kernel.git/arch/x86/kernel/head64.c, branch linux-5.9.y

mm: reorder includes after introduction of linux/pgtable.h

2020-06-09T16:39:13Z

The replacement of with made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s

" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include " % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org Signed-off-by: Linus Torvalds

mm: introduce include/linux/pgtable.h

2020-06-09T16:39:13Z

The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds

x86/boot/64: Make level2_kernel_pgt pages invalid outside kernel area

2019-10-11T16:38:15Z

Our hardware (UV aka Superdome Flex) has address ranges marked reserved by the BIOS. Access to these ranges is caught as an error, causing the BIOS to halt the system. Initial page tables mapped a large range of physical addresses that were not checked against the list of BIOS reserved addresses, and sometimes included reserved addresses in part of the mapped range. Including the reserved range in the map allowed processor speculative accesses to the reserved range, triggering a BIOS halt. Used early in booting, the page table level2_kernel_pgt addresses 1 GiB divided into 2 MiB pages, and it was set up to linearly map a full 1 GiB of physical addresses that included the physical address range of the kernel image, as chosen by KASLR. But this also included a large range of unused addresses on either side of the kernel image. And unlike the kernel image's physical address range, this extra mapped space was not checked against the BIOS tables of usable RAM addresses. So there were times when the addresses chosen by KASLR would result in processor accessible mappings of BIOS reserved physical addresses. The kernel code did not directly access any of this extra mapped space, but having it mapped allowed the processor to issue speculative accesses into reserved memory, causing system halts. This was encountered somewhat rarely on a normal system boot, and much more often when starting the crash kernel if "crashkernel=512M,high" was specified on the command line (this heavily restricts the physical address of the crash kernel, in our case usually within 1 GiB of reserved space). The solution is to invalidate the pages of this table outside the kernel image's space before the page table is activated. It fixes this problem on our hardware. [ bp: Touchups. ] Signed-off-by: Steve Wahl Signed-off-by: Borislav Petkov Acked-by: Dave Hansen Acked-by: Kirill A. Shutemov Cc: Baoquan He Cc: Brijesh Singh Cc: dimitri.sivanich@hpe.com Cc: Feng Tang Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jordan Borgner Cc: Juergen Gross Cc: mike.travis@hpe.com Cc: russ.anderson@hpe.com Cc: stable@vger.kernel.org Cc: Thomas Gleixner Cc: x86-ml Cc: Zhenzhong Duan Link: https://lkml.kernel.org/r/9c011ee51b081534a7a15065b1681d200298b530.1569358539.git.steve.wahl@hpe.com

x86/boot/64: Add missing fixup_pointer() for next_early_pgt access

2019-06-26T05:25:09Z

__startup_64() uses fixup_pointer() to access global variables in a position-independent fashion. Access to next_early_pgt was wrapped into the helper, but one instance in the 5-level paging branch was missed. GCC generates a R_X86_64_PC32 PC-relative relocation for the access which doesn't trigger the issue, but Clang emmits a R_X86_64_32S which leads to an invalid memory access and system reboot. Fixes: 187e91fe5e91 ("x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt'") Signed-off-by: Kirill A. Shutemov Signed-off-by: Thomas Gleixner Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Alexander Potapenko Link: https://lkml.kernel.org/r/20190620112422.29264-1-kirill.shutemov@linux.intel.com

x86/boot/64: Fix crash if kernel image crosses page table boundary

2019-06-26T05:25:09Z

A kernel which boots in 5-level paging mode crashes in a small percentage of cases if KASLR is enabled. This issue was tracked down to the case when the kernel image unpacks in a way that it crosses an 1G boundary. The crash is caused by an overrun of the PMD page table in __startup_64() and corruption of P4D page table allocated next to it. This particular issue is not visible with 4-level paging as P4D page tables are not used. But the P4D and the PUD calculation have similar problems. The PMD index calculation is wrong due to operator precedence, which fails to confine the PMDs in the PMD array on wrap around. The P4D calculation for 5-level paging and the PUD calculation calculate the first index correctly, but then blindly increment it which causes the same issue when a kernel image is located across a 512G and for 5-level paging across a 46T boundary. This wrap around mishandling was introduced when these parts moved from assembly to C. Restore it to the correct behaviour. Fixes: c88d71508e36 ("x86/boot/64: Rewrite startup_64() in C") Signed-off-by: Kirill A. Shutemov Signed-off-by: Thomas Gleixner Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/20190620112345.28833-1-kirill.shutemov@linux.intel.com

x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address to setup_header")

2018-11-20T08:43:10Z

Peter Anvin pointed out that commit: ae7e1238e68f2a ("x86/boot: Add ACPI RSDP address to setup_header") should be reverted as setup_header should only contain items set by the legacy BIOS. So revert said commit. Instead of fully reverting the dependent commit of: e7b66d16fe4172 ("x86/acpi, x86/boot: Take RSDP address for boot params if available") just remove the setup_header reference in order to replace it by a boot_params in a followup patch. Suggested-by: "H. Peter Anvin" Signed-off-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: daniel.kiper@oracle.com Cc: sstabellini@kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181120072529.5489-2-jgross@suse.com Signed-off-by: Ingo Molnar

x86: Clean up 'sizeof x' => 'sizeof(x)'

2018-10-29T06:13:28Z

"sizeof(x)" is the canonical coding style used in arch/x86 most of the time. Fix the few places that didn't follow the convention. (Also do some whitespace cleanups in a few places while at it.) [ mingo: Rewrote the changelog. ] Signed-off-by: Jordan Borgner Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20181028125828.7rgammkgzep2wpam@JordanDesktop Signed-off-by: Ingo Molnar

x86/boot: Add ACPI RSDP address to setup_header

2018-10-10T08:44:22Z

Xen PVH guests receive the address of the RSDP table from Xen. In order to support booting a Xen PVH guest via Grub2 using the standard x86 boot entry we need a way for Grub2 to pass the RSDP address to the kernel. For this purpose expand the struct setup_header to hold the physical address of the RSDP address. Being zero means it isn't specified and has to be located the legacy way (searching through low memory or EBDA). While documenting the new setup_header layout and protocol version 2.14 add the missing documentation of protocol version 2.13. There are Grub2 versions in several distros with a downstream patch violating the boot protocol by writing past the end of setup_header. This requires another update of the boot protocol to enable the kernel to distinguish between a specified RSDP address and one filled with garbage by such a broken Grub2. From protocol 2.14 on Grub2 will write the version it is supporting (but never a higher value than found to be supported by the kernel) ored with 0x8000 to the version field of setup_header. This enables the kernel to know up to which field Grub2 has written information to. All fields after that are supposed to be clobbered. Signed-off-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boris.ostrovsky@oracle.com Cc: bp@alien8.de Cc: corbet@lwn.net Cc: linux-doc@vger.kernel.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20181010061456.22238-3-jgross@suse.com Signed-off-by: Ingo Molnar

x86/mm: Expand static page table for fixmap space

2018-09-20T21:17:22Z

We met a kernel panic when enabling earlycon, which is due to the fixmap address of earlycon is not statically setup. Currently the static fixmap setup in head_64.S only covers 2M virtual address space, while it actually could be in 4M space with different kernel configurations, e.g. when VSYSCALL emulation is disabled. So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2, and add a build time check to ensure that the fixmap is covered by the initial static page tables. Fixes: 1ad83c858c7d ("x86_64,vsyscall: Make vsyscall emulation configurable") Suggested-by: Thomas Gleixner Signed-off-by: Feng Tang Signed-off-by: Thomas Gleixner Tested-by: kernel test robot Reviewed-by: Juergen Gross (Xen parts) Cc: H Peter Anvin Cc: Peter Zijlstra Cc: Michal Hocko Cc: Yinghai Lu Cc: Dave Hansen Cc: Andi Kleen Cc: Andy Lutomirsky Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com

x86/mm: Add .bss..decrypted section to hold shared variables

2018-09-15T18:48:45Z

kvmclock defines few static variables which are shared with the hypervisor during the kvmclock initialization. When SEV is active, memory is encrypted with a guest-specific key, and if the guest OS wants to share the memory region with the hypervisor then it must clear the C-bit before sharing it. Currently, we use kernel_physical_mapping_init() to split large pages before clearing the C-bit on shared pages. But it fails when called from the kvmclock initialization (mainly because the memblock allocator is not ready that early during boot). Add a __bss_decrypted section attribute which can be used when defining such shared variable. The so-defined variables will be placed in the .bss..decrypted section. This section will be mapped with C=0 early during boot. The .bss..decrypted section has a big chunk of memory that may be unused when memory encryption is not active, free it when memory encryption is not active. Suggested-by: Thomas Gleixner Signed-off-by: Brijesh Singh Signed-off-by: Thomas Gleixner Cc: Tom Lendacky Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Paolo Bonzini Cc: Sean Christopherson Cc: Radim Krčmář Cc: kvm@vger.kernel.org Link: https://lkml.kernel.org/r/1536932759-12905-2-git-send-email-brijesh.singh@amd.com