x86, 386 removal: Remove CONFIG_X86_POPAD_OK

The check_popad() routine tested for a 386-specific bug, and never
actually did anything useful with it anyway other than print a
message.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1354132230-21854-8-git-send-email-hpa@linux.intel.com

arch/x86/Kconfig.cpu

@@ -325,10 +325,6 @@ config X86_INVD_BUG
 	def_bool y
 	depends on M486
 
-config X86_POPAD_OK
-	def_bool y
-	depends on X86_32
-
 config X86_ALIGNMENT_16
 	def_bool y
 	depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1

arch/x86/kernel/cpu/bugs.c

@@ -106,33 +106,6 @@ static void __init check_hlt(void)
 	pr_cont("OK\n");
 }
 
-/*
- *	Most 386 processors have a bug where a POPAD can lock the
- *	machine even from user space.
- */
-
-static void __init check_popad(void)
-{
-#ifndef CONFIG_X86_POPAD_OK
-	int res, inp = (int) &res;
-
-	pr_info("Checking for popad bug... ");
-	__asm__ __volatile__(
-	  "movl $12345678,%%eax; movl $0,%%edi; pusha; popa; movl (%%edx,%%edi),%%ecx "
-	  : "=&a" (res)
-	  : "d" (inp)
-	  : "ecx", "edi");
-	/*
-	 * If this fails, it means that any user program may lock the
-	 * CPU hard. Too bad.
-	 */
-	if (res != 12345678)
-		pr_cont("Buggy\n");
-	else
-		pr_cont("OK\n");
-#endif
-}
-
 /*
  * Check whether we are able to run this kernel safely on SMP.
  *
@@ -157,7 +130,6 @@ void __init check_bugs(void)
 #endif
 	check_config();
 	check_hlt();
-	check_popad();
 	init_utsname()->machine[1] =
 		'0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
 	alternative_instructions();