Commits
Dave Young committed 3eddc69ffeb
x86 early_ioremap: Increase FIX_BTMAPS_SLOTS to 8
3.16 kernel boot fail with earlyprintk=efi, it keeps scrolling at the
bottom line of screen.
Bisected, the first bad commit is below:
commit 86dfc6f339886559d80ee0d4bd20fe5ee90450f0
Author: Lv Zheng <lv.zheng@intel.com>
Date: Fri Apr 4 12:38:57 2014 +0800
ACPICA: Tables: Fix table checksums verification before installation.
I did some debugging by enabling both serial and efi earlyprintk, below is
some debug dmesg, seems early_ioremap fails in scroll up function due to
no free slot, see below dmesg output:
WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:116 __early_ioremap+0x90/0x1c4()
__early_ioremap(ed00c800, 00000c80) not found slot
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.17.0-rc1+ #204
Hardware name: Hewlett-Packard HP Z420 Workstation/1589, BIOS J61 v03.15 05/09/2013
Call Trace:
dump_stack+0x4e/0x7a
warn_slowpath_common+0x75/0x8e
? __early_ioremap+0x90/0x1c4
warn_slowpath_fmt+0x47/0x49
__early_ioremap+0x90/0x1c4
? sprintf+0x46/0x48
early_ioremap+0x13/0x15
early_efi_map+0x24/0x26
early_efi_scroll_up+0x6d/0xc0
early_efi_write+0x1b0/0x214
call_console_drivers.constprop.21+0x73/0x7e
console_unlock+0x151/0x3b2
? vprintk_emit+0x49f/0x532
vprintk_emit+0x521/0x532
? console_unlock+0x383/0x3b2
printk+0x4f/0x51
acpi_os_vprintf+0x2b/0x2d
acpi_os_printf+0x43/0x45
acpi_info+0x5c/0x63
? __acpi_map_table+0x13/0x18
? acpi_os_map_iomem+0x21/0x147
acpi_tb_print_table_header+0x177/0x186
acpi_tb_install_table_with_override+0x4b/0x62
acpi_tb_install_standard_table+0xd9/0x215
? early_ioremap+0x13/0x15
? __acpi_map_table+0x13/0x18
acpi_tb_parse_root_table+0x16e/0x1b4
acpi_initialize_tables+0x57/0x59
acpi_table_init+0x50/0xce
acpi_boot_table_init+0x1e/0x85
setup_arch+0x9b7/0xcc4
start_kernel+0x94/0x42d
? early_idt_handlers+0x120/0x120
x86_64_start_reservations+0x2a/0x2c
x86_64_start_kernel+0xf3/0x100
Quote reply from Lv.zheng about the early ioremap slot usage in this case:
"""
In early_efi_scroll_up(), 2 mapping entries will be used for the src/dst screen buffer.
In drivers/acpi/acpica/tbutils.c, we've improved the early table loading code in acpi_tb_parse_root_table().
We now need 2 mapping entries:
1. One mapping entry is used for RSDT table mapping. Each RSDT entry contains an address for another ACPI table.
2. For each entry in RSDP, we need another mapping entry to map the table to perform necessary check/override before installing it.
When acpi_tb_parse_root_table() prints something through EFI earlyprintk console, we'll have 4 mapping entries used.
The current 4 slots setting of early_ioremap() seems to be too small for such a use case.
"""
Thus increase the slot to 8 in this patch to fix this issue.
boot-time mappings become 512 page with this patch.
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: <stable@vger.kernel.org> # v3.16
Signed-off-by: Matt Fleming <matt.fleming@intel.com>