s390/boot: convert initial lowcore to C

Convert initial lowcore to C and use proper defines and structures to
initialize it. This should make the z/VM ipl procedure a bit less magic.
Acked-by: NPeter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: NVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: NHeiko Carstens <hca@linux.ibm.com>

arch/s390/boot/Makefile

@@ -37,7 +37,7 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 
 obj-y	:= head.o als.o startup.o mem_detect.o ipl_parm.o ipl_report.o
 obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
-obj-y	+= version.o pgm_check_info.o ctype.o
+obj-y	+= version.o pgm_check_info.o ctype.o ipl_data.o
 obj-$(findstring y, $(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) $(CONFIG_PGSTE))	+= uv.o
 obj-$(CONFIG_RELOCATABLE)	+= machine_kexec_reloc.o
 obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o

arch/s390/boot/boot.h

@@ -2,9 +2,12 @@
 #ifndef BOOT_BOOT_H
 #define BOOT_BOOT_H
 
-#include <asm/extable.h>
 #include <linux/types.h>
 
+#define IPL_START	0x200
+
+#ifndef __ASSEMBLY__
+
 void startup_kernel(void);
 unsigned long detect_memory(void);
 bool is_ipl_block_dump(void);
@@ -31,4 +34,5 @@ extern char _stack_start[], _stack_end[];
 
 unsigned long read_ipl_report(unsigned long safe_offset);
 
+#endif /* __ASSEMBLY__ */
 #endif /* BOOT_BOOT_H */

arch/s390/boot/head.S

@@ -27,61 +27,15 @@
 #include <asm/page.h>
 #include <asm/ptrace.h>
 #include <asm/sclp.h>
+#include "boot.h"
 
 #define ARCH_OFFSET	4
 
 #define EP_OFFSET	0x10008
 #define EP_STRING	"S390EP"
-
-#define IPL_START	0x200
+#define IPL_BS		0x730
 
 __HEAD
-
-#define IPL_BS	0x730
-	.org	0
-	.long	0x00080000,0x80000000+IPL_START	# The first 24 bytes are loaded
-	.long	0x02000018,0x60000050		# by ipl to addresses 0-23.
-	.long	0x02000068,0x60000050		# (a PSW and two CCWs).
-	.fill	80-24,1,0x40			# bytes 24-79 are discarded !!
-	.long	0x020000f0,0x60000050		# The next 160 byte are loaded
-	.long	0x02000140,0x60000050		# to addresses 0x18-0xb7
-	.long	0x02000190,0x60000050		# They form the continuation
-	.long	0x020001e0,0x60000050		# of the CCW program started
-	.long	0x02000230,0x60000050		# by ipl and load the range
-	.long	0x02000280,0x60000050		# 0x0f0-0x730 from the image
-	.long	0x020002d0,0x60000050		# to the range 0x0f0-0x730
-	.long	0x02000320,0x60000050		# in memory. At the end of
-	.long	0x02000370,0x60000050		# the channel program the PSW
-	.long	0x020003c0,0x60000050		# at location 0 is loaded.
-	.long	0x02000410,0x60000050		# Initial processing starts
-	.long	0x02000460,0x60000050		# at 0x200 = iplstart.
-	.long	0x020004b0,0x60000050
-	.long	0x02000500,0x60000050
-	.long	0x02000550,0x60000050
-	.long	0x020005a0,0x60000050
-	.long	0x020005f0,0x60000050
-	.long	0x02000640,0x60000050
-	.long	0x02000690,0x60000050
-	.long	0x020006e0,0x20000050
-
-# The restart psw points to ipl_entry, which allows to load a kernel image
-# into memory and starting it by a psw restart on any cpu.
-# All other default psw new locations contain a disabled wait psw where the
-# address indicates which psw was loaded.
-	.org	__LC_RST_NEW_PSW
-	.quad	0,IPL_START
-	.org	__LC_EXT_NEW_PSW
-	.quad	0x0002000180000000,__LC_EXT_NEW_PSW
-	.org	__LC_SVC_NEW_PSW
-	.quad	0x0002000180000000,__LC_SVC_NEW_PSW
-	.org	__LC_PGM_NEW_PSW
-	.quad	0x0002000180000000,__LC_PGM_NEW_PSW
-	.org	__LC_MCK_NEW_PSW
-	.quad	0x0002000180000000,__LC_MCK_NEW_PSW
-	.org	__LC_IO_NEW_PSW
-	.quad	0x0002000180000000,__LC_IO_NEW_PSW
-
-	.org	IPL_START
 ipl_start:
 	j	.Liplcont
 #
@@ -279,10 +233,10 @@ ipl_start:
 # this is called either by the ipl loader or directly by PSW restart
 # or linload or SALIPL
 #
-	.org	STARTUP_NORMAL_OFFSET
+	.org	STARTUP_NORMAL_OFFSET - IPL_START
 SYM_CODE_START(startup)
 	j	startup_normal
-	.org	EP_OFFSET
+	.org	EP_OFFSET - IPL_START
 #
 # This is a list of s390 kernel entry points. At address 0x1000f the number of
 # valid entry points is stored.
@@ -294,7 +248,7 @@ SYM_CODE_START(startup)
 #
 # kdump startup-code, running in 64 bit absolute addressing mode
 #
-	.org	STARTUP_KDUMP_OFFSET
+	.org	STARTUP_KDUMP_OFFSET - IPL_START
 	j	startup_kdump
 SYM_CODE_END(startup)
 SYM_CODE_START_LOCAL(startup_normal)
@@ -384,7 +338,7 @@ SYM_CODE_END(startup_pgm_check_handler)
 # params at 10400 (setup.h)
 # Must be keept in sync with struct parmarea in setup.h
 #
-	.org	PARMAREA
+	.org	PARMAREA - IPL_START
 SYM_DATA_START(parmarea)
 	.quad	0			# IPL_DEVICE
 	.quad	0			# INITRD_START
@@ -394,8 +348,8 @@ SYM_DATA_START(parmarea)
 	.quad	kernel_version		# points to kernel version string
 	.quad	COMMAND_LINE_SIZE
 
-	.org	COMMAND_LINE
+	.org	COMMAND_LINE - IPL_START
 	.byte	"root=/dev/ram0 ro"
 	.byte	0
-	.org	PARMAREA+__PARMAREA_SIZE
+	.org	PARMAREA+__PARMAREA_SIZE - IPL_START
 SYM_DATA_END(parmarea)

arch/s390/boot/ipl_data.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/compat.h>
+#include <linux/ptrace.h>
+#include <asm/cio.h>
+#include <asm/asm-offsets.h>
+#include "boot.h"
+
+#define CCW0(cmd, addr, cnt, flg) \
+	{ .cmd_code = cmd, .cda = addr, .count = cnt, .flags = flg, }
+
+#define PSW_MASK_DISABLED (PSW_MASK_WAIT | PSW_MASK_EA | PSW_MASK_BA)
+
+struct ipl_lowcore {
+	psw_t32		ipl_psw;			/* 0x0000 */
+	struct ccw0	ccwpgm[2];			/* 0x0008 */
+	u8		fill[56];			/* 0x0018 */
+	struct ccw0	ccwpgmcc[20];			/* 0x0050 */
+	u8		pad_0xf0[0x01a0-0x00f0];	/* 0x00f0 */
+	psw_t		restart_psw;			/* 0x01a0 */
+	psw_t		external_new_psw;		/* 0x01b0 */
+	psw_t		svc_new_psw;			/* 0x01c0 */
+	psw_t		program_new_psw;		/* 0x01d0 */
+	psw_t		mcck_new_psw;			/* 0x01e0 */
+	psw_t		io_new_psw;			/* 0x01f0 */
+};
+
+/*
+ * Initial lowcore for IPL: the first 24 bytes are loaded by IPL to
+ * addresses 0-23 (a PSW and two CCWs). Bytes 24-79 are discarded.
+ * The next 160 bytes are loaded to addresses 0x18-0xb7. They form
+ * the continuation of the CCW program started by IPL and load the
+ * range 0x0f0-0x730 from the image to the range 0x0f0-0x730 in
+ * memory. At the end of the channel program the PSW at location 0 is
+ * loaded.
+ * Initial processing starts at 0x200 = iplstart.
+ *
+ * The restart psw points to iplstart which allows to load a kernel
+ * image into memory and starting it by a psw restart on any cpu. All
+ * other default psw new locations contain a disabled wait psw where
+ * the address indicates which psw was loaded.
+ *
+ * Note that the 'file' utility can detect s390 kernel images. For
+ * that to succeed the two initial CCWs, and the 0x40 fill bytes must
+ * be present.
+ */
+struct ipl_lowcore ipl_lowcore __section(".ipldata") = {
+	.ipl_psw = { .mask = PSW32_MASK_BASE, .addr = PSW32_ADDR_AMODE | IPL_START },
+	.ccwpgm = {
+		[ 0] = CCW0(CCW_CMD_READ_IPL, 0x018, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 1] = CCW0(CCW_CMD_READ_IPL, 0x068, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+	},
+	.fill = {
+		[ 0 ... 55] = 0x40,
+	},
+	.ccwpgmcc = {
+		[ 0] = CCW0(CCW_CMD_READ_IPL, 0x0f0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 1] = CCW0(CCW_CMD_READ_IPL, 0x140, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 2] = CCW0(CCW_CMD_READ_IPL, 0x190, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 3] = CCW0(CCW_CMD_READ_IPL, 0x1e0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 4] = CCW0(CCW_CMD_READ_IPL, 0x230, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 5] = CCW0(CCW_CMD_READ_IPL, 0x280, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 6] = CCW0(CCW_CMD_READ_IPL, 0x2d0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 7] = CCW0(CCW_CMD_READ_IPL, 0x320, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 8] = CCW0(CCW_CMD_READ_IPL, 0x370, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[ 9] = CCW0(CCW_CMD_READ_IPL, 0x3c0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[10] = CCW0(CCW_CMD_READ_IPL, 0x410, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[11] = CCW0(CCW_CMD_READ_IPL, 0x460, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[12] = CCW0(CCW_CMD_READ_IPL, 0x4b0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[13] = CCW0(CCW_CMD_READ_IPL, 0x500, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[14] = CCW0(CCW_CMD_READ_IPL, 0x550, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[15] = CCW0(CCW_CMD_READ_IPL, 0x5a0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[16] = CCW0(CCW_CMD_READ_IPL, 0x5f0, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[17] = CCW0(CCW_CMD_READ_IPL, 0x640, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[18] = CCW0(CCW_CMD_READ_IPL, 0x690, 0x50, CCW_FLAG_SLI | CCW_FLAG_CC),
+		[19] = CCW0(CCW_CMD_READ_IPL, 0x6e0, 0x50, CCW_FLAG_SLI),
+	},
+	.restart_psw	  = { .mask = 0, .addr = IPL_START, },
+	.external_new_psw = { .mask = PSW_MASK_DISABLED, .addr = __LC_EXT_NEW_PSW, },
+	.svc_new_psw	  = { .mask = PSW_MASK_DISABLED, .addr = __LC_SVC_NEW_PSW, },
+	.program_new_psw  = { .mask = PSW_MASK_DISABLED, .addr = __LC_PGM_NEW_PSW, },
+	.mcck_new_psw	  = { .mask = PSW_MASK_DISABLED, .addr = __LC_MCK_NEW_PSW, },
+	.io_new_psw	  = { .mask = PSW_MASK_DISABLED, .addr = __LC_IO_NEW_PSW, },
+};

arch/s390/boot/vmlinux.lds.S

@@ -4,6 +4,7 @@
 #include <asm/thread_info.h>
 #include <asm/page.h>
 #include <asm/sclp.h>
+#include "boot.h"
 
 OUTPUT_FORMAT("elf64-s390", "elf64-s390", "elf64-s390")
 OUTPUT_ARCH(s390:64-bit)
@@ -13,6 +14,10 @@ ENTRY(startup)
 SECTIONS
 {
 	. = 0;
+	.ipldata : {
+		*(.ipldata)
+	}
+	. = IPL_START;
 	.head.text : {
 		_head = . ;
 		HEAD_TEXT