Raoni Fassina Firmino 24321ac668 powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics ... Commit 0138ba5783 ("powerpc/64/signal: Balance return predictor stack in signal trampoline") changed __kernel_sigtramp_rt64() VDSO and trampoline code, and introduced a regression in the way glibc's backtrace()[1] detects the signal-handler stack frame. Apart from the practical implications, __kernel_sigtramp_rt64() was a VDSO function with the semantics that it is a function you can call from userspace to end a signal handling. Now this semantics are no longer valid. I believe the aforementioned change affects all releases since 5.9. This patch tries to fix both the semantics and practical aspect of __kernel_sigtramp_rt64() returning it to the previous code, whilst keeping the intended behaviour of 0138ba5783 by adding a new symbol to serve as the jump target from the kernel to the trampoline. Now the trampoline has two parts, a new entry point and the old return point. [1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-January/223194.html Fixes: 0138ba5783 ("powerpc/64/signal: Balance return predictor stack in signal trampoline") Cc: stable@vger.kernel.org # v5.9+ Signed-off-by: Raoni Fassina Firmino <raoni@linux.ibm.com> Acked-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Minor tweaks to change log formatting, add stable tag] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210201200505.iz46ubcizipnkcxe@work-tp		2021-02-02 22:14:41 +11:00
..
.gitignore	.gitignore: add SPDX License Identifier	2020-03-25 11:50:48 +01:00
cacheflush.S	powerpc/vdso: Merge __kernel_sync_dicache_p5() into __kernel_sync_dicache()	2020-12-04 01:01:17 +11:00
datapage.S	powerpc/vdso: Remove __kernel_datapage_offset	2020-12-04 01:01:18 +11:00
gen_vdso_offsets.sh	powerpc/vdso: Retrieve sigtramp offsets at buildtime	2020-12-04 01:01:17 +11:00
getcpu.S	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156	2019-05-30 11:26:35 -07:00
gettimeofday.S	powerpc/vdso: Switch VDSO to generic C implementation.	2020-12-04 01:01:10 +11:00
Makefile	powerpc/vdso64: remove meaningless vgettimeofday.o build rule	2021-01-30 22:23:42 +11:00
note.S
sigtramp.S	powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics	2021-02-02 22:14:41 +11:00
vdso64.lds.S	powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics	2021-02-02 22:14:41 +11:00
vgettimeofday.c	powerpc/vdso: Prepare for switching VDSO to generic C implementation.	2020-12-04 01:01:10 +11:00