From 8ade83390930d61c64fe3ab49081990c9d43d0d2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 16 Sep 2021 09:04:04 +0200 Subject: [PATCH] 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 Reviewed-by: Michael Schmitz Tested-by: Michael Schmitz Link: https://lore.kernel.org/r/20210916070405.52750-6-hch@lst.de Signed-off-by: Geert Uytterhoeven --- arch/m68k/include/asm/uaccess.h | 105 +++++++++++++++++++++++++------- 1 file changed, 84 insertions(+), 21 deletions(-) diff --git a/arch/m68k/include/asm/uaccess.h b/arch/m68k/include/asm/uaccess.h index 288ef7d11a7a..65581a7874d4 100644 --- a/arch/m68k/include/asm/uaccess.h +++ b/arch/m68k/include/asm/uaccess.h @@ -39,9 +39,9 @@ static inline int access_ok(const void __user *addr, #define MOVES "move" #endif -#define __put_user_asm(res, x, ptr, bwl, reg, err) \ +#define __put_user_asm(inst, res, x, ptr, bwl, reg, err) \ asm volatile ("\n" \ - "1: "MOVES"."#bwl" %2,%1\n" \ + "1: "inst"."#bwl" %2,%1\n" \ "2:\n" \ " .section .fixup,\"ax\"\n" \ " .even\n" \ @@ -57,13 +57,13 @@ asm volatile ("\n" \ : "+d" (res), "=m" (*(ptr)) \ : #reg (x), "i" (err)) -#define __put_user_asm8(res, x, ptr) \ +#define __put_user_asm8(inst, res, x, ptr) \ do { \ const void *__pu_ptr = (const void __force *)(ptr); \ \ asm volatile ("\n" \ - "1: "MOVES".l %2,(%1)+\n" \ - "2: "MOVES".l %R2,(%1)\n" \ + "1: "inst".l %2,(%1)+\n" \ + "2: "inst".l %R2,(%1)\n" \ "3:\n" \ " .section .fixup,\"ax\"\n" \ " .even\n" \ @@ -94,16 +94,16 @@ do { \ __chk_user_ptr(ptr); \ switch (sizeof (*(ptr))) { \ case 1: \ - __put_user_asm(__pu_err, __pu_val, ptr, b, d, -EFAULT); \ + __put_user_asm(MOVES, __pu_err, __pu_val, ptr, b, d, -EFAULT); \ break; \ case 2: \ - __put_user_asm(__pu_err, __pu_val, ptr, w, r, -EFAULT); \ + __put_user_asm(MOVES, __pu_err, __pu_val, ptr, w, r, -EFAULT); \ break; \ case 4: \ - __put_user_asm(__pu_err, __pu_val, ptr, l, r, -EFAULT); \ + __put_user_asm(MOVES, __pu_err, __pu_val, ptr, l, r, -EFAULT); \ break; \ case 8: \ - __put_user_asm8(__pu_err, __pu_val, ptr); \ + __put_user_asm8(MOVES, __pu_err, __pu_val, ptr); \ break; \ default: \ BUILD_BUG(); \ @@ -113,10 +113,10 @@ do { \ #define put_user(x, ptr) __put_user(x, ptr) -#define __get_user_asm(res, x, ptr, type, bwl, reg, err) ({ \ +#define __get_user_asm(inst, res, x, ptr, type, bwl, reg, err) ({ \ type __gu_val; \ asm volatile ("\n" \ - "1: "MOVES"."#bwl" %2,%1\n" \ + "1: "inst"."#bwl" %2,%1\n" \ "2:\n" \ " .section .fixup,\"ax\"\n" \ " .even\n" \ @@ -134,7 +134,7 @@ do { \ (x) = (__force typeof(*(ptr)))(__force unsigned long)__gu_val; \ }) -#define __get_user_asm8(res, x, ptr) \ +#define __get_user_asm8(inst, res, x, ptr) \ do { \ const void *__gu_ptr = (const void __force *)(ptr); \ union { \ @@ -143,8 +143,8 @@ do { \ } __gu_val; \ \ asm volatile ("\n" \ - "1: "MOVES".l (%2)+,%1\n" \ - "2: "MOVES".l (%2),%R1\n" \ + "1: "inst".l (%2)+,%1\n" \ + "2: "inst".l (%2),%R1\n" \ "3:\n" \ " .section .fixup,\"ax\"\n" \ " .even\n" \ @@ -172,16 +172,16 @@ do { \ __chk_user_ptr(ptr); \ switch (sizeof(*(ptr))) { \ case 1: \ - __get_user_asm(__gu_err, x, ptr, u8, b, d, -EFAULT); \ + __get_user_asm(MOVES, __gu_err, x, ptr, u8, b, d, -EFAULT); \ break; \ case 2: \ - __get_user_asm(__gu_err, x, ptr, u16, w, r, -EFAULT); \ + __get_user_asm(MOVES, __gu_err, x, ptr, u16, w, r, -EFAULT); \ break; \ case 4: \ - __get_user_asm(__gu_err, x, ptr, u32, l, r, -EFAULT); \ + __get_user_asm(MOVES, __gu_err, x, ptr, u32, l, r, -EFAULT); \ break; \ case 8: \ - __get_user_asm8(__gu_err, x, ptr); \ + __get_user_asm8(MOVES, __gu_err, x, ptr); \ break; \ default: \ BUILD_BUG(); \ @@ -330,16 +330,19 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n) switch (n) { case 1: - __put_user_asm(res, *(u8 *)from, (u8 __user *)to, b, d, 1); + __put_user_asm(MOVES, res, *(u8 *)from, (u8 __user *)to, + b, d, 1); break; case 2: - __put_user_asm(res, *(u16 *)from, (u16 __user *)to, w, r, 2); + __put_user_asm(MOVES, res, *(u16 *)from, (u16 __user *)to, + w, r, 2); break; case 3: __constant_copy_to_user_asm(res, to, from, tmp, 3, w, b,); break; case 4: - __put_user_asm(res, *(u32 *)from, (u32 __user *)to, l, r, 4); + __put_user_asm(MOVES, res, *(u32 *)from, (u32 __user *)to, + l, r, 4); break; case 5: __constant_copy_to_user_asm(res, to, from, tmp, 5, l, b,); @@ -388,6 +391,66 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n) #define INLINE_COPY_FROM_USER #define INLINE_COPY_TO_USER +#define HAVE_GET_KERNEL_NOFAULT + +#define __get_kernel_nofault(dst, src, type, err_label) \ +do { \ + type *__gk_dst = (type *)(dst); \ + type *__gk_src = (type *)(src); \ + int __gk_err = 0; \ + \ + switch (sizeof(type)) { \ + case 1: \ + __get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \ + u8, b, d, -EFAULT); \ + break; \ + case 2: \ + __get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \ + u16, w, r, -EFAULT); \ + break; \ + case 4: \ + __get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \ + u32, l, r, -EFAULT); \ + break; \ + case 8: \ + __get_user_asm8("move", __gk_err, *__gk_dst, __gk_src); \ + break; \ + default: \ + BUILD_BUG(); \ + } \ + if (unlikely(__gk_err)) \ + goto err_label; \ +} while (0) + +#define __put_kernel_nofault(dst, src, type, err_label) \ +do { \ + type __pk_src = *(type *)(src); \ + type *__pk_dst = (type *)(dst); \ + int __pk_err = 0; \ + \ + switch (sizeof(type)) { \ + case 1: \ + __put_user_asm("move", __pk_err, __pk_src, __pk_dst, \ + b, d, -EFAULT); \ + break; \ + case 2: \ + __put_user_asm("move", __pk_err, __pk_src, __pk_dst, \ + w, r, -EFAULT); \ + break; \ + case 4: \ + __put_user_asm("move", __pk_err, __pk_src, __pk_dst, \ + l, r, -EFAULT); \ + break; \ + case 8: \ + __put_user_asm8("move", __pk_err, __pk_src, __pk_dst); \ + break; \ + default: \ + BUILD_BUG(); \ + } \ + if (unlikely(__pk_err)) \ + goto err_label; \ +} while (0) + #define user_addr_max() \ (uaccess_kernel() ? ~0UL : TASK_SIZE) -- 2.34.1