Revert "UBUNTU: SAUCE: rfi-flush: Support more than one flush type at once"

This reverts commit 313e806c.

CVE-2017-5754

BugLink: http://bugs.launchpad.net/bugs/1756121

The functionality of this commit is provided by the following upstream
patch series:
  * powerpc/64s: Allow control of RFI flush via debugfs
  * powerpc/64s: Wire up cpu_show_meltdown()
  * powerpc/powernv: Check device-tree for RFI flush settings
  * powerpc/pseries: Query hypervisor for RFI flush settings
  * powerpc/64s: Support disabling RFI flush with no_rfi_flush and nopti
  * powerpc/64s: Add support for RFI flush of L1-D cache
  * powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL
  * powerpc/64: Convert the syscall exit path to use RFI_TO_USER/KERNEL
  * powerpc/64: Convert fast_exception_return to use RFI_TO_USER/KERNEL
  * powerpc/64s: Simple RFI macro conversions
  * powerpc/64: Add macros for annotating the destination of rfid/hrfid
  * powerpc/pseries: Add H_GET_CPU_CHARACTERISTICS flags & wrapper
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

arch/powerpc/kernel/setup_64.c

@@ -833,7 +833,7 @@ static int __init disable_hardlockup_detector(void)
 early_initcall(disable_hardlockup_detector);
 #endif
 #ifdef CONFIG_PPC_BOOK3S_64
-static enum l1d_flush_type enabled_flush_types;
+static enum l1d_flush_type l1d_flush_type;
 static void *l1d_flush_fallback_area;
 bool rfi_flush;
 
@@ -851,7 +851,7 @@ void rfi_flush_enable(bool enable)
 		return;
 
 	if (enable) {
-		do_rfi_flush_fixups(enabled_flush_types);
+		do_rfi_flush_fixups(l1d_flush_type);
 		on_each_cpu(do_nothing, NULL, 1);
 	} else
 		do_rfi_flush_fixups(L1D_FLUSH_NONE);
@@ -859,9 +859,9 @@ void rfi_flush_enable(bool enable)
 	rfi_flush = enable;
 }
 
-void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
+void __init setup_rfi_flush(enum l1d_flush_type type, bool enable)
 {
-	if (types & L1D_FLUSH_FALLBACK) {
+	if (type == L1D_FLUSH_FALLBACK) {
 		int cpu;
 		u64 l1d_size = ppc64_caches.dsize;
 		u64 limit = min(safe_stack_limit(), ppc64_rma_size);
@@ -893,15 +893,12 @@ void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
 			paca[cpu].l1d_flush_congruence = c;
 			paca[cpu].l1d_flush_sets = c / 128;
 		}
-	}
-
-	if (types & L1D_FLUSH_ORI)
+	} else if (type == L1D_FLUSH_ORI)
 		pr_info("rfi-fixups: Using ori type flush\n");
-
-	if (types & L1D_FLUSH_MTTRIG)
+	else if (type == L1D_FLUSH_MTTRIG)
 		pr_info("rfi-fixups: Using mttrig type flush\n");
 
-	enabled_flush_types = types;
+	l1d_flush_type = type;
 	rfi_flush_enable(enable);
 }
 #endif /* CONFIG_PPC_BOOK3S_64 */

arch/powerpc/lib/feature-fixups.c

@@ -116,34 +116,34 @@ void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 #ifdef CONFIG_PPC_BOOK3S_64
 void do_rfi_flush_fixups(enum l1d_flush_type types)
 {
-	unsigned int instrs[2], *dest;
 	long *start, *end;
+	unsigned int instr, *dest;
 	int i;
 
+	switch (type) {
+	case L1D_FLUSH_FALLBACK:
+		instr = 0x48000008; /* b .+8 to fallback flush */
+		break;
+	case L1D_FLUSH_ORI:
+		instr = 0x63de0000; /* ori 30,30,0 */
+		break;
+	case L1D_FLUSH_MTTRIG:
+		instr = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
+		break;
+	default:
+		instr = 0x60000000; /* nop */
+		break;
+	}
+
 	start = PTRRELOC(&__start___rfi_flush_fixup),
 	end = PTRRELOC(&__stop___rfi_flush_fixup);
 
-	instrs[0] = 0x60000000; /* nop */
-	instrs[1] = 0x60000000; /* nop */
-
-	if (types & L1D_FLUSH_FALLBACK)
-		/* b .+8 to fallback flush */
-		instrs[1] = 0x48000008;
-
-	i = 0;
-	if (types & L1D_FLUSH_ORI)
-		instrs[i++] = 0x63de0000; /* ori 30,30,0 */
-
-	if (types & L1D_FLUSH_MTTRIG)
-		instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
-
 	for (i = 0; start < end; start++, i++) {
 		dest = (void *)start + *start;
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
-
-		patch_instruction(dest, instrs[0]);
-		patch_instruction(dest + 1, instrs[1]);
+		patch_instruction(dest, 0x60000000);
+		patch_instruction(dest + 1, instr);
 	}
 
 	printk(KERN_DEBUG "rfi-fixups: patched %d locations\n", i);