From 63bcff2a307b9bcc712a8251eb27df8b2e117967 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 21 Sep 2012 12:43:12 -0700 Subject: [PATCH] x86, smap: Add STAC and CLAC instructions to control user space access When Supervisor Mode Access Prevention (SMAP) is enabled, access to userspace from the kernel is controlled by the AC flag. To make the performance of manipulating that flag acceptable, there are two new instructions, STAC and CLAC, to set and clear it. This patch adds those instructions, via alternative(), when the SMAP feature is enabled. It also adds X86_EFLAGS_AC unconditionally to the SYSCALL entry mask; there is simply no reason to make that one conditional. Signed-off-by: H. Peter Anvin Link: http://lkml.kernel.org/r/1348256595-29119-9-git-send-email-hpa@linux.intel.com --- arch/x86/ia32/ia32entry.S | 6 ++++++ arch/x86/include/asm/fpu-internal.h | 10 ++++++---- arch/x86/include/asm/futex.h | 19 ++++++++++++------ arch/x86/include/asm/smap.h | 4 ++-- arch/x86/include/asm/uaccess.h | 31 ++++++++++++++++++----------- arch/x86/include/asm/xsave.h | 10 ++++++---- arch/x86/kernel/cpu/common.c | 3 ++- arch/x86/kernel/entry_64.S | 11 +++++++++- arch/x86/lib/copy_user_64.S | 7 +++++++ arch/x86/lib/copy_user_nocache_64.S | 3 +++ arch/x86/lib/getuser.S | 10 ++++++++++ arch/x86/lib/putuser.S | 8 +++++++- arch/x86/lib/usercopy_32.c | 13 +++++++++++- arch/x86/lib/usercopy_64.c | 3 +++ 14 files changed, 106 insertions(+), 32 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 20e5f7ba0e6b..9c289504e680 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -146,8 +147,10 @@ ENTRY(ia32_sysenter_target) SAVE_ARGS 0,1,0 /* no need to do an access_ok check here because rbp has been 32bit zero extended */ + ASM_STAC 1: movl (%rbp),%ebp _ASM_EXTABLE(1b,ia32_badarg) + ASM_CLAC orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) CFI_REMEMBER_STATE @@ -301,8 +304,10 @@ ENTRY(ia32_cstar_target) /* no need to do an access_ok check here because r8 has been 32bit zero extended */ /* hardware stack frame is complete now */ + ASM_STAC 1: movl (%r8),%r9d _ASM_EXTABLE(1b,ia32_badarg) + ASM_CLAC orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) CFI_REMEMBER_STATE @@ -365,6 +370,7 @@ cstar_tracesys: END(ia32_cstar_target) ia32_badarg: + ASM_CLAC movq $-EFAULT,%rax jmp ia32_sysret CFI_ENDPROC diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 75f4c6d6a331..0fe13583a028 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -126,8 +126,9 @@ static inline int fxsave_user(struct i387_fxsave_struct __user *fx) /* See comment in fxsave() below. */ #ifdef CONFIG_AS_FXSAVEQ - asm volatile("1: fxsaveq %[fx]\n\t" - "2:\n" + asm volatile(ASM_STAC "\n" + "1: fxsaveq %[fx]\n\t" + "2: " ASM_CLAC "\n" ".section .fixup,\"ax\"\n" "3: movl $-1,%[err]\n" " jmp 2b\n" @@ -136,8 +137,9 @@ static inline int fxsave_user(struct i387_fxsave_struct __user *fx) : [err] "=r" (err), [fx] "=m" (*fx) : "0" (0)); #else - asm volatile("1: rex64/fxsave (%[fx])\n\t" - "2:\n" + asm volatile(ASM_STAC "\n" + "1: rex64/fxsave (%[fx])\n\t" + "2: " ASM_CLAC "\n" ".section .fixup,\"ax\"\n" "3: movl $-1,%[err]\n" " jmp 2b\n" diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h index 71ecbcba1a4e..f373046e63ec 100644 --- a/arch/x86/include/asm/futex.h +++ b/arch/x86/include/asm/futex.h @@ -9,10 +9,13 @@ #include #include #include +#include #define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \ - asm volatile("1:\t" insn "\n" \ - "2:\t.section .fixup,\"ax\"\n" \ + asm volatile("\t" ASM_STAC "\n" \ + "1:\t" insn "\n" \ + "2:\t" ASM_CLAC "\n" \ + "\t.section .fixup,\"ax\"\n" \ "3:\tmov\t%3, %1\n" \ "\tjmp\t2b\n" \ "\t.previous\n" \ @@ -21,12 +24,14 @@ : "i" (-EFAULT), "0" (oparg), "1" (0)) #define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \ - asm volatile("1:\tmovl %2, %0\n" \ + asm volatile("\t" ASM_STAC "\n" \ + "1:\tmovl %2, %0\n" \ "\tmovl\t%0, %3\n" \ "\t" insn "\n" \ "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \ "\tjnz\t1b\n" \ - "3:\t.section .fixup,\"ax\"\n" \ + "3:\t" ASM_CLAC "\n" \ + "\t.section .fixup,\"ax\"\n" \ "4:\tmov\t%5, %1\n" \ "\tjmp\t3b\n" \ "\t.previous\n" \ @@ -122,8 +127,10 @@ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) return -EFAULT; - asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" - "2:\t.section .fixup, \"ax\"\n" + asm volatile("\t" ASM_STAC "\n" + "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" + "2:\t" ASM_CLAC "\n" + "\t.section .fixup, \"ax\"\n" "3:\tmov %3, %0\n" "\tjmp 2b\n" "\t.previous\n" diff --git a/arch/x86/include/asm/smap.h b/arch/x86/include/asm/smap.h index 3989c2492eb5..8d3120f4e270 100644 --- a/arch/x86/include/asm/smap.h +++ b/arch/x86/include/asm/smap.h @@ -58,13 +58,13 @@ #ifdef CONFIG_X86_SMAP -static inline void clac(void) +static __always_inline void clac(void) { /* Note: a barrier is implicit in alternative() */ alternative(ASM_NOP3, __stringify(__ASM_CLAC), X86_FEATURE_SMAP); } -static inline void stac(void) +static __always_inline void stac(void) { /* Note: a barrier is implicit in alternative() */ alternative(ASM_NOP3, __stringify(__ASM_STAC), X86_FEATURE_SMAP); diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 2c7df3d184f2..b92ece13c238 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -9,6 +9,7 @@ #include #include #include +#include #define VERIFY_READ 0 #define VERIFY_WRITE 1 @@ -192,9 +193,10 @@ extern int __get_user_bad(void); #ifdef CONFIG_X86_32 #define __put_user_asm_u64(x, addr, err, errret) \ - asm volatile("1: movl %%eax,0(%2)\n" \ + asm volatile(ASM_STAC "\n" \ + "1: movl %%eax,0(%2)\n" \ "2: movl %%edx,4(%2)\n" \ - "3:\n" \ + "3: " ASM_CLAC "\n" \ ".section .fixup,\"ax\"\n" \ "4: movl %3,%0\n" \ " jmp 3b\n" \ @@ -205,9 +207,10 @@ extern int __get_user_bad(void); : "A" (x), "r" (addr), "i" (errret), "0" (err)) #define __put_user_asm_ex_u64(x, addr) \ - asm volatile("1: movl %%eax,0(%1)\n" \ + asm volatile(ASM_STAC "\n" \ + "1: movl %%eax,0(%1)\n" \ "2: movl %%edx,4(%1)\n" \ - "3:\n" \ + "3: " ASM_CLAC "\n" \ _ASM_EXTABLE_EX(1b, 2b) \ _ASM_EXTABLE_EX(2b, 3b) \ : : "A" (x), "r" (addr)) @@ -379,8 +382,9 @@ do { \ } while (0) #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ - asm volatile("1: mov"itype" %2,%"rtype"1\n" \ - "2:\n" \ + asm volatile(ASM_STAC "\n" \ + "1: mov"itype" %2,%"rtype"1\n" \ + "2: " ASM_CLAC "\n" \ ".section .fixup,\"ax\"\n" \ "3: mov %3,%0\n" \ " xor"itype" %"rtype"1,%"rtype"1\n" \ @@ -412,8 +416,9 @@ do { \ } while (0) #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ - asm volatile("1: mov"itype" %1,%"rtype"0\n" \ - "2:\n" \ + asm volatile(ASM_STAC "\n" \ + "1: mov"itype" %1,%"rtype"0\n" \ + "2: " ASM_CLAC "\n" \ _ASM_EXTABLE_EX(1b, 2b) \ : ltype(x) : "m" (__m(addr))) @@ -443,8 +448,9 @@ struct __large_struct { unsigned long buf[100]; }; * aliasing issues. */ #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ - asm volatile("1: mov"itype" %"rtype"1,%2\n" \ - "2:\n" \ + asm volatile(ASM_STAC "\n" \ + "1: mov"itype" %"rtype"1,%2\n" \ + "2: " ASM_CLAC "\n" \ ".section .fixup,\"ax\"\n" \ "3: mov %3,%0\n" \ " jmp 2b\n" \ @@ -454,8 +460,9 @@ struct __large_struct { unsigned long buf[100]; }; : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ - asm volatile("1: mov"itype" %"rtype"0,%1\n" \ - "2:\n" \ + asm volatile(ASM_STAC "\n" \ + "1: mov"itype" %"rtype"0,%1\n" \ + "2: " ASM_CLAC "\n" \ _ASM_EXTABLE_EX(1b, 2b) \ : : ltype(x), "m" (__m(addr))) diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 8a1b6f9b594a..2a923bd54341 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -74,8 +74,9 @@ static inline int xsave_user(struct xsave_struct __user *buf) if (unlikely(err)) return -EFAULT; - __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n" - "2:\n" + __asm__ __volatile__(ASM_STAC "\n" + "1: .byte " REX_PREFIX "0x0f,0xae,0x27\n" + "2: " ASM_CLAC "\n" ".section .fixup,\"ax\"\n" "3: movl $-1,%[err]\n" " jmp 2b\n" @@ -97,8 +98,9 @@ static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask) u32 lmask = mask; u32 hmask = mask >> 32; - __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n" - "2:\n" + __asm__ __volatile__(ASM_STAC "\n" + "1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n" + "2: " ASM_CLAC "\n" ".section .fixup,\"ax\"\n" "3: movl $-1,%[err]\n" " jmp 2b\n" diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a5fbc3c5fccc..cd43e525fde8 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1113,7 +1113,8 @@ void syscall_init(void) /* Flags to clear on syscall */ wrmsrl(MSR_SYSCALL_MASK, - X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL); + X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF| + X86_EFLAGS_IOPL|X86_EFLAGS_AC); } unsigned long kernel_eflags; diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 69babd8c834f..ce87e3d10c63 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -56,6 +56,7 @@ #include #include #include +#include #include /* Avoid __ASSEMBLER__'ifying just for this. */ @@ -465,7 +466,8 @@ END(ret_from_fork) * System call entry. Up to 6 arguments in registers are supported. * * SYSCALL does not save anything on the stack and does not change the - * stack pointer. + * stack pointer. However, it does mask the flags register for us, so + * CLD and CLAC are not needed. */ /* @@ -884,6 +886,7 @@ END(interrupt) */ .p2align CONFIG_X86_L1_CACHE_SHIFT common_interrupt: + ASM_CLAC XCPT_FRAME addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */ interrupt do_IRQ @@ -1023,6 +1026,7 @@ END(common_interrupt) */ .macro apicinterrupt num sym do_sym ENTRY(\sym) + ASM_CLAC INTR_FRAME pushq_cfi $~(\num) .Lcommon_\sym: @@ -1077,6 +1081,7 @@ apicinterrupt IRQ_WORK_VECTOR \ */ .macro zeroentry sym do_sym ENTRY(\sym) + ASM_CLAC INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ @@ -1094,6 +1099,7 @@ END(\sym) .macro paranoidzeroentry sym do_sym ENTRY(\sym) + ASM_CLAC INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ @@ -1112,6 +1118,7 @@ END(\sym) #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8) .macro paranoidzeroentry_ist sym do_sym ist ENTRY(\sym) + ASM_CLAC INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ @@ -1131,6 +1138,7 @@ END(\sym) .macro errorentry sym do_sym ENTRY(\sym) + ASM_CLAC XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME subq $ORIG_RAX-R15, %rsp @@ -1149,6 +1157,7 @@ END(\sym) /* error code is on the stack already */ .macro paranoiderrorentry sym do_sym ENTRY(\sym) + ASM_CLAC XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME subq $ORIG_RAX-R15, %rsp diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S index 5b2995f4557a..a30ca15be21c 100644 --- a/arch/x86/lib/copy_user_64.S +++ b/arch/x86/lib/copy_user_64.S @@ -17,6 +17,7 @@ #include #include #include +#include /* * By placing feature2 after feature1 in altinstructions section, we logically @@ -130,6 +131,7 @@ ENDPROC(bad_from_user) */ ENTRY(copy_user_generic_unrolled) CFI_STARTPROC + ASM_STAC cmpl $8,%edx jb 20f /* less then 8 bytes, go to byte copy loop */ ALIGN_DESTINATION @@ -177,6 +179,7 @@ ENTRY(copy_user_generic_unrolled) decl %ecx jnz 21b 23: xor %eax,%eax + ASM_CLAC ret .section .fixup,"ax" @@ -232,6 +235,7 @@ ENDPROC(copy_user_generic_unrolled) */ ENTRY(copy_user_generic_string) CFI_STARTPROC + ASM_STAC andl %edx,%edx jz 4f cmpl $8,%edx @@ -246,6 +250,7 @@ ENTRY(copy_user_generic_string) 3: rep movsb 4: xorl %eax,%eax + ASM_CLAC ret .section .fixup,"ax" @@ -273,12 +278,14 @@ ENDPROC(copy_user_generic_string) */ ENTRY(copy_user_enhanced_fast_string) CFI_STARTPROC + ASM_STAC andl %edx,%edx jz 2f movl %edx,%ecx 1: rep movsb 2: xorl %eax,%eax + ASM_CLAC ret .section .fixup,"ax" diff --git a/arch/x86/lib/copy_user_nocache_64.S b/arch/x86/lib/copy_user_nocache_64.S index cacddc7163eb..6a4f43c2d9e6 100644 --- a/arch/x86/lib/copy_user_nocache_64.S +++ b/arch/x86/lib/copy_user_nocache_64.S @@ -15,6 +15,7 @@ #include #include #include +#include .macro ALIGN_DESTINATION #ifdef FIX_ALIGNMENT @@ -48,6 +49,7 @@ */ ENTRY(__copy_user_nocache) CFI_STARTPROC + ASM_STAC cmpl $8,%edx jb 20f /* less then 8 bytes, go to byte copy loop */ ALIGN_DESTINATION @@ -95,6 +97,7 @@ ENTRY(__copy_user_nocache) decl %ecx jnz 21b 23: xorl %eax,%eax + ASM_CLAC sfence ret diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index b33b1fb1e6d4..156b9c804670 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -33,6 +33,7 @@ #include #include #include +#include .text ENTRY(__get_user_1) @@ -40,8 +41,10 @@ ENTRY(__get_user_1) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + ASM_STAC 1: movzb (%_ASM_AX),%edx xor %eax,%eax + ASM_CLAC ret CFI_ENDPROC ENDPROC(__get_user_1) @@ -53,8 +56,10 @@ ENTRY(__get_user_2) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + ASM_STAC 2: movzwl -1(%_ASM_AX),%edx xor %eax,%eax + ASM_CLAC ret CFI_ENDPROC ENDPROC(__get_user_2) @@ -66,8 +71,10 @@ ENTRY(__get_user_4) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + ASM_STAC 3: mov -3(%_ASM_AX),%edx xor %eax,%eax + ASM_CLAC ret CFI_ENDPROC ENDPROC(__get_user_4) @@ -80,8 +87,10 @@ ENTRY(__get_user_8) GET_THREAD_INFO(%_ASM_DX) cmp TI_addr_limit(%_ASM_DX),%_ASM_AX jae bad_get_user + ASM_STAC 4: movq -7(%_ASM_AX),%_ASM_DX xor %eax,%eax + ASM_CLAC ret CFI_ENDPROC ENDPROC(__get_user_8) @@ -91,6 +100,7 @@ bad_get_user: CFI_STARTPROC xor %edx,%edx mov $(-EFAULT),%_ASM_AX + ASM_CLAC ret CFI_ENDPROC END(bad_get_user) diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S index 7f951c8f76c4..fc6ba17a7eec 100644 --- a/arch/x86/lib/putuser.S +++ b/arch/x86/lib/putuser.S @@ -15,6 +15,7 @@ #include #include #include +#include /* @@ -31,7 +32,8 @@ #define ENTER CFI_STARTPROC ; \ GET_THREAD_INFO(%_ASM_BX) -#define EXIT ret ; \ +#define EXIT ASM_CLAC ; \ + ret ; \ CFI_ENDPROC .text @@ -39,6 +41,7 @@ ENTRY(__put_user_1) ENTER cmp TI_addr_limit(%_ASM_BX),%_ASM_CX jae bad_put_user + ASM_STAC 1: movb %al,(%_ASM_CX) xor %eax,%eax EXIT @@ -50,6 +53,7 @@ ENTRY(__put_user_2) sub $1,%_ASM_BX cmp %_ASM_BX,%_ASM_CX jae bad_put_user + ASM_STAC 2: movw %ax,(%_ASM_CX) xor %eax,%eax EXIT @@ -61,6 +65,7 @@ ENTRY(__put_user_4) sub $3,%_ASM_BX cmp %_ASM_BX,%_ASM_CX jae bad_put_user + ASM_STAC 3: movl %eax,(%_ASM_CX) xor %eax,%eax EXIT @@ -72,6 +77,7 @@ ENTRY(__put_user_8) sub $7,%_ASM_BX cmp %_ASM_BX,%_ASM_CX jae bad_put_user + ASM_STAC 4: mov %_ASM_AX,(%_ASM_CX) #ifdef CONFIG_X86_32 5: movl %edx,4(%_ASM_CX) diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c index 1781b2f950e2..98f6d6b68f5a 100644 --- a/arch/x86/lib/usercopy_32.c +++ b/arch/x86/lib/usercopy_32.c @@ -42,10 +42,11 @@ do { \ int __d0; \ might_fault(); \ __asm__ __volatile__( \ + ASM_STAC "\n" \ "0: rep; stosl\n" \ " movl %2,%0\n" \ "1: rep; stosb\n" \ - "2:\n" \ + "2: " ASM_CLAC "\n" \ ".section .fixup,\"ax\"\n" \ "3: lea 0(%2,%0,4),%0\n" \ " jmp 2b\n" \ @@ -626,10 +627,12 @@ survive: return n; } #endif + stac(); if (movsl_is_ok(to, from, n)) __copy_user(to, from, n); else n = __copy_user_intel(to, from, n); + clac(); return n; } EXPORT_SYMBOL(__copy_to_user_ll); @@ -637,10 +640,12 @@ EXPORT_SYMBOL(__copy_to_user_ll); unsigned long __copy_from_user_ll(void *to, const void __user *from, unsigned long n) { + stac(); if (movsl_is_ok(to, from, n)) __copy_user_zeroing(to, from, n); else n = __copy_user_zeroing_intel(to, from, n); + clac(); return n; } EXPORT_SYMBOL(__copy_from_user_ll); @@ -648,11 +653,13 @@ EXPORT_SYMBOL(__copy_from_user_ll); unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from, unsigned long n) { + stac(); if (movsl_is_ok(to, from, n)) __copy_user(to, from, n); else n = __copy_user_intel((void __user *)to, (const void *)from, n); + clac(); return n; } EXPORT_SYMBOL(__copy_from_user_ll_nozero); @@ -660,6 +667,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nozero); unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from, unsigned long n) { + stac(); #ifdef CONFIG_X86_INTEL_USERCOPY if (n > 64 && cpu_has_xmm2) n = __copy_user_zeroing_intel_nocache(to, from, n); @@ -668,6 +676,7 @@ unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from, #else __copy_user_zeroing(to, from, n); #endif + clac(); return n; } EXPORT_SYMBOL(__copy_from_user_ll_nocache); @@ -675,6 +684,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocache); unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from, unsigned long n) { + stac(); #ifdef CONFIG_X86_INTEL_USERCOPY if (n > 64 && cpu_has_xmm2) n = __copy_user_intel_nocache(to, from, n); @@ -683,6 +693,7 @@ unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *fr #else __copy_user(to, from, n); #endif + clac(); return n; } EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero); diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index e5b130bc2d0e..05928aae911e 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -18,6 +18,7 @@ unsigned long __clear_user(void __user *addr, unsigned long size) might_fault(); /* no memory constraint because it doesn't change any memory gcc knows about */ + stac(); asm volatile( " testq %[size8],%[size8]\n" " jz 4f\n" @@ -40,6 +41,7 @@ unsigned long __clear_user(void __user *addr, unsigned long size) : [size8] "=&c"(size), [dst] "=&D" (__d0) : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr), [zero] "r" (0UL), [eight] "r" (8UL)); + clac(); return size; } EXPORT_SYMBOL(__clear_user); @@ -82,5 +84,6 @@ copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest) for (c = 0, zero_len = len; zerorest && zero_len; --zero_len) if (__put_user_nocheck(c, to++, sizeof(char))) break; + clac(); return len; } -- 2.20.1