linux-stable.git/arch, branch v6.6.82

x86/boot/32: Temporarily map initrd for microcode loading

2025-03-09T08:55:04+00:00

commit 4c585af7180c147062c636a927a2fc2b6a7072f5 upstream

Early microcode loading on 32-bit runs in physical address mode because
the initrd is not covered by the initial page tables. That results in
a horrible mess all over the microcode loader code.

Provide a temporary mapping for the initrd in the initial page tables by
appending it to the actual initial mapping starting with a new PGD or
PMD depending on the configured page table levels ([non-]PAE).

The page table entries are located after _brk_end so they are not
permanently using memory space. The mapping is invalidated right away in
i386_start_kernel() after the early microcode loader has run.

This prepares for removing the physical address mode oddities from all
over the microcode loader code, which in turn allows further cleanups.

Provide the map and unmap code and document the place where the
microcode loader needs to be invoked with a comment.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20231017211722.292291436@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/microcode: Provide CONFIG_MICROCODE_INITRD32

2025-03-09T08:55:03+00:00

commit fdbd43819400e74c1c20a646969ea8f71706eb2b upstream

Create an aggregate config switch which covers X86_32, MICROCODE and
BLK_DEV_INITRD to avoid lengthy #ifdeffery in upcoming code.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20231017211722.236208250@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/boot/32: Restructure mk_early_pgtbl_32()

2025-03-09T08:55:03+00:00

commit 69ba866db281c768d5ecca909361ea4c4e71d57e upstream

Prepare it for adding a temporary initrd mapping by splitting out the
actual map loop.

No functional change.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20231017211722.175910753@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/boot/32: De-uglify the 2/3 level paging difference in mk_early_pgtbl_32()

2025-03-09T08:55:03+00:00

commit a62f4ca106fd250e9247decd100f3905131fc1fe upstream

Move the ifdeffery out of the function and use proper typedefs to make it
work for both 2 and 3 level paging.

No functional change.

  [ bp: Move mk_early_pgtbl_32() declaration into a header. ]

Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20231017211722.111059491@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/boot: Use __pa_nodebug() in mk_early_pgtbl_32()

2025-03-09T08:55:03+00:00

commit 1e2dd572d2b773b5b8882aae66e5f0328d562aa9 upstream

Use the existing macro instead of undefining and redefining __pa().

No functional change.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20231017211722.051625827@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/boot/32: Disable stackprotector and tracing for mk_early_pgtbl_32()

2025-03-09T08:55:03+00:00

commit 242db7589460ca94e28c51ffbddd621756f97e11 upstream

Stackprotector cannot work before paging is enabled. The read from the per
CPU variable __stack_chk_guard is always accessing the virtual address
either directly on UP or via FS on SMP. In physical address mode this
results in an access to memory above 3GB.

So this works by chance as the hardware returns the same value when there
is no RAM at this physical address. When there is RAM populated above 3G
then the read is by chance the same as nothing changes that memory during
the very early boot stage.

Stop relying on pure luck and disable the stack protector for the only C
function which is called during early boot before paging is enabled.

Remove function tracing from the whole source file as there is no way to
trace this at all, but in case of CONFIG_DYNAMIC_FTRACE=n
mk_early_pgtbl_32() would access global function tracer variables in
physical address mode which again might work by chance.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20231002115902.156063939@linutronix.de
Signed-off-by: Greg Kroah-Hartman

x86/microcode/AMD: Fix a -Wsometimes-uninitialized clang false positive

2025-03-07T15:45:57+00:00

commit 5343558a868e7e635b40baa2e46bf53df1a2d131 upstream.

Initialize equiv_id in order to shut up:

  arch/x86/kernel/cpu/microcode/amd.c:714:6: warning: variable 'equiv_id' is \
  used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
        if (x86_family(bsp_cpuid_1_eax) < 0x17) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

because clang doesn't do interprocedural analysis for warnings to see
that this variable won't be used uninitialized.

Fixes: 94838d230a6c ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202407291815.gJBST0P3-lkp@intel.com/
Signed-off-by: Borislav Petkov (AMD) 
Signed-off-by: Greg Kroah-Hartman

x86/microcode/AMD: Load only SHA256-checksummed patches

2025-03-07T15:45:56+00:00

commit 50cef76d5cb0e199cda19f026842560f6eedc4f7 upstream

Load patches for which the driver carries a SHA256 checksum of the patch
blob.

This can be disabled by adding "microcode.amd_sha_check=off" on the
kernel cmdline. But it is highly NOT recommended.

Signed-off-by: Borislav Petkov (AMD) 
Signed-off-by: Greg Kroah-Hartman

x86/microcode/AMD: Add get_patch_level()

2025-03-07T15:45:56+00:00

commit 037e81fb9d2dfe7b31fd97e5f578854e38f09887 upstream

Put the MSR_AMD64_PATCH_LEVEL reading of the current microcode revision
the hw has, into a separate function.

Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20250211163648.30531-6-bp@kernel.org
Signed-off-by: Greg Kroah-Hartman

x86/microcode/AMD: Get rid of the _load_microcode_amd() forward declaration

2025-03-07T15:45:56+00:00

commit b39c387164879eef71886fc93cee5ca7dd7bf500 upstream

Simply move save_microcode_in_initrd() down.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20250211163648.30531-5-bp@kernel.org
Signed-off-by: Greg Kroah-Hartman