Raoni Fassina Firmino 7f546959b3 powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics ... commit 24321ac668e452a4942598533d267805f291fdc9 upstream. 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 Now this semantics are no longer valid.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 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-02-13 13:55:02 +01:00
..
boot	powerpc/boot: Fix build of dts/fsl	2020-12-30 11:54:01 +01:00
configs	powerpc updates for 5.10	2020-10-16 12:21:15 -07:00
crypto
include	powerpc/64s: fix scv entry fallback flush vs interrupt	2021-01-27 11:55:12 +01:00
kernel	powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics	2021-02-13 13:55:02 +01:00
kexec
kvm	KVM: PPC: Book3S HV: XIVE: Fix vCPU id sanity check	2020-12-01 21:45:51 +11:00
lib	powerpc/64s: fix scv entry fallback flush vs interrupt	2021-01-27 11:55:12 +01:00
math-emu
mm	powerpc/mm: Fix verification of MMU_FTR_TYPE_44x	2020-12-30 11:54:16 +01:00
net
oprofile
perf	powerpc/perf: Exclude kernel samples while counting events in user space.	2020-12-30 11:54:10 +01:00
platforms	powerpc/64: irq replay remove decrementer overflow check	2021-01-06 14:56:54 +01:00
purgatory
sysdev	powerpc: sysdev: add missing iounmap() on error in mpic_msgr_probe()	2021-01-06 14:56:53 +01:00
tools
xmon	powerpc/xmon: Change printk() to pr_cont()	2020-12-30 11:54:16 +01:00
Kbuild
Kconfig	kbuild: Hoist '--orphan-handling' into Kconfig	2020-12-01 22:45:36 +09:00
Kconfig.debug
Makefile	Kbuild fixes for v5.10 (2nd)	2020-12-06 10:31:39 -08:00
Makefile.postlink