From: Al Viro Date: Sun, 22 Oct 2023 23:34:28 +0000 (-0400) Subject: sparc32: fix a braino in fault handling in csum_and_copy_..._user() X-Git-Tag: v6.6.7~1664^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1f36cd05e0081f2c75769a551d584c4ffb2a5660;p=platform%2Fkernel%2Flinux-starfive.git 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 --- diff --git a/arch/sparc/lib/checksum_32.S b/arch/sparc/lib/checksum_32.S index 84ad709..66eda40 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