diff mbox series

[v4,26/35] s390/diag: Unpoison diag224() output buffer

Message ID 20240613153924.961511-27-iii@linux.ibm.com (mailing list archive)
State New
Headers show
Series kmsan: Enable on s390 | expand

Commit Message

Ilya Leoshkevich June 13, 2024, 3:34 p.m. UTC 
Diagnose 224 stores 4k bytes, which currently cannot be deduced from
the inline assembly constraints. This leads to KMSAN false positives.

Fix the constraints by using a 4k-sized struct instead of a raw
pointer. While at it, prettify them too.

Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 arch/s390/kernel/diag.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

Alexander Potapenko June 18, 2024, 9:26 a.m. UTC | #1 
On Thu, Jun 13, 2024 at 5:40 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>
> Diagnose 224 stores 4k bytes, which currently cannot be deduced from
> the inline assembly constraints. This leads to KMSAN false positives.
>
> Fix the constraints by using a 4k-sized struct instead of a raw
> pointer. While at it, prettify them too.
>
> Suggested-by: Heiko Carstens <hca@linux.ibm.com>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
diff mbox series

Patch

diff --git a/arch/s390/kernel/diag.c b/arch/s390/kernel/diag.c
index 8dee9aa0ec95..8a7009618ba7 100644
--- a/arch/s390/kernel/diag.c
+++ b/arch/s390/kernel/diag.c
@@ -278,12 +278,14 @@  int diag224(void *ptr)
 	int rc = -EOPNOTSUPP;
 
 	diag_stat_inc(DIAG_STAT_X224);
-	asm volatile(
-		"	diag	%1,%2,0x224\n"
-		"0:	lhi	%0,0x0\n"
+	asm volatile("\n"
+		"	diag	%[type],%[addr],0x224\n"
+		"0:	lhi	%[rc],0\n"
 		"1:\n"
 		EX_TABLE(0b,1b)
-		: "+d" (rc) :"d" (0), "d" (addr) : "memory");
+		: [rc] "+d" (rc)
+		, "=m" (*(struct { char buf[PAGE_SIZE]; } *)ptr)
+		: [type] "d" (0), [addr] "d" (addr));
 	return rc;
 }
 EXPORT_SYMBOL(diag224);