diff options
author | H. Peter Anvin <hpa@linux.intel.com> | 2012-09-21 12:43:12 -0700 |
---|---|---|
committer | H. Peter Anvin <hpa@linux.intel.com> | 2012-09-21 12:45:27 -0700 |
commit | 63bcff2a307b9bcc712a8251eb27df8b2e117967 (patch) | |
tree | 0a23a378d2c967edf63e9bb2b5df2288bf30859c /arch/x86/include/asm | |
parent | a052858fabb376b695f2c125633daa6728e0f284 (diff) | |
download | blackbird-op-linux-63bcff2a307b9bcc712a8251eb27df8b2e117967.tar.gz blackbird-op-linux-63bcff2a307b9bcc712a8251eb27df8b2e117967.zip |
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 <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-9-git-send-email-hpa@linux.intel.com
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r-- | arch/x86/include/asm/fpu-internal.h | 10 | ||||
-rw-r--r-- | arch/x86/include/asm/futex.h | 19 | ||||
-rw-r--r-- | arch/x86/include/asm/smap.h | 4 | ||||
-rw-r--r-- | arch/x86/include/asm/uaccess.h | 31 | ||||
-rw-r--r-- | arch/x86/include/asm/xsave.h | 10 |
5 files changed, 46 insertions, 28 deletions
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 <asm/asm.h> #include <asm/errno.h> #include <asm/processor.h> +#include <asm/smap.h> #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 <linux/string.h> #include <asm/asm.h> #include <asm/page.h> +#include <asm/smap.h> #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" |