/* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
/* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
/* Copyright (C) 2014 OSCAR lab, Stony Brook University
This file is part of Graphene Library OS.
Graphene Library OS 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 3 of the
License, or (at your option) any later version.
Graphene Library OS 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 . */
/*
* shim_brk.c
*
* Implementation of system call "brk".
*/
#include
#include
#include
#include
#include
#include
#include
#include
#define BRK_SIZE 4096
unsigned long brk_max_size = 0;
struct shim_brk_info {
void * brk_start;
void * brk_end;
void * brk_current;
};
static struct shim_brk_info region;
DEFINE_PROFILE_OCCURENCE(brk, memory);
DEFINE_PROFILE_OCCURENCE(brk_count, memory);
DEFINE_PROFILE_OCCURENCE(brk_migrate_count, memory);
void get_brk_region (void ** start, void ** end, void ** current)
{
master_lock();
*start = region.brk_start;
*end = region.brk_end;
*current = region.brk_current;
master_unlock();
}
int init_brk_region (void)
{
if (region.brk_start)
return 0;
if (!brk_max_size) {
char brk_cfg[CONFIG_MAX];
if (root_config &&
get_config(root_config, "sys.brk.size", brk_cfg, CONFIG_MAX) > 0)
brk_max_size = parse_int(brk_cfg);
if (!brk_max_size)
brk_max_size = DEFAULT_BRK_MAX_SIZE;
}
void * brk_region = get_unmapped_vma(brk_max_size,
MAP_PRIVATE|MAP_ANONYMOUS);
void * end_brk_region = NULL;
// brk region assigned
brk_region = (void *) DkVirtualMemoryAlloc(brk_region, brk_max_size, 0,
PAL_PROT_READ|PAL_PROT_WRITE);
if (!brk_region)
return -ENOMEM;
ADD_PROFILE_OCCURENCE(brk, brk_max_size);
INC_PROFILE_OCCURENCE(brk_count);
end_brk_region = brk_region + BRK_SIZE;
region.brk_start = brk_region;
region.brk_end = end_brk_region;
region.brk_current = brk_region;
debug("brk area: %p - %p\n", brk_region, end_brk_region);
debug("brk reserved area: %p - %p\n", end_brk_region,
brk_region + brk_max_size);
bkeep_mmap(brk_region, BRK_SIZE, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, NULL, 0, "[heap]");
bkeep_mmap(end_brk_region, brk_max_size - BRK_SIZE,
PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE|VMA_UNMAPPED,
NULL, 0, NULL);
return 0;
}
int init_brk (void)
{
master_lock();
if (!region.brk_start) {
master_unlock();
return 0;
}
int ret = shim_do_munmap(region.brk_start,
region.brk_end - region.brk_start);
if (ret < 0) {
master_unlock();
return ret;
}
region.brk_start = region.brk_end = region.brk_current = NULL;
master_unlock();
return 0;
}
void * shim_do_brk (void * brk)
{
master_lock();
init_brk_region();
if (!brk) {
unchanged:
brk = region.brk_current;
goto out;
}
if (brk < region.brk_start)
goto unchanged;
if (brk > region.brk_end) {
if (brk > region.brk_start + brk_max_size)
goto unchanged;
void * brk_end = region.brk_end;
while (brk_end < brk)
brk_end += BRK_SIZE;
debug("brk area: %p - %p\n", region.brk_start, brk_end);
debug("brk reserved area: %p - %p\n", brk_end,
region.brk_start + brk_max_size);
bkeep_mmap(region.brk_start, brk_end - region.brk_start,
PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, NULL, 0, "heap");
region.brk_current = brk;
region.brk_end = brk_end;
goto out;
}
region.brk_current = brk;
out:
master_unlock();
return brk;
}
BEGIN_CP_FUNC(brk)
{
if (region.brk_start) {
ADD_CP_FUNC_ENTRY(region.brk_start);
ADD_CP_ENTRY(ADDR, region.brk_current);
ADD_CP_ENTRY(SIZE, region.brk_end - region.brk_start);
assert(brk_max_size);
ADD_CP_ENTRY(SIZE, brk_max_size);
}
}
END_CP_FUNC(bek)
BEGIN_RS_FUNC(brk)
{
region.brk_start = (void *) GET_CP_FUNC_ENTRY();
region.brk_current = (void *) GET_CP_ENTRY(ADDR);
region.brk_end = region.brk_start + GET_CP_ENTRY(SIZE);
brk_max_size = GET_CP_ENTRY(SIZE);
debug("brk area: %p - %p\n", region.brk_start, region.brk_end);
unsigned long brk_size = region.brk_end - region.brk_start;
if (brk_size < brk_max_size) {
void * brk_region = (void *) DkVirtualMemoryAlloc(region.brk_end,
brk_max_size - brk_size, 0,
PAL_PROT_READ|PAL_PROT_WRITE);
if (brk_region != region.brk_end)
return -EACCES;
ADD_PROFILE_OCCURENCE(brk, brk_max_size - brk_size);
INC_PROFILE_OCCURENCE(brk_migrate_count);
debug("brk reserved area: %p - %p\n", region.brk_end,
region.brk_start + brk_max_size);
bkeep_mmap(region.brk_end, brk_max_size - brk_size,
PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE|VMA_UNMAPPED, NULL, 0,
NULL);
}
DEBUG_RS("current=%p,region=%p-%p", region.brk_current, region.brk_start,
region.brk_end);
}
END_RS_FUNC(brk)