Commit-ID: f69fa9a91f60fff6f2d8b658b7d84d235d9d89b7 Gitweb: http://git.kernel.org/tip/f69fa9a91f60fff6f2d8b658b7d84d235d9d89b7 Author: H. Peter Anvin <[email protected]> AuthorDate: Thu, 29 Aug 2013 13:34:50 -0700 Committer: H. Peter Anvin <[email protected]> CommitDate: Thu, 29 Aug 2013 13:34:50 -0700
x86, doc: Update uaccess.h comment to reflect clang changes Update comment in uaccess.h to reflect the changes for clang support: gcc only cares about the base register (most architectures don't encode the size of the operation in the operands like x86 does, and so it is treated effectively like a register number), whereas clang tries to enforce the size -- but not for register pairs. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]> Cc: Jan-Simon Möller <[email protected]> --- arch/x86/include/asm/uaccess.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index f715fee..5838fa9 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -153,11 +153,14 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) * Careful: we have to cast the result to the type of the pointer * for sign reasons. * - * The use of %edx as the register specifier is a bit of a + * The use of _ASM_DX as the register specifier is a bit of a * simplification, as gcc only cares about it as the starting point * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits * (%ecx being the next register in gcc's x86 register sequence), and * %rdx on 64 bits. + * + * Clang/LLVM cares about the size of the register, but still wants + * the base register for something that ends up being a pair. */ #define get_user(x, ptr) \ ({ \ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
