linux

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Linus Torvalds b29f377119 x86/boot changes for v6.9:

- Continuing work by Ard Biesheuvel to improve the x86 early startup code,
    with the long-term goal to make it position independent:
 
       - Get rid of early accesses to global objects, either by moving them
         to the stack, deferring the access until later, or dropping the
         globals entirely.
 
       - Move all code that runs early via the 1:1 mapping into .head.text,
         and move code that does not out of it, so that build time checks can
         be added later to ensure that no inadvertent absolute references were
         emitted into code that does not tolerate them.
 
       - Remove fixup_pointer() and occurrences of __pa_symbol(), which rely
         on the compiler emitting absolute references, which is not guaranteed.
 
  - Improve the early console code.
 
  - Add early console message about ignored NMIs, so that users are at least
    warned about their existence - even if we cannot do anything about them.
 
  - Improve the kexec code's kernel load address handling.
 
  - Enable more X86S (simplified x86) bits.
 
  - Simplify early boot GDT handling
 
  - Micro-optimize the boot code a bit
 
  - Misc cleanups.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-boot-2024-03-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:

 - Continuing work by Ard Biesheuvel to improve the x86 early startup
   code, with the long-term goal to make it position independent:

      - Get rid of early accesses to global objects, either by moving
        them to the stack, deferring the access until later, or dropping
        the globals entirely

      - Move all code that runs early via the 1:1 mapping into
        .head.text, and move code that does not out of it, so that build
        time checks can be added later to ensure that no inadvertent
        absolute references were emitted into code that does not
        tolerate them

      - Remove fixup_pointer() and occurrences of __pa_symbol(), which
        rely on the compiler emitting absolute references, which is not
        guaranteed

 - Improve the early console code

 - Add early console message about ignored NMIs, so that users are at
   least warned about their existence - even if we cannot do anything
   about them

 - Improve the kexec code's kernel load address handling

 - Enable more X86S (simplified x86) bits

 - Simplify early boot GDT handling

 - Micro-optimize the boot code a bit

 - Misc cleanups

* tag 'x86-boot-2024-03-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  x86/sev: Move early startup code into .head.text section
  x86/sme: Move early SME kernel encryption handling into .head.text
  x86/boot: Move mem_encrypt= parsing to the decompressor
  efi/libstub: Add generic support for parsing mem_encrypt=
  x86/startup_64: Simplify virtual switch on primary boot
  x86/startup_64: Simplify calculation of initial page table address
  x86/startup_64: Defer assignment of 5-level paging global variables
  x86/startup_64: Simplify CR4 handling in startup code
  x86/boot: Use 32-bit XOR to clear registers
  efi/x86: Set the PE/COFF header's NX compat flag unconditionally
  x86/boot/64: Load the final kernel GDT during early boot directly, remove startup_gdt[]
  x86/boot/64: Use RIP_REL_REF() to access early_top_pgt[]
  x86/boot/64: Use RIP_REL_REF() to access early page tables
  x86/boot/64: Use RIP_REL_REF() to access '__supported_pte_mask'
  x86/boot/64: Use RIP_REL_REF() to access early_dynamic_pgts[]
  x86/boot/64: Use RIP_REL_REF() to assign 'phys_base'
  x86/boot/64: Simplify global variable accesses in GDT/IDT programming
  x86/trampoline: Bypass compat mode in trampoline_start64() if not needed
  kexec: Allocate kernel above bzImage's pref_address
  x86/boot: Add a message about ignored early NMIs
  ...

2024-03-12 09:58:57 -07:00

ABI

x86/rfds: Mitigate Register File Data Sampling (RFDS)

2024-03-11 13:13:48 -07:00

accel

docs/accel: correct links to mailing list archives

2024-01-23 14:45:50 -07:00

accounting

…

admin-guide

* Mitigate RFDS vulnerability

2024-03-12 09:31:39 -07:00