s390/boot: rename mem_detect to physmem_info

In preparation to extending mem_detect with additional information like
reserved ranges rename it to more generic physmem_info. This new naming
also help to avoid confusion by using more exact terms like "physmem
online ranges", etc.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 191 insertions, 0 deletions

diff --git a/arch/s390/boot/physmem_info.c b/arch/s390/boot/physmem_info.c
new file mode 100644
index 000000000000..dc2e4d0abfab
--- /dev/null
+++ b/arch/s390/boot/physmem_info.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <asm/setup.h>
+#include <asm/processor.h>
+#include <asm/sclp.h>
+#include <asm/sections.h>
+#include <asm/physmem_info.h>
+#include <asm/sparsemem.h>
+#include "decompressor.h"
+#include "boot.h"
+
+struct physmem_info __bootdata(physmem_info);
+
+/* up to 256 storage elements, 1020 subincrements each */
+#define ENTRIES_EXTENDED_MAX						       \
+	(256 * (1020 / 2) * sizeof(struct physmem_range))
+
+static struct physmem_range *__get_physmem_range_ptr(u32 n)
+{
+	if (n < MEM_INLINED_ENTRIES)
+		return &physmem_info.online[n];
+	return &physmem_info.online_extended[n - MEM_INLINED_ENTRIES];
+}
+
+/*
+ * sequential calls to add_physmem_online_range with adjacent memory ranges
+ * are merged together into single memory range.
+ */
+void add_physmem_online_range(u64 start, u64 end)
+{
+	struct physmem_range *range;
+
+	if (physmem_info.range_count) {
+		range = __get_physmem_range_ptr(physmem_info.range_count - 1);
+		if (range->end == start) {
+			range->end = end;
+			return;
+		}
+	}
+
+	range = __get_physmem_range_ptr(physmem_info.range_count);
+	range->start = start;
+	range->end = end;
+	physmem_info.range_count++;
+}
+
+static int __diag260(unsigned long rx1, unsigned long rx2)
+{
+	unsigned long reg1, reg2, ry;
+	union register_pair rx;
+	psw_t old;
+	int rc;
+
+	rx.even = rx1;
+	rx.odd	= rx2;
+	ry = 0x10; /* storage configuration */
+	rc = -1;   /* fail */
+	asm volatile(
+		"	mvc	0(16,%[psw_old]),0(%[psw_pgm])\n"
+		"	epsw	%[reg1],%[reg2]\n"
+		"	st	%[reg1],0(%[psw_pgm])\n"
+		"	st	%[reg2],4(%[psw_pgm])\n"
+		"	larl	%[reg1],1f\n"
+		"	stg	%[reg1],8(%[psw_pgm])\n"
+		"	diag	%[rx],%[ry],0x260\n"
+		"	ipm	%[rc]\n"
+		"	srl	%[rc],28\n"
+		"1:	mvc	0(16,%[psw_pgm]),0(%[psw_old])\n"
+		: [reg1] "=&d" (reg1),
+		  [reg2] "=&a" (reg2),
+		  [rc] "+&d" (rc),
+		  [ry] "+&d" (ry),
+		  "+Q" (S390_lowcore.program_new_psw),
+		  "=Q" (old)
+		: [rx] "d" (rx.pair),
+		  [psw_old] "a" (&old),
+		  [psw_pgm] "a" (&S390_lowcore.program_new_psw)
+		: "cc", "memory");
+	return rc == 0 ? ry : -1;
+}
+
+static int diag260(void)
+{
+	int rc, i;
+
+	struct {
+		unsigned long start;
+		unsigned long end;
+	} storage_extents[8] __aligned(16); /* VM supports up to 8 extends */
+
+	memset(storage_extents, 0, sizeof(storage_extents));
+	rc = __diag260((unsigned long)storage_extents, sizeof(storage_extents));
+	if (rc == -1)
+		return -1;
+
+	for (i = 0; i < min_t(int, rc, ARRAY_SIZE(storage_extents)); i++)
+		add_physmem_online_range(storage_extents[i].start, storage_extents[i].end + 1);
+	return 0;
+}
+
+static int tprot(unsigned long addr)
+{
+	unsigned long reg1, reg2;
+	int rc = -EFAULT;
+	psw_t old;
+
+	asm volatile(
+		"	mvc	0(16,%[psw_old]),0(%[psw_pgm])\n"
+		"	epsw	%[reg1],%[reg2]\n"
+		"	st	%[reg1],0(%[psw_pgm])\n"
+		"	st	%[reg2],4(%[psw_pgm])\n"
+		"	larl	%[reg1],1f\n"
+		"	stg	%[reg1],8(%[psw_pgm])\n"
+		"	tprot	0(%[addr]),0\n"
+		"	ipm	%[rc]\n"
+		"	srl	%[rc],28\n"
+		"1:	mvc	0(16,%[psw_pgm]),0(%[psw_old])\n"
+		: [reg1] "=&d" (reg1),
+		  [reg2] "=&a" (reg2),
+		  [rc] "+&d" (rc),
+		  "=Q" (S390_lowcore.program_new_psw.addr),
+		  "=Q" (old)
+		: [psw_old] "a" (&old),
+		  [psw_pgm] "a" (&S390_lowcore.program_new_psw),
+		  [addr] "a" (addr)
+		: "cc", "memory");
+	return rc;
+}
+
+static unsigned long search_mem_end(void)
+{
+	unsigned long range = 1 << (MAX_PHYSMEM_BITS - 20); /* in 1MB blocks */
+	unsigned long offset = 0;
+	unsigned long pivot;
+
+	while (range > 1) {
+		range >>= 1;
+		pivot = offset + range;
+		if (!tprot(pivot << 20))
+			offset = pivot;
+	}
+	return (offset + 1) << 20;
+}
+
+unsigned long detect_memory(unsigned long *safe_addr)
+{
+	unsigned long max_physmem_end = 0;
+
+	sclp_early_get_memsize(&max_physmem_end);
+	physmem_info.online_extended = (struct physmem_range *)ALIGN(*safe_addr, sizeof(u64));
+
+	if (!sclp_early_read_storage_info()) {
+		physmem_info.info_source = MEM_DETECT_SCLP_STOR_INFO;
+	} else if (!diag260()) {
+		physmem_info.info_source = MEM_DETECT_DIAG260;
+		max_physmem_end = max_physmem_end ?: get_physmem_usable_end();
+	} else if (max_physmem_end) {
+		add_physmem_online_range(0, max_physmem_end);
+		physmem_info.info_source = MEM_DETECT_SCLP_READ_INFO;
+	} else {
+		max_physmem_end = search_mem_end();
+		add_physmem_online_range(0, max_physmem_end);
+		physmem_info.info_source = MEM_DETECT_BIN_SEARCH;
+	}
+
+	if (physmem_info.range_count > MEM_INLINED_ENTRIES) {
+		*safe_addr += (physmem_info.range_count - MEM_INLINED_ENTRIES) *
+			      sizeof(struct physmem_range);
+	}
+
+	return max_physmem_end;
+}
+
+void physmem_set_usable_limit(unsigned long limit)
+{
+	struct physmem_range *range;
+	int i;
+
+	/* make sure mem_detect.usable ends up within online memory block */
+	for (i = 0; i < physmem_info.range_count; i++) {
+		range = __get_physmem_range_ptr(i);
+		if (range->start >= limit)
+			break;
+		if (range->end >= limit) {
+			physmem_info.usable = limit;
+			break;
+		}
+		physmem_info.usable = range->end;
+	}
+}