From: Harald Freudenberger <freude@xxxxxxxxxxxxx>
commit 32e8bd6423fc127d2b37bdcf804fd76af3bbec79 upstream.
Instead of calling BUG() at runtime introduce and use a prototype for a
non-existing function to produce a link error during compile when a not
supported opcode is used with the __cpacf_query() or __cpacf_check_opcode()
inline functions.
Suggested-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxx>
Reviewed-by: Holger Dengler <dengler@xxxxxxxxxxxxx>
Reviewed-by: Juergen Christ <jchrist@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/include/asm/cpacf.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/arch/s390/include/asm/cpacf.h
+++ b/arch/s390/include/asm/cpacf.h
@@ -161,6 +161,13 @@
typedef struct { unsigned char bytes[16]; } cpacf_mask_t;
+/*
+ * Prototype for a not existing function to produce a link
+ * error if __cpacf_query() or __cpacf_check_opcode() is used
+ * with an invalid compile time const opcode.
+ */
+void __cpacf_bad_opcode(void);
+
static __always_inline void __cpacf_query_rre(u32 opc, u8 r1, u8 r2,
cpacf_mask_t *mask)
{
@@ -232,7 +239,7 @@ static __always_inline void __cpacf_quer
__cpacf_query_rre(CPACF_PRNO, 2, 4, mask);
break;
default:
- BUG();
+ __cpacf_bad_opcode();
}
}
@@ -257,7 +264,8 @@ static __always_inline int __cpacf_check
case CPACF_KMA:
return test_facility(146); /* check for MSA8 */
default:
- BUG();
+ __cpacf_bad_opcode();
+ return 0;
}
}
Patches currently in stable-queue which might be from freude@xxxxxxxxxxxxx are
queue-5.15/s390-ap-fix-crash-in-ap-internal-function-modify_bitmap.patch
queue-5.15/s390-cpacf-make-use-of-invalid-opcode-produce-a-link-error.patch
queue-5.15/s390-cpacf-split-and-rework-cpacf-query-functions.patch
