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[PATCH 26/58] MIPS: asm: uaccess: Use EVA instructions wrappers

To: <linux-mips@linux-mips.org>
Subject: [PATCH 26/58] MIPS: asm: uaccess: Use EVA instructions wrappers
From: Markos Chandras <markos.chandras@imgtec.com>
Date: Mon, 27 Jan 2014 20:19:13 +0000
Cc: Markos Chandras <markos.chandras@imgtec.com>
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Use the EVA instruction wrappers from asm.h to perform
read/write operations from userland.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
---
 arch/mips/include/asm/uaccess.h | 133 ++++++++++++++++++++++++++++++++--------
 1 file changed, 109 insertions(+), 24 deletions(-)

diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index 9c6f5ce..522fc41 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -6,6 +6,7 @@
  * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  * Copyright (C) 2007  Maciej W. Rozycki
+ * Copyright (C) 2014, Imagination Technologies Ltd.
  */
 #ifndef _ASM_UACCESS_H
 #define _ASM_UACCESS_H
@@ -13,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/thread_info.h>
+#include <asm/asm.h>
 
 /*
  * The fs value determines whether argument validity checking should be
@@ -222,11 +224,44 @@ struct __large_struct { unsigned long buf[100]; };
  * Yuck.  We need two variants, one for 64bit operation and one
  * for 32 bit mode and old iron.
  */
+#ifndef CONFIG_EVA
+#define __get_kernel_common(val, size, ptr) __get_user_common(val, size, ptr)
+#else
+/*
+ * Kernel specific functions for EVA. We need to use normal load instructions
+ * to read data from kernel when operating in EVA mode. We use these macros to
+ * avoid redefining __get_user_asm for EVA.
+ */
+#undef _loadd
+#undef _loadw
+#undef _loadh
+#undef _loadb
+#ifdef CONFIG_32BIT
+#define _loadd                 _loadw
+#else
+#define _loadd(reg, addr)      "ld " reg ", " addr
+#endif
+#define _loadw(reg, addr)      "lw " reg ", " addr
+#define _loadh(reg, addr)      "lh " reg ", " addr
+#define _loadb(reg, addr)      "lb " reg ", " addr
+
+#define __get_kernel_common(val, size, ptr)                            \
+do {                                                                   \
+       switch (size) {                                                 \
+       case 1: __get_user_asm(val, _loadb, ptr); break;                \
+       case 2: __get_user_asm(val, _loadh, ptr); break;                \
+       case 4: __get_user_asm(val, _loadw, ptr); break;                \
+       case 8: __GET_USER_DW(val, _loadd, ptr); break;                 \
+       default: __get_user_unknown(); break;                           \
+       }                                                               \
+} while (0)
+#endif
+
 #ifdef CONFIG_32BIT
 #define __GET_USER_DW(val, insn, ptr) __get_user_asm_ll32(val, insn, ptr)
 #endif
 #ifdef CONFIG_64BIT
-#define __GET_USER_DW(val, insn, ptr) __get_user_asm(val, "ld", ptr)
+#define __GET_USER_DW(val, insn, ptr) __get_user_asm(val, insn, ptr)
 #endif
 
 extern void __get_user_unknown(void);
@@ -234,10 +269,10 @@ extern void __get_user_unknown(void);
 #define __get_user_common(val, size, ptr)                              \
 do {                                                                   \
        switch (size) {                                                 \
-       case 1: __get_user_asm(val, "lb", ptr); break;                  \
-       case 2: __get_user_asm(val, "lh", ptr); break;                  \
-       case 4: __get_user_asm(val, "lw", ptr); break;                  \
-       case 8: __GET_USER_DW(val, "lw", ptr); break;                   \
+       case 1: __get_user_asm(val, user_lb, ptr); break;               \
+       case 2: __get_user_asm(val, user_lh, ptr); break;               \
+       case 4: __get_user_asm(val, user_lw, ptr); break;               \
+       case 8: __GET_USER_DW(val, user_ld, ptr); break;                \
        default: __get_user_unknown(); break;                           \
        }                                                               \
 } while (0)
@@ -246,8 +281,12 @@ do {                                                       
                \
 ({                                                                     \
        int __gu_err;                                                   \
                                                                        \
-       __chk_user_ptr(ptr);                                            \
-       __get_user_common((x), size, ptr);                              \
+       if (segment_eq(get_fs(), get_ds())) {                           \
+               __get_kernel_common((x), size, ptr);                    \
+       } else {                                                        \
+               __chk_user_ptr(ptr);                                    \
+               __get_user_common((x), size, ptr);                      \
+       }                                                               \
        __gu_err;                                                       \
 })
 
@@ -257,8 +296,12 @@ do {                                                       
                \
        const __typeof__(*(ptr)) __user * __gu_ptr = (ptr);             \
                                                                        \
        might_fault();                                                  \
-       if (likely(access_ok(VERIFY_READ,  __gu_ptr, size)))            \
-               __get_user_common((x), size, __gu_ptr);                 \
+       if (likely(access_ok(VERIFY_READ,  __gu_ptr, size))) {          \
+               if (segment_eq(get_fs(), get_ds()))                     \
+                       __get_kernel_common((x), size, __gu_ptr);       \
+               else                                                    \
+                       __get_user_common((x), size, __gu_ptr);         \
+       }                                                               \
                                                                        \
        __gu_err;                                                       \
 })
@@ -268,7 +311,7 @@ do {                                                        
                \
        long __gu_tmp;                                                  \
                                                                        \
        __asm__ __volatile__(                                           \
-       "1:     " insn "        %1, %3                          \n"     \
+       "1:     "insn("%1", "%3")"                              \n"     \
        "2:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section .fixup,\"ax\"                          \n"     \
@@ -295,8 +338,8 @@ do {                                                        
                \
        } __gu_tmp;                                                     \
                                                                        \
        __asm__ __volatile__(                                           \
-       "1:     " insn "        %1, (%3)                        \n"     \
-       "2:     " insn "        %D1, 4(%3)                      \n"     \
+       "1:     " insn("%1", "(%3)")"                           \n"     \
+       "2:     " insn("%D1", "4(%3)")"                         \n"     \
        "3:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section        .fixup,\"ax\"                   \n"     \
@@ -315,6 +358,40 @@ do {                                                       
                \
        (val) = __gu_tmp.t;                                             \
 }
 
+#ifndef CONFIG_EVA
+#define __put_kernel_common(ptr, size) __put_user_common(ptr, size)
+#else
+/*
+ * Kernel specific functions for EVA. We need to use normal load instructions
+ * to read data from kernel when operating in EVA mode. We use these macros to
+ * avoid redefining __get_user_asm for EVA.
+ */
+#undef _stored
+#undef _storew
+#undef _storeh
+#undef _storeb
+#ifdef CONFIG_32BIT
+#define _stored                        _storew
+#else
+#define _stored(reg, addr)     "ld " reg ", " addr
+#endif
+
+#define _storew(reg, addr)     "sw " reg ", " addr
+#define _storeh(reg, addr)     "sh " reg ", " addr
+#define _storeb(reg, addr)     "sb " reg ", " addr
+
+#define __put_kernel_common(ptr, size)                                 \
+do {                                                                   \
+       switch (size) {                                                 \
+       case 1: __put_user_asm(_storeb, ptr); break;                    \
+       case 2: __put_user_asm(_storeh, ptr); break;                    \
+       case 4: __put_user_asm(_storew, ptr); break;                    \
+       case 8: __PUT_USER_DW(_stored, ptr); break;                     \
+       default: __put_user_unknown(); break;                           \
+       }                                                               \
+} while(0)
+#endif
+
 /*
  * Yuck.  We need two variants, one for 64bit operation and one
  * for 32 bit mode and old iron.
@@ -323,16 +400,16 @@ do {                                                      
                \
 #define __PUT_USER_DW(insn, ptr) __put_user_asm_ll32(insn, ptr)
 #endif
 #ifdef CONFIG_64BIT
-#define __PUT_USER_DW(insn, ptr) __put_user_asm("sd", ptr)
+#define __PUT_USER_DW(insn, ptr) __put_user_asm(insn, ptr)
 #endif
 
 #define __put_user_common(ptr, size)                                   \
 do {                                                                   \
        switch (size) {                                                 \
-       case 1: __put_user_asm("sb", ptr); break;                       \
-       case 2: __put_user_asm("sh", ptr); break;                       \
-       case 4: __put_user_asm("sw", ptr); break;                       \
-       case 8: __PUT_USER_DW("sw", ptr); break;                        \
+       case 1: __put_user_asm(user_sb, ptr); break;                    \
+       case 2: __put_user_asm(user_sh, ptr); break;                    \
+       case 4: __put_user_asm(user_sw, ptr); break;                    \
+       case 8: __PUT_USER_DW(user_sd, ptr); break;                     \
        default: __put_user_unknown(); break;                           \
        }                                                               \
 } while (0)
@@ -342,9 +419,13 @@ do {                                                       
                \
        __typeof__(*(ptr)) __pu_val;                                    \
        int __pu_err = 0;                                               \
                                                                        \
-       __chk_user_ptr(ptr);                                            \
        __pu_val = (x);                                                 \
-       __put_user_common(ptr, size);                                   \
+       if (segment_eq(get_fs(), get_ds())) {                           \
+               __put_kernel_common(ptr, size);                         \
+       } else {                                                        \
+               __chk_user_ptr(ptr);                                    \
+               __put_user_common(ptr, size);                           \
+       }                                                               \
        __pu_err;                                                       \
 })
 
@@ -355,8 +436,12 @@ do {                                                       
                \
        int __pu_err = -EFAULT;                                         \
                                                                        \
        might_fault();                                                  \
-       if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size)))          \
-               __put_user_common(__pu_addr, size);                     \
+       if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {        \
+               if (segment_eq(get_fs(), get_ds()))                     \
+                       __put_kernel_common(__pu_addr, size);           \
+               else                                                    \
+                       __put_user_common(__pu_addr, size);             \
+       }                                                               \
                                                                        \
        __pu_err;                                                       \
 })
@@ -364,7 +449,7 @@ do {                                                        
                \
 #define __put_user_asm(insn, ptr)                                      \
 {                                                                      \
        __asm__ __volatile__(                                           \
-       "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
+       "1:     "insn("%z2", "%3")"     # __put_user_asm        \n"     \
        "2:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section        .fixup,\"ax\"                   \n"     \
@@ -382,8 +467,8 @@ do {                                                        
                \
 #define __put_user_asm_ll32(insn, ptr)                                 \
 {                                                                      \
        __asm__ __volatile__(                                           \
-       "1:     " insn "        %2, (%3)# __put_user_asm_ll32   \n"     \
-       "2:     " insn "        %D2, 4(%3)                      \n"     \
+       "1:     "insn("%2", "(%3)")"    # __put_user_asm_ll32   \n"     \
+       "2:     "insn("%D2", "4(%3)")"                          \n"     \
        "3:                                                     \n"     \
        "       .insn                                           \n"     \
        "       .section        .fixup,\"ax\"                   \n"     \
-- 
1.8.5.3



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