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target: hppa: Fix unaligned double word accesses for hppa64

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Unaligned 64-bit accesses were found in Linux to clobber carry bits,
resulting in bad results if an arithmetic operation involving a
carry bit was executed after an unaligned 64-bit operation.

hppa 2.0 defines additional carry bits in PSW register bits 32..39.
When restoring PSW after executing an unaligned instruction trap, those
bits were not cleared and ended up to be active all the time. Since there
are no bits other than the upper carry bits needed in the upper 32 bit of
env->psw and since those are stored in env->psw_cb, just clear the entire
upper 32 bit when storing psw to solve the problem unconditionally.

Fixes: 931adff314 ("target/hppa: Update cpu_hppa_get/put_psw for hppa64")
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Charlie Jenkins <charlie@rivosinc.com>
Cc: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Guenter Roeck 2024-02-16 17:58:11 -08:00 committed by Helge Deller
parent e1007b6bab
commit a9bdc4c95e
1 changed files with 2 additions and 1 deletions
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3
target/hppa/helper.c
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@ -76,7 +76,8 @@ void cpu_hppa_put_psw(CPUHPPAState *env, target_ulong psw)
}
psw &= ~reserved;
env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
env->psw = psw & (uint32_t)~(PSW_N | PSW_V | PSW_CB);
env->psw_n = (psw / PSW_N) & 1;
env->psw_v = -((psw / PSW_V) & 1);