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m68k: Provide __{get,put}_kernel_nofault
Allow non-faulting access to kernel addresses without overriding the address space. Implemented by passing the instruction name to the low-level assembly macros as an argument, and force the use of the normal move instructions for kernel access. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Michael Schmitz <schmitzmic@gmail.com> Tested-by: Michael Schmitz <schmitzmic@gmail.com> Link: https://lore.kernel.org/r/20210916070405.52750-6-hch@lst.de Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Christoph Hellwig
Geert Uytterhoeven
parent
01eec1af5e
commit
8ade833909
1 changed files with 84 additions and 21 deletions
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@ -39,9 +39,9 @@ static inline int access_ok(const void __user *addr,
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#define MOVES "move"
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#endif
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#define __put_user_asm(res, x, ptr, bwl, reg, err) \
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#define __put_user_asm(inst, res, x, ptr, bwl, reg, err) \
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asm volatile ("\n" \
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"1: "MOVES"."#bwl" %2,%1\n" \
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"1: "inst"."#bwl" %2,%1\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .even\n" \
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@ -57,13 +57,13 @@ asm volatile ("\n" \
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: "+d" (res), "=m" (*(ptr)) \
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: #reg (x), "i" (err))
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#define __put_user_asm8(res, x, ptr) \
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#define __put_user_asm8(inst, res, x, ptr) \
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do { \
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const void *__pu_ptr = (const void __force *)(ptr); \
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\
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asm volatile ("\n" \
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"1: "MOVES".l %2,(%1)+\n" \
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"2: "MOVES".l %R2,(%1)\n" \
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"1: "inst".l %2,(%1)+\n" \
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"2: "inst".l %R2,(%1)\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .even\n" \
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@ -94,16 +94,16 @@ do { \
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__chk_user_ptr(ptr); \
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switch (sizeof (*(ptr))) { \
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case 1: \
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__put_user_asm(__pu_err, __pu_val, ptr, b, d, -EFAULT); \
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__put_user_asm(MOVES, __pu_err, __pu_val, ptr, b, d, -EFAULT); \
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break; \
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case 2: \
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__put_user_asm(__pu_err, __pu_val, ptr, w, r, -EFAULT); \
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__put_user_asm(MOVES, __pu_err, __pu_val, ptr, w, r, -EFAULT); \
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break; \
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case 4: \
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__put_user_asm(__pu_err, __pu_val, ptr, l, r, -EFAULT); \
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__put_user_asm(MOVES, __pu_err, __pu_val, ptr, l, r, -EFAULT); \
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break; \
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case 8: \
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__put_user_asm8(__pu_err, __pu_val, ptr); \
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__put_user_asm8(MOVES, __pu_err, __pu_val, ptr); \
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break; \
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default: \
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BUILD_BUG(); \
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@ -113,10 +113,10 @@ do { \
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#define put_user(x, ptr) __put_user(x, ptr)
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#define __get_user_asm(res, x, ptr, type, bwl, reg, err) ({ \
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#define __get_user_asm(inst, res, x, ptr, type, bwl, reg, err) ({ \
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type __gu_val; \
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asm volatile ("\n" \
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"1: "MOVES"."#bwl" %2,%1\n" \
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"1: "inst"."#bwl" %2,%1\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .even\n" \
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@ -134,7 +134,7 @@ do { \
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(x) = (__force typeof(*(ptr)))(__force unsigned long)__gu_val; \
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})
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#define __get_user_asm8(res, x, ptr) \
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#define __get_user_asm8(inst, res, x, ptr) \
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do { \
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const void *__gu_ptr = (const void __force *)(ptr); \
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union { \
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@ -143,8 +143,8 @@ do { \
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} __gu_val; \
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\
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asm volatile ("\n" \
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"1: "MOVES".l (%2)+,%1\n" \
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"2: "MOVES".l (%2),%R1\n" \
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"1: "inst".l (%2)+,%1\n" \
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"2: "inst".l (%2),%R1\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .even\n" \
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@ -172,16 +172,16 @@ do { \
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__chk_user_ptr(ptr); \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__get_user_asm(__gu_err, x, ptr, u8, b, d, -EFAULT); \
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__get_user_asm(MOVES, __gu_err, x, ptr, u8, b, d, -EFAULT); \
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break; \
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case 2: \
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__get_user_asm(__gu_err, x, ptr, u16, w, r, -EFAULT); \
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__get_user_asm(MOVES, __gu_err, x, ptr, u16, w, r, -EFAULT); \
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break; \
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case 4: \
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__get_user_asm(__gu_err, x, ptr, u32, l, r, -EFAULT); \
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__get_user_asm(MOVES, __gu_err, x, ptr, u32, l, r, -EFAULT); \
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break; \
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case 8: \
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__get_user_asm8(__gu_err, x, ptr); \
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__get_user_asm8(MOVES, __gu_err, x, ptr); \
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break; \
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default: \
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BUILD_BUG(); \
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@ -330,16 +330,19 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
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switch (n) {
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case 1:
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__put_user_asm(res, *(u8 *)from, (u8 __user *)to, b, d, 1);
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__put_user_asm(MOVES, res, *(u8 *)from, (u8 __user *)to,
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b, d, 1);
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break;
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case 2:
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__put_user_asm(res, *(u16 *)from, (u16 __user *)to, w, r, 2);
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__put_user_asm(MOVES, res, *(u16 *)from, (u16 __user *)to,
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w, r, 2);
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break;
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case 3:
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__constant_copy_to_user_asm(res, to, from, tmp, 3, w, b,);
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break;
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case 4:
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__put_user_asm(res, *(u32 *)from, (u32 __user *)to, l, r, 4);
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__put_user_asm(MOVES, res, *(u32 *)from, (u32 __user *)to,
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l, r, 4);
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break;
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case 5:
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__constant_copy_to_user_asm(res, to, from, tmp, 5, l, b,);
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@ -388,6 +391,66 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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#define INLINE_COPY_FROM_USER
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#define INLINE_COPY_TO_USER
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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do { \
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type *__gk_dst = (type *)(dst); \
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type *__gk_src = (type *)(src); \
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int __gk_err = 0; \
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\
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switch (sizeof(type)) { \
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case 1: \
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__get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \
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u8, b, d, -EFAULT); \
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break; \
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case 2: \
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__get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \
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u16, w, r, -EFAULT); \
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break; \
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case 4: \
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__get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \
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u32, l, r, -EFAULT); \
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break; \
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case 8: \
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__get_user_asm8("move", __gk_err, *__gk_dst, __gk_src); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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if (unlikely(__gk_err)) \
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goto err_label; \
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} while (0)
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#define __put_kernel_nofault(dst, src, type, err_label) \
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do { \
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type __pk_src = *(type *)(src); \
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type *__pk_dst = (type *)(dst); \
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int __pk_err = 0; \
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\
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switch (sizeof(type)) { \
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case 1: \
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__put_user_asm("move", __pk_err, __pk_src, __pk_dst, \
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b, d, -EFAULT); \
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break; \
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case 2: \
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__put_user_asm("move", __pk_err, __pk_src, __pk_dst, \
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w, r, -EFAULT); \
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break; \
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case 4: \
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__put_user_asm("move", __pk_err, __pk_src, __pk_dst, \
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l, r, -EFAULT); \
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break; \
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case 8: \
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__put_user_asm8("move", __pk_err, __pk_src, __pk_dst); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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if (unlikely(__pk_err)) \
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goto err_label; \
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} while (0)
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#define user_addr_max() \
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(uaccess_kernel() ? ~0UL : TASK_SIZE)
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