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int faulter_tid = l4_get_sender();
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if (tag != L4_IPC_TAG_PFAULT) {
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PWRN("got an unexpected IPC from %d", faulter_tid);
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continue;
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}
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/* copy fault information from message registers */
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struct fault_kdata fault_kdata;
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for (unsigned i = 0; i < sizeof(fault_kdata_t)/sizeof(umword_t); i++)
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((umword_t *)&fault_kdata)[i] = read_mr(MR_UNUSED_START + i);
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Fault fault(fault_kdata);
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if (verbose_page_faults)
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print_page_fault(fault, faulter_tid);
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/* determine corresponding page in our own address space */
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_pf_addr = fault.addr();
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_pf_write = fault.type() == Fault::WRITE;
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_pf_ip = fault.ip();
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_last = faulter_tid;
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return;
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}
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}
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void Ipc_pager::reply_and_wait_for_fault()
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{
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/* install mapping */
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umword_t flags = _reply_mapping.writeable() ? MAP_USR_RW
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: MAP_USR_RO;
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/*
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* XXX: remove heuristics for mapping device registers.
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*/
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if (_reply_mapping.from_phys() == 0x10120000 /* LCD */
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|| _reply_mapping.from_phys() == 0x10006000 /* keyboard */
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|| _reply_mapping.from_phys() == 0x10007000) /* mouse */
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flags = MAP_USR_IO;
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int ret = l4_map((void *)_reply_mapping.from_phys(),
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(void *)_reply_mapping.to_virt(),
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_reply_mapping.num_pages(), flags, _last.tid);
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/* wake up faulter if mapping succeeded */
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if (ret < 0)
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PERR("l4_map returned %d, putting thread %d to sleep", ret, _last.tid);
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else
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acknowledge_wakeup();
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/* wait for next page fault */
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wait_for_fault();
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}
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void Ipc_pager::acknowledge_wakeup()
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{
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enum { SUCCESS = 0 };
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l4_set_sender(_last.tid);
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l4_ipc_return(SUCCESS);
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}
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Ipc_pager::Ipc_pager() : Native_capability(thread_myself(), 0) { }
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