From: Ville Syrjälä <ville.syrj...@linux.intel.com> Implement __get_user_8() for x86-32. It will return the 64bit result in edx:eax register pair, and ecx is used to pass in the address and return the error value.
For consistency, change the register assignment for all other __get_user_x() variants, so that address is passed in ecx/rcx, the error value is returned in ecx/rcx, and eax/rax contains the actual value. This is a partial refresh of a patch [1] by Jamie Lokier from 2004. Only the minimal changes to implement 64bit get_user() were picked from the original patch. [1] http://article.gmane.org/gmane.linux.kernel/198823 Cc: Jamie Lokier <ja...@shareable.org> Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com> --- arch/x86/include/asm/uaccess.h | 17 ++++++-- arch/x86/kernel/i386_ksyms_32.c | 1 + arch/x86/lib/getuser.S | 82 ++++++++++++++++++++++++++------------ 3 files changed, 69 insertions(+), 31 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 7ccf8d1..3f4387e 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -127,7 +127,7 @@ extern int __get_user_bad(void); #define __get_user_x(size, ret, x, ptr) \ asm volatile("call __get_user_" #size \ - : "=a" (ret), "=d" (x) \ + : "=c" (ret), "=a" (x) \ : "0" (ptr)) \ /* Careful: we have to cast the result to the type of the pointer @@ -151,8 +151,11 @@ extern int __get_user_bad(void); * On error, the variable @x is set to zero. */ #ifdef CONFIG_X86_32 -#define __get_user_8(__ret_gu, __val_gu, ptr) \ - __get_user_x(X, __ret_gu, __val_gu, ptr) +#define __get_user_8(ret, x, ptr) \ + asm volatile("call __get_user_8" \ + : "=c" (ret), "=A" (x) \ + : "0" (ptr)) \ + #else #define __get_user_8(__ret_gu, __val_gu, ptr) \ __get_user_x(8, __ret_gu, __val_gu, ptr) @@ -162,6 +165,7 @@ extern int __get_user_bad(void); ({ \ int __ret_gu; \ unsigned long __val_gu; \ + unsigned long long __val_gu8; \ __chk_user_ptr(ptr); \ might_fault(); \ switch (sizeof(*(ptr))) { \ @@ -175,13 +179,16 @@ extern int __get_user_bad(void); __get_user_x(4, __ret_gu, __val_gu, ptr); \ break; \ case 8: \ - __get_user_8(__ret_gu, __val_gu, ptr); \ + __get_user_8(__ret_gu, __val_gu8, ptr); \ break; \ default: \ __get_user_x(X, __ret_gu, __val_gu, ptr); \ break; \ } \ - (x) = (__typeof__(*(ptr)))__val_gu; \ + if (sizeof(*(ptr)) == 8) \ + (x) = (__typeof__(*(ptr)))__val_gu8; \ + else \ + (x) = (__typeof__(*(ptr)))__val_gu; \ __ret_gu; \ }) diff --git a/arch/x86/kernel/i386_ksyms_32.c b/arch/x86/kernel/i386_ksyms_32.c index 9c3bd4a..0fa6912 100644 --- a/arch/x86/kernel/i386_ksyms_32.c +++ b/arch/x86/kernel/i386_ksyms_32.c @@ -26,6 +26,7 @@ EXPORT_SYMBOL(csum_partial_copy_generic); EXPORT_SYMBOL(__get_user_1); EXPORT_SYMBOL(__get_user_2); EXPORT_SYMBOL(__get_user_4); +EXPORT_SYMBOL(__get_user_8); EXPORT_SYMBOL(__put_user_1); EXPORT_SYMBOL(__put_user_2); diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 156b9c8..38afef0 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -14,12 +14,11 @@ /* * __get_user_X * - * Inputs: %[r|e]ax contains the address. - * The register is modified, but all changes are undone - * before returning because the C code doesn't know about it. + * Inputs: %[r|e]cx contains the address. * - * Outputs: %[r|e]ax is error code (0 or -EFAULT) - * %[r|e]dx contains zero-extended value + * Outputs: %[r|e]cx is error code (0 or -EFAULT) + * %[r|e]ax contains zero-extended value + * %edx contains the high bits of the value for __get_user_8 on x86-32 * * * These functions should not modify any other registers, @@ -38,12 +37,12 @@ .text ENTRY(__get_user_1) CFI_STARTPROC - GET_THREAD_INFO(%_ASM_DX) - cmp TI_addr_limit(%_ASM_DX),%_ASM_AX + GET_THREAD_INFO(%_ASM_AX) + cmp TI_addr_limit(%_ASM_AX),%_ASM_CX jae bad_get_user ASM_STAC -1: movzb (%_ASM_AX),%edx - xor %eax,%eax +1: movzb (%_ASM_CX),%eax + xor %ecx,%ecx ASM_CLAC ret CFI_ENDPROC @@ -51,14 +50,14 @@ ENDPROC(__get_user_1) ENTRY(__get_user_2) CFI_STARTPROC - add $1,%_ASM_AX + add $1,%_ASM_CX jc bad_get_user - GET_THREAD_INFO(%_ASM_DX) - cmp TI_addr_limit(%_ASM_DX),%_ASM_AX + GET_THREAD_INFO(%_ASM_AX) + cmp TI_addr_limit(%_ASM_AX),%_ASM_CX jae bad_get_user ASM_STAC -2: movzwl -1(%_ASM_AX),%edx - xor %eax,%eax +2: movzwl -1(%_ASM_CX),%eax + xor %ecx,%ecx ASM_CLAC ret CFI_ENDPROC @@ -66,14 +65,14 @@ ENDPROC(__get_user_2) ENTRY(__get_user_4) CFI_STARTPROC - add $3,%_ASM_AX + add $3,%_ASM_CX jc bad_get_user - GET_THREAD_INFO(%_ASM_DX) - cmp TI_addr_limit(%_ASM_DX),%_ASM_AX + GET_THREAD_INFO(%_ASM_AX) + cmp TI_addr_limit(%_ASM_AX),%_ASM_CX jae bad_get_user ASM_STAC -3: mov -3(%_ASM_AX),%edx - xor %eax,%eax +3: mov -3(%_ASM_CX),%eax + xor %ecx,%ecx ASM_CLAC ret CFI_ENDPROC @@ -82,14 +81,30 @@ ENDPROC(__get_user_4) #ifdef CONFIG_X86_64 ENTRY(__get_user_8) CFI_STARTPROC - add $7,%_ASM_AX + add $7,%_ASM_CX jc bad_get_user - GET_THREAD_INFO(%_ASM_DX) - cmp TI_addr_limit(%_ASM_DX),%_ASM_AX + GET_THREAD_INFO(%_ASM_AX) + cmp TI_addr_limit(%_ASM_AX),%_ASM_CX jae bad_get_user ASM_STAC -4: movq -7(%_ASM_AX),%_ASM_DX - xor %eax,%eax +4: movq -7(%_ASM_CX),%_ASM_AX + xor %ecx,%ecx + ASM_CLAC + ret + CFI_ENDPROC +ENDPROC(__get_user_8) +#else +ENTRY(__get_user_8) + CFI_STARTPROC + add $7,%_ASM_CX + jc bad_get_user_8 + GET_THREAD_INFO(%_ASM_AX) + cmp TI_addr_limit(%_ASM_AX),%_ASM_CX + jae bad_get_user_8 + ASM_STAC +4: mov -7(%_ASM_CX),%eax +5: mov -3(%_ASM_CX),%edx + xor %ecx,%ecx ASM_CLAC ret CFI_ENDPROC @@ -98,16 +113,31 @@ ENDPROC(__get_user_8) bad_get_user: CFI_STARTPROC - xor %edx,%edx - mov $(-EFAULT),%_ASM_AX + xor %eax,%eax + mov $(-EFAULT),%_ASM_CX ASM_CLAC ret CFI_ENDPROC END(bad_get_user) +#ifdef CONFIG_X86_32 +bad_get_user_8: + CFI_STARTPROC + xor %eax,%eax + xor %edx,%edx + mov $(-EFAULT),%_ASM_CX + ASM_CLAC + ret + CFI_ENDPROC +END(bad_get_user_8) +#endif + _ASM_EXTABLE(1b,bad_get_user) _ASM_EXTABLE(2b,bad_get_user) _ASM_EXTABLE(3b,bad_get_user) #ifdef CONFIG_X86_64 _ASM_EXTABLE(4b,bad_get_user) +#else + _ASM_EXTABLE(4b,bad_get_user_8) + _ASM_EXTABLE(5b,bad_get_user_8) #endif -- 1.7.8.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
