[PATCH v2 5/6] sparc32: move early memory setup to setup_arch
From: Magnus Lindholm
Date: Sun Aug 30 2026 - 08:08:43 EST
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().
Use for_each_mem_pfn_range() to find the lowmem boundary and replace
last_valid_pfn with the standard max_low_pfn variable. This tightens
LEON's _pfn_valid() upper bound from all RAM to the lowmem limit, with no
functional change because LEON does not use highmem.
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/leon.h | 2 +-
arch/sparc/include/asm/pgtable_32.h | 3 +-
arch/sparc/include/asm/pgtsrmmu.h | 2 +-
arch/sparc/kernel/setup_32.c | 115 +++++++++++++-----------
arch/sparc/mm/init_32.c | 132 +---------------------------
arch/sparc/mm/srmmu.c | 6 --
6 files changed, 69 insertions(+), 191 deletions(-)
diff --git a/arch/sparc/include/asm/leon.h b/arch/sparc/include/asm/leon.h
index 053a24b67aed..815131c77ed7 100644
--- a/arch/sparc/include/asm/leon.h
+++ b/arch/sparc/include/asm/leon.h
@@ -251,7 +251,7 @@ extern int leon_ipi_irq;
/* macros used in leon_mm.c */
#define PFN(x) ((x) >> PAGE_SHIFT)
-#define _pfn_valid(pfn) ((pfn < last_valid_pfn) && (pfn >= PFN(phys_base)))
+#define _pfn_valid(pfn) ((pfn < max_low_pfn) && (pfn >= PFN(phys_base)))
#define _SRMMU_PTE_PMASK_LEON 0xffffffff
/*
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/include/asm/pgtsrmmu.h b/arch/sparc/include/asm/pgtsrmmu.h
index a265822a475e..9ce7558113f8 100644
--- a/arch/sparc/include/asm/pgtsrmmu.h
+++ b/arch/sparc/include/asm/pgtsrmmu.h
@@ -98,7 +98,7 @@
restore %g0, %g0, %g0;
#ifndef __ASSEMBLER__
-extern unsigned long last_valid_pfn;
+extern unsigned long max_low_pfn;
/* This makes sense. Honest it does - Anton */
/* XXX Yes but it's ugly as sin. FIXME. -KMW */
diff --git a/arch/sparc/kernel/setup_32.c b/arch/sparc/kernel/setup_32.c
index 795714959da6..c3c3274e55af 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 +255,74 @@ 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 start_pfn, end_pfn;
+ unsigned long last_pfn = 0;
+ int i;
+
+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn,
+ NULL) {
+ if (start_pfn >= limit) {
+ if (last_pfn < limit)
+ limit = last_pfn;
+ break;
+ }
- 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;
+ last_pfn = end_pfn;
+ }
- if (end <= base)
- continue; /* wholly below - drop it */
- if (start < base)
- start = base; /* straddles - trim the front */
+ return limit;
+}
- sp_banks[j].base_addr = start;
- sp_banks[j].num_bytes = end - start;
- j++;
+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);
}
- sp_banks[j].base_addr = 0;
- sp_banks[j].num_bytes = 0;
+
+ 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_low_pfn = PFN_DOWN(memblock_end_of_DRAM());
+ highend_pfn = max_low_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 +353,6 @@ 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 +387,7 @@ 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 6880d9cb30a5..ac4462f1cf76 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c
@@ -35,66 +35,13 @@
#include "mm_32.h"
-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;
@@ -124,83 +71,6 @@ 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.
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 3029527a5a9f..cf66a108b411 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -59,8 +59,6 @@ int vac_line_size;
extern struct resource sparc_iomap;
-extern unsigned long last_valid_pfn;
-
static pgd_t *srmmu_swapper_pg_dir;
const struct sparc32_cachetlb_ops *sparc32_cachetlb_ops;
@@ -884,7 +882,6 @@ 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 +907,6 @@ 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