Do not use unsupported syscalls

src/coreclr/gc/unix/gcenv.unix.cpp

@@ -244,6 +244,7 @@ bool GCToOSInterface::Initialize()
         // Verify that the s_helperPage is really aligned to the g_SystemInfo.dwPageSize
         assert((((size_t)g_helperPage) & (OS_PAGE_SIZE - 1)) == 0);
 
+#ifndef TARGET_BROWSER
         // Locking the page ensures that it stays in memory during the two mprotect
         // calls in the FlushProcessWriteBuffers below. If the page was unmapped between
         // those calls, they would not have the expected effect of generating IPI.
@@ -253,6 +254,9 @@ bool GCToOSInterface::Initialize()
         {
             return false;
         }
+#else
+        int status;
+#endif // !TARGET_BROWSER
 
         status = pthread_mutex_init(&g_flushProcessWriteBuffersMutex, NULL);
         if (status != 0)
@@ -576,7 +580,7 @@ static void* VirtualReserveInner(size_t size, size_t alignment, uint32_t flags,
         }
 
         pRetVal = pAlignedRetVal;
-#ifdef MADV_DONTDUMP
+#if defined(MADV_DONTDUMP) && !defined(TARGET_BROWSER)
         // Do not include reserved uncommitted memory in coredump.
         if (!committing)
         {
@@ -624,9 +628,13 @@ bool GCToOSInterface::VirtualRelease(void* address, size_t size)
 //  true if it has succeeded, false if it has failed
 static bool VirtualCommitInner(void* address, size_t size, uint16_t node, bool newMemory)
 {
+#ifndef TARGET_BROWSER
     bool success = mprotect(address, size, PROT_WRITE | PROT_READ) == 0;
+#else
+    bool success = true;
+#endif // !TARGET_BROWSER
 
-#ifdef MADV_DODUMP
+#if defined(MADV_DONTDUMP) && !defined(TARGET_BROWSER)
     if (success && !newMemory)
     {
         // Include committed memory in coredump. New memory is included by default.

src/coreclr/pal/src/exception/signal.cpp

@@ -219,13 +219,15 @@ BOOL SEHInitializeSignals(CorUnix::CPalThread *pthrCurrent, DWORD flags)
             return FALSE;
         }
 
+#ifndef TARGET_BROWSER
         // create a guard page for the alternate stack
         int st = mprotect((void*)g_stackOverflowHandlerStack, GetVirtualPageSize(), PROT_NONE);
         if (st != 0)
         {
             munmap((void*)g_stackOverflowHandlerStack, stackOverflowStackSize);
             return FALSE;
         }
+#endif // TARGET_BROWSER
 
         g_stackOverflowHandlerStack = (void*)((size_t)g_stackOverflowHandlerStack + stackOverflowStackSize);
 #endif // HAVE_MACH_EXCEPTIONS

src/coreclr/pal/src/map/virtual.cpp

@@ -641,7 +641,7 @@ static LPVOID ReserveVirtualMemory(
     }
 #endif  // MMAP_ANON_IGNORES_PROTECTION
 
-#ifdef MADV_DONTDUMP
+#if defined(MADV_DONTDUMP) && !defined(TARGET_BROWSER)
     // Do not include reserved uncommitted memory in coredump.
     if (!(fAllocationType & MEM_COMMIT))
     {
@@ -730,14 +730,16 @@ VIRTUALCommitMemory(
 
     nProtect = W32toUnixAccessControl(flProtect);
 
+#ifndef TARGET_BROWSER
     // Commit the pages
     if (mprotect((void *) StartBoundary, MemSize, nProtect) != 0)
     {
         ERROR("mprotect() failed! Error(%d)=%s\n", errno, strerror(errno));
         goto error;
     }
+#endif
 
-#ifdef MADV_DODUMP
+#if defined(MADV_DONTDUMP) && !defined(TARGET_BROWSER)
     // Include committed memory in coredump. Any newly allocated memory included by default.
     if (!IsNewMemory)
     {
@@ -748,7 +750,9 @@ VIRTUALCommitMemory(
     pRetVal = (void *) StartBoundary;
     goto done;
 
+#ifndef TARGET_BROWSER
 error:
+#endif
     if ( flAllocationType & MEM_RESERVE || IsLocallyReserved )
     {
         munmap( pRetVal, MemSize );
@@ -1073,7 +1077,7 @@ VirtualFree(
             }
 #endif  // MMAP_ANON_IGNORES_PROTECTION
 
-#ifdef MADV_DONTDUMP
+#if defined(MADV_DONTDUMP) && !defined(TARGET_BROWSER)
             // Do not include freed memory in coredump.
             madvise((LPVOID) StartBoundary, MemSize, MADV_DONTDUMP);
 #endif
@@ -1207,9 +1211,11 @@ VirtualProtect(
     }
 
     pEntry = VIRTUALFindRegionInformation( StartBoundary );
+#ifndef TARGET_BROWSER
     if ( 0 == mprotect( (LPVOID)StartBoundary, MemSize,
                    W32toUnixAccessControl( flNewProtect ) ) )
     {
+#endif // !TARGET_BROWSER
         /* Reset the access protection. */
         TRACE( "Number of pages to change %d, starting page %d \n",
                NumberOfPagesToChange, OffSet );
@@ -1220,13 +1226,14 @@ VirtualProtect(
          */
         *lpflOldProtect = PAGE_EXECUTE_READWRITE;
 
-#ifdef MADV_DONTDUMP
+#if defined(MADV_DONTDUMP) && !defined(TARGET_BROWSER)
         // Include or exclude memory from coredump based on the protection.
         int advise = flNewProtect == PAGE_NOACCESS ? MADV_DONTDUMP : MADV_DODUMP;
         madvise((LPVOID)StartBoundary, MemSize, advise);
 #endif
 
         bRetVal = TRUE;
+#ifndef TARGET_BROWSER
     }
     else
     {
@@ -1240,6 +1247,7 @@ VirtualProtect(
             SetLastError( ERROR_INVALID_ACCESS );
         }
     }
+#endif // !TARGET_BROWSER
 ExitVirtualProtect:
     minipal_mutex_leave(&virtual_critsec);
 

src/coreclr/pal/src/thread/process.cpp

@@ -2610,6 +2610,7 @@ InitializeFlushProcessWriteBuffers()
     // Verify that the s_helperPage is really aligned to the GetVirtualPageSize()
     _ASSERTE((((SIZE_T)s_helperPage) & (GetVirtualPageSize() - 1)) == 0);
 
+#ifndef TARGET_BROWSER
     // Locking the page ensures that it stays in memory during the two mprotect
     // calls in the FlushProcessWriteBuffers below. If the page was unmapped between
     // those calls, they would not have the expected effect of generating IPI.
@@ -2619,6 +2620,9 @@ InitializeFlushProcessWriteBuffers()
     {
         return FALSE;
     }
+#else
+    int status;
+#endif // !TARGET_BROWSER
 
     status = pthread_mutex_init(&flushProcessWriteBuffersMutex, NULL);
     if (status != 0)
@@ -2664,18 +2668,22 @@ FlushProcessWriteBuffers()
         int status = pthread_mutex_lock(&flushProcessWriteBuffersMutex);
         FATAL_ASSERT(status == 0, "Failed to lock the flushProcessWriteBuffersMutex lock");
 
+#ifndef TARGET_BROWSER
         // Changing a helper memory page protection from read / write to no access
         // causes the OS to issue IPI to flush TLBs on all processors. This also
         // results in flushing the processor buffers.
         status = mprotect(s_helperPage, GetVirtualPageSize(), PROT_READ | PROT_WRITE);
         FATAL_ASSERT(status == 0, "Failed to change helper page protection to read / write");
+#endif // !TARGET_BROWSER
 
         // Ensure that the page is dirty before we change the protection so that
         // we prevent the OS from skipping the global TLB flush.
         InterlockedIncrement(s_helperPage);
 
+#ifndef TARGET_BROWSER
         status = mprotect(s_helperPage, GetVirtualPageSize(), PROT_NONE);
         FATAL_ASSERT(status == 0, "Failed to change helper page protection to no access");
+#endif // !TARGET_BROWSER
 
         status = pthread_mutex_unlock(&flushProcessWriteBuffersMutex);
         FATAL_ASSERT(status == 0, "Failed to unlock the flushProcessWriteBuffersMutex lock");