diff options
| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2012-10-05 14:52:18 (GMT) |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-10-09 12:17:01 (GMT) |
| commit | c972cc60c23f5a6309292bfcc91a441743ba027e (patch) | |
| tree | 04f8fc1d4e78979d28a897a90bba5c3321555967 /arch/s390/include | |
| parent | 021d48be48481821f6e3f53028915c0571874135 (diff) | |
| download | linux-c972cc60c23f5a6309292bfcc91a441743ba027e.tar.xz | |
s390/vmalloc: have separate modules area
Add a special module area on top of the vmalloc area, which may be only
used for modules and bpf jit generated code.
This makes sure that inter module branches will always happen without a
trampoline and in addition having all the code within a 2GB frame is
branch prediction unit friendly.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include')
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 75b91bb..dd647c9 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -119,13 +119,12 @@ static inline int is_zero_pfn(unsigned long pfn) #ifndef __ASSEMBLY__ /* - * The vmalloc area will always be on the topmost area of the kernel - * mapping. We reserve 96MB (31bit) / 128GB (64bit) for vmalloc, - * which should be enough for any sane case. - * By putting vmalloc at the top, we maximise the gap between physical - * memory and vmalloc to catch misplaced memory accesses. As a side - * effect, this also makes sure that 64 bit module code cannot be used - * as system call address. + * The vmalloc and module area will always be on the topmost area of the kernel + * mapping. We reserve 96MB (31bit) / 128GB (64bit) for vmalloc and modules. + * On 64 bit kernels we have a 2GB area at the top of the vmalloc area where + * modules will reside. That makes sure that inter module branches always + * happen without trampolines and in addition the placement within a 2GB frame + * is branch prediction unit friendly. */ extern unsigned long VMALLOC_START; extern unsigned long VMALLOC_END; @@ -133,6 +132,14 @@ extern struct page *vmemmap; #define VMEM_MAX_PHYS ((unsigned long) vmemmap) +#ifdef CONFIG_64BIT +extern unsigned long MODULES_VADDR; +extern unsigned long MODULES_END; +#define MODULES_VADDR MODULES_VADDR +#define MODULES_END MODULES_END +#define MODULES_LEN (1UL << 31) +#endif + /* * A 31 bit pagetable entry of S390 has following format: * | PFRA | | OS | |