From 1f36cd05e0081f2c75769a551d584c4ffb2a5660 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 22 Oct 2023 19:34:28 -0400 Subject: [PATCH] sparc32: fix a braino in fault handling in csum_and_copy_..._user() Fault handler used to make non-trivial calls, so it needed to set a stack frame up. Used to be save ... - grab a stack frame, old %o... become %i... .... ret - go back to address originally in %o7, currently %i7 restore - switch to previous stack frame, in delay slot Non-trivial calls had been gone since ab5e8b331244 and that code should have become retl - go back to address in %o7 clr %o0 - have return value set to 0 What it had become instead was ret - go back to address in %i7 - return address of *caller* clr %o0 - have return value set to 0 which is not good, to put it mildly - we forcibly return 0 from csum_and_copy_{from,to}_iter() (which is what the call of that thing had been inlined into) and do that without dropping the stack frame of said csum_and_copy_..._iter(). Confuses the hell out of the caller of csum_and_copy_..._iter(), obviously... Reviewed-by: Sam Ravnborg Fixes: ab5e8b331244 "sparc32: propagate the calling conventions change down to __csum_partial_copy_sparc_generic()" Signed-off-by: Al Viro --- arch/sparc/lib/checksum_32.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sparc/lib/checksum_32.S b/arch/sparc/lib/checksum_32.S index 84ad709cbecb..66eda40fce36 100644 --- a/arch/sparc/lib/checksum_32.S +++ b/arch/sparc/lib/checksum_32.S @@ -453,5 +453,5 @@ ccslow: cmp %g1, 0 * we only bother with faults on loads... */ cc_fault: - ret + retl clr %o0