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a1ff57416a
When configured with CONFIG_PPC_EARLY_DEBUG_OPAL=y the kernel expects
the OPAL entry and base addresses to be passed in r8 and r9
respectively. Currently the wrapper does not attempt to restore these
values before entering the decompressed kernel which causes the kernel
to branch into whatever happens to be in r9 when doing a write to the
OPAL console in early boot.
This patch adds a platform_ops hook that can be used to branch into the
new kernel. The OPAL console driver patches this at runtime so that if
the console is used it will be restored just prior to entering the
kernel.
Fixes: 656ad58ef1 ("powerpc/boot: Add OPAL console to epapr wrappers")
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
109 lines
2.6 KiB
C
109 lines
2.6 KiB
C
/*
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* Copyright (c) 2016 IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include "ops.h"
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#include "stdio.h"
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#include "io.h"
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#include <libfdt.h>
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#include "../include/asm/opal-api.h"
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#ifdef __powerpc64__
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/* Global OPAL struct used by opal-call.S */
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struct opal {
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u64 base;
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u64 entry;
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} opal;
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static u32 opal_con_id;
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/* see opal-wrappers.S */
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int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
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int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
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int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
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int64_t opal_console_flush(uint64_t term_number);
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int64_t opal_poll_events(uint64_t *outstanding_event_mask);
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void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
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static int opal_con_open(void)
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{
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/*
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* When OPAL loads the boot kernel it stashes the OPAL base and entry
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* address in r8 and r9 so the kernel can use the OPAL console
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* before unflattening the devicetree. While executing the wrapper will
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* probably trash r8 and r9 so this kentry hook restores them before
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* entering the decompressed kernel.
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*/
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platform_ops.kentry = opal_kentry;
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return 0;
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}
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static void opal_con_putc(unsigned char c)
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{
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int64_t rc;
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uint64_t olen, len;
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do {
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rc = opal_console_write_buffer_space(opal_con_id, &olen);
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len = be64_to_cpu(olen);
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if (rc)
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return;
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opal_poll_events(NULL);
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} while (len < 1);
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olen = cpu_to_be64(1);
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opal_console_write(opal_con_id, &olen, &c);
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}
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static void opal_con_close(void)
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{
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opal_console_flush(opal_con_id);
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}
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static void opal_init(void)
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{
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void *opal_node;
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opal_node = finddevice("/ibm,opal");
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if (!opal_node)
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return;
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if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
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return;
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opal.base = be64_to_cpu(opal.base);
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if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
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return;
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opal.entry = be64_to_cpu(opal.entry);
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}
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int opal_console_init(void *devp, struct serial_console_data *scdp)
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{
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opal_init();
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if (devp) {
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int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
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if (n != sizeof(u32))
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return -1;
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opal_con_id = be32_to_cpu(opal_con_id);
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} else
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opal_con_id = 0;
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scdp->open = opal_con_open;
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scdp->putc = opal_con_putc;
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scdp->close = opal_con_close;
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return 0;
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}
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#else
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int opal_console_init(void *devp, struct serial_console_data *scdp)
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{
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return -1;
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}
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#endif /* __powerpc64__ */
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