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: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/arch/s390/boot/ipl_data.c b/arch/s390/boot/ipl_data.c
new file mode 100644
index 000000000000..90749e3b2fa6
--- /dev/null
+++ b/arch/s390/boot/ipl_data.c
@@ -0,0 +1,84 @@
+// 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, },
+};