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s390/vmalloc: have separate modules area

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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>
This commit is contained in:
Heiko Carstens
2012-10-05 16:52:18 +02:00
committed by Martin Schwidefsky
parent 021d48be48
commit c972cc60c2
4 changed files with 46 additions and 12 deletions
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13
arch/s390/kernel/setup.c
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@@ -105,6 +105,11 @@ EXPORT_SYMBOL(VMALLOC_END);
struct page *vmemmap;
EXPORT_SYMBOL(vmemmap);
#ifdef CONFIG_64BIT
unsigned long MODULES_VADDR;
unsigned long MODULES_END;
#endif
/* An array with a pointer to the lowcore of every CPU. */
struct _lowcore *lowcore_ptr[NR_CPUS];
EXPORT_SYMBOL(lowcore_ptr);
@@ -544,19 +549,23 @@ static void __init setup_memory_end(void)
/* Choose kernel address space layout: 2, 3, or 4 levels. */
#ifdef CONFIG_64BIT
vmalloc_size = VMALLOC_END ?: 128UL << 30;
vmalloc_size = VMALLOC_END ?: (128UL << 30) - MODULES_LEN;
tmp = (memory_end ?: real_memory_size) / PAGE_SIZE;
tmp = tmp * (sizeof(struct page) + PAGE_SIZE) + vmalloc_size;
if (tmp <= (1UL << 42))
vmax = 1UL << 42; /* 3-level kernel page table */
else
vmax = 1UL << 53; /* 4-level kernel page table */
/* module area is at the end of the kernel address space. */
MODULES_END = vmax;
MODULES_VADDR = MODULES_END - MODULES_LEN;
VMALLOC_END = MODULES_VADDR;
#else
vmalloc_size = VMALLOC_END ?: 96UL << 20;
vmax = 1UL << 31; /* 2-level kernel page table */
#endif
/* vmalloc area is at the end of the kernel address space. */
VMALLOC_END = vmax;
#endif
VMALLOC_START = vmax - vmalloc_size;
/* Split remaining virtual space between 1:1 mapping & vmemmap array */