x86/cpu: Rename srso_(.*)_alias to srso_alias_\1

For a more consistent namespace.

  [ bp: Fixup names in the doc too. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230814121148.976236447@infradead.org

Author: Peter Zijlstra

Documentation/admin-guide/hw-vuln/srso.rst

@@ -141,8 +141,8 @@ sequence.
 To ensure the safety of this mitigation, the kernel must ensure that the
 safe return sequence is itself free from attacker interference.  In Zen3
 and Zen4, this is accomplished by creating a BTB alias between the
-untraining function srso_untrain_ret_alias() and the safe return
-function srso_safe_ret_alias() which results in evicting a potentially
+untraining function srso_alias_untrain_ret() and the safe return
+function srso_alias_safe_ret() which results in evicting a potentially
 poisoned BTB entry and using that safe one for all function returns.
 
 In older Zen1 and Zen2, this is accomplished using a reinterpretation

arch/x86/include/asm/nospec-branch.h

@@ -300,7 +300,7 @@
 
 #ifdef CONFIG_CPU_SRSO
 	ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
-			  "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
+			  "call srso_alias_untrain_ret", X86_FEATURE_SRSO_ALIAS
 #endif
 .endm
 
@@ -316,7 +316,7 @@
 
 #ifdef CONFIG_CPU_SRSO
 	ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
-			  "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
+			  "call srso_alias_untrain_ret", X86_FEATURE_SRSO_ALIAS
 #endif
 .endm
 
@@ -353,7 +353,7 @@ extern void srso_alias_return_thunk(void);
 
 extern void retbleed_untrain_ret(void);
 extern void srso_untrain_ret(void);
-extern void srso_untrain_ret_alias(void);
+extern void srso_alias_untrain_ret(void);
 
 extern void entry_ibpb(void);
 

arch/x86/kernel/vmlinux.lds.S

@@ -147,10 +147,10 @@ SECTIONS
 
 #ifdef CONFIG_CPU_SRSO
 		/*
-		 * See the comment above srso_untrain_ret_alias()'s
+		 * See the comment above srso_alias_untrain_ret()'s
 		 * definition.
 		 */
-		. = srso_untrain_ret_alias | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20);
+		. = srso_alias_untrain_ret | (1 << 2) | (1 << 8) | (1 << 14) | (1 << 20);
 		*(.text..__x86.rethunk_safe)
 #endif
 		ALIGN_ENTRY_TEXT_END
@@ -536,8 +536,8 @@ INIT_PER_CPU(irq_stack_backing_store);
  * Instead do: (A | B) - (A & B) in order to compute the XOR
  * of the two function addresses:
  */
-. = 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)),
+. = ASSERT(((ABSOLUTE(srso_alias_untrain_ret) | srso_alias_safe_ret) -
+		(ABSOLUTE(srso_alias_untrain_ret) & srso_alias_safe_ret)) == ((1 << 2) | (1 << 8) | (1 << 14) | (1 << 20)),
 		"SRSO function pair won't alias");
 #endif
 

arch/x86/lib/retpoline.S

@@ -133,56 +133,56 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
 #ifdef CONFIG_RETHUNK
 
 /*
- * srso_untrain_ret_alias() and srso_safe_ret_alias() are placed at
+ * srso_alias_untrain_ret() and srso_alias_safe_ret() are placed at
  * special addresses:
  *
- * - srso_untrain_ret_alias() is 2M aligned
- * - srso_safe_ret_alias() is also in the same 2M page but bits 2, 8, 14
+ * - srso_alias_untrain_ret() is 2M aligned
+ * - srso_alias_safe_ret() is also in the same 2M page but bits 2, 8, 14
  * and 20 in its virtual address are set (while those bits in the
- * srso_untrain_ret_alias() function are cleared).
+ * srso_alias_untrain_ret() function are cleared).
  *
  * This guarantees that those two addresses will alias in the branch
  * target buffer of Zen3/4 generations, leading to any potential
  * poisoned entries at that BTB slot to get evicted.
  *
- * As a result, srso_safe_ret_alias() becomes a safe return.
+ * As a result, srso_alias_safe_ret() becomes a safe return.
  */
 #ifdef CONFIG_CPU_SRSO
 	.section .text..__x86.rethunk_untrain
 
-SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
+SYM_START(srso_alias_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
 	UNWIND_HINT_FUNC
 	ANNOTATE_NOENDBR
 	ASM_NOP2
 	lfence
 	jmp srso_alias_return_thunk
-SYM_FUNC_END(srso_untrain_ret_alias)
-__EXPORT_THUNK(srso_untrain_ret_alias)
+SYM_FUNC_END(srso_alias_untrain_ret)
+__EXPORT_THUNK(srso_alias_untrain_ret)
 
 	.section .text..__x86.rethunk_safe
 #else
 /* dummy definition for alternatives */
-SYM_START(srso_untrain_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
+SYM_START(srso_alias_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
 	ANNOTATE_UNRET_SAFE
 	ret
 	int3
-SYM_FUNC_END(srso_untrain_ret_alias)
+SYM_FUNC_END(srso_alias_untrain_ret)
 #endif
 
-SYM_START(srso_safe_ret_alias, SYM_L_GLOBAL, SYM_A_NONE)
+SYM_START(srso_alias_safe_ret, SYM_L_GLOBAL, SYM_A_NONE)
 	lea 8(%_ASM_SP), %_ASM_SP
 	UNWIND_HINT_FUNC
 	ANNOTATE_UNRET_SAFE
 	ret
 	int3
-SYM_FUNC_END(srso_safe_ret_alias)
+SYM_FUNC_END(srso_alias_safe_ret)
 
 	.section .text..__x86.return_thunk
 
 SYM_CODE_START(srso_alias_return_thunk)
 	UNWIND_HINT_FUNC
 	ANNOTATE_NOENDBR
-	call srso_safe_ret_alias
+	call srso_alias_safe_ret
 	ud2
 SYM_CODE_END(srso_alias_return_thunk)