Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c
new file mode 100644
index 0000000..62e7c13
--- /dev/null
+++ b/arch/s390/boot/mem_detect.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <asm/sclp.h>
+#include <asm/sections.h>
+#include <asm/mem_detect.h>
+#include <asm/sparsemem.h>
+#include "compressed/decompressor.h"
+#include "boot.h"
+
+unsigned long __bootdata(max_physmem_end);
+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))
+
+/*
+ * To avoid corrupting old kernel memory during dump, find lowest memory
+ * chunk possible either right after the kernel end (decompressed kernel) or
+ * after initrd (if it is present and there is no hole between the kernel end
+ * and initrd)
+ */
+static void *mem_detect_alloc_extended(void)
+{
+ unsigned long offset = ALIGN(mem_safe_offset(), sizeof(u64));
+
+ if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE &&
+ INITRD_START < offset + ENTRIES_EXTENDED_MAX)
+ offset = ALIGN(INITRD_START + INITRD_SIZE, sizeof(u64));
+
+ return (void *)offset;
+}
+
+static struct mem_detect_block *__get_mem_detect_block_ptr(u32 n)
+{
+ if (n < MEM_INLINED_ENTRIES)
+ return &mem_detect.entries[n];
+ if (unlikely(!mem_detect.entries_extended))
+ mem_detect.entries_extended = mem_detect_alloc_extended();
+ 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)
+{
+ register unsigned long _rx1 asm("2") = rx1;
+ register unsigned long _rx2 asm("3") = rx2;
+ register unsigned long _ry asm("4") = 0x10; /* storage configuration */
+ int rc = -1; /* fail */
+ unsigned long reg1, reg2;
+ psw_t old = S390_lowcore.program_new_psw;
+
+ asm volatile(
+ " epsw %0,%1\n"
+ " st %0,%[psw_pgm]\n"
+ " st %1,%[psw_pgm]+4\n"
+ " larl %0,1f\n"
+ " stg %0,%[psw_pgm]+8\n"
+ " diag %[rx],%[ry],0x260\n"
+ " ipm %[rc]\n"
+ " srl %[rc],28\n"
+ "1:\n"
+ : "=&d" (reg1), "=&a" (reg2),
+ [psw_pgm] "=Q" (S390_lowcore.program_new_psw),
+ [rc] "+&d" (rc), [ry] "+d" (_ry)
+ : [rx] "d" (_rx1), "d" (_rx2)
+ : "cc", "memory");
+ S390_lowcore.program_new_psw = old;
+ 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 pgm_addr;
+ int rc = -EFAULT;
+ psw_t old = S390_lowcore.program_new_psw;
+
+ S390_lowcore.program_new_psw.mask = __extract_psw();
+ asm volatile(
+ " larl %[pgm_addr],1f\n"
+ " stg %[pgm_addr],%[psw_pgm_addr]\n"
+ " tprot 0(%[addr]),0\n"
+ " ipm %[rc]\n"
+ " srl %[rc],28\n"
+ "1:\n"
+ : [pgm_addr] "=&d"(pgm_addr),
+ [psw_pgm_addr] "=Q"(S390_lowcore.program_new_psw.addr),
+ [rc] "+&d"(rc)
+ : [addr] "a"(addr)
+ : "cc", "memory");
+ S390_lowcore.program_new_psw = old;
+ return rc;
+}
+
+static void 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;
+ }
+
+ add_mem_detect_block(0, (offset + 1) << 20);
+}
+
+void detect_memory(void)
+{
+ sclp_early_get_memsize(&max_physmem_end);
+
+ if (!sclp_early_read_storage_info()) {
+ mem_detect.info_source = MEM_DETECT_SCLP_STOR_INFO;
+ return;
+ }
+
+ if (!diag260()) {
+ mem_detect.info_source = MEM_DETECT_DIAG260;
+ return;
+ }
+
+ if (max_physmem_end) {
+ add_mem_detect_block(0, max_physmem_end);
+ mem_detect.info_source = MEM_DETECT_SCLP_READ_INFO;
+ return;
+ }
+
+ search_mem_end();
+ mem_detect.info_source = MEM_DETECT_BIN_SEARCH;
+ max_physmem_end = get_mem_detect_end();
+}