[PATCH v5 0/6] sparc32: replace sp_banks with memblock

[PATCH v5 0/6] sparc32: replace sp_banks with memblock

[Magnus Lindholm]

Replace the sparc32-private sp_banks memory description with memblock.

The first two patches convert the SRMMU consumers that already run after
bootmem_init() has populated memblock. The third patch moves memblock
population to prom_meminit() and applies the mem= limit there. Patch 4
removes an unused address bitmap before patch 5 moves the early memory
setup into setup_32.c. Patch 6 removes the now-unused sp_banks array.

This work is based on an earlier eight-patch series by Sam Ravnborg.
Patch 2 directly carries over Sam's memblock sizing conversion. The series
has otherwise been substantially reorganized and reworked for the current
kernel. It retains the sparc32 mem= command-line option by using
memblock_enforce_memory_limit() and uses memblock's exclusive range-end
semantics throughout.

The series applies on top of Andreas Larsson's for-next branch at
22a749706e3b (sparc64: decide the TSB huge-page window fixup before the
bank switch), which includes the sparc32 relocation and Viking fixes.
setup_memory() preserves the sun4m/sun4d PAGE_OFFSET probe and diagnostics
from that branch, removing RAM below the mapped physical address using
memblock instead of trimming sp_banks.

Link: https://lore.kernel.org/sparclinux/20260816075141.3489194-1-linmag7@gmail.com/T/#t

The v1 series was boot tested on a Sun SPARCstation 20 with dual
SuperSPARC-II CPUs (SM71).
The v2 series was boot tested on a Sun SPARCstation 20 with dual
ROSS HyperSPARC (RT626) CPUs.
The v3 series was cross-compiled with the SPARCstation 20 and LEON
configurations as well as boot tested on a Sun SPARCstation 20
with dual ROSS HyperSPARC (RT626) CPUs.
The v4 series was cross-compiled with the SPARCstation 20 SMP configuration
and a sparc32_defconfig-derived LEON configuration, both with HIGHMEM
enabled. Boot tested on a SPARCstation 20 SMP (ROSS).
The v5 series was cross-compiled with the SPARCstation 20 SMP and LEON
configurations, both with HIGHMEM enabled. Boot tested on a SPARCstation 20
SMP (ROSS).

Changes in v5:
- Rebase onto Andreas Larsson's for-next branch, resolving the patch 5
  conflict and preserving the updated phys_base handling, including the
  sun4m/sun4d probe restriction and diagnostics, from the relocation fixes.
- Retain Sam's Reviewed-by tags on all six patches.

Changes in v4:
- Use max_pfn in LEON's _pfn_valid() check, preserving the bounds of
  last_valid_pfn instead of restricting the check to lowmem, as requested
  by Andreas Larsson.
- Correct the description: LEON systems can use highmem.
- Carry Sam's Reviewed-by tag on patch 5; all six patches now retain his
  review tags.
- Rebase onto Linux 7.3-rc1 plus the three prerequisite patches; adjust
  patch 6's context without changing its code changes.

Changes in v3:
- Add Sam's Reviewed-by tag to patch 4.
- Initialize max_pfn in patch 5 and use it as the highmem zone limit.
- Use PHYS_PFN() instead of open-coded PAGE_SHIFT conversions in patch 5.
- Remove the obsolete highstart_pfn and highend_pfn declarations.
- Use the generic PFN limit declarations from linux/memblock.h.
- Document removal of the duplicate private HIGHMEM summary.

Changes in v2:
- Add Sam's Reviewed-by tags to patches 1-3 and 6. Patch 6 is the
  unchanged source change from patch 5 in v1, renumbered by the new patch.
- Drop the unused sparc_valid_addr_bitmap in a preparation patch.
- Use for_each_mem_pfn_range() and the standard max_low_pfn variable in
  the early memory setup. The change to LEON's PFN check made in v2 is
  corrected in v4 to preserve its original bounds.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/20260817153237.GA702187@ravnborg.org
Link: https://lore.kernel.org/r/20260901214611.60560-1-linmag7@gmail.com

Magnus Lindholm (6):
  sparc32: use memblock when mapping the kernel
  sparc32: use memblock to find available system memory
  sparc32: populate memblock from the PROM memory map
  sparc32: drop unused valid address bitmap
  sparc32: move early memory setup to setup_arch
  sparc32: drop sp_banks

 arch/sparc/include/asm/highmem.h    |   3 -
 arch/sparc/include/asm/leon.h       |   2 +-
 arch/sparc/include/asm/page_32.h    |  16 ---
 arch/sparc/include/asm/pgtable_32.h |   3 +-
 arch/sparc/include/asm/pgtsrmmu.h   |   1 -
 arch/sparc/kernel/setup_32.c        | 117 ++++++++++---------
 arch/sparc/mm/init_32.c             | 167 +---------------------------
 arch/sparc/mm/leon_mm.c             |   1 +
 arch/sparc/mm/srmmu.c               |  69 ++++--------
 arch/sparc/prom/memory.c            |  51 ++-------
 10 files changed, 103 insertions(+), 327 deletions(-)


base-commit: 22a749706e3b0f857d5169a61f2f86a160eb9abd
-- 
2.43.0

[PATCH v5 1/6] sparc32: use memblock when mapping the kernel

[Magnus Lindholm]

memblock already contains the available memory ranges when map_kernel()
runs. Iterate those ranges directly and remove the sp_banks-specific
mapping helper. memblock range ends are exclusive, so use end - start as
the range size.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/sparc/mm/srmmu.c | 47 +++++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 26 deletions(-)

diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 9a74902ad181..110e2f248c60 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -817,39 +817,34 @@ static void __init do_large_mapping(unsigned long vaddr, unsigned long phys_base
 	*__nocache_fix(pgdp) = __pgd(big_pte);
 }
 
-/* Map sp_bank entry SP_ENTRY, starting at virtual address VBASE. */
-static unsigned long __init map_spbank(unsigned long vbase, int sp_entry)
-{
-	unsigned long pstart = (sp_banks[sp_entry].base_addr & PGDIR_MASK);
-	unsigned long vstart = (vbase & PGDIR_MASK);
-	unsigned long vend = PGDIR_ALIGN(vbase + sp_banks[sp_entry].num_bytes);
-	/* Map "low" memory only */
-	const unsigned long min_vaddr = PAGE_OFFSET;
-	const unsigned long max_vaddr = PAGE_OFFSET + SRMMU_MAXMEM;
-
-	if (vstart < min_vaddr || vstart >= max_vaddr)
-		return vstart;
-
-	if (vend > max_vaddr || vend < min_vaddr)
-		vend = max_vaddr;
-
-	while (vstart < vend) {
-		do_large_mapping(vstart, pstart);
-		vstart += PGDIR_SIZE; pstart += PGDIR_SIZE;
-	}
-	return vstart;
-}
-
 static void __init map_kernel(void)
 {
-	int i;
+	phys_addr_t start, end;
+	u64 i;
 
 	if (phys_base > 0) {
 		do_large_mapping(PAGE_OFFSET, phys_base);
 	}
 
-	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
-		map_spbank((unsigned long)__va(sp_banks[i].base_addr), i);
+	for_each_mem_range(i, &start, &end) {
+		unsigned long vbase = (unsigned long)__va(start);
+		unsigned long pstart = start & PGDIR_MASK;
+		unsigned long vstart = vbase & PGDIR_MASK;
+		unsigned long vend = PGDIR_ALIGN(vbase + end - start);
+		const unsigned long min_vaddr = PAGE_OFFSET;
+		const unsigned long max_vaddr = PAGE_OFFSET + SRMMU_MAXMEM;
+
+		/* Map low memory only. */
+		if (vstart < min_vaddr || vstart >= max_vaddr)
+			continue;
+		if (vend > max_vaddr || vend < min_vaddr)
+			vend = max_vaddr;
+
+		while (vstart < vend) {
+			do_large_mapping(vstart, pstart);
+			vstart += PGDIR_SIZE;
+			pstart += PGDIR_SIZE;
+		}
 	}
 }
 
-- 
2.43.0

[PATCH v5 2/6] sparc32: use memblock to find available system memory

[Magnus Lindholm]

The SRMMU nocache pool is sized after memblock has been populated. Use
memblock_phys_mem_size() instead of summing the private sp_banks array.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/sparc/mm/srmmu.c | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 110e2f248c60..7b57a10c961f 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -226,25 +226,13 @@ void srmmu_free_nocache(void *addr, int size)
 static void srmmu_early_allocate_ptable_skeleton(unsigned long start,
 						 unsigned long end);
 
-/* Return how much physical memory we have.  */
-static unsigned long __init probe_memory(void)
-{
-	unsigned long total = 0;
-	int i;
-
-	for (i = 0; sp_banks[i].num_bytes; i++)
-		total += sp_banks[i].num_bytes;
-
-	return total;
-}
-
 /*
  * Reserve nocache dynamically proportionally to the amount of
  * system RAM. -- Tomas Szepe <szepe@pinerecords.com>, June 2002
  */
 static void __init srmmu_nocache_calcsize(void)
 {
-	unsigned long sysmemavail = probe_memory() / 1024;
+	unsigned long sysmemavail = memblock_phys_mem_size() / 1024;
 	int srmmu_nocache_npages;
 
 	srmmu_nocache_npages =
-- 
2.43.0

[PATCH v5 3/6] sparc32: populate memblock from the PROM memory map

[Magnus Lindholm]

Add each available PROM memory range to memblock as it is discovered.
Keep populating sp_banks temporarily so the remaining users continue to
work while they are converted in the following patches.

Since the complete PROM map is now present before bootmem_init(), enforce
the mem= limit after the legacy bank processing. Adding a smaller
overlapping range would otherwise leave memory beyond the requested limit
in memblock during this intermediate commit.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/sparc/mm/init_32.c  | 3 +++
 arch/sparc/prom/memory.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index e0e66f91ceeb..75050dfbc2ea 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c
@@ -165,6 +165,9 @@ unsigned long __init bootmem_init(unsigned long *pages_avail)
 		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.
 	 */
diff --git a/arch/sparc/prom/memory.c b/arch/sparc/prom/memory.c
index 269d6ab5ef5e..59962bc0bc82 100644
--- a/arch/sparc/prom/memory.c
+++ b/arch/sparc/prom/memory.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/memblock.h>
 #include <linux/sort.h>
 #include <linux/init.h>
 
@@ -23,6 +24,7 @@ static int __init prom_meminit_v0(void)
 	for (p = *(romvec->pv_v0mem.v0_available); p; p = p->theres_more) {
 		sp_banks[index].base_addr = (unsigned long) p->start_adr;
 		sp_banks[index].num_bytes = p->num_bytes;
+		memblock_add(p->start_adr, p->num_bytes & PAGE_MASK);
 		index++;
 	}
 
@@ -42,6 +44,7 @@ static int __init prom_meminit_v2(void)
 	for (i = 0; i < num_ents; i++) {
 		sp_banks[i].base_addr = reg[i].phys_addr;
 		sp_banks[i].num_bytes = reg[i].reg_size;
+		memblock_add(reg[i].phys_addr, reg[i].reg_size & PAGE_MASK);
 	}
 
 	return num_ents;
-- 
2.43.0

[PATCH v5 4/6] sparc32: drop unused valid address bitmap

[Magnus Lindholm]

sparc_valid_addr_bitmap is populated during early memory setup but never
read. Remove the bitmap, its allocation and the population helper.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/sparc/mm/init_32.c | 36 ------------------------------------
 1 file changed, 36 deletions(-)

diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index 75050dfbc2ea..6880d9cb30a5 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c
@@ -13,7 +13,6 @@
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
-#include <linux/string.h>
 #include <linux/types.h>
 #include <linux/ptrace.h>
 #include <linux/mman.h>
@@ -24,7 +23,6 @@
 #include <linux/highmem.h>
 #include <linux/memblock.h>
 #include <linux/pagemap.h>
-#include <linux/poison.h>
 #include <linux/gfp.h>
 
 #include <asm/sections.h>
@@ -37,8 +35,6 @@
 
 #include "mm_32.h"
 
-static unsigned long *sparc_valid_addr_bitmap;
-
 unsigned long phys_base;
 EXPORT_SYMBOL(phys_base);
 
@@ -218,27 +214,8 @@ void __init paging_init(void)
 	device_scan();
 }
 
-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;
-
-		while (start < end) {
-			set_bit(start >> 20, sparc_valid_addr_bitmap);
-			start += PAGE_SIZE;
-		}
-	}
-}
-
 void __init arch_mm_preinit(void)
 {
-	int i;
-
 	if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
 		prom_printf("BUG: fixmap and pkmap areas overlap\n");
 		prom_printf("pkbase: 0x%lx pkend: 0x%lx fixstart 0x%lx\n",
@@ -248,19 +225,6 @@ void __init arch_mm_preinit(void)
 		prom_printf("Please mail sparclinux@vger.kernel.org.\n");
 		prom_halt();
 	}
-
-	i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5);
-	i += 1;
-	sparc_valid_addr_bitmap = (unsigned long *)
-		memblock_alloc(i << 2, SMP_CACHE_BYTES);
-
-	if (sparc_valid_addr_bitmap == NULL) {
-		prom_printf("mem_init: Cannot alloc valid_addr_bitmap.\n");
-		prom_halt();
-	}
-	memset(sparc_valid_addr_bitmap, 0, i << 2);
-
-	taint_real_pages();
 }
 
 void sparc_flush_page_to_ram(struct page *page)
-- 
2.43.0

[PATCH v5 5/6] 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().

Use for_each_mem_pfn_range() to find the lowmem boundary and set the
standard max_pfn variable to the end of physical memory. Use max_pfn as
the highmem zone limit and replace last_valid_pfn with max_pfn in LEON's
_pfn_valid() check, preserving its existing bounds, including highmem.

The removed bootmem code also printed a private HIGHMEM summary. Generic
memory initialization already reports the highmem zone, so do not retain
the duplicate message.

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@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/sparc/include/asm/highmem.h    |   3 -
 arch/sparc/include/asm/leon.h       |   2 +-
 arch/sparc/include/asm/pgtable_32.h |   3 +-
 arch/sparc/include/asm/pgtsrmmu.h   |   1 -
 arch/sparc/kernel/setup_32.c        | 117 +++++++++++++-----------
 arch/sparc/mm/init_32.c             | 132 +---------------------------
 arch/sparc/mm/leon_mm.c             |   1 +
 arch/sparc/mm/srmmu.c               |   8 +-
 8 files changed, 72 insertions(+), 195 deletions(-)

diff --git a/arch/sparc/include/asm/highmem.h b/arch/sparc/include/asm/highmem.h
index c7b2e208328b..b1b915ac604d 100644
--- a/arch/sparc/include/asm/highmem.h
+++ b/arch/sparc/include/asm/highmem.h
@@ -26,9 +26,6 @@
 #include <asm/vaddrs.h>
 #include <asm/pgtsrmmu.h>
 
-/* declarations for highmem.c */
-extern unsigned long highstart_pfn, highend_pfn;
-
 #define kmap_prot __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE)
 extern pte_t *pkmap_page_table;
 
diff --git a/arch/sparc/include/asm/leon.h b/arch/sparc/include/asm/leon.h
index 053a24b67aed..2a1bdc2c2f1d 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_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..a2a6c8564c3e 100644
--- a/arch/sparc/include/asm/pgtsrmmu.h
+++ b/arch/sparc/include/asm/pgtsrmmu.h
@@ -98,7 +98,6 @@
 	 restore %g0, %g0, %g0;
 
 #ifndef __ASSEMBLER__
-extern unsigned long last_valid_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 6d7d6fb5c49d..246533fba60d 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 +255,76 @@ 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);
+
+static unsigned long __init calc_max_low_pfn(void)
 {
-	int i, j = 0;
+	unsigned long limit = pfn_base + PHYS_PFN(SRMMU_MAXMEM);
+	unsigned long start_pfn, end_pfn;
+	unsigned long last_pfn = 0;
+	int 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_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
+		if (start_pfn >= limit) {
+			if (last_pfn < limit)
+				limit = last_pfn;
+			break;
+		}
 
-		if (end <= base)
-			continue;		/* wholly below - drop it */
-		if (start < base)
-			start = base;		/* straddles - trim the front */
+		last_pfn = end_pfn;
+	}
 
-		sp_banks[j].base_addr = start;
-		sp_banks[j].num_bytes = end - start;
-		j++;
+	return limit;
+}
+
+static void __init setup_memory(void)
+{
+	unsigned long ram_base = memblock_start_of_DRAM();
+	unsigned long size;
+
+	memblock_set_bottom_up(true);
+	memblock_allow_resize();
+
+	phys_base = ram_base;
+	/* phys_base must describe what PAGE_OFFSET maps to, not where RAM starts. */
+	if (sparc_cpu_model == sun4m || sparc_cpu_model == sun4d) {
+		unsigned long real_base = __get_phys(PAGE_OFFSET);
+
+		prom_printf("phys_base: RAM starts at 0x%lx, kernel is at 0x%lx\n",
+			    phys_base, real_base);
+
+		if (real_base && real_base != phys_base) {
+			phys_base = real_base;
+			memblock_remove(0, phys_base);
+			prom_printf("phys_base: adopted 0x%lx, RAM below it dropped\n",
+				    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_PFN(phys_base);
+	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
+	max_low_pfn = max_pfn;
+
+	if (max_low_pfn > pfn_base + PHYS_PFN(SRMMU_MAXMEM))
+		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 +355,6 @@ 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 +389,7 @@ 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. */
-	if (sparc_cpu_model == sun4m || sparc_cpu_model == sun4d) {
-		unsigned long real_base = __get_phys(PAGE_OFFSET);
-
-		prom_printf("phys_base: RAM starts at 0x%lx, kernel is at 0x%lx\n",
-			    phys_base, real_base);
-
-		if (real_base && real_base != phys_base) {
-			phys_base = real_base;
-			trim_sp_banks_below(phys_base);
-			prom_printf("phys_base: adopted 0x%lx, RAM below it dropped\n",
-				    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/leon_mm.c b/arch/sparc/mm/leon_mm.c
index 1dc9b3d70eda..a43c5ffbbbe5 100644
--- a/arch/sparc/mm/leon_mm.c
+++ b/arch/sparc/mm/leon_mm.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/memblock.h>
 #include <linux/mm.h>
 #include <asm/asi.h>
 #include <asm/leon.h>
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 7b57a10c961f..444295c20b94 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;
@@ -842,7 +840,7 @@ void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
 {
 	max_zone_pfns[ZONE_DMA] = max_low_pfn;
 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
-	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
+	max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
 }
 
 void __init srmmu_paging_init(void)
@@ -855,7 +853,6 @@ 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. */
@@ -881,9 +878,6 @@ 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

[PATCH v5 6/6] sparc32: drop sp_banks

[Magnus Lindholm]

All memory-map consumers now use memblock. Stop duplicating the PROM map
in sp_banks and remove the array, its type, and its fixed bank limit.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/sparc/include/asm/page_32.h | 16 -----------
 arch/sparc/mm/init_32.c          |  2 --
 arch/sparc/prom/memory.c         | 48 ++++----------------------------
 3 files changed, 6 insertions(+), 60 deletions(-)

diff --git a/arch/sparc/include/asm/page_32.h b/arch/sparc/include/asm/page_32.h
index 9f0b54f70908..7429291fb118 100644
--- a/arch/sparc/include/asm/page_32.h
+++ b/arch/sparc/include/asm/page_32.h
@@ -28,22 +28,6 @@
 		(void)(vaddr);			\
 	} while (0)
 
-/* The following structure is used to hold the physical
- * memory configuration of the machine.  This is filled in
- * prom_meminit() and is later used by mem_init() to set up
- * mem_map[].  We statically allocate SPARC_PHYS_BANKS+1 of
- * these structs, this is arbitrary.  The entry after the
- * last valid one has num_bytes==0.
- */
-struct sparc_phys_banks {
-  unsigned long base_addr;
-  unsigned long num_bytes;
-};
-
-#define SPARC_PHYS_BANKS 32
-
-extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];
-
 /* passing structs on the Sparc slow us down tremendously... */
 
 /* #define STRICT_MM_TYPECHECKS */
diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index ac4462f1cf76..2f693b70dbd8 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c
@@ -35,8 +35,6 @@
 
 #include "mm_32.h"
 
-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;
diff --git a/arch/sparc/prom/memory.c b/arch/sparc/prom/memory.c
index 59962bc0bc82..3f65bde2bb89 100644
--- a/arch/sparc/prom/memory.c
+++ b/arch/sparc/prom/memory.c
@@ -8,30 +8,21 @@
 
 #include <linux/kernel.h>
 #include <linux/memblock.h>
-#include <linux/sort.h>
 #include <linux/init.h>
 
 #include <asm/openprom.h>
 #include <asm/oplib.h>
 #include <asm/page.h>
 
-static int __init prom_meminit_v0(void)
+static void __init prom_meminit_v0(void)
 {
 	struct linux_mlist_v0 *p;
-	int index;
 
-	index = 0;
-	for (p = *(romvec->pv_v0mem.v0_available); p; p = p->theres_more) {
-		sp_banks[index].base_addr = (unsigned long) p->start_adr;
-		sp_banks[index].num_bytes = p->num_bytes;
+	for (p = *(romvec->pv_v0mem.v0_available); p; p = p->theres_more)
 		memblock_add(p->start_adr, p->num_bytes & PAGE_MASK);
-		index++;
-	}
-
-	return index;
 }
 
-static int __init prom_meminit_v2(void)
+static void __init prom_meminit_v2(void)
 {
 	struct linux_prom_registers reg[64];
 	phandle node;
@@ -41,51 +32,24 @@ static int __init prom_meminit_v2(void)
 	size = prom_getproperty(node, "available", (char *) reg, sizeof(reg));
 	num_ents = size / sizeof(struct linux_prom_registers);
 
-	for (i = 0; i < num_ents; i++) {
-		sp_banks[i].base_addr = reg[i].phys_addr;
-		sp_banks[i].num_bytes = reg[i].reg_size;
+	for (i = 0; i < num_ents; i++)
 		memblock_add(reg[i].phys_addr, reg[i].reg_size & PAGE_MASK);
-	}
-
-	return num_ents;
-}
-
-static int sp_banks_cmp(const void *a, const void *b)
-{
-	const struct sparc_phys_banks *x = a, *y = b;
-
-	if (x->base_addr > y->base_addr)
-		return 1;
-	if (x->base_addr < y->base_addr)
-		return -1;
-	return 0;
 }
 
 /* Initialize the memory lists based upon the prom version. */
 void __init prom_meminit(void)
 {
-	int i, num_ents = 0;
-
 	switch (prom_vers) {
 	case PROM_V0:
-		num_ents = prom_meminit_v0();
+		prom_meminit_v0();
 		break;
 
 	case PROM_V2:
 	case PROM_V3:
-		num_ents = prom_meminit_v2();
+		prom_meminit_v2();
 		break;
 
 	default:
 		break;
 	}
-	sort(sp_banks, num_ents, sizeof(struct sparc_phys_banks),
-	     sp_banks_cmp, NULL);
-
-	/* Sentinel.  */
-	sp_banks[num_ents].base_addr = 0xdeadbeef;
-	sp_banks[num_ents].num_bytes = 0;
-
-	for (i = 0; i < num_ents; i++)
-		sp_banks[i].num_bytes &= PAGE_MASK;
 }
-- 
2.43.0

Re: [PATCH v5 0/6] sparc32: replace sp_banks with memblock

[Andreas Larsson]

On 2026-10-07 19:41, Magnus Lindholm wrote:
> Replace the sparc32-private sp_banks memory description with memblock.
> 
> The first two patches convert the SRMMU consumers that already run after
> bootmem_init() has populated memblock. The third patch moves memblock
> population to prom_meminit() and applies the mem= limit there. Patch 4
> removes an unused address bitmap before patch 5 moves the early memory
> setup into setup_32.c. Patch 6 removes the now-unused sp_banks array.
> 
> This work is based on an earlier eight-patch series by Sam Ravnborg.
> Patch 2 directly carries over Sam's memblock sizing conversion. The series
> has otherwise been substantially reorganized and reworked for the current
> kernel. It retains the sparc32 mem= command-line option by using
> memblock_enforce_memory_limit() and uses memblock's exclusive range-end
> semantics throughout.
> 
> The series applies on top of Andreas Larsson's for-next branch at
> 22a749706e3b (sparc64: decide the TSB huge-page window fixup before the
> bank switch), which includes the sparc32 relocation and Viking fixes.
> setup_memory() preserves the sun4m/sun4d PAGE_OFFSET probe and diagnostics
> from that branch, removing RAM below the mapped physical address using
> memblock instead of trimming sp_banks.
> 
> Link: https://lore.kernel.org/sparclinux/20260816075141.3489194-1-linmag7@gmail.com/T/#t
> 
> The v1 series was boot tested on a Sun SPARCstation 20 with dual
> SuperSPARC-II CPUs (SM71).
> The v2 series was boot tested on a Sun SPARCstation 20 with dual
> ROSS HyperSPARC (RT626) CPUs.
> The v3 series was cross-compiled with the SPARCstation 20 and LEON
> configurations as well as boot tested on a Sun SPARCstation 20
> with dual ROSS HyperSPARC (RT626) CPUs.
> The v4 series was cross-compiled with the SPARCstation 20 SMP configuration
> and a sparc32_defconfig-derived LEON configuration, both with HIGHMEM
> enabled. Boot tested on a SPARCstation 20 SMP (ROSS).
> The v5 series was cross-compiled with the SPARCstation 20 SMP and LEON
> configurations, both with HIGHMEM enabled. Boot tested on a SPARCstation 20
> SMP (ROSS).
> 
> Changes in v5:
> - Rebase onto Andreas Larsson's for-next branch, resolving the patch 5
>   conflict and preserving the updated phys_base handling, including the
>   sun4m/sun4d probe restriction and diagnostics, from the relocation fixes.
> - Retain Sam's Reviewed-by tags on all six patches.
> 
> Changes in v4:
> - Use max_pfn in LEON's _pfn_valid() check, preserving the bounds of
>   last_valid_pfn instead of restricting the check to lowmem, as requested
>   by Andreas Larsson.
> - Correct the description: LEON systems can use highmem.
> - Carry Sam's Reviewed-by tag on patch 5; all six patches now retain his
>   review tags.
> - Rebase onto Linux 7.3-rc1 plus the three prerequisite patches; adjust
>   patch 6's context without changing its code changes.
> 
> Changes in v3:
> - Add Sam's Reviewed-by tag to patch 4.
> - Initialize max_pfn in patch 5 and use it as the highmem zone limit.
> - Use PHYS_PFN() instead of open-coded PAGE_SHIFT conversions in patch 5.
> - Remove the obsolete highstart_pfn and highend_pfn declarations.
> - Use the generic PFN limit declarations from linux/memblock.h.
> - Document removal of the duplicate private HIGHMEM summary.
> 
> Changes in v2:
> - Add Sam's Reviewed-by tags to patches 1-3 and 6. Patch 6 is the
>   unchanged source change from patch 5 in v1, renumbered by the new patch.
> - Drop the unused sparc_valid_addr_bitmap in a preparation patch.
> - Use for_each_mem_pfn_range() and the standard max_low_pfn variable in
>   the early memory setup. The change to LEON's PFN check made in v2 is
>   corrected in v4 to preserve its original bounds.
> 
> Suggested-by: Sam Ravnborg <sam@ravnborg.org>
> Link: https://lore.kernel.org/r/20260817153237.GA702187@ravnborg.org
> Link: https://lore.kernel.org/r/20260901214611.60560-1-linmag7@gmail.com
> 
> Magnus Lindholm (6):
>   sparc32: use memblock when mapping the kernel
>   sparc32: use memblock to find available system memory
>   sparc32: populate memblock from the PROM memory map
>   sparc32: drop unused valid address bitmap
>   sparc32: move early memory setup to setup_arch
>   sparc32: drop sp_banks
> 
>  arch/sparc/include/asm/highmem.h    |   3 -
>  arch/sparc/include/asm/leon.h       |   2 +-
>  arch/sparc/include/asm/page_32.h    |  16 ---
>  arch/sparc/include/asm/pgtable_32.h |   3 +-
>  arch/sparc/include/asm/pgtsrmmu.h   |   1 -
>  arch/sparc/kernel/setup_32.c        | 117 ++++++++++---------
>  arch/sparc/mm/init_32.c             | 167 +---------------------------
>  arch/sparc/mm/leon_mm.c             |   1 +
>  arch/sparc/mm/srmmu.c               |  69 ++++--------
>  arch/sparc/prom/memory.c            |  51 ++-------
>  10 files changed, 103 insertions(+), 327 deletions(-)
> 
> 
> base-commit: 22a749706e3b0f857d5169a61f2f86a160eb9abd

Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Tested-by: Andreas Larsson <andreas@gaisler.com>

Picking this up to my for-next.

Thanks,
Andreas