From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/arch/powerpc/kernel/vdso64/sigtramp.S | 28 +++++++++++++++-------------
1 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/kernel/arch/powerpc/kernel/vdso64/sigtramp.S b/kernel/arch/powerpc/kernel/vdso64/sigtramp.S
index 542c6f4..2d40675 100644
--- a/kernel/arch/powerpc/kernel/vdso64/sigtramp.S
+++ b/kernel/arch/powerpc/kernel/vdso64/sigtramp.S
@@ -1,15 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Signal trampoline for 64 bits processes in a ppc64 kernel for
* use in the vDSO
*
* Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), IBM Corp.
* Copyright (C) 2004 Alan Modra (amodra@au.ibm.com)), IBM Corp.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
*/
+#include <asm/cache.h> /* IFETCH_ALIGN_BYTES */
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/unistd.h>
@@ -18,21 +15,26 @@
.text
-/* The nop here is a hack. The dwarf2 unwind routines subtract 1 from
- the return address to get an address in the middle of the presumed
- call instruction. Since we don't have a call here, we artificially
- extend the range covered by the unwind info by padding before the
- real start. */
- nop
+/*
+ * __kernel_start_sigtramp_rt64 and __kernel_sigtramp_rt64 together
+ * are one function split in two parts. The kernel jumps to the former
+ * and the signal handler indirectly (by blr) returns to the latter.
+ * __kernel_sigtramp_rt64 needs to point to the return address so
+ * glibc can correctly identify the trampoline stack frame.
+ */
.balign 8
+ .balign IFETCH_ALIGN_BYTES
+V_FUNCTION_BEGIN(__kernel_start_sigtramp_rt64)
+.Lsigrt_start:
+ bctrl /* call the handler */
+V_FUNCTION_END(__kernel_start_sigtramp_rt64)
V_FUNCTION_BEGIN(__kernel_sigtramp_rt64)
-.Lsigrt_start = . - 4
addi r1, r1, __SIGNAL_FRAMESIZE
li r0,__NR_rt_sigreturn
sc
.Lsigrt_end:
V_FUNCTION_END(__kernel_sigtramp_rt64)
-/* The ".balign 8" above and the following zeros mimic the old stack
+/* The .balign 8 above and the following zeros mimic the old stack
trampoline layout. The last magic value is the ucontext pointer,
chosen in such a way that older libgcc unwind code returns a zero
for a sigcontext pointer. */
--
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