s390: setup kernel memory layout early

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>

2 files changed, 4 insertions, 54 deletions

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 146d01700a55..9145ef983f38 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -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();
diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 370f664580af..6be2167943bb 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -52,7 +52,7 @@ void __init setup_uv(void)
 	unsigned long uv_stor_base;
 
 	/*
-	 * keep these conditions in line with kasan init code has_uv_sec_stor_limit()
+	 * keep these conditions in line with has_uv_sec_stor_limit()
 	 */
 	if (!is_prot_virt_host())
 		return;
@@ -91,12 +91,6 @@ fail:
 	prot_virt_host = 0;
 }
 
-void adjust_to_uv_max(unsigned long *vmax)
-{
-	if (uv_info.max_sec_stor_addr)
-		*vmax = min_t(unsigned long, *vmax, uv_info.max_sec_stor_addr);
-}
-
 /*
  * Requests the Ultravisor to pin the page in the shared state. This will
  * cause an intercept when the guest attempts to unshare the pinned page.