Merge tag 'v4.9.127' into imx_4.9.x_2.3.0_ga

This is the 4.9.127 stable release

Conflicts:
	drivers/gpu/drm/imx/imx-ldb.c
	drivers/staging/android/ion/ion_priv.h

6 files changed, 55 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ac67a76550bd..8103adacbc83 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -651,6 +651,45 @@ EXPORT_SYMBOL_GPL(l1tf_mitigation);
 enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
 EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation);
 
+/*
+ * These CPUs all support 44bits physical address space internally in the
+ * cache but CPUID can report a smaller number of physical address bits.
+ *
+ * The L1TF mitigation uses the top most address bit for the inversion of
+ * non present PTEs. When the installed memory reaches into the top most
+ * address bit due to memory holes, which has been observed on machines
+ * which report 36bits physical address bits and have 32G RAM installed,
+ * then the mitigation range check in l1tf_select_mitigation() triggers.
+ * This is a false positive because the mitigation is still possible due to
+ * the fact that the cache uses 44bit internally. Use the cache bits
+ * instead of the reported physical bits and adjust them on the affected
+ * machines to 44bit if the reported bits are less than 44.
+ */
+static void override_cache_bits(struct cpuinfo_x86 *c)
+{
+	if (c->x86 != 6)
+		return;
+
+	switch (c->x86_model) {
+	case INTEL_FAM6_NEHALEM:
+	case INTEL_FAM6_WESTMERE:
+	case INTEL_FAM6_SANDYBRIDGE:
+	case INTEL_FAM6_IVYBRIDGE:
+	case INTEL_FAM6_HASWELL_CORE:
+	case INTEL_FAM6_HASWELL_ULT:
+	case INTEL_FAM6_HASWELL_GT3E:
+	case INTEL_FAM6_BROADWELL_CORE:
+	case INTEL_FAM6_BROADWELL_GT3E:
+	case INTEL_FAM6_SKYLAKE_MOBILE:
+	case INTEL_FAM6_SKYLAKE_DESKTOP:
+	case INTEL_FAM6_KABYLAKE_MOBILE:
+	case INTEL_FAM6_KABYLAKE_DESKTOP:
+		if (c->x86_cache_bits < 44)
+			c->x86_cache_bits = 44;
+		break;
+	}
+}
+
 static void __init l1tf_select_mitigation(void)
 {
 	u64 half_pa;
@@ -658,6 +697,8 @@ static void __init l1tf_select_mitigation(void)
 	if (!boot_cpu_has_bug(X86_BUG_L1TF))
 		return;
 
+	override_cache_bits(&boot_cpu_data);
+
 	switch (l1tf_mitigation) {
 	case L1TF_MITIGATION_OFF:
 	case L1TF_MITIGATION_FLUSH_NOWARN:
@@ -677,14 +718,13 @@ static void __init l1tf_select_mitigation(void)
 	return;
 #endif
 
-	/*
-	 * This is extremely unlikely to happen because almost all
-	 * systems have far more MAX_PA/2 than RAM can be fit into
-	 * DIMM slots.
-	 */
 	half_pa = (u64)l1tf_pfn_limit() << PAGE_SHIFT;
 	if (e820_any_mapped(half_pa, ULLONG_MAX - half_pa, E820_RAM)) {
 		pr_warn("System has more than MAX_PA/2 memory. L1TF mitigation not effective.\n");
+		pr_info("You may make it effective by booting the kernel with mem=%llu parameter.\n",
+				half_pa);
+		pr_info("However, doing so will make a part of your RAM unusable.\n");
+		pr_info("Reading https://www.kernel.org/doc/html/latest/admin-guide/l1tf.html might help you decide.\n");
 		return;
 	}
 
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 13471b71bec7..dc0850bb74be 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -882,6 +882,7 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
 			}
 		}
 #endif
+	c->x86_cache_bits = c->x86_phys_bits;
 }
 
 static const __initconst struct x86_cpu_id cpu_no_speculation[] = {
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 9ad86c4bf360..cee0fec0d232 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -109,6 +109,9 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
 	if (cpu_has(c, X86_FEATURE_HYPERVISOR))
 		return false;
 
+	if (c->x86 != 6)
+		return false;
+
 	for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) {
 		if (c->x86_model == spectre_bad_microcodes[i].model &&
 		    c->x86_stepping == spectre_bad_microcodes[i].stepping)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 85f854b98a9d..3576ece9ef88 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -15,6 +15,7 @@
 #include <linux/bug.h>
 #include <linux/nmi.h>
 #include <linux/sysfs.h>
+#include <linux/kasan.h>
 
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
@@ -229,7 +230,10 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 	 * We're not going to return, but we might be on an IST stack or
 	 * have very little stack space left.  Rewind the stack and kill
 	 * the task.
+	 * Before we rewind the stack, we have to tell KASAN that we're going to
+	 * reuse the task stack and that existing poisons are invalid.
 	 */
+	kasan_unpoison_task_stack(current);
 	rewind_stack_do_exit(signr);
 }
 NOKPROBE_SYMBOL(oops_end);
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 3407b148c240..490f9be3fda2 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -529,7 +529,7 @@ static int bzImage64_cleanup(void *loader_data)
 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
 {
 	return verify_pefile_signature(kernel, kernel_len,
-				       NULL,
+				       VERIFY_USE_SECONDARY_KEYRING,
 				       VERIFYING_KEXEC_PE_SIGNATURE);
 }
 #endif
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index dffe81d3c261..a2661814bde0 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -360,6 +360,7 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 	start_thread_common(regs, new_ip, new_sp,
 			    __USER_CS, __USER_DS, 0);
 }
+EXPORT_SYMBOL_GPL(start_thread);
 
 #ifdef CONFIG_COMPAT
 void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp)