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-rw-r--r--linux-user/mmap.c120
1 files changed, 114 insertions, 6 deletions
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index fd315aaabb..39da6dfb40 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -216,6 +216,40 @@ static abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
unsigned long last_brk;
+/* Subroutine of mmap_find_vma, used when we have pre-allocated a chunk
+ of guest address space. */
+static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size)
+{
+ abi_ulong addr;
+ abi_ulong last_addr;
+ int prot;
+ int looped = 0;
+
+ if (size > reserved_va) {
+ return (abi_ulong)-1;
+ }
+
+ last_addr = start;
+ for (addr = start; last_addr + size != addr; addr += qemu_host_page_size) {
+ if (last_addr + size >= reserved_va
+ || (abi_ulong)(last_addr + size) < last_addr) {
+ if (looped) {
+ return (abi_ulong)-1;
+ }
+ last_addr = qemu_host_page_size;
+ addr = 0;
+ looped = 1;
+ continue;
+ }
+ prot = page_get_flags(addr);
+ if (prot) {
+ last_addr = addr + qemu_host_page_size;
+ }
+ }
+ mmap_next_start = addr;
+ return last_addr;
+}
+
/*
* Find and reserve a free memory area of size 'size'. The search
* starts at 'start'.
@@ -237,6 +271,10 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
size = HOST_PAGE_ALIGN(size);
+ if (reserved_va) {
+ return mmap_find_vma_reserved(start, size);
+ }
+
addr = start;
wrapped = repeat = 0;
prev = 0;
@@ -525,6 +563,47 @@ fail:
return -1;
}
+static void mmap_reserve(abi_ulong start, abi_ulong size)
+{
+ abi_ulong real_start;
+ abi_ulong real_end;
+ abi_ulong addr;
+ abi_ulong end;
+ int prot;
+
+ real_start = start & qemu_host_page_mask;
+ real_end = HOST_PAGE_ALIGN(start + size);
+ end = start + size;
+ if (start > real_start) {
+ /* handle host page containing start */
+ prot = 0;
+ for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr);
+ }
+ if (real_end == real_start + qemu_host_page_size) {
+ for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr);
+ }
+ end = real_end;
+ }
+ if (prot != 0)
+ real_start += qemu_host_page_size;
+ }
+ if (end < real_end) {
+ prot = 0;
+ for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+ prot |= page_get_flags(addr);
+ }
+ if (prot != 0)
+ real_end -= qemu_host_page_size;
+ }
+ if (real_start != real_end) {
+ mmap(g2h(real_start), real_end - real_start, PROT_NONE,
+ MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE,
+ -1, 0);
+ }
+}
+
int target_munmap(abi_ulong start, abi_ulong len)
{
abi_ulong end, real_start, real_end, addr;
@@ -572,7 +651,11 @@ int target_munmap(abi_ulong start, abi_ulong len)
ret = 0;
/* unmap what we can */
if (real_start < real_end) {
- ret = munmap(g2h(real_start), real_end - real_start);
+ if (reserved_va) {
+ mmap_reserve(real_start, real_end - real_start);
+ } else {
+ ret = munmap(g2h(real_start), real_end - real_start);
+ }
}
if (ret == 0)
@@ -590,12 +673,18 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
mmap_lock();
- if (flags & MREMAP_FIXED)
+ if (flags & MREMAP_FIXED) {
host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
old_size, new_size,
flags,
- new_addr);
- else if (flags & MREMAP_MAYMOVE) {
+ g2h(new_addr));
+
+ if (reserved_va && host_addr != MAP_FAILED) {
+ /* If new and old addresses overlap then the above mremap will
+ already have failed with EINVAL. */
+ mmap_reserve(old_addr, old_size);
+ }
+ } else if (flags & MREMAP_MAYMOVE) {
abi_ulong mmap_start;
mmap_start = mmap_find_vma(0, new_size);
@@ -603,13 +692,32 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
if (mmap_start == -1) {
errno = ENOMEM;
host_addr = MAP_FAILED;
- } else
+ } else {
host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
old_size, new_size,
flags | MREMAP_FIXED,
g2h(mmap_start));
+ mmap_reserve(old_addr, old_size);
+ }
} else {
- host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
+ int prot = 0;
+ if (reserved_va && old_size < new_size) {
+ abi_ulong addr;
+ for (addr = old_addr + old_size;
+ addr < old_addr + new_size;
+ addr++) {
+ prot |= page_get_flags(addr);
+ }
+ }
+ if (prot == 0) {
+ host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
+ if (host_addr != MAP_FAILED && reserved_va && old_size > new_size) {
+ mmap_reserve(old_addr + old_size, new_size - old_size);
+ }
+ } else {
+ errno = ENOMEM;
+ host_addr = MAP_FAILED;
+ }
/* Check if address fits target address space */
if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
/* Revert mremap() changes */