From 4d5f2c28a88f83d390e80407f55a8a02ead33878 Mon Sep 17 00:00:00 2001
From: Steve Reinhardt <steve.reinhardt@amd.com>
Date: Sat, 22 Oct 2011 22:30:07 -0700
Subject: syscall_emul: implement MAP_FIXED option to mmap()

---
 src/sim/syscall_emul.hh | 47 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

(limited to 'src/sim/syscall_emul.hh')

diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index d119adc24..9bcf58844 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -1027,20 +1027,45 @@ mmapFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
         return -EINVAL;
     }
 
-    if (start != 0) {
-        warn("mmap: ignoring suggested map address 0x%x, using 0x%x",
-             start, p->mmap_end);
+    // are we ok with clobbering existing mappings?  only set this to
+    // true if the user has been warned.
+    bool clobber = false;
+
+    // try to use the caller-provided address if there is one
+    bool use_provided_address = (start != 0);
+
+    if (use_provided_address) {
+        // check to see if the desired address is already in use
+        if (!p->pTable->isUnmapped(start, length)) {
+            // there are existing mappings in the desired range
+            // whether we clobber them or not depends on whether the caller
+            // specified MAP_FIXED
+            if (flags & OS::TGT_MAP_FIXED) {
+                // MAP_FIXED specified: clobber existing mappings
+                warn("mmap: MAP_FIXED at 0x%x overwrites existing mappings\n",
+                     start);
+                clobber = true;
+            } else {
+                // MAP_FIXED not specified: ignore suggested start address
+                warn("mmap: ignoring suggested map address 0x%x\n", start);
+                use_provided_address = false;
+            }
+        }
     }
 
-    // pick next address from our "mmap region"
-    if (OS::mmapGrowsDown()) {
-        start = p->mmap_end - length;
-        p->mmap_end = start;
-    } else {
-        start = p->mmap_end;
-        p->mmap_end += length;
+    if (!use_provided_address) {
+        // no address provided, or provided address unusable:
+        // pick next address from our "mmap region"
+        if (OS::mmapGrowsDown()) {
+            start = p->mmap_end - length;
+            p->mmap_end = start;
+        } else {
+            start = p->mmap_end;
+            p->mmap_end += length;
+        }
     }
-    p->pTable->allocate(start, length);
+
+    p->pTable->allocate(start, length, clobber);
 
     return start;
 }
-- 
cgit v1.2.3


From 6f9d294e8685f49d91af48065736ac1d67e53718 Mon Sep 17 00:00:00 2001
From: Steve Reinhardt <steve.reinhardt@amd.com>
Date: Sat, 22 Oct 2011 22:30:08 -0700
Subject: SE: move page allocation from PageTable to Process

PageTable supported an allocate() call that called back
through the Process to allocate memory, but did not have
a method to map addresses without allocating new pages.
It makes more sense for Process to do the allocation, so
this method was renamed allocateMem() and moved to Process,
and uses a new map() call on PageTable.

The remaining uses of the process pointer in PageTable
were only to get the name and the PID, so by passing these
in directly in the constructor, we can make PageTable
completely independent of Process.
---
 src/sim/syscall_emul.hh | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

(limited to 'src/sim/syscall_emul.hh')

diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index 9bcf58844..50bf1a52f 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -677,7 +677,7 @@ mremapFunc(SyscallDesc *desc, int callnum, LiveProcess *process, ThreadContext *
     if (new_length > old_length) {
         if ((start + old_length) == process->mmap_end) {
             uint64_t diff = new_length - old_length;
-            process->pTable->allocate(process->mmap_end, diff);
+            process->allocateMem(process->mmap_end, diff);
             process->mmap_end += diff;
             return start;
         } else {
@@ -691,15 +691,15 @@ mremapFunc(SyscallDesc *desc, int callnum, LiveProcess *process, ThreadContext *
                         process->mmap_end, process->mmap_end + new_length, new_length);
                 start = process->mmap_end;
                 // add on the remaining unallocated pages
-                process->pTable->allocate(start + old_length, new_length - old_length);
+                process->allocateMem(start + old_length,
+                                     new_length - old_length);
                 process->mmap_end += new_length;
                 warn("returning %08p as start\n", start);
                 return start;
             }
         }
     } else {
-        process->pTable->deallocate(start + new_length, old_length -
-                new_length);
+        process->pTable->unmap(start + new_length, old_length - new_length);
         return start;
     }
 }
@@ -1065,7 +1065,7 @@ mmapFunc(SyscallDesc *desc, int num, LiveProcess *p, ThreadContext *tc)
         }
     }
 
-    p->pTable->allocate(start, length, clobber);
+    p->allocateMem(start, length, clobber);
 
     return start;
 }
-- 
cgit v1.2.3