qiurui
/
Centos-kernel-stream-9
mirror of https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

x86/srso: Fix build breakage with the LLVM linker 

JIRA: https://issues.redhat.com/browse/RHEL-8594
CVE: CVE-2023-20569

commit cbe8ded48b939b9d55d2c5589ab56caa7b530709
Author: Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 9 Aug 2023 09:40:26 -0700

    x86/srso: Fix build breakage with the LLVM linker

    The assertion added to verify the difference in bits set of the
    addresses of srso_untrain_ret_alias() and srso_safe_ret_alias() would fail
    to link in LLVM's ld.lld linker with the following error:

      ld.lld: error: ./arch/x86/kernel/vmlinux.lds:210: at least one side of
      the expression must be absolute
      ld.lld: error: ./arch/x86/kernel/vmlinux.lds:211: at least one side of
      the expression must be absolute

    Use ABSOLUTE to evaluate the expression referring to at least one of the
    symbols so that LLD can evaluate the linker script.

    Also, add linker version info to the comment about XOR being unsupported
    in either ld.bfd or ld.lld until somewhat recently.

    Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
    Closes: https://lore.kernel.org/llvm/CA+G9fYsdUeNu-gwbs0+T6XHi4hYYk=Y9725-wFhZ7gJMspLDRA@mail.gmail.com/
    Reported-by: Nathan Chancellor <nathan@kernel.org>
    Reported-by: Daniel Kolesa <daniel@octaforge.org>
    Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
    Suggested-by: Sven Volkinsfeld <thyrc@gmx.net>
    Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
    Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
    Link: https://github.com/ClangBuiltLinux/linux/issues/1907
    Link: https://lore.kernel.org/r/20230809-gds-v1-1-eaac90b0cbcc@google.com

Signed-off-by: Waiman Long <longman@redhat.com>
This commit is contained in:
Waiman Long 2023-09-25 13:57:22 -04:00
parent 0d4f3eda56
commit c652fb198e
1 changed files with 9 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/x86/kernel/vmlinux.lds.S
View File

@ -520,11 +520,17 @@ INIT_PER_CPU(irq_stack_backing_store);
#ifdef CONFIG_CPU_SRSO
/*
* GNU ld cannot do XOR so do: (A | B) - (A & B) in order to compute the XOR
* GNU ld cannot do XOR until 2.41.
* https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f6f78318fca803c4907fb8d7f6ded8295f1947b1
*
* LLVM lld cannot do XOR until lld-17.
* https://github.com/llvm/llvm-project/commit/fae96104d4378166cbe5c875ef8ed808a356f3fb
*
* Instead do: (A | B) - (A & B) in order to compute the XOR
* of the two function addresses:
*/
. = ASSERT(((srso_untrain_ret_alias | srso_safe_ret_alias) -
(srso_untrain_ret_alias & srso_safe_ret_alias)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)),
. = ASSERT(((ABSOLUTE(srso_untrain_ret_alias) | srso_safe_ret_alias) -
(ABSOLUTE(srso_untrain_ret_alias) & srso_safe_ret_alias)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)),
"SRSO function pair won't alias");
#endif