Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/l…

…inux/kernel/git/tip/tip Pull x86 fixes from Peter Anvin. * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86-64, modify_ldt: Make support for 16-bit segments a runtime option x86, mm, hugetlb: Add missing TLB page invalidation for hugetlb_cow() x86, rdrand: When nordrand is specified, disable RDSEED as well
mariux64 · May 20, 2014 · 172de65 · 172de65
2 parents 95d0858 + fa81511
commit 172de65
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Showing 5 changed files with 17 additions and 5 deletions.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
@@ -2218,10 +2218,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	noreplace-smp	[X86-32,SMP] Don't replace SMP instructions
 			with UP alternatives
 
-	nordrand	[X86] Disable the direct use of the RDRAND
-			instruction even if it is supported by the
-			processor.  RDRAND is still available to user
-			space applications.
+	nordrand	[X86] Disable kernel use of the RDRAND and
+			RDSEED instructions even if they are supported
+			by the processor.  RDRAND and RDSEED are still
+			available to user space applications.
 
 	noresume	[SWSUSP] Disables resume and restores original swap
 			space.

diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
@@ -52,6 +52,7 @@ static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
 					 unsigned long addr, pte_t *ptep)
 {
+	ptep_clear_flush(vma, addr, ptep);
 }
 
 static inline int huge_pte_none(pte_t pte)

diff --git a/arch/x86/kernel/cpu/rdrand.c b/arch/x86/kernel/cpu/rdrand.c
@@ -27,6 +27,7 @@
 static int __init x86_rdrand_setup(char *s)
 {
 	setup_clear_cpu_cap(X86_FEATURE_RDRAND);
+	setup_clear_cpu_cap(X86_FEATURE_RDSEED);
 	return 1;
 }
 __setup("nordrand", x86_rdrand_setup);

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
@@ -20,6 +20,8 @@
 #include <asm/mmu_context.h>
 #include <asm/syscalls.h>
 
+int sysctl_ldt16 = 0;
+
 #ifdef CONFIG_SMP
 static void flush_ldt(void *current_mm)
 {
@@ -234,7 +236,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode)
 	 * IRET leaking the high bits of the kernel stack address.
 	 */
 #ifdef CONFIG_X86_64
-	if (!ldt_info.seg_32bit) {
+	if (!ldt_info.seg_32bit && !sysctl_ldt16) {
 		error = -EINVAL;
 		goto out_unlock;
 	}

diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
@@ -39,6 +39,7 @@
 #ifdef CONFIG_X86_64
 #define vdso_enabled			sysctl_vsyscall32
 #define arch_setup_additional_pages	syscall32_setup_pages
+extern int sysctl_ldt16;
 #endif
 
 /*
@@ -249,6 +250,13 @@ static struct ctl_table abi_table2[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+	{
+		.procname	= "ldt16",
+		.data		= &sysctl_ldt16,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
 	{}
 };