Revert "ANDROID: x86: map CFI jump tables in pti_clone_entry_text"

This reverts commit 52fb2d451e as CFI is
being removed from the tree to come back later as a "clean" set of
patches.

Bug: 145210207
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6c8f64c167fb5544063688708a633d7f4a758559

arch/x86/include/asm/sections.h

@@ -8,7 +8,6 @@
 #include <asm/extable.h>
 
 extern char __brk_base[], __brk_limit[];
-extern char __cfi_jt_start[], __cfi_jt_end[];
 extern char __end_rodata_aligned[];
 
 #if defined(CONFIG_X86_64)

arch/x86/kernel/vmlinux.lds.S

@@ -144,13 +144,6 @@ SECTIONS
 		*(.text.__x86.indirect_thunk)
 		__indirect_thunk_end = .;
 #endif
-
-#ifdef CONFIG_CFI_CLANG
-		. = ALIGN(PAGE_SIZE);
-		__cfi_jt_start = .;
-		*(.text..L.cfi.jumptable .text..L.cfi.jumptable.*)
-		__cfi_jt_end = .;
-#endif
 	} :text =0xcccc
 
 	/* End of text section, which should occupy whole number of pages */
@@ -458,7 +451,3 @@ INIT_PER_CPU(irq_stack_backing_store);
            "kexec control code size is too big");
 #endif
 
-#ifdef CONFIG_CFI_CLANG
-. = ASSERT((__cfi_jt_end - __cfi_jt_start > 0),
-	   "CFI jump table is empty");
-#endif

arch/x86/mm/pti.c

@@ -499,15 +499,6 @@ static void pti_clone_entry_text(void)
 	pti_clone_pgtable((unsigned long) __entry_text_start,
 			  (unsigned long) __entry_text_end,
 			  PTI_CLONE_PMD);
-
-	/*
-	 * If CFI is enabled, also map jump tables, so the entry code can
-	 * make indirect calls.
-	 */
-	if (IS_ENABLED(CONFIG_CFI_CLANG))
-		pti_clone_pgtable((unsigned long) __cfi_jt_start,
-				  (unsigned long) __cfi_jt_end,
-				  PTI_CLONE_PMD);
 }
 
 /*