[PATCH 4/5] sparc32: move early memory setup to setup_arch

[Magnus Lindholm]

Move the early memory configuration out of SRMMU paging setup and next to
the rest of setup_arch(). Derive the PFN limits from memblock, reserve the
kernel and initrd there, and retain mem= support with
memblock_enforce_memory_limit().

When PAGE_OFFSET maps a relocated kernel, remove memory below phys_base
from memblock because it cannot be reached through the linear map. This
replaces the equivalent trimming of sp_banks.

Suggested-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Signed-off-by: Magnus Lindholm <linmag7@xxxxxxxxx>
---
 arch/sparc/include/asm/pgtable_32.h |   3 +-
 arch/sparc/kernel/setup_32.c        | 118 +++++++++++++----------
 arch/sparc/mm/init_32.c             | 140 +---------------------------
 arch/sparc/mm/srmmu.c               |   4 -
 4 files changed, 73 insertions(+), 192 deletions(-)

diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index f89b1250661d..91a6032cf6a2 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -37,8 +37,7 @@ struct vm_area_struct;
 struct page;
 
 void load_mmu(void);
-unsigned long calc_highpages(void);
-unsigned long __init bootmem_init(unsigned long *pages_avail);
+void __init find_ramdisk(unsigned long end_of_phys_memory);
 
 #define pte_ERROR(e)   __builtin_trap()
 #define pmd_ERROR(e)   __builtin_trap()
diff --git a/arch/sparc/kernel/setup_32.c b/arch/sparc/kernel/setup_32.c
index 795714959da6..e5f1c3ee36df 100644
--- a/arch/sparc/kernel/setup_32.c
+++ b/arch/sparc/kernel/setup_32.c
@@ -23,6 +23,7 @@
 #include <linux/syscalls.h>
 #include <linux/kdev_t.h>
 #include <linux/major.h>
+#include <linux/memblock.h>
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
@@ -254,28 +255,77 @@ static __init void leon_patch(void)
 
 struct tt_entry *sparc_ttable;
 
-/* Drop RAM below the kernel; the linear map runs upward from phys_base
- * and cannot reach it.
- */
-static void __init trim_sp_banks_below(unsigned long base)
+unsigned long phys_base;
+EXPORT_SYMBOL(phys_base);
+
+unsigned long pfn_base;
+EXPORT_SYMBOL(pfn_base);
+
+unsigned long highend_pfn;
+
+static unsigned long __init calc_max_low_pfn(void)
 {
-	int i, j = 0;
+	unsigned long limit = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
+	unsigned long last_pfn = 0;
+	phys_addr_t start, end;
+	u64 i;
 
-	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
-		unsigned long start = sp_banks[i].base_addr;
-		unsigned long end = start + sp_banks[i].num_bytes;
+	for_each_mem_range(i, &start, &end) {
+		unsigned long start_pfn = PFN_DOWN(start);
 
-		if (end <= base)
-			continue;		/* wholly below - drop it */
-		if (start < base)
-			start = base;		/* straddles - trim the front */
+		if (start_pfn >= limit) {
+			if (last_pfn < limit)
+				limit = last_pfn;
+			break;
+		}
 
-		sp_banks[j].base_addr = start;
-		sp_banks[j].num_bytes = end - start;
-		j++;
+		last_pfn = PFN_DOWN(end);
 	}
-	sp_banks[j].base_addr = 0;
-	sp_banks[j].num_bytes = 0;
+
+	return limit;
+}
+
+static void __init setup_memory(void)
+{
+	unsigned long ram_base = memblock_start_of_DRAM();
+	unsigned long real_base = __get_phys(PAGE_OFFSET);
+	unsigned long size;
+
+	memblock_set_bottom_up(true);
+	memblock_allow_resize();
+
+	phys_base = ram_base;
+	if (real_base && real_base != phys_base) {
+		prom_printf("phys_base: RAM starts 0x%x but kernel is at 0x%x\n",
+			    (unsigned int)phys_base, (unsigned int)real_base);
+		phys_base = real_base;
+		memblock_remove(0, phys_base);
+		prom_printf("phys_base: adopted 0x%x, RAM below it dropped\n",
+			    (unsigned int)phys_base);
+	}
+
+	if (cmdline_memory_size)
+		memblock_enforce_memory_limit(cmdline_memory_size);
+
+	min_low_pfn = PFN_DOWN(memblock_start_of_DRAM());
+	pfn_base = phys_base >> PAGE_SHIFT;
+	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
+	last_valid_pfn = max_pfn;
+	max_low_pfn = max_pfn;
+	highend_pfn = max_pfn;
+
+	if (max_low_pfn > pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT))
+		max_low_pfn = calc_max_low_pfn();
+
+	find_ramdisk(memblock_end_of_DRAM());
+
+	/* Reserve the kernel text/data/bss. */
+	size = __pa(PAGE_ALIGN((unsigned long)&_end)) - phys_base;
+	memblock_reserve(phys_base, size);
+	memblock_add(phys_base, size);
+
+	/* Only allow low memory to be allocated by memblock. */
+	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
 }
 
 /* Called from head_32.S - before we have setup anything
@@ -306,9 +356,6 @@ void __init sparc32_start_kernel(struct linux_romvec *rp)
 
 void __init setup_arch(char **cmdline_p)
 {
-	int i;
-	unsigned long highest_paddr;
-
 	sparc_ttable = &trapbase[0];
 
 	/* Initialize PROM console and command line. */
@@ -343,36 +390,7 @@ void __init setup_arch(char **cmdline_p)
 
 	idprom_init();
 	load_mmu();
-
-	phys_base = 0xffffffffUL;
-	highest_paddr = 0UL;
-	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
-		unsigned long top;
-
-		if (sp_banks[i].base_addr < phys_base)
-			phys_base = sp_banks[i].base_addr;
-		top = sp_banks[i].base_addr +
-			sp_banks[i].num_bytes;
-		if (highest_paddr < top)
-			highest_paddr = top;
-	}
-
-	/* phys_base must describe what PAGE_OFFSET maps to, not where RAM starts. */
-	{
-		unsigned long real_base = __get_phys(PAGE_OFFSET);
-
-		if (real_base && real_base != phys_base) {
-			prom_printf("phys_base: RAM starts 0x%x but kernel is at 0x%x\n",
-				    (unsigned int)phys_base,
-				    (unsigned int)real_base);
-			phys_base = real_base;
-			trim_sp_banks_below(phys_base);
-			prom_printf("phys_base: adopted 0x%x, RAM below it dropped\n",
-				    (unsigned int)phys_base);
-		}
-	}
-
-	pfn_base = phys_base >> PAGE_SHIFT;
+	setup_memory();
 
 	if (!root_flags)
 		root_mountflags &= ~MS_RDONLY;
diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index 75050dfbc2ea..62c41d896421 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c
@@ -39,66 +39,15 @@
 
 static unsigned long *sparc_valid_addr_bitmap;
 
-unsigned long phys_base;
-EXPORT_SYMBOL(phys_base);
-
-unsigned long pfn_base;
-EXPORT_SYMBOL(pfn_base);
-
 struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];
 
 /* Initial ramdisk setup */
 extern unsigned int sparc_ramdisk_image;
 extern unsigned int sparc_ramdisk_size;
 
-unsigned long highstart_pfn, highend_pfn;
-
 unsigned long last_valid_pfn;
 
-unsigned long calc_highpages(void)
-{
-	int i;
-	int nr = 0;
-
-	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
-		unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
-		unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
-
-		if (end_pfn <= max_low_pfn)
-			continue;
-
-		if (start_pfn < max_low_pfn)
-			start_pfn = max_low_pfn;
-
-		nr += end_pfn - start_pfn;
-	}
-
-	return nr;
-}
-
-static unsigned long calc_max_low_pfn(void)
-{
-	int i;
-	unsigned long tmp = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
-	unsigned long curr_pfn, last_pfn;
-
-	last_pfn = (sp_banks[0].base_addr + sp_banks[0].num_bytes) >> PAGE_SHIFT;
-	for (i = 1; sp_banks[i].num_bytes != 0; i++) {
-		curr_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
-
-		if (curr_pfn >= tmp) {
-			if (last_pfn < tmp)
-				tmp = last_pfn;
-			break;
-		}
-
-		last_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
-	}
-
-	return tmp;
-}
-
-static void __init find_ramdisk(unsigned long end_of_phys_memory)
+void __init find_ramdisk(unsigned long end_of_phys_memory)
 {
 #ifdef CONFIG_BLK_DEV_INITRD
 	unsigned long size;
@@ -128,83 +77,6 @@ static void __init find_ramdisk(unsigned long end_of_phys_memory)
 #endif
 }
 
-unsigned long __init bootmem_init(unsigned long *pages_avail)
-{
-	unsigned long start_pfn, bytes_avail, size;
-	unsigned long end_of_phys_memory = 0;
-	unsigned long high_pages = 0;
-	int i;
-
-	memblock_set_bottom_up(true);
-	memblock_allow_resize();
-
-	bytes_avail = 0UL;
-	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
-		end_of_phys_memory = sp_banks[i].base_addr +
-			sp_banks[i].num_bytes;
-		bytes_avail += sp_banks[i].num_bytes;
-		if (cmdline_memory_size) {
-			if (bytes_avail > cmdline_memory_size) {
-				unsigned long slack = bytes_avail - cmdline_memory_size;
-
-				bytes_avail -= slack;
-				end_of_phys_memory -= slack;
-
-				sp_banks[i].num_bytes -= slack;
-				if (sp_banks[i].num_bytes == 0) {
-					sp_banks[i].base_addr = 0xdeadbeef;
-				} else {
-					memblock_add(sp_banks[i].base_addr,
-						     sp_banks[i].num_bytes);
-					sp_banks[i+1].num_bytes = 0;
-					sp_banks[i+1].base_addr = 0xdeadbeef;
-				}
-				break;
-			}
-		}
-		memblock_add(sp_banks[i].base_addr, sp_banks[i].num_bytes);
-	}
-
-	if (cmdline_memory_size)
-		memblock_enforce_memory_limit(cmdline_memory_size);
-
-	/* Start with page aligned address of last symbol in kernel
-	 * image.
-	 */
-	start_pfn  = (unsigned long)__pa(PAGE_ALIGN((unsigned long) &_end));
-
-	/* Now shift down to get the real physical page frame number. */
-	start_pfn >>= PAGE_SHIFT;
-
-	max_pfn = end_of_phys_memory >> PAGE_SHIFT;
-
-	max_low_pfn = max_pfn;
-	highstart_pfn = highend_pfn = max_pfn;
-
-	if (max_low_pfn > pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT)) {
-		highstart_pfn = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
-		max_low_pfn = calc_max_low_pfn();
-		high_pages = calc_highpages();
-		printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
-		    high_pages >> (20 - PAGE_SHIFT));
-	}
-
-	find_ramdisk(end_of_phys_memory);
-
-	/* Reserve the kernel text/data/bss. */
-	size = (start_pfn << PAGE_SHIFT) - phys_base;
-	memblock_reserve(phys_base, size);
-	memblock_add(phys_base, size);
-
-	size = memblock_phys_mem_size() - memblock_reserved_size();
-	*pages_avail = (size >> PAGE_SHIFT) - high_pages;
-
-	/* Only allow low memory to be allocated via memblock allocation */
-	memblock_set_current_limit(max_low_pfn << PAGE_SHIFT);
-
-	return max_pfn;
-}
-
 /*
  * paging_init() sets up the page tables: We call the MMU specific
  * init routine based upon the Sun model type on the Sparc.
@@ -220,14 +92,10 @@ void __init paging_init(void)
 
 static void __init taint_real_pages(void)
 {
-	int i;
-
-	for (i = 0; sp_banks[i].num_bytes; i++) {
-		unsigned long start, end;
-
-		start = sp_banks[i].base_addr;
-		end = start + sp_banks[i].num_bytes;
+	phys_addr_t start, end;
+	u64 i;
 
+	for_each_mem_range(i, &start, &end) {
 		while (start < end) {
 			set_bit(start >> 20, sparc_valid_addr_bitmap);
 			start += PAGE_SIZE;
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 3029527a5a9f..272e430f8bd8 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -884,7 +884,6 @@ void __init srmmu_paging_init(void)
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
-	unsigned long pages_avail;
 
 	init_mm.context = (unsigned long) NO_CONTEXT;
 	sparc_iomap.start = SUN4M_IOBASE_VADDR;	/* 16MB of IOSPACE on all sun4m's. */
@@ -910,9 +909,6 @@ void __init srmmu_paging_init(void)
 		prom_halt();
 	}
 
-	pages_avail = 0;
-	last_valid_pfn = bootmem_init(&pages_avail);
-
 	srmmu_nocache_calcsize();
 	srmmu_nocache_init();
 	srmmu_inherit_prom_mappings(0xfe400000, (LINUX_OPPROM_ENDVM - PAGE_SIZE));
-- 
2.43.0