[PATCH 5.15 212/279] Revert "parisc: Reduce sigreturn trampoline to 3 instructions"

Greg Kroah-Hartman
2021-11-24T14:01:57Z

From: Helge Deller <deller@gmx.de>

commit 79df39d535c7a3770856fe9f5aba8c0ad1eebdb6 upstream.

This reverts commit e4f2006f1287e7ea17660490569cff323772dac4.

This patch shows problems with signal handling. Revert it for now.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.15
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/parisc/include/asm/rt_sigframe.h | 2 +-
arch/parisc/kernel/signal.c | 13 +++++++------
arch/parisc/kernel/signal32.h | 2 +-
3 files changed, 9 insertions(+), 8 deletions(-)

--- a/arch/parisc/include/asm/rt_sigframe.h
+++ b/arch/parisc/include/asm/rt_sigframe.h
@@ -2,7 +2,7 @@
#ifndef _ASM_PARISC_RT_SIGFRAME_H
#define _ASM_PARISC_RT_SIGFRAME_H

-#define SIGRETURN_TRAMP 3
+#define SIGRETURN_TRAMP 4
#define SIGRESTARTBLOCK_TRAMP 5
#define TRAMP_SIZE (SIGRETURN_TRAMP + SIGRESTARTBLOCK_TRAMP)

--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -288,21 +288,22 @@ setup_rt_frame(struct ksignal *ksig, sig
already in userspace. The first words of tramp are used to
save the previous sigrestartblock trampoline that might be
on the stack. We start the sigreturn trampoline at
- SIGRESTARTBLOCK_TRAMP. */
+ SIGRESTARTBLOCK_TRAMP+X. */
err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
&frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
- err |= __put_user(INSN_BLE_SR2_R0,
+ err |= __put_user(INSN_LDI_R20,
&frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
- err |= __put_user(INSN_LDI_R20,
+ err |= __put_user(INSN_BLE_SR2_R0,
&frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
+ err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);

- start = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP+0];
- end = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP+3];
+ start = (unsigned long) &frame->tramp[0];
+ end = (unsigned long) &frame->tramp[TRAMP_SIZE];
flush_user_dcache_range_asm(start, end);
flush_user_icache_range_asm(start, end);

/* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
- * TRAMP Words 5-7, Length 3 = SIGRETURN_TRAMP
+ * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
* So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
*/
rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
--- a/arch/parisc/kernel/signal32.h
+++ b/arch/parisc/kernel/signal32.h
@@ -36,7 +36,7 @@ struct compat_regfile {
compat_int_t rf_sar;
};

-#define COMPAT_SIGRETURN_TRAMP 3
+#define COMPAT_SIGRETURN_TRAMP 4
#define COMPAT_SIGRESTARTBLOCK_TRAMP 5
#define COMPAT_TRAMP_SIZE (COMPAT_SIGRETURN_TRAMP + \
COMPAT_SIGRESTARTBLOCK_TRAMP)