fadump: Remove the phyp assisted dump code.

Remove the phyp assisted dump implementation which is not is use.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Documentation/powerpc/phyp-assisted-dump.txt

-
-                   Hypervisor-Assisted Dump
-                   ------------------------
-                       November 2007
-
-The goal of hypervisor-assisted dump is to enable the dump of
-a crashed system, and to do so from a fully-reset system, and
-to minimize the total elapsed time until the system is back
-in production use.
-
-As compared to kdump or other strategies, hypervisor-assisted
-dump offers several strong, practical advantages:
-
--- Unlike kdump, the system has been reset, and loaded
-   with a fresh copy of the kernel.  In particular,
-   PCI and I/O devices have been reinitialized and are
-   in a clean, consistent state.
--- As the dump is performed, the dumped memory becomes
-   immediately available to the system for normal use.
--- After the dump is completed, no further reboots are
-   required; the system will be fully usable, and running
-   in its normal, production mode on its normal kernel.
-
-The above can only be accomplished by coordination with,
-and assistance from the hypervisor. The procedure is
-as follows:
-
--- When a system crashes, the hypervisor will save
-   the low 256MB of RAM to a previously registered
-   save region. It will also save system state, system
-   registers, and hardware PTE's.
-
--- After the low 256MB area has been saved, the
-   hypervisor will reset PCI and other hardware state.
-   It will *not* clear RAM. It will then launch the
-   bootloader, as normal.
-
--- The freshly booted kernel will notice that there
-   is a new node (ibm,dump-kernel) in the device tree,
-   indicating that there is crash data available from
-   a previous boot. It will boot into only 256MB of RAM,
-   reserving the rest of system memory.
-
--- Userspace tools will parse /sys/kernel/release_region
-   and read /proc/vmcore to obtain the contents of memory,
-   which holds the previous crashed kernel. The userspace
-   tools may copy this info to disk, or network, nas, san,
-   iscsi, etc. as desired.
-
-   For Example: the values in /sys/kernel/release-region
-   would look something like this (address-range pairs).
-   CPU:0x177fee000-0x10000: HPTE:0x177ffe020-0x1000: /
-   DUMP:0x177fff020-0x10000000, 0x10000000-0x16F1D370A
-
--- As the userspace tools complete saving a portion of
-   dump, they echo an offset and size to
-   /sys/kernel/release_region to release the reserved
-   memory back to general use.
-
-   An example of this is:
-     "echo 0x40000000 0x10000000 > /sys/kernel/release_region"
-   which will release 256MB at the 1GB boundary.
-
-Please note that the hypervisor-assisted dump feature
-is only available on Power6-based systems with recent
-firmware versions.
-
-Implementation details:
-----------------------
-
-During boot, a check is made to see if firmware supports
-this feature on this particular machine. If it does, then
-we check to see if a active dump is waiting for us. If yes
-then everything but 256 MB of RAM is reserved during early
-boot. This area is released once we collect a dump from user
-land scripts that are run. If there is dump data, then
-the /sys/kernel/release_region file is created, and
-the reserved memory is held.
-
-If there is no waiting dump data, then only the highest
-256MB of the ram is reserved as a scratch area. This area
-is *not* released: this region will be kept permanently
-reserved, so that it can act as a receptacle for a copy
-of the low 256MB in the case a crash does occur. See,
-however, "open issues" below, as to whether
-such a reserved region is really needed.
-
-Currently the dump will be copied from /proc/vmcore to a
-a new file upon user intervention. The starting address
-to be read and the range for each data point in provided
-in /sys/kernel/release_region.
-
-The tools to examine the dump will be same as the ones
-used for kdump.
-
-General notes:
---------------
-Security: please note that there are potential security issues
-with any sort of dump mechanism. In particular, plaintext
-(unencrypted) data, and possibly passwords, may be present in
-the dump data. Userspace tools must take adequate precautions to
-preserve security.
-
-Open issues/ToDo:
-------------
- o The various code paths that tell the hypervisor that a crash
-   occurred, vs. it simply being a normal reboot, should be
-   reviewed, and possibly clarified/fixed.
-
- o Instead of using /sys/kernel, should there be a /sys/dump
-   instead? There is a dump_subsys being created by the s390 code,
-   perhaps the pseries code should use a similar layout as well.
-
- o Is reserving a 256MB region really required? The goal of
-   reserving a 256MB scratch area is to make sure that no
-   important crash data is clobbered when the hypervisor
-   save low mem to the scratch area. But, if one could assure
-   that nothing important is located in some 256MB area, then
-   it would not need to be reserved. Something that can be
-   improved in subsequent versions.
-
- o Still working the kdump team to integrate this with kdump,
-   some work remains but this would not affect the current
-   patches.
-
- o Still need to write a shell script, to copy the dump away.
-   Currently I am parsing it manually.

arch/powerpc/Kconfig

@@ -376,16 +376,6 @@ config CRASH_DUMP
 	  The same kernel binary can be used as production kernel and dump
 	  capture kernel.
 
-config PHYP_DUMP
-	bool "Hypervisor-assisted dump (EXPERIMENTAL)"
-	depends on PPC_PSERIES && EXPERIMENTAL
-	help
-	  Hypervisor-assisted dump is meant to be a kdump replacement
-	  offering robustness and speed not possible without system
-	  hypervisor assistance.
-
-	  If unsure, say "N"
-
 config FA_DUMP
 	bool "Firmware-assisted dump"
 	depends on PPC64 && PPC_RTAS && CRASH_DUMP

arch/powerpc/include/asm/phyp_dump.h

-/*
- * Hypervisor-assisted dump
- *
- * Linas Vepstas, Manish Ahuja 2008
- * Copyright 2008 IBM Corp.
- *
- *      This program is free software; you can redistribute it and/or
- *      modify it under the terms of the GNU General Public License
- *      as published by the Free Software Foundation; either version
- *      2 of the License, or (at your option) any later version.
- */
-
-#ifndef _PPC64_PHYP_DUMP_H
-#define _PPC64_PHYP_DUMP_H
-
-#ifdef CONFIG_PHYP_DUMP
-
-/* The RMR region will be saved for later dumping
- * whenever the kernel crashes. Set this to 256MB. */
-#define PHYP_DUMP_RMR_START 0x0
-#define PHYP_DUMP_RMR_END   (1UL<<28)
-
-struct phyp_dump {
-	/* Memory that is reserved during very early boot. */
-	unsigned long init_reserve_start;
-	unsigned long init_reserve_size;
-	/* cmd line options during boot */
-	unsigned long reserve_bootvar;
-	unsigned long phyp_dump_at_boot;
-	/* Check status during boot if dump supported, active & present*/
-	unsigned long phyp_dump_configured;
-	unsigned long phyp_dump_is_active;
-	/* store cpu & hpte size */
-	unsigned long cpu_state_size;
-	unsigned long hpte_region_size;
-	/* previous scratch area values */
-	unsigned long reserved_scratch_addr;
-	unsigned long reserved_scratch_size;
-};
-
-extern struct phyp_dump *phyp_dump_info;
-
-int early_init_dt_scan_phyp_dump(unsigned long node,
-		const char *uname, int depth, void *data);
-
-#endif /* CONFIG_PHYP_DUMP */
-#endif /* _PPC64_PHYP_DUMP_H */

arch/powerpc/kernel/prom.c

@@ -52,7 +52,6 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
-#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 #include <asm/opal.h>
 #include <asm/fadump.h>
@@ -616,86 +615,6 @@ static void __init early_reserve_mem(void)
 	}
 }
 
-#ifdef CONFIG_PHYP_DUMP
-/**
- * phyp_dump_calculate_reserve_size() - reserve variable boot area 5% or arg
- *
- * Function to find the largest size we need to reserve
- * during early boot process.
- *
- * It either looks for boot param and returns that OR
- * returns larger of 256 or 5% rounded down to multiples of 256MB.
- *
- */
-static inline unsigned long phyp_dump_calculate_reserve_size(void)
-{
-	unsigned long tmp;
-
-	if (phyp_dump_info->reserve_bootvar)
-		return phyp_dump_info->reserve_bootvar;
-
-	/* divide by 20 to get 5% of value */
-	tmp = memblock_end_of_DRAM();
-	do_div(tmp, 20);
-
-	/* round it down in multiples of 256 */
-	tmp = tmp & ~0x0FFFFFFFUL;
-
-	return (tmp > PHYP_DUMP_RMR_END ? tmp : PHYP_DUMP_RMR_END);
-}
-
-/**
- * phyp_dump_reserve_mem() - reserve all not-yet-dumped mmemory
- *
- * This routine may reserve memory regions in the kernel only
- * if the system is supported and a dump was taken in last
- * boot instance or if the hardware is supported and the
- * scratch area needs to be setup. In other instances it returns
- * without reserving anything. The memory in case of dump being
- * active is freed when the dump is collected (by userland tools).
- */
-static void __init phyp_dump_reserve_mem(void)
-{
-	unsigned long base, size;
-	unsigned long variable_reserve_size;
-
-	if (!phyp_dump_info->phyp_dump_configured) {
-		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
-		return;
-	}
-
-	if (!phyp_dump_info->phyp_dump_at_boot) {
-		printk(KERN_INFO "Phyp-dump disabled at boot time\n");
-		return;
-	}
-
-	variable_reserve_size = phyp_dump_calculate_reserve_size();
-
-	if (phyp_dump_info->phyp_dump_is_active) {
-		/* Reserve *everything* above RMR.Area freed by userland tools*/
-		base = variable_reserve_size;
-		size = memblock_end_of_DRAM() - base;
-
-		/* XXX crashed_ram_end is wrong, since it may be beyond
-		 * the memory_limit, it will need to be adjusted. */
-		memblock_reserve(base, size);
-
-		phyp_dump_info->init_reserve_start = base;
-		phyp_dump_info->init_reserve_size = size;
-	} else {
-		size = phyp_dump_info->cpu_state_size +
-			phyp_dump_info->hpte_region_size +
-			variable_reserve_size;
-		base = memblock_end_of_DRAM() - size;
-		memblock_reserve(base, size);
-		phyp_dump_info->init_reserve_start = base;
-		phyp_dump_info->init_reserve_size = size;
-	}
-}
-#else
-static inline void __init phyp_dump_reserve_mem(void) {}
-#endif /* CONFIG_PHYP_DUMP  && CONFIG_PPC_RTAS */
-
 void __init early_init_devtree(void *params)
 {
 	phys_addr_t limit;
@@ -715,11 +634,6 @@ void __init early_init_devtree(void *params)
 	of_scan_flat_dt(early_init_dt_scan_opal, NULL);
 #endif
 
-#ifdef CONFIG_PHYP_DUMP
-	/* scan tree to see if dump occurred during last boot */
-	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
-#endif
-
 #ifdef CONFIG_FA_DUMP
 	/* scan tree to see if dump is active during last boot */
 	of_scan_flat_dt(early_init_dt_scan_fw_dump, NULL);
@@ -765,7 +679,6 @@ void __init early_init_devtree(void *params)
 #endif
 		reserve_crashkernel();
 	early_reserve_mem();
-	phyp_dump_reserve_mem();
 
 	/*
 	 * Ensure that total memory size is page-aligned, because otherwise

arch/powerpc/platforms/pseries/Makefile

@@ -18,7 +18,6 @@ obj-$(CONFIG_MEMORY_HOTPLUG)	+= hotplug-memory.o
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
-obj-$(CONFIG_PHYP_DUMP)		+= phyp_dump.o
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_DTL)		+= dtl.o
 obj-$(CONFIG_IO_EVENT_IRQ)	+= io_event_irq.o