linux_dsm_epyc7002/arch/x86/boot
Xunlei Pang 66aad4fdf2 x86/mm: Add support for gbpages to kernel_ident_mapping_init()
Kernel identity mappings on x86-64 kernels are created in two
ways: by the early x86 boot code, or by kernel_ident_mapping_init().

Native kernels (which is the dominant usecase) use the former,
but the kexec and the hibernation code uses kernel_ident_mapping_init().

There's a subtle difference between these two ways of how identity
mappings are created, the current kernel_ident_mapping_init() code
creates identity mappings always using 2MB page(PMD level) - while
the native kernel boot path also utilizes gbpages where available.

This difference is suboptimal both for performance and for memory
usage: kernel_ident_mapping_init() needs to allocate pages for the
page tables when creating the new identity mappings.

This patch adds 1GB page(PUD level) support to kernel_ident_mapping_init()
to address these concerns.

The primary advantage would be better TLB coverage/performance,
because we'd utilize 1GB TLBs instead of 2MB ones.

It is also useful for machines with large number of memory to
save paging structure allocations(around 4MB/TB using 2MB page)
when setting identity mappings for all the memory, after using
1GB page it will consume only 8KB/TB.

( Note that this change alone does not activate gbpages in kexec,
  we are doing that in a separate patch. )

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: akpm@linux-foundation.org
Cc: kexec@lists.infradead.org
Link: http://lkml.kernel.org/r/1493862171-8799-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-08 08:28:40 +02:00
..
compressed x86/mm: Add support for gbpages to kernel_ident_mapping_init() 2017-05-08 08:28:40 +02:00
tools x86/boot: Remove unused 'is_big_kernel' variable 2016-02-16 09:16:58 +01:00
.gitignore x86: remove offsets.h from .gitignore and dontdiff 2012-11-19 14:10:53 +01:00
a20.c x86, setup: "glove box" BIOS interrupts in the core boot code 2009-04-09 16:08:11 -07:00
apm.c x86, setup: "glove box" BIOS interrupts in the APM code 2009-04-09 16:08:11 -07:00
bioscall.S x86, boot: Move intcall() to the .inittext section 2014-01-04 14:29:08 -08:00
bitops.h x86, asm: use bool for bitops and other assembly outputs 2016-06-08 12:41:20 -07:00
boot.h x86/boot: Fix BSS corruption/overwrite bug in early x86 kernel startup 2017-04-20 10:05:23 +02:00
cmdline.c x86, boot: Pass cmd_line_ptr with unsigned long instead 2013-01-29 15:26:09 -08:00
code16gcc.h x86, build: Change code16gcc.h from a C header to an assembly header 2014-06-04 13:16:48 -07:00
copy.S x86, boot: Use .code16 instead of .code16gcc 2014-01-04 13:59:06 -08:00
cpu.c Revert "x86/boot: Fail the boot if !M486 and CPUID is missing" 2016-12-19 11:54:20 +01:00
cpucheck.c x86/boot: Detect 5-level paging support 2017-04-04 08:22:33 +02:00
cpuflags.c x86/boot: Detect 5-level paging support 2017-04-04 08:22:33 +02:00
cpuflags.h x86/mm: Disallow running with 32-bit PTEs to work around erratum 2016-07-13 09:43:25 +02:00
ctype.h x86, setup: Rename BOOT_ISDIGIT_H to BOOT_CTYPE_H 2015-01-13 11:59:04 +01:00
early_serial_console.c x86/boot: Add missing file header comments 2016-05-10 10:12:03 +02:00
edd.c x86, boot: Create a separate string.h file to provide standard string functions 2014-03-19 15:43:45 -07:00
header.S x86/boot/e820: Remove assembly guard from asm/e820/types.h 2017-01-28 09:31:15 +01:00
install.sh kbuild: use INSTALLKERNEL to select customized installkernel script 2009-09-20 12:18:14 +02:00
main.c x86/boot: Obsolete the MCA sys_desc_table 2015-07-21 10:55:11 +02:00
Makefile x86/boot/build: Remove always empty $(USERINCLUDE) 2016-11-07 07:30:01 +01:00
memory.c x86/boot/e820: Separate the E820 ABI structures from the in-kernel structures 2017-01-29 13:39:32 +01:00
mkcpustr.c x86/cpufeature: Carve out X86_FEATURE_* 2016-01-30 11:22:17 +01:00
mtools.conf.in i386: move boot 2007-10-11 11:16:45 +02:00
pm.c x86: remove zImage support 2009-03-11 11:00:00 -07:00
pmjump.S x86, setup: move 32-bit code to .text32 2009-03-17 15:26:06 -07:00
printf.c x86/boot: Fix a sanity check in printf.c 2013-08-14 11:48:41 +02:00
regs.c x86, boot: Create a separate string.h file to provide standard string functions 2014-03-19 15:43:45 -07:00
setup.ld x86, boot: Define the 2.12 bzImage boot protocol 2013-01-27 15:56:37 -08:00
string.c Merge branch 'linus' into x86/boot, to pick up fixes 2017-01-28 09:30:11 +01:00
string.h x86/boot: Add missing declaration of string functions 2017-01-09 11:53:05 +01:00
tty.c x86, setup: reorganize the early console setup 2010-08-02 15:51:56 -07:00
version.c kbuild: move utsrelease.h to include/generated 2009-12-12 13:08:15 +01:00
vesa.h x86-boot: don't request VBE2 information 2008-03-07 16:39:14 +01:00
video-bios.c x86: fix usage of bios intcall() 2009-07-04 12:56:32 -07:00
video-mode.c x86/mm: Fix regression with huge pages on PAE 2015-12-04 09:14:27 +01:00
video-vesa.c x86, boot: Create a separate string.h file to provide standard string functions 2014-03-19 15:43:45 -07:00
video-vga.c x86, setup: Set ax register in boot vga query 2010-06-10 15:24:29 -07:00
video.c x86/mm: Fix regression with huge pages on PAE 2015-12-04 09:14:27 +01:00
video.h x86/boot/video: Move the 'video_segment' variable to video.c 2015-02-19 00:25:05 +01:00