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+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * HPMC (High Priority Machine Check) handler.
+ *
+ * Copyright (C) 1999 Philipp Rumpf <prumpf@tux.org>
+ * Copyright (C) 1999 Hewlett-Packard (Frank Rowand)
+ * Copyright (C) 2000 Hewlett-Packard (John Marvin)
+ */
+
+
+/*
+ * This HPMC handler retrieves the HPMC pim data, resets IO and
+ * returns to the default trap handler with code set to 1 (HPMC).
+ * The default trap handler calls handle interruption, which
+ * does a stack and register dump. This at least allows kernel
+ * developers to get back to C code in virtual mode, where they
+ * have the option to examine and print values from memory that
+ * would help in debugging an HPMC caused by a software bug.
+ *
+ * There is more to do here:
+ *
+ * 1) On MP systems we need to synchronize processors
+ * before calling pdc/iodc.
+ * 2) We should be checking the system state and not
+ * returning to the fault handler if things are really
+ * bad.
+ *
+ */
+
+ .level 1.1
+
+#include <asm/assembly.h>
+#include <asm/pdc.h>
+#include <asm/psw.h>
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+ /*
+ * stack for os_hpmc, the HPMC handler.
+ * buffer for IODC procedures (for the HPMC handler).
+ *
+ * IODC requires 7K byte stack. That leaves 1K byte for os_hpmc.
+ */
+
+ .import toc_stack,data
+#define hpmc_stack toc_stack /* re-use the TOC stack */
+
+#define HPMC_IODC_BUF_SIZE 0x8000
+
+ __PAGE_ALIGNED_BSS
+ .align 4096
+hpmc_iodc_buf:
+ .block HPMC_IODC_BUF_SIZE
+
+ .section .bss
+ .align 8
+hpmc_raddr:
+ .block 128
+
+#define HPMC_PIM_DATA_SIZE 896 /* Enough to hold all architected 2.0 state */
+
+ .section .bss
+ .align 8
+ENTRY(hpmc_pim_data)
+ .block HPMC_PIM_DATA_SIZE
+END(hpmc_pim_data)
+
+ .text
+
+ .import intr_save, code
+ .align 16
+ENTRY(os_hpmc)
+.os_hpmc:
+
+ /*
+ * registers modified:
+ *
+ * Using callee saves registers without saving them. The
+ * original values are in the pim dump if we need them.
+ *
+ * r2 (rp) return pointer
+ * r3 address of PDCE_PROC
+ * r4 scratch
+ * r5 scratch
+ * r23 (arg3) procedure arg
+ * r24 (arg2) procedure arg
+ * r25 (arg1) procedure arg
+ * r26 (arg0) procedure arg
+ * r30 (sp) stack pointer
+ *
+ * registers read:
+ *
+ * r26 contains address of PDCE_PROC on entry
+ * r28 (ret0) return value from procedure
+ */
+
+ copy arg0, %r3 /* save address of PDCE_PROC */
+
+ /*
+ * disable nested HPMCs
+ *
+ * Increment os_hpmc checksum to invalidate it.
+ * Do this before turning the PSW M bit off.
+ */
+
+ mfctl %cr14, %r4
+ ldw 52(%r4),%r5
+ addi 1,%r5,%r5
+ stw %r5,52(%r4)
+
+ /* MP_FIXME: synchronize all processors. */
+
+ /* Setup stack pointer. */
+
+ load32 PA(hpmc_stack),sp
+
+ ldo 128(sp),sp /* leave room for arguments */
+
+ /*
+ * Most PDC routines require that the M bit be off.
+ * So turn on the Q bit and turn off the M bit.
+ */
+
+ ldi PSW_SM_Q,%r4 /* PSW Q on, PSW M off */
+ mtctl %r4,ipsw
+ mtctl %r0,pcsq
+ mtctl %r0,pcsq
+ load32 PA(os_hpmc_1),%r4
+ mtctl %r4,pcoq
+ ldo 4(%r4),%r4
+ mtctl %r4,pcoq
+ rfi
+ nop
+
+os_hpmc_1:
+
+ /* Call PDC_PIM to get HPMC pim info */
+
+ /*
+ * Note that on some newer boxes, PDC_PIM must be called
+ * before PDC_IO if you want IO to be reset. PDC_PIM sets
+ * a flag that PDC_IO examines.
+ */
+
+ ldo PDC_PIM(%r0), arg0
+ ldo PDC_PIM_HPMC(%r0),arg1 /* Transfer HPMC data */
+ load32 PA(hpmc_raddr),arg2
+ load32 PA(hpmc_pim_data),arg3
+ load32 HPMC_PIM_DATA_SIZE,%r4
+ stw %r4,-52(sp)
+
+ ldil L%PA(os_hpmc_2), rp
+ bv (r3) /* call pdce_proc */
+ ldo R%PA(os_hpmc_2)(rp), rp
+
+os_hpmc_2:
+ comib,<> 0,ret0, os_hpmc_fail
+
+ /* Reset IO by calling the hversion dependent PDC_IO routine */
+
+ ldo PDC_IO(%r0),arg0
+ ldo 0(%r0),arg1 /* log IO errors */
+ ldo 0(%r0),arg2 /* reserved */
+ ldo 0(%r0),arg3 /* reserved */
+ stw %r0,-52(sp) /* reserved */
+
+ ldil L%PA(os_hpmc_3),rp
+ bv (%r3) /* call pdce_proc */
+ ldo R%PA(os_hpmc_3)(rp),rp
+
+os_hpmc_3:
+
+ /* FIXME? Check for errors from PDC_IO (-1 might be OK) */
+
+ /*
+ * Initialize the IODC console device (HPA,SPA, path etc.
+ * are stored on page 0.
+ */
+
+ /*
+ * Load IODC into hpmc_iodc_buf by calling PDC_IODC.
+ * Note that PDC_IODC handles flushing the appropriate
+ * data and instruction cache lines.
+ */
+
+ ldo PDC_IODC(%r0),arg0
+ ldo PDC_IODC_READ(%r0),arg1
+ load32 PA(hpmc_raddr),arg2
+ ldw BOOT_CONSOLE_HPA_OFFSET(%r0),arg3 /* console hpa */
+ ldo PDC_IODC_RI_INIT(%r0),%r4
+ stw %r4,-52(sp)
+ load32 PA(hpmc_iodc_buf),%r4
+ stw %r4,-56(sp)
+ load32 HPMC_IODC_BUF_SIZE,%r4
+ stw %r4,-60(sp)
+
+ ldil L%PA(os_hpmc_4),rp
+ bv (%r3) /* call pdce_proc */
+ ldo R%PA(os_hpmc_4)(rp),rp
+
+os_hpmc_4:
+ comib,<> 0,ret0,os_hpmc_fail
+
+ /* Call the entry init (just loaded by PDC_IODC) */
+
+ ldw BOOT_CONSOLE_HPA_OFFSET(%r0),arg0 /* console hpa */
+ ldo ENTRY_INIT_MOD_DEV(%r0), arg1
+ ldw BOOT_CONSOLE_SPA_OFFSET(%r0),arg2 /* console spa */
+ depi 0,31,11,arg2 /* clear bits 21-31 */
+ ldo BOOT_CONSOLE_PATH_OFFSET(%r0),arg3 /* console path */
+ load32 PA(hpmc_raddr),%r4
+ stw %r4, -52(sp)
+ stw %r0, -56(sp) /* HV */
+ stw %r0, -60(sp) /* HV */
+ stw %r0, -64(sp) /* HV */
+ stw %r0, -68(sp) /* lang, must be zero */
+
+ load32 PA(hpmc_iodc_buf),%r5
+ ldil L%PA(os_hpmc_5),rp
+ bv (%r5)
+ ldo R%PA(os_hpmc_5)(rp),rp
+
+os_hpmc_5:
+ comib,<> 0,ret0,os_hpmc_fail
+
+ /* Prepare to call intr_save */
+
+ /*
+ * Load kernel page directory (load into user also, since
+ * we don't intend to ever return to user land anyway)
+ */
+
+ load32 PA(swapper_pg_dir),%r4
+ mtctl %r4,%cr24 /* Initialize kernel root pointer */
+ mtctl %r4,%cr25 /* Initialize user root pointer */
+
+ /* Clear sr4-sr7 */
+
+ mtsp %r0, %sr4
+ mtsp %r0, %sr5
+ mtsp %r0, %sr6
+ mtsp %r0, %sr7
+
+ tovirt_r1 %r30 /* make sp virtual */
+
+ rsm PSW_SM_Q,%r0 /* Clear Q bit */
+ ldi 1,%r8 /* Set trap code to "1" for HPMC */
+ load32 PA(intr_save),%r1
+ be 0(%sr7,%r1)
+ nop
+
+os_hpmc_fail:
+
+ /*
+ * Reset the system
+ *
+ * Some systems may lockup from a broadcast reset, so try the
+ * hversion PDC_BROADCAST_RESET() first.
+ * MP_FIXME: reset all processors if more than one central bus.
+ */
+
+ /* PDC_BROADCAST_RESET() */
+
+ ldo PDC_BROADCAST_RESET(%r0),arg0
+ ldo 0(%r0),arg1 /* do reset */
+
+ ldil L%PA(os_hpmc_6),rp
+ bv (%r3) /* call pdce_proc */
+ ldo R%PA(os_hpmc_6)(rp),rp
+
+os_hpmc_6:
+
+ /*
+ * possible return values:
+ * -1 non-existent procedure
+ * -2 non-existent option
+ * -16 unaligned stack
+ *
+ * If call returned, do a broadcast reset.
+ */
+
+ ldil L%0xfffc0000,%r4 /* IO_BROADCAST */
+ ldo 5(%r0),%r5
+ stw %r5,48(%r4) /* CMD_RESET to IO_COMMAND offset */
+
+ b .
+ nop
+ .align 16 /* make function length multiple of 16 bytes */