diff options
| author | Benjamin LaHaise <bcrl@kvack.org> | 2016-03-09 15:05:56 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-13 13:01:03 +0200 |
| commit | b2f680380ddf2f003882e59e00acd6c1952f91fc (patch) | |
| tree | 4ea0aaea572cb99b0f619957fe7a463168fcebfe /arch/x86/include/asm/uaccess.h | |
| parent | 1886297ce0c8d563a08c8a8c4c0b97743e06cd37 (diff) | |
x86/mm/32: Add support for 64-bit __get_user() on 32-bit kernels
The existing __get_user() implementation does not support fetching
64-bit values on 32-bit x86. Implement this in a way that does not
generate any incorrect warnings as cautioned by Russell King.
Test code available at:
http://www.kvack.org/~bcrl/x86_32-get_user.tar .
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index a969ae607be8..8b3fb76b489b 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -333,7 +333,26 @@ do { \ } while (0) #ifdef CONFIG_X86_32 -#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() +#define __get_user_asm_u64(x, ptr, retval, errret) \ +({ \ + __typeof__(ptr) __ptr = (ptr); \ + asm volatile(ASM_STAC "\n" \ + "1: movl %2,%%eax\n" \ + "2: movl %3,%%edx\n" \ + "3: " ASM_CLAC "\n" \ + ".section .fixup,\"ax\"\n" \ + "4: mov %4,%0\n" \ + " xorl %%eax,%%eax\n" \ + " xorl %%edx,%%edx\n" \ + " jmp 3b\n" \ + ".previous\n" \ + _ASM_EXTABLE(1b, 4b) \ + _ASM_EXTABLE(2b, 4b) \ + : "=r" (retval), "=A"(x) \ + : "m" (__m(__ptr)), "m" __m(((u32 *)(__ptr)) + 1), \ + "i" (errret), "0" (retval)); \ +}) + #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() #else #define __get_user_asm_u64(x, ptr, retval, errret) \ @@ -420,7 +439,7 @@ do { \ #define __get_user_nocheck(x, ptr, size) \ ({ \ int __gu_err; \ - unsigned long __gu_val; \ + __inttype(*(ptr)) __gu_val; \ __uaccess_begin(); \ __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ __uaccess_end(); \ |