* [PATCH v2 09/14] powerpc: Add NULLIFY_GPRS macros for register clears
@ 2022-07-25 6:29 Rohan McLure
2022-08-08 7:42 ` Andrew Donnellan
0 siblings, 1 reply; 3+ messages in thread
From: Rohan McLure @ 2022-07-25 6:29 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Rohan McLure, npiggin
Macros for restoring and saving registers to and from the stack exist.
Provide macros with the same interface for clearing a range of gprs by
setting each register's value in that range to zero.
The resulting macros are called NULLIFY_GPRS and NULLIFY_NVGPRS, keeping
with the naming of the accompanying restore and save macros, and usage
of nullify to describe this operation elsewhere in the kernel.
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
---
V1 -> V2: Change 'ZERO' usage in naming to 'NULLIFY', a more obvious verb
---
arch/powerpc/include/asm/ppc_asm.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 83c02f5a7f2a..d6c46082bf7f 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -33,6 +33,20 @@
.endr
.endm
+/*
+ * This expands to a sequence of register clears for regs start to end
+ * inclusive, of the form:
+ *
+ * li rN, 0
+ */
+.macro NULLIFY_REGS start, end
+ .Lreg=\start
+ .rept (\end - \start + 1)
+ li .Lreg, 0
+ .Lreg=.Lreg+1
+ .endr
+.endm
+
/*
* Macros for storing registers into and loading registers from
* exception frames.
@@ -49,6 +63,14 @@
#define REST_NVGPRS(base) REST_GPRS(13, 31, base)
#endif
+#define NULLIFY_GPRS(start, end) NULLIFY_REGS start, end
+#ifdef __powerpc64__
+#define NULLIFY_NVGPRS() NULLIFY_GPRS(14, 31)
+#else
+#define NULLIFY_NVGPRS() NULLIFY_GPRS(13, 31)
+#endif
+#define NULLIFY_GPR(n) NULLIFY_GPRS(n, n)
+
#define SAVE_GPR(n, base) SAVE_GPRS(n, n, base)
#define REST_GPR(n, base) REST_GPRS(n, n, base)
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2 09/14] powerpc: Add NULLIFY_GPRS macros for register clears
2022-07-25 6:29 [PATCH v2 09/14] powerpc: Add NULLIFY_GPRS macros for register clears Rohan McLure
@ 2022-08-08 7:42 ` Andrew Donnellan
2022-08-08 10:55 ` Christophe Leroy
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Donnellan @ 2022-08-08 7:42 UTC (permalink / raw)
To: Rohan McLure, linuxppc-dev; +Cc: npiggin
On Mon, 2022-07-25 at 16:29 +1000, Rohan McLure wrote:
> Macros for restoring and saving registers to and from the stack
> exist.
> Provide macros with the same interface for clearing a range of gprs
> by
> setting each register's value in that range to zero.
>
> The resulting macros are called NULLIFY_GPRS and NULLIFY_NVGPRS,
> keeping
> with the naming of the accompanying restore and save macros, and
> usage
> of nullify to describe this operation elsewhere in the kernel.
>
> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
> ---
> V1 -> V2: Change 'ZERO' usage in naming to 'NULLIFY', a more obvious
> verb
And I see you've addressed my comment re 32 v 64 bit from V1 as well.
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> arch/powerpc/include/asm/ppc_asm.h | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/ppc_asm.h
> b/arch/powerpc/include/asm/ppc_asm.h
> index 83c02f5a7f2a..d6c46082bf7f 100644
> --- a/arch/powerpc/include/asm/ppc_asm.h
> +++ b/arch/powerpc/include/asm/ppc_asm.h
> @@ -33,6 +33,20 @@
> .endr
> .endm
>
> +/*
> + * This expands to a sequence of register clears for regs start to
> end
> + * inclusive, of the form:
> + *
> + * li rN, 0
> + */
> +.macro NULLIFY_REGS start, end
> + .Lreg=\start
> + .rept (\end - \start + 1)
> + li .Lreg, 0
> + .Lreg=.Lreg+1
> + .endr
> +.endm
> +
I suppose this could be done using the existing OP_REGS macro,
something like OP_REGS li, 0, start, end, 0, 0 - but a load immediate
is semantically a bit different from the existing uses of OP_REGS so I
don't mind either way
> /*
> * Macros for storing registers into and loading registers from
> * exception frames.
> @@ -49,6 +63,14 @@
> #define REST_NVGPRS(base) REST_GPRS(13, 31, base)
> #endif
>
> +#define NULLIFY_GPRS(start, end) NULLIFY_REGS start,
> end
> +#ifdef __powerpc64__
> +#define NULLIFY_NVGPRS() NULLIFY_GPRS(14, 31)
> +#else
> +#define NULLIFY_NVGPRS() NULLIFY_GPRS(13, 31)
> +#endif
> +#define NULLIFY_GPR(n) NULLIFY_GPRS(n, n)
> +
> #define SAVE_GPR(n, base) SAVE_GPRS(n, n, base)
> #define REST_GPR(n, base) REST_GPRS(n, n, base)
>
--
Andrew Donnellan OzLabs, ADL Canberra
ajd@linux.ibm.com IBM Australia Limited
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2 09/14] powerpc: Add NULLIFY_GPRS macros for register clears
2022-08-08 7:42 ` Andrew Donnellan
@ 2022-08-08 10:55 ` Christophe Leroy
0 siblings, 0 replies; 3+ messages in thread
From: Christophe Leroy @ 2022-08-08 10:55 UTC (permalink / raw)
To: Andrew Donnellan, Rohan McLure, linuxppc-dev@lists.ozlabs.org
Cc: npiggin@gmail.com
Le 08/08/2022 à 09:42, Andrew Donnellan a écrit :
> On Mon, 2022-07-25 at 16:29 +1000, Rohan McLure wrote:
>> Macros for restoring and saving registers to and from the stack
>> exist.
>> Provide macros with the same interface for clearing a range of gprs
>> by
>> setting each register's value in that range to zero.
>>
>> The resulting macros are called NULLIFY_GPRS and NULLIFY_NVGPRS,
>> keeping
>> with the naming of the accompanying restore and save macros, and
>> usage
>> of nullify to describe this operation elsewhere in the kernel.
>>
>> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
>> ---
>> V1 -> V2: Change 'ZERO' usage in naming to 'NULLIFY', a more obvious
>> verb
>
> And I see you've addressed my comment re 32 v 64 bit from V1 as well.
>
> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
>
>> ---
>> arch/powerpc/include/asm/ppc_asm.h | 22 ++++++++++++++++++++++
>> 1 file changed, 22 insertions(+)
>>
>> diff --git a/arch/powerpc/include/asm/ppc_asm.h
>> b/arch/powerpc/include/asm/ppc_asm.h
>> index 83c02f5a7f2a..d6c46082bf7f 100644
>> --- a/arch/powerpc/include/asm/ppc_asm.h
>> +++ b/arch/powerpc/include/asm/ppc_asm.h
>> @@ -33,6 +33,20 @@
>> .endr
>> .endm
>>
>> +/*
>> + * This expands to a sequence of register clears for regs start to
>> end
>> + * inclusive, of the form:
>> + *
>> + * li rN, 0
>> + */
>> +.macro NULLIFY_REGS start, end
>> + .Lreg=\start
>> + .rept (\end - \start + 1)
>> + li .Lreg, 0
>> + .Lreg=.Lreg+1
>> + .endr
>> +.endm
>> +
>
> I suppose this could be done using the existing OP_REGS macro,
> something like OP_REGS li, 0, start, end, 0, 0 - but a load immediate
> is semantically a bit different from the existing uses of OP_REGS so I
> don't mind either way
Not sure it would work. You'd get:
li .Lreg, 0 + 0 * .Lreg(0)
Even if it works that would be odd.
>
>> /*
>> * Macros for storing registers into and loading registers from
>> * exception frames.
>> @@ -49,6 +63,14 @@
>> #define REST_NVGPRS(base) REST_GPRS(13, 31, base)
>> #endif
>>
>> +#define NULLIFY_GPRS(start, end) NULLIFY_REGS start,
>> end
>> +#ifdef __powerpc64__
>> +#define NULLIFY_NVGPRS() NULLIFY_GPRS(14, 31)
>> +#else
>> +#define NULLIFY_NVGPRS() NULLIFY_GPRS(13, 31)
>> +#endif
>> +#define NULLIFY_GPR(n) NULLIFY_GPRS(n, n)
>> +
>> #define SAVE_GPR(n, base) SAVE_GPRS(n, n, base)
>> #define REST_GPR(n, base) REST_GPRS(n, n, base)
>>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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