path: root/mm
diff options
authorDave Young <>2014-08-26 09:06:41 (GMT)
committerGreg Kroah-Hartman <>2014-10-05 21:54:11 (GMT)
commit09338bb96a7ce2a8da60a0230e7b01b707eec778 (patch)
tree150baf27b7df7b67ebb570838a1c4c196198f791 /mm
parentbdbdc4076c10ae9d3a83b37c79fc74827e776bf9 (diff)
x86 early_ioremap: Increase FIX_BTMAPS_SLOTS to 8
commit 3eddc69ffeba092d288c386646bfa5ec0fce25fd upstream. 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 <> 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 <> Signed-off-by: Matt Fleming <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions