Can we worry about this after the merge window? ville.syrj...@linux.intel.com wrote:
>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 -- Sent from my mobile phone. 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