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kernel_optimize_test/arch/blackfin/kernel/ptrace.c
David Howells 8feae13110 NOMMU: Make VMAs per MM as for MMU-mode linux 
Make VMAs per mm_struct as for MMU-mode linux.  This solves two problems:

 (1) In SYSV SHM where nattch for a segment does not reflect the number of
     shmat's (and forks) done.

 (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an
     exec'ing process when VM_EXECUTABLE is specified, regardless of the fact
     that a VMA might be shared and already have its vm_mm assigned to another
     process or a dead process.

A new struct (vm_region) is introduced to track a mapped region and to remember
the circumstances under which it may be shared and the vm_list_struct structure
is discarded as it's no longer required.

This patch makes the following additional changes:

 (1) Regions are now allocated with alloc_pages() rather than kmalloc() and
     with no recourse to __GFP_COMP, so the pages are not composite.  Instead,
     each page has a reference on it held by the region.  Anything else that is
     interested in such a page will have to get a reference on it to retain it.
     When the pages are released due to unmapping, each page is passed to
     put_page() and will be freed when the page usage count reaches zero.

 (2) Excess pages are trimmed after an allocation as the allocation must be
     made as a power-of-2 quantity of pages.

 (3) VMAs are added to the parent MM's R/B tree and mmap lists.  As an MM may
     end up with overlapping VMAs within the tree, the VMA struct address is
     appended to the sort key.

 (4) Non-anonymous VMAs are now added to the backing inode's prio list.

 (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of
     the backing region.  The VMA and region structs will be split if
     necessary.

 (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory
     segment instead of all the attachments at that addresss.  Multiple
     shmat()'s return the same address under NOMMU-mode instead of different
     virtual addresses as under MMU-mode.

 (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode.

 (8) /proc/maps is now the global list of mapped regions, and may list bits
     that aren't actually mapped anywhere.

 (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount
     of RAM currently allocated by mmap to hold mappable regions that can't be
     mapped directly.  These are copies of the backing device or file if not
     anonymous.

These changes make NOMMU mode more similar to MMU mode.  The downside is that
NOMMU mode requires some extra memory to track things over NOMMU without this
patch (VMAs are no longer shared, and there are now region structs).

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Mike Frysinger <vapier.adi@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
2009-01-08 12:04:47 +00:00

442 lines
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/*
* File: arch/blackfin/kernel/ptrace.c
* Based on: Taken from linux/kernel/ptrace.c
* Author: linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
*
* Created: 1/23/92
* Description:
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/asm-offsets.h>
#include <asm/dma.h>
#include <asm/fixed_code.h>
#include <asm/mem_map.h>
#define TEXT_OFFSET 0
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/* determines which bits in the SYSCFG reg the user has access to. */
/* 1 = access 0 = no access */
#define SYSCFG_MASK 0x0007 /* SYSCFG reg */
/* sets the trace bits. */
#define TRACE_BITS 0x0001
/* Find the stack offset for a register, relative to thread.esp0. */
#define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
/*
* Get the address of the live pt_regs for the specified task.
* These are saved onto the top kernel stack when the process
* is not running.
*
* Note: if a user thread is execve'd from kernel space, the
* kernel stack will not be empty on entry to the kernel, so
* ptracing these tasks will fail.
*/
static inline struct pt_regs *get_user_regs(struct task_struct *task)
{
return (struct pt_regs *)
((unsigned long)task_stack_page(task) +
(THREAD_SIZE - sizeof(struct pt_regs)));
}
/*
* Get all user integer registers.
*/
static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
{
struct pt_regs regs;
memcpy(&regs, get_user_regs(tsk), sizeof(regs));
regs.usp = tsk->thread.usp;
return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
}
/* Mapping from PT_xxx to the stack offset at which the register is
* saved. Notice that usp has no stack-slot and needs to be treated
* specially (see get_reg/put_reg below).
*/
/*
* Get contents of register REGNO in task TASK.
*/
static inline long get_reg(struct task_struct *task, int regno)
{
unsigned char *reg_ptr;
struct pt_regs *regs =
(struct pt_regs *)((unsigned long)task_stack_page(task) +
(THREAD_SIZE - sizeof(struct pt_regs)));
reg_ptr = (char *)regs;
switch (regno) {
case PT_USP:
return task->thread.usp;
default:
if (regno <= 216)
return *(long *)(reg_ptr + regno);
}
/* slight mystery ... never seems to come here but kernel misbehaves without this code! */
printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
return 0;
}
/*
* Write contents of register REGNO in task TASK.
*/
static inline int
put_reg(struct task_struct *task, int regno, unsigned long data)
{
char *reg_ptr;
struct pt_regs *regs =
(struct pt_regs *)((unsigned long)task_stack_page(task) +
(THREAD_SIZE - sizeof(struct pt_regs)));
reg_ptr = (char *)regs;
switch (regno) {
case PT_PC:
/*********************************************************************/
/* At this point the kernel is most likely in exception. */
/* The RETX register will be used to populate the pc of the process. */
/*********************************************************************/
regs->retx = data;
regs->pc = data;
break;
case PT_RETX:
break; /* regs->retx = data; break; */
case PT_USP:
regs->usp = data;
task->thread.usp = data;
break;
default:
if (regno <= 216)
*(long *)(reg_ptr + regno) = data;
}
return 0;
}
/*
* check that an address falls within the bounds of the target process's memory mappings
*/
static inline int is_user_addr_valid(struct task_struct *child,
unsigned long start, unsigned long len)
{
struct vm_area_struct *vma;
struct sram_list_struct *sraml;
/* overflow */
if (start + len < start)
return -EIO;
vma = find_vma(child->mm, start);
if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
return 0;
for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
if (start >= (unsigned long)sraml->addr
&& start + len < (unsigned long)sraml->addr + sraml->length)
return 0;
if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
return 0;
return -EIO;
}
void ptrace_enable(struct task_struct *child)
{
unsigned long tmp;
tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
put_reg(child, PT_SYSCFG, tmp);
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
unsigned long tmp;
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
put_reg(child, PT_SYSCFG, tmp);
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
unsigned long __user *datap = (unsigned long __user *)data;
switch (request) {
/* when I and D space are separate, these will need to be fixed. */
case PTRACE_PEEKDATA:
pr_debug("ptrace: PEEKDATA\n");
/* fall through */
case PTRACE_PEEKTEXT: /* read word at location addr. */
{
unsigned long tmp = 0;
int copied;
ret = -EIO;
pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %ld\n", addr, sizeof(data));
if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
break;
pr_debug("ptrace: user address is valid\n");
if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
&& addr + sizeof(tmp) <= get_l1_code_start() + L1_CODE_LENGTH) {
safe_dma_memcpy (&tmp, (const void *)(addr), sizeof(tmp));
copied = sizeof(tmp);
} else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
&& addr + sizeof(tmp) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
memcpy(&tmp, (const void *)(addr), sizeof(tmp));
copied = sizeof(tmp);
} else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
&& addr + sizeof(tmp) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
memcpy(&tmp, (const void *)(addr), sizeof(tmp));
copied = sizeof(tmp);
} else if (addr >= FIXED_CODE_START
&& addr + sizeof(tmp) <= FIXED_CODE_END) {
memcpy(&tmp, (const void *)(addr), sizeof(tmp));
copied = sizeof(tmp);
} else
copied = access_process_vm(child, addr, &tmp,
sizeof(tmp), 0);
pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
if (copied != sizeof(tmp))
break;
ret = put_user(tmp, datap);
break;
}
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR:
{
unsigned long tmp;
ret = -EIO;
tmp = 0;
if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
"0 - %x sizeof(pt_regs) is %lx\n",
(int)addr, sizeof(struct pt_regs));
break;
}
if (addr == sizeof(struct pt_regs)) {
/* PT_TEXT_ADDR */
tmp = child->mm->start_code + TEXT_OFFSET;
} else if (addr == (sizeof(struct pt_regs) + 4)) {
/* PT_TEXT_END_ADDR */
tmp = child->mm->end_code;
} else if (addr == (sizeof(struct pt_regs) + 8)) {
/* PT_DATA_ADDR */
tmp = child->mm->start_data;
#ifdef CONFIG_BINFMT_ELF_FDPIC
} else if (addr == (sizeof(struct pt_regs) + 12)) {
tmp = child->mm->context.exec_fdpic_loadmap;
} else if (addr == (sizeof(struct pt_regs) + 16)) {
tmp = child->mm->context.interp_fdpic_loadmap;
#endif
} else {
tmp = get_reg(child, addr);
}
ret = put_user(tmp, datap);
break;
}
/* when I and D space are separate, this will have to be fixed. */
case PTRACE_POKEDATA:
pr_debug("ptrace: PTRACE_PEEKDATA\n");
/* fall through */
case PTRACE_POKETEXT: /* write the word at location addr. */
{
int copied;
ret = -EIO;
pr_debug("ptrace: POKETEXT at addr 0x%08lx + %ld bytes %lx\n",
addr, sizeof(data), data);
if (is_user_addr_valid(child, addr, sizeof(data)) < 0)
break;
pr_debug("ptrace: user address is valid\n");
if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
&& addr + sizeof(data) <= get_l1_code_start() + L1_CODE_LENGTH) {
safe_dma_memcpy ((void *)(addr), &data, sizeof(data));
copied = sizeof(data);
} else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
&& addr + sizeof(data) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
memcpy((void *)(addr), &data, sizeof(data));
copied = sizeof(data);
} else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
&& addr + sizeof(data) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
memcpy((void *)(addr), &data, sizeof(data));
copied = sizeof(data);
} else if (addr >= FIXED_CODE_START
&& addr + sizeof(data) <= FIXED_CODE_END) {
memcpy((void *)(addr), &data, sizeof(data));
copied = sizeof(data);
} else
copied = access_process_vm(child, addr, &data,
sizeof(data), 1);
pr_debug("ptrace: copied size %d\n", copied);
if (copied != sizeof(data))
break;
ret = 0;
break;
}
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
break;
}
if (addr >= (sizeof(struct pt_regs))) {
ret = 0;
break;
}
if (addr == PT_SYSCFG) {
data &= SYSCFG_MASK;
data |= get_reg(child, PT_SYSCFG);
}
ret = put_reg(child, addr, data);
break;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: /* restart after signal. */
pr_debug("ptrace: syscall/cont\n");
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSCALL)
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
ptrace_disable(child);
pr_debug("ptrace: before wake_up_process\n");
wake_up_process(child);
ret = 0;
break;
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL:
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
ptrace_disable(child);
wake_up_process(child);
break;
case PTRACE_SINGLESTEP: /* set the trap flag. */
pr_debug("ptrace: single step\n");
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
ptrace_enable(child);
child->exit_code = data;
wake_up_process(child);
ret = 0;
break;
case PTRACE_GETREGS:
/* Get all gp regs from the child. */
ret = ptrace_getregs(child, datap);
break;
case PTRACE_SETREGS:
printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
/* Set all gp regs in the child. */
ret = 0;
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage void syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/* the 0x80 provides a way for the tracing parent to distinguish
* between a syscall stop and SIGTRAP delivery
*/
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
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