From: Sven Schnelle <svens@stackframe.org>
Date: Wed, 15 Oct 2025 21:21:41 +0000 (+0200)
Subject: parisc: entry: set W bit for !compat tasks in syscall_restore_rfi()
X-Git-Tag: v6.12.64~176
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2aa65e353fb542385df91bf2402eaf53d88cea9d;p=thirdparty%2Fkernel%2Fstable.git

parisc: entry: set W bit for !compat tasks in syscall_restore_rfi()

commit 5fb1d3ce3e74a4530042795e1e065422295f1371 upstream.

When the kernel leaves to userspace via syscall_restore_rfi(), the
W bit is not set in the new PSW. This doesn't cause any problems
because there's no 64 bit userspace for parisc. Simple static binaries
are usually loaded at addresses way below the 32 bit limit so the W bit
doesn't matter.

Fix this by setting the W bit when TIF_32BIT is not set.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/parisc/kernel/asm-offsets.c b/arch/parisc/kernel/asm-offsets.c
index 9abfe65492c65..3de4b5933b107 100644
--- a/arch/parisc/kernel/asm-offsets.c
+++ b/arch/parisc/kernel/asm-offsets.c
@@ -258,6 +258,8 @@ int main(void)
 	BLANK();
 	DEFINE(TIF_BLOCKSTEP_PA_BIT, 31-TIF_BLOCKSTEP);
 	DEFINE(TIF_SINGLESTEP_PA_BIT, 31-TIF_SINGLESTEP);
+	DEFINE(TIF_32BIT_PA_BIT, 31-TIF_32BIT);
+
 	BLANK();
 	DEFINE(ASM_PMD_SHIFT, PMD_SHIFT);
 	DEFINE(ASM_PGDIR_SHIFT, PGDIR_SHIFT);
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index bb383487e302d..e04c5d806c105 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -1846,6 +1846,10 @@ syscall_restore_rfi:
 	extru,= %r19,TIF_BLOCKSTEP_PA_BIT,1,%r0
 	depi	-1,7,1,%r20			   /* T bit */
 
+#ifdef CONFIG_64BIT
+	extru,<> %r19,TIF_32BIT_PA_BIT,1,%r0
+	depi	-1,4,1,%r20			   /* W bit */
+#endif
 	STREG	%r20,TASK_PT_PSW(%r1)
 
 	/* Always store space registers, since sr3 can be changed (e.g. fork) */
@@ -1859,7 +1863,6 @@ syscall_restore_rfi:
 	STREG   %r25,TASK_PT_IASQ0(%r1)
 	STREG   %r25,TASK_PT_IASQ1(%r1)
 
-	/* XXX W bit??? */
 	/* Now if old D bit is clear, it means we didn't save all registers
 	 * on syscall entry, so do that now.  This only happens on TRACEME
 	 * calls, or if someone attached to us while we were on a syscall.