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s390: setup kernel memory layout early

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Currently there are two separate places where kernel memory layout has
to be known and adjusted:
1. early kasan setup.
2. paging setup later.

Those 2 places had to be kept in sync and adjusted to reflect peculiar
technical details of one another. With additional factors which influence
kernel memory layout like ultravisor secure storage limit, complexity
of keeping two things in sync grew up even more.

Besides that if we look forward towards creating identity mapping and
enabling DAT before jumping into uncompressed kernel - that would also
require full knowledge of and control over kernel memory layout.

So, de-duplicate and move kernel memory layout setup logic into
the decompressor.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Vasily Gorbik
2020-10-06 22:12:39 +02:00
parent b5415c8f97
commit 0c4f2623b9
10 changed files with 136 additions and 96 deletions
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50
arch/s390/kernel/setup.c
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@@ -96,7 +96,6 @@ unsigned long int_hwcap = 0;
int __bootdata(noexec_disabled);
unsigned long __bootdata(ident_map_size);
unsigned long __bootdata(vmalloc_size);
struct mem_detect_info __bootdata(mem_detect);
struct exception_table_entry *__bootdata_preserved(__start_dma_ex_table);
@@ -545,53 +544,10 @@ static void __init setup_resources(void)
#endif
}
static void __init setup_ident_map_size(void)
static void __init setup_memory_end(void)
{
unsigned long vmax, tmp;
/* Choose kernel address space layout: 3 or 4 levels. */
tmp = ident_map_size / PAGE_SIZE;
tmp = tmp * (sizeof(struct page) + PAGE_SIZE);
if (tmp + vmalloc_size + MODULES_LEN <= _REGION2_SIZE)
vmax = _REGION2_SIZE; /* 3-level kernel page table */
else
vmax = _REGION1_SIZE; /* 4-level kernel page table */
/* module area is at the end of the kernel address space. */
MODULES_END = vmax;
if (is_prot_virt_host())
adjust_to_uv_max(&MODULES_END);
#ifdef CONFIG_KASAN
vmax = _REGION1_SIZE;
MODULES_END = kasan_vmax;
#endif
MODULES_VADDR = MODULES_END - MODULES_LEN;
VMALLOC_END = MODULES_VADDR;
VMALLOC_START = VMALLOC_END - vmalloc_size;
/* Split remaining virtual space between 1:1 mapping & vmemmap array */
tmp = VMALLOC_START / (PAGE_SIZE + sizeof(struct page));
/* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
tmp = SECTION_ALIGN_UP(tmp);
tmp = VMALLOC_START - tmp * sizeof(struct page);
tmp &= ~((vmax >> 11) - 1); /* align to page table level */
tmp = min(tmp, 1UL << MAX_PHYSMEM_BITS);
vmemmap = (struct page *) tmp;
/* Take care that ident_map_size <= vmemmap */
ident_map_size = min(ident_map_size, (unsigned long)vmemmap);
#ifdef CONFIG_KASAN
ident_map_size = min(ident_map_size, KASAN_SHADOW_START);
#endif
vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page);
#ifdef CONFIG_KASAN
/* move vmemmap above kasan shadow only if stands in a way */
if (KASAN_SHADOW_END > (unsigned long)vmemmap &&
(unsigned long)vmemmap + vmemmap_size > KASAN_SHADOW_START)
vmemmap = max(vmemmap, (struct page *)KASAN_SHADOW_END);
#endif
max_pfn = max_low_pfn = PFN_DOWN(ident_map_size);
memblock_remove(ident_map_size, ULONG_MAX);
max_pfn = max_low_pfn = PFN_DOWN(ident_map_size);
pr_notice("The maximum memory size is %luMB\n", ident_map_size >> 20);
}
@@ -1132,7 +1088,7 @@ void __init setup_arch(char **cmdline_p)
remove_oldmem();
setup_uv();
setup_ident_map_size();
setup_memory_end();
setup_memory();
dma_contiguous_reserve(ident_map_size);
vmcp_cma_reserve();