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[PATCH 1/5] target/hppa: Fix unaligned double word accesses for hppa64

deller@kernel.org posted 5 patches 8 months, 4 weeks ago
Maintainers: Richard Henderson <richard.henderson@linaro.org>
[PATCH 1/5] target/hppa: Fix unaligned double word accesses for hppa64
Posted by deller@kernel.org 8 months, 4 weeks ago 
From: Guenter Roeck <linux@roeck-us.net>

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.
Clearing bit 32..39 in psw prior to restoring it solves the problem.

Fixes: 931adff31478 ("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>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/hppa/helper.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target/hppa/helper.c b/target/hppa/helper.c
index 859644c47a..7b798d1227 100644
--- a/target/hppa/helper.c
+++ b/target/hppa/helper.c
@@ -76,7 +76,12 @@ void cpu_hppa_put_psw(CPUHPPAState *env, target_ulong psw)
     }
     psw &= ~reserved;
 
-    env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
+    if (hppa_is_pa20(env)) {
+        env->psw = psw & ~(PSW_N | PSW_V | PSW_CB | 0xff00000000ull);
+    } else {
+        env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
+    }
+
     env->psw_n = (psw / PSW_N) & 1;
     env->psw_v = -((psw / PSW_V) & 1);
 
-- 
2.44.0
Re: [PATCH 1/5] target/hppa: Fix unaligned double word accesses for hppa64
Posted by Richard Henderson 8 months, 4 weeks ago 
On 3/2/24 12:35, deller@kernel.org wrote:
> From: Guenter Roeck <linux@roeck-us.net>
> 
> 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.
> Clearing bit 32..39 in psw prior to restoring it solves the problem.
> 
> Fixes: 931adff31478 ("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>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/hppa/helper.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/target/hppa/helper.c b/target/hppa/helper.c
> index 859644c47a..7b798d1227 100644
> --- a/target/hppa/helper.c
> +++ b/target/hppa/helper.c
> @@ -76,7 +76,12 @@ void cpu_hppa_put_psw(CPUHPPAState *env, target_ulong psw)
>       }
>       psw &= ~reserved;
>   
> -    env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
> +    if (hppa_is_pa20(env)) {
> +        env->psw = psw & ~(PSW_N | PSW_V | PSW_CB | 0xff00000000ull);
> +    } else {
> +        env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
> +    }

https://patchew.org/QEMU/20240217015811.1975411-1-linux@roeck-us.net/

was the better version.


r~
Re: [PATCH 1/5] target/hppa: Fix unaligned double word accesses for hppa64
Posted by Helge Deller 8 months, 4 weeks ago 
On 3/3/24 03:10, Richard Henderson wrote:
> On 3/2/24 12:35, deller@kernel.org wrote:
>> From: Guenter Roeck <linux@roeck-us.net>
>>
>> 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.
>> Clearing bit 32..39 in psw prior to restoring it solves the problem.
>>
>> Fixes: 931adff31478 ("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>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   target/hppa/helper.c | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/target/hppa/helper.c b/target/hppa/helper.c
>> index 859644c47a..7b798d1227 100644
>> --- a/target/hppa/helper.c
>> +++ b/target/hppa/helper.c
>> @@ -76,7 +76,12 @@ void cpu_hppa_put_psw(CPUHPPAState *env, target_ulong psw)
>>       }
>>       psw &= ~reserved;
>> -    env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
>> +    if (hppa_is_pa20(env)) {
>> +        env->psw = psw & ~(PSW_N | PSW_V | PSW_CB | 0xff00000000ull);
>> +    } else {
>> +        env->psw = psw & ~(PSW_N | PSW_V | PSW_CB);
>> +    }
>
> https://patchew.org/QEMU/20240217015811.1975411-1-linux@roeck-us.net/
> was the better version.

Oh, yes. Will use that one in the pull request.
Thanks!
Helge

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