Merge tag 'x86-urgent-2024-05-18' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull x86 fixes from Ingo Molnar:

 - Fix a NOP-patching bug that resulted in valid but suboptimal
   NOP sequences in certain cases

 - Fix build warnings related to fall-through control flow

* tag 'x86-urgent-2024-05-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/alternatives: Use the correct length when optimizing NOPs
  x86/boot: Address clang -Wimplicit-fallthrough in vsprintf()
  x86/boot: Add a fallthrough annotation

diff --combined arch/x86/boot/Makefile
index 1cf24ff6acac024aaed08118711991779d5bd867,343aef6d752ff0dd325a86bb97cd08a8c20a5396..9cc0ff6e9067d574488a35573eff4d0f8449e398
--- 1/arch/x86/boot/Makefile
--- 2/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@@ -9,6 -9,19 +9,6 @@@
  # Changed by many, many contributors over the years.
  #
  
 -# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
 -KASAN_SANITIZE                        := n
 -KCSAN_SANITIZE                        := n
 -KMSAN_SANITIZE                        := n
 -OBJECT_FILES_NON_STANDARD     := y
 -
 -# Kernel does not boot with kcov instrumentation here.
 -# One of the problems observed was insertion of __sanitizer_cov_trace_pc()
 -# callback into middle of per-cpu data enabling code. Thus the callback observed
 -# inconsistent state and crashed. We are interested mostly in syscall coverage,
 -# so boot code is not interesting anyway.
 -KCOV_INSTRUMENT               := n
 -
  # If you want to preset the SVGA mode, uncomment the next line and
  # set SVGA_MODE to whatever number you want.
  # Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
@@@ -56,6 -69,9 +56,7 @@@ KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_
  KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
  KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
  KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
 -GCOV_PROFILE := n
 -UBSAN_SANITIZE := n
+ KBUILD_CFLAGS += $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
  
  $(obj)/bzImage: asflags-y  := $(SVGA_MODE)
  
@@@ -114,7 -130,7 +115,7 @@@ targets += mtools.con
  # genimage.sh requires bash, but it also has a bunch of other
  # external dependencies.
  quiet_cmd_genimage = GENIMAGE $3
 -cmd_genimage = $(BASH) $(srctree)/$(src)/genimage.sh $2 $3 $(obj)/bzImage \
 +      cmd_genimage = $(BASH) $(src)/genimage.sh $2 $3 $(obj)/bzImage \
                $(obj)/mtools.conf '$(FDARGS)' $(FDINITRD)
  
  PHONY += bzdisk fdimage fdimage144 fdimage288 hdimage isoimage