Commit 0cc4746c authored by Michael Ellerman's avatar Michael Ellerman Committed by Paul Mackerras
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[PATCH] powerpc: Reroute interrupts from 0 + offset to PHYSICAL_START + offset



Regardless of where the kernel's linked we always get interrupts at low
addresses. This patch creates a trampoline in the first 3 pages of memory,
where interrupts land, and patches those addresses to jump into the real
kernel code at PHYSICAL_START.

We also need to reserve the trampoline code and a bit more in prom.c
Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 8c4f1f29
......@@ -34,6 +34,7 @@ obj-$(CONFIG_IBMVIO) += vio.o
obj-$(CONFIG_IBMEBUS) += ibmebus.o
obj-$(CONFIG_GENERIC_TBSYNC) += smp-tbsync.o
obj64-$(CONFIG_PPC_MULTIPLATFORM) += nvram_64.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
ifeq ($(CONFIG_PPC_MERGE),y)
......
/*
* Routines for doing kexec-based kdump.
*
* Copyright (C) 2005, IBM Corp.
*
* Created by: Michael Ellerman
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#undef DEBUG
#include <asm/kdump.h>
#include <asm/lmb.h>
#include <asm/firmware.h>
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
static void __init create_trampoline(unsigned long addr)
{
/* The maximum range of a single instruction branch, is the current
* instruction's address + (32 MB - 4) bytes. For the trampoline we
* need to branch to current address + 32 MB. So we insert a nop at
* the trampoline address, then the next instruction (+ 4 bytes)
* does a branch to (32 MB - 4). The net effect is that when we
* branch to "addr" we jump to ("addr" + 32 MB). Although it requires
* two instructions it doesn't require any registers.
*/
create_instruction(addr, 0x60000000); /* nop */
create_branch(addr + 4, addr + PHYSICAL_START, 0);
}
void __init kdump_setup(void)
{
unsigned long i;
DBG(" -> kdump_setup()\n");
for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
create_trampoline(i);
}
create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
DBG(" <- kdump_setup()\n");
}
......@@ -37,6 +37,7 @@
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/mmu.h>
......@@ -1335,11 +1336,14 @@ void __init early_init_devtree(void *params)
of_scan_flat_dt(early_init_dt_scan_memory, NULL);
lmb_enforce_memory_limit(memory_limit);
lmb_analyze();
lmb_reserve(0, __pa(klimit));
DBG("Phys. mem: %lx\n", lmb_phys_mem_size());
/* Reserve LMB regions used by kernel, initrd, dt, etc... */
lmb_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
#ifdef CONFIG_CRASH_DUMP
lmb_reserve(0, KDUMP_RESERVE_LIMIT);
#endif
early_reserve_mem();
DBG("Scanning CPUs ...\n");
......
......@@ -34,6 +34,7 @@
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/prom.h>
#include <asm/processor.h>
#include <asm/pgtable.h>
......@@ -268,6 +269,10 @@ void __init early_setup(unsigned long dt_ptr)
}
ppc_md = **mach;
#ifdef CONFIG_CRASH_DUMP
kdump_setup();
#endif
DBG("Found, Initializing memory management...\n");
/*
......
#ifndef _PPC64_KDUMP_H
#define _PPC64_KDUMP_H
/* How many bytes to reserve at zero for kdump. The reserve limit should
* be greater or equal to the trampoline's end address. */
#define KDUMP_RESERVE_LIMIT 0x8000
#define KDUMP_TRAMPOLINE_START 0x0100
#define KDUMP_TRAMPOLINE_END 0x3000
extern void kdump_setup(void);
#endif /* __PPC64_KDUMP_H */
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