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Date: Sun, 14 Apr 2024 12:51:17 +0000
From: "Nick Hudson" <skrll@netbsd.org>
Subject: CVS commit: src/sys/arch/aarch64/aarch64
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Module Name:	src
Committed By:	skrll
Date:		Sun Apr 14 12:51:17 UTC 2024

Modified Files:
	src/sys/arch/aarch64/aarch64: cpu_machdep.c sig_machdep.c

Log Message:
kern/58149: aarch64: Cannot return from a signal handler if SP was misaligned when the signal arrived

Apply the kernel diff from the PR

1. sendsig_siginfo() previously assumed that user SP was always aligned to
   16 bytes and could call signal handlers with SP misaligned. This is a
   wrong assumption because aarch64 demands that SP is aligned *only while*
   it's being used to access memory. Now it properly aligns it before
   pusing anything on the stack.

2. cpu_mcontext_validate() used to check if _REG_SP was aligned and
   considered the ucontext invalid otherwise. This meant if a signal was
   sent to a process whose SP was misaligned, the signal handler would fail
   to return because the ucontext passed from the kernel was an invalid
   one. Now setcontext(2) doesn't complain about misaligned SP.


To generate a diff of this commit:
cvs rdiff -u -r1.14 -r1.15 src/sys/arch/aarch64/aarch64/cpu_machdep.c
cvs rdiff -u -r1.8 -r1.9 src/sys/arch/aarch64/aarch64/sig_machdep.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.