[S390] vmalloc: add vmalloc kernel parameter support

With the kernel parameter 'vmalloc=<size>' the size of the vmalloc area
can be specified. This can be used to increase or decrease the size of
the area. Works in the same way as on some other architectures.
This can be useful for features which make excessive use of vmalloc and
wouldn't work otherwise.
The default sizes remain unchanged: 96MB for 31 bit kernels and 1GB for
64 bit kernels.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 5caddd4f7bedd74ed7fa9078c8cf4d97bdfc2227..60a7b1a1702ff478b60177b2ac161341a2882873 100644 (file)
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -112,12 +112,15 @@ extern char empty_zero_page[PAGE_SIZE];
  * effect, this also makes sure that 64 bit module code cannot be used
  * as system call address.
  */
+
+extern unsigned long VMALLOC_START;
+
 #ifndef __s390x__
-#define VMALLOC_START  0x78000000UL
+#define VMALLOC_SIZE   (96UL << 20)
 #define VMALLOC_END    0x7e000000UL
 #define VMEM_MAP_END   0x80000000UL
 #else /* __s390x__ */
-#define VMALLOC_START  0x3e000000000UL
+#define VMALLOC_SIZE   (1UL << 30)
 #define VMALLOC_END    0x3e040000000UL
 #define VMEM_MAP_END   0x40000000000UL
 #endif /* __s390x__ */

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index be6c1cf4ad5ae8922f039ab2100b2e50183553f2..4ca8e826bf303b4d8694f0757fe8b471ba52d099 100644 (file)
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -1,7 +1,5 @@
 /*
- *  arch/s390/mm/pgtable.c
- *
- *    Copyright IBM Corp. 2007
+ *    Copyright IBM Corp. 2007,2009
  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
  */
 
@@ -53,6 +51,18 @@ void clear_table_pgstes(unsigned long *table)
 
 #endif
 
+unsigned long VMALLOC_START = VMALLOC_END - VMALLOC_SIZE;
+EXPORT_SYMBOL(VMALLOC_START);
+
+static int __init parse_vmalloc(char *arg)
+{
+       if (!arg)
+               return -EINVAL;
+       VMALLOC_START = (VMALLOC_END - memparse(arg, &arg)) & PAGE_MASK;
+       return 0;
+}
+early_param("vmalloc", parse_vmalloc);
+
 unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec)
 {
        struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);