Merge tag 'x86_bugs_for_v6.5_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mitigation fixes from Borislav Petkov:
 "The first set of fallout fixes after the embargo madness. There will
  be another set next week too.

   - A first series of cleanups/unifications and documentation
     improvements to the SRSO and GDS mitigations code which got
     postponed to after the embargo date

   - Fix the SRSO aliasing addresses assertion so that the LLVM linker
     can parse it too"

* tag 'x86_bugs_for_v6.5_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  driver core: cpu: Fix the fallback cpu_show_gds() name
  x86: Move gds_ucode_mitigated() declaration to header
  x86/speculation: Add cpu_show_gds() prototype
  driver core: cpu: Make cpu_show_not_affected() static
  x86/srso: Fix build breakage with the LLVM linker
  Documentation/srso: Document IBPB aspect and fix formatting
  driver core: cpu: Unify redundant silly stubs
  Documentation/hw-vuln: Unify filename specification in index

3 files changed, 11 insertions, 5 deletions

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 973db0406528..4ae2773b873d 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -731,4 +731,6 @@ bool arch_is_platform_page(u64 paddr);
 #define arch_is_platform_page arch_is_platform_page
 #endif
 
+extern bool gds_ucode_mitigated(void);
+
 #endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index e76813230192..ef06211bae4c 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -529,11 +529,17 @@ 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
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 19d9ff92d699..c381770bcbf1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -314,8 +314,6 @@ u64 __read_mostly host_xcr0;
 
 static struct kmem_cache *x86_emulator_cache;
 
-extern bool gds_ucode_mitigated(void);
-
 /*
  * When called, it means the previous get/set msr reached an invalid msr.
  * Return true if we want to ignore/silent this failed msr access.