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-rw-r--r--arch/s390/boot/mem_detect.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c
new file mode 100644
index 000000000..daa159317
--- /dev/null
+++ b/arch/s390/boot/mem_detect.c
@@ -0,0 +1,173 @@
+// 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/mem_detect.h>
+#include <asm/sparsemem.h>
+#include "decompressor.h"
+#include "boot.h"
+
+struct mem_detect_info __bootdata(mem_detect);
+
+/* up to 256 storage elements, 1020 subincrements each */
+#define ENTRIES_EXTENDED_MAX \
+ (256 * (1020 / 2) * sizeof(struct mem_detect_block))
+
+static struct mem_detect_block *__get_mem_detect_block_ptr(u32 n)
+{
+ if (n < MEM_INLINED_ENTRIES)
+ return &mem_detect.entries[n];
+ return &mem_detect.entries_extended[n - MEM_INLINED_ENTRIES];
+}
+
+/*
+ * sequential calls to add_mem_detect_block with adjacent memory areas
+ * are merged together into single memory block.
+ */
+void add_mem_detect_block(u64 start, u64 end)
+{
+ struct mem_detect_block *block;
+
+ if (mem_detect.count) {
+ block = __get_mem_detect_block_ptr(mem_detect.count - 1);
+ if (block->end == start) {
+ block->end = end;
+ return;
+ }
+ }
+
+ block = __get_mem_detect_block_ptr(mem_detect.count);
+ block->start = start;
+ block->end = end;
+ mem_detect.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_mem_detect_block(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);
+ mem_detect.entries_extended = (struct mem_detect_block *)ALIGN(*safe_addr, sizeof(u64));
+
+ if (!sclp_early_read_storage_info()) {
+ mem_detect.info_source = MEM_DETECT_SCLP_STOR_INFO;
+ } else if (!diag260()) {
+ mem_detect.info_source = MEM_DETECT_DIAG260;
+ max_physmem_end = max_physmem_end ?: get_mem_detect_end();
+ } else if (max_physmem_end) {
+ add_mem_detect_block(0, max_physmem_end);
+ mem_detect.info_source = MEM_DETECT_SCLP_READ_INFO;
+ } else {
+ max_physmem_end = search_mem_end();
+ add_mem_detect_block(0, max_physmem_end);
+ mem_detect.info_source = MEM_DETECT_BIN_SEARCH;
+ }
+
+ if (mem_detect.count > MEM_INLINED_ENTRIES) {
+ *safe_addr += (mem_detect.count - MEM_INLINED_ENTRIES) *
+ sizeof(struct mem_detect_block);
+ }
+
+ return max_physmem_end;
+}