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Ard Biesheuvel 0982fd6bf0 x86/sev: Fix position dependent variable references in startup code 
commit 1c811d403a upstream.

The early startup code executes from a 1:1 mapping of memory, which
differs from the mapping that the code was linked and/or relocated to
run at. The latter mapping is not active yet at this point, and so
symbol references that rely on it will fault.

Given that the core kernel is built without -fPIC, symbol references are
typically emitted as absolute, and so any such references occuring in
the early startup code will therefore crash the kernel.

While an attempt was made to work around this for the early SEV/SME
startup code, by forcing RIP-relative addressing for certain global
SEV/SME variables via inline assembly (see snp_cpuid_get_table() for
example), RIP-relative addressing must be pervasively enforced for
SEV/SME global variables when accessed prior to page table fixups.

__startup_64() already handles this issue for select non-SEV/SME global
variables using fixup_pointer(), which adjusts the pointer relative to a
`physaddr` argument. To avoid having to pass around this `physaddr`
argument across all functions needing to apply pointer fixups, introduce
a macro RIP_RELATIVE_REF() which generates a RIP-relative reference to
a given global variable. It is used where necessary to force
RIP-relative accesses to global variables.

For backporting purposes, this patch makes no attempt at cleaning up
other occurrences of this pattern, involving either inline asm or
fixup_pointer(). Those will be addressed later.

  [ bp: Call it "rip_rel_ref" everywhere like other code shortens
    "rIP-relative reference" and make the asm wrapper __always_inline. ]

Co-developed-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Kevin Loughlin <kevinloughlin@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/all/20240130220845.1978329-1-kevinloughlin@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-04-03 15:28:50 +02:00
arch x86/sev: Fix position dependent variable references in startup code 2024-04-03 15:28:50 +02:00
block Revert "block/mq-deadline: use correct way to throttling write requests" 2024-04-03 15:28:33 +02:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: jitter - fix CRYPTO_JITTERENTROPY help text 2024-03-26 18:19:52 -04:00
Documentation x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT 2024-04-03 15:28:50 +02:00
drivers vfio/fsl-mc: Block calling interrupt handler without trigger 2024-04-03 15:28:49 +02:00
fs btrfs: fix deadlock with fiemap and extent locking 2024-04-03 15:28:49 +02:00
include vfio: Introduce interface to flush virqfd inject workqueue 2024-04-03 15:28:49 +02:00
init init/Kconfig: lower GCC version check for -Warray-bounds 2024-04-03 15:28:41 +02:00
io_uring io_uring: clean rings on NO_MMAP alloc fail 2024-04-03 15:28:31 +02:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel tracing: Use .flush() call to wake up readers 2024-04-03 15:28:41 +02:00
lib pci_iounmap(): Fix MMIO mapping leak 2024-04-03 15:28:17 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm, vmscan: prevent infinite loop for costly GFP_NOIO | __GFP_RETRY_MAYFAIL allocations 2024-04-03 15:28:44 +02:00
net xfrm: Avoid clang fortify warning in copy_to_user_tmpl() 2024-04-03 15:28:40 +02:00
rust rust: upgrade to Rust 1.73.0 2024-02-16 19:10:43 +01:00
samples work around gcc bugs with 'asm goto' with outputs 2024-02-23 09:24:47 +01:00
scripts kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 2024-04-03 15:28:29 +02:00
security landlock: Warn once if a Landlock action is requested while disabled 2024-04-03 15:28:27 +02:00
sound ASoC: amd: yc: Revert "Fix non-functional mic on Lenovo 21J2" 2024-04-03 15:28:46 +02:00
tools selftests: mptcp: diag: return KSFT_FAIL not test_cnt 2024-04-03 15:28:40 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-03 15:28:18 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add Catherine as xfs maintainer for 6.6.y 2024-02-16 19:10:43 +01:00
Makefile Linux 6.6.23 2024-03-26 18:22:53 -04:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.