From d19f5e41b344a057bb2450024a807476f30978d2 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 25 Mar 2017 11:59:15 +0100 Subject: parisc: Clean up fixup routines for get_user()/put_user() Al Viro noticed that userspace accesses via get_user()/put_user() can be simplified a lot with regard to usage of the exception handling. This patch implements a fixup routine for get_user() and put_user() in such that the exception handler will automatically load -EFAULT into the register %r8 (the error value) in case on a fault on userspace. Additionally the fixup routine will zero the target register on fault in case of a get_user() call. The target register is extracted out of the faulting assembly instruction. This patch brings a few benefits over the old implementation: 1. Exception handling gets much cleaner, easier and smaller in size. 2. Helper functions like fixup_get_user_skip_1 (all of fixup.S) can be dropped. 3. No need to hardcode %r9 as target register for get_user() any longer. This helps the compiler register allocator and thus creates less assembler statements. 4. No dependency on the exception_data contents any longer. 5. Nested faults will be handled cleanly. Reported-by: Al Viro Cc: # v4.9+ Signed-off-by: Helge Deller --- arch/parisc/lib/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/parisc/lib/Makefile') diff --git a/arch/parisc/lib/Makefile b/arch/parisc/lib/Makefile index 8fa92b8d839a..f2dac4d73b1b 100644 --- a/arch/parisc/lib/Makefile +++ b/arch/parisc/lib/Makefile @@ -2,7 +2,7 @@ # Makefile for parisc-specific library files # -lib-y := lusercopy.o bitops.o checksum.o io.o memset.o fixup.o memcpy.o \ +lib-y := lusercopy.o bitops.o checksum.o io.o memset.o memcpy.o \ ucmpdi2.o delay.o obj-y := iomap.o -- cgit