5.4-stable review patch. If anyone has any objections, please let me know.
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From: Harald Freudenberger freude@linux.ibm.com
[ Upstream commit 32e8bd6423fc127d2b37bdcf804fd76af3bbec79 ]
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@linux.ibm.com Signed-off-by: Harald Freudenberger freude@linux.ibm.com Reviewed-by: Holger Dengler dengler@linux.ibm.com Reviewed-by: Juergen Christ jchrist@linux.ibm.com Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/include/asm/cpacf.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/s390/include/asm/cpacf.h b/arch/s390/include/asm/cpacf.h index fa31f71cf5746..0f6ff2008a159 100644 --- 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_query(unsigned int opcode, __cpacf_query_rre(CPACF_PRNO, 2, 4, mask); break; default: - BUG(); + __cpacf_bad_opcode(); } }
@@ -257,7 +264,8 @@ static __always_inline int __cpacf_check_opcode(unsigned int opcode) case CPACF_KMA: return test_facility(146); /* check for MSA8 */ default: - BUG(); + __cpacf_bad_opcode(); + return 0; } }