From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Thu, 12 Nov 2015 14:24:57 +0100 Subject: [PATCH v6 13/17] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it In-Reply-To: References: <1446507046-24604-1-git-send-email-ynorov@caviumnetworks.com> <4796230.MStNPjWNEu@wuerfel> Message-ID: <16446627.b0Lo936ZJj@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thursday 12 November 2015 10:44:55 Andreas Schwab wrote: > Arnd Bergmann writes: > > > What do you mean with 32-bit off_t? > > An ABI with 32-bit off_t, ie. all currently implemented 32-bit ABIs. > > > Do you mean that glibc emulates a 32-bit off_t on top of the 64-bit > > __kernel_loff_t? > > Glibc is bridging the user-space ABI to the kernel ABI. Ok, but why? The kernel headers for all recent architectures (arc, c6x, h8300, hexagon, metag, nios2, openrisc, tile and unicore32) deliberately leave out the __kernel_off_t based system calls to simplify the ABI in a way that we never have to support a 32-bit off_t in user space. Are there programs that require using a 32-bit off_t by default on 32-bit architectures but not on 64-bit architectures? Did the previous version of the ilp32 patch set also emulate this the same way? Arnd