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s390/cpacf: Make use of invalid opcode produce a link error

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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@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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Harald Freudenberger 2024-05-14 10:09:32 +02:00 committed by Greg Kroah-Hartman
parent edaaf1f94e
commit 08de19f2b7
1 changed files with 10 additions and 2 deletions
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12
arch/s390/include/asm/cpacf.h
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@ -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;
}
}