ACPICA: Tables: Add mechanism to control early table checksum verification.

It is reported that Linux x86 kernel cannot map large tables. The following
large SSDT table on such platform fails to pass checksum verification and
cannot be installed:
 ACPI: SSDT 0x00000000B9638018 07A0C4 (v02 INTEL  S2600CP  00004000 INTL 20100331)

It sounds strange that in the 64-bit virtual memory address space, we
cannot map a single ACPI table to do checksum verification. The root cause
is:
 1. ACPICA doesn't split IO memory mapping and table mapping;
 2. Linux x86 OSL implements acpi_os_map_memory() using a size limited fix-map
    mechanism during early boot stage, which is more suitable for only IO
    mappings.

ACPICA originally only mapped table header for signature validation, and
this header mapping is required by OSL override mechanism. There was no
checksum verification because we could not map the whole table using this
OSL. While the following ACPICA commit enforces checksum verification by
mapping the whole table during Linux boot stage and it finally triggers
this issue on some platforms:
 Commit: 86dfc6f339886559d80ee0d4bd20fe5ee90450f0
 Subject: ACPICA: Tables: Fix table checksums verification before installation.

Before doing further cleanups for the OSL table mapping and override
implementation, this patch introduces an option for such OSPMs to
temporarily discard the checksum verification feature. It then can be
re-enabled easily when the ACPICA and the underlying OSL is ready.

This patch also deletes a comment around the limitation of mappings because
it is not correct. The limitation is not how many times we can map in the
early stage, but the OSL mapping facility may not be suitable for mapping
the ACPI tables and thus may complain us the size limitation.

The acpi_tb_verify_table() is renamed to acpi_tb_verify_temp_table() due to the
work around added, it now only applies to the table descriptor that hasn't
been installed and cannot be used in other cases. Lv Zheng.

Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI: Fix x86 regression related to early mapping size limitation

The following warning message is triggered:
 WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:136 __early_ioremap+0x11f/0x1f2()
 Modules linked in:
 CPU: 0 PID: 0 Comm: swapper Not tainted 3.15.0-rc1-00017-g86dfc6f3-dirty #298
 Hardware name: Intel Corporation S2600CP/S2600CP, BIOS SE5C600.86B.99.99.x036.091920111209 09/19/2011
  0000000000000009 ffffffff81b75c40 ffffffff817c627b 0000000000000000
  ffffffff81b75c78 ffffffff81067b5d 000000000000007b 8000000000000563
  00000000b96b20dc 0000000000000001 ffffffffff300e0c ffffffff81b75c88
 Call Trace:
  [<ffffffff817c627b>] dump_stack+0x45/0x56
  [<ffffffff81067b5d>] warn_slowpath_common+0x7d/0xa0
  [<ffffffff81067c3a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff81d4b9d5>] __early_ioremap+0x11f/0x1f2
  [<ffffffff81d4bc5b>] early_ioremap+0x13/0x15
  [<ffffffff81d2b8f3>] __acpi_map_table+0x13/0x18
  [<ffffffff817b8d1a>] acpi_os_map_memory+0x26/0x14e
  [<ffffffff813ff018>] acpi_tb_acquire_table+0x42/0x70
  [<ffffffff813ff086>] acpi_tb_validate_table+0x27/0x37
  [<ffffffff813ff0e5>] acpi_tb_verify_table+0x22/0xd8
  [<ffffffff813ff6a8>] acpi_tb_install_non_fixed_table+0x60/0x1c9
  [<ffffffff81d61024>] acpi_tb_parse_root_table+0x218/0x26a
  [<ffffffff81d1b120>] ? early_idt_handlers+0x120/0x120
  [<ffffffff81d610cd>] acpi_initialize_tables+0x57/0x59
  [<ffffffff81d5f25d>] acpi_table_init+0x1b/0x99
  [<ffffffff81d2bca0>] acpi_boot_table_init+0x1e/0x85
  [<ffffffff81d23043>] setup_arch+0x99d/0xcc6
  [<ffffffff81d1b120>] ? early_idt_handlers+0x120/0x120
  [<ffffffff81d1bbbe>] start_kernel+0x8b/0x415
  [<ffffffff81d1b120>] ? early_idt_handlers+0x120/0x120
  [<ffffffff81d1b5ee>] x86_64_start_reservations+0x2a/0x2c
  [<ffffffff81d1b72e>] x86_64_start_kernel+0x13e/0x14d
 ---[ end trace 11ae599a1898f4e7 ]---
when installing the following table during early stage:
 ACPI: SSDT 0x00000000B9638018 07A0C4 (v02 INTEL  S2600CP  00004000 INTL 20100331)
The regression is caused by the size limitation of the x86 early IO mapping.

The root cause is:
 1. ACPICA doesn't split IO memory mapping and table mapping;
 2. Linux x86 OSL implements acpi_os_map_memory() using a size limited fix-map
    mechanism during early boot stage, which is more suitable for only IO
    mappings.

This patch fixes this issue by utilizing acpi_gbl_verify_table_checksum to
disable the table mapping during early stage and enabling it again for the
late stage. In this way, the normal code path is not affected. Then after
the code related to the root cause is cleaned up, the early checksum
verification can be easily re-enabled.

A new boot parameter - acpi_force_table_verification is introduced for
the platforms that require the checksum verification to stop loading bad
tables.

This fix also covers the checksum verification for the table overrides. Now
large tables can also be overridden using the initrd override mechanism.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reported-and-tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpica' into bleeding-edge

* acpica:
  ACPI: Fix x86 regression related to early mapping size limitation
  ACPICA: Tables: Add mechanism to control early table checksum verification.
PM / hibernate: fixed typo in comment

Fix a trivial comment typo (s/mam/map) in kernel/power/swap.c.

Signed-off-by: Niv Yehezkel <executerx@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-sleep' into bleeding-edge

* pm-sleep:
  PM / hibernate: fixed typo in comment