changeset aa7a67647c7b in /z/repo/m5
details: http://repo.m5sim.org/m5?cmd=changeset;node=aa7a67647c7b
description:
syscall emul: fix Power Linux mmap constant, plus other cleanup
We were getting a spurious warning in the regressions that turned
out to be due to having the wrong value for TGT_MAP_ANONYMOUS for
Power Linux, but in the process of tracking it down I ended up
doing some cleanup of the mmap handling in general.
diffstat:
src/arch/power/linux/linux.hh | 2 +-
src/sim/process.cc | 6 +++---
src/sim/syscall_emul.hh | 31 ++++++++++++++++++-------------
3 files changed, 22 insertions(+), 17 deletions(-)
diffs (92 lines):
diff -r fd20dcf1a9aa -r aa7a67647c7b src/arch/power/linux/linux.hh
--- a/src/arch/power/linux/linux.hh Mon May 23 14:29:23 2011 -0700
+++ b/src/arch/power/linux/linux.hh Mon May 23 14:29:23 2011 -0700
@@ -126,7 +126,7 @@
//@}
/// For mmap().
- static const unsigned TGT_MAP_ANONYMOUS = 0x800;
+ static const unsigned TGT_MAP_ANONYMOUS = 0x20;
//@{
/// ioctl() command codes.
diff -r fd20dcf1a9aa -r aa7a67647c7b src/sim/process.cc
--- a/src/sim/process.cc Mon May 23 14:29:23 2011 -0700
+++ b/src/sim/process.cc Mon May 23 14:29:23 2011 -0700
@@ -313,7 +313,7 @@
int
Process::sim_fd(int tgt_fd)
{
- if (tgt_fd > MAX_FD)
+ if (tgt_fd < 0 || tgt_fd > MAX_FD)
return -1;
return fd_map[tgt_fd].fd;
@@ -322,8 +322,8 @@
Process::FdMap *
Process::sim_fd_obj(int tgt_fd)
{
- if (tgt_fd > MAX_FD)
- panic("sim_fd_obj called in fd out of range.");
+ if (tgt_fd < 0 || tgt_fd > MAX_FD)
+ return NULL;
return &fd_map[tgt_fd];
}
diff -r fd20dcf1a9aa -r aa7a67647c7b src/sim/syscall_emul.hh
--- a/src/sim/syscall_emul.hh Mon May 23 14:29:23 2011 -0700
+++ b/src/sim/syscall_emul.hh Mon May 23 14:29:23 2011 -0700
@@ -989,13 +989,8 @@
/// We don't really handle mmap(). If the target is mmaping an
/// anonymous region or /dev/zero, we can get away with doing basically
/// nothing (since memory is initialized to zero and the simulator
-/// doesn't really check addresses anyway). Always print a warning,
-/// since this could be seriously broken if we're not mapping
-/// /dev/zero.
-//
-/// Someday we should explicitly check for /dev/zero in open, flag the
-/// file descriptor, and fail (or implement!) a non-anonymous mmap to
-/// anything else.
+/// doesn't really check addresses anyway).
+///
template <class OS>
SyscallReturn
mmapFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
@@ -1005,9 +1000,24 @@
uint64_t length = p->getSyscallArg(tc, index);
index++; // int prot = p->getSyscallArg(tc, index);
int flags = p->getSyscallArg(tc, index);
- int fd = p->sim_fd(p->getSyscallArg(tc, index));
+ int tgt_fd = p->getSyscallArg(tc, index);
// int offset = p->getSyscallArg(tc, index);
+ if (!(flags & OS::TGT_MAP_ANONYMOUS)) {
+ Process::FdMap *fd_map = p->sim_fd_obj(tgt_fd);
+ if (!fd_map || fd_map->fd < 0) {
+ warn("mmap failing: target fd %d is not valid\n", tgt_fd);
+ return -EBADF;
+ }
+
+ if (fd_map->filename != "/dev/zero") {
+ // This is very likely broken, but leave a warning here
+ // (rather than panic) in case /dev/zero is known by
+ // another name on some platform
+ warn("allowing mmap of file %s; mmap not supported on files"
+ " other than /dev/zero\n", fd_map->filename);
+ }
+ }
if ((start % TheISA::VMPageSize) != 0 ||
(length % TheISA::VMPageSize) != 0) {
@@ -1032,11 +1042,6 @@
}
p->pTable->allocate(start, length);
- if (!(flags & OS::TGT_MAP_ANONYMOUS)) {
- warn("allowing mmap of file @ fd %d. "
- "This will break if not /dev/zero.", fd);
- }
-
return start;
}
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