[PATCH v2] LoongArch: Libvtv add loongarch support.

[PATCH v2] LoongArch: Libvtv add loongarch support.

[Lulu Cheng]

v1 - > v2:

1. When the macro __loongarch_lp64 is defined, the VTV_PAGE_SIZE is set to 64K.
2. In the vtv_malloc.cc file __vtv_malloc_init function, it does not check
   whether VTV_PAGE_SIZE is equal to the system page size, if the macro
   __loongarch_lp64 is defined.

All regression tests of libvtv passed.

                === libvtv Summary ===

# of expected passes            176

But I haven't tested the performance yet.

-----------------------------------
Co-Authored-By: qijingwen <qijingwen@loongson.cn>

include/ChangeLog:

	* vtv-change-permission.h (defined):
	(VTV_PAGE_SIZE): Under the loongarch64 architecture,
	set VTV_PAGE_SIZE to 64K.

libvtv/ChangeLog:

	* configure.tgt: Add loongarch support.
	* vtv_malloc.cc (defined): If macro __loongarch_lp64 is
	defined, then don't check whether VTV_PAGE_SIZE is the
	same as the system page size.
---
 include/vtv-change-permission.h | 4 ++++
 libvtv/configure.tgt            | 3 +++
 libvtv/vtv_malloc.cc            | 5 +++++
 3 files changed, 12 insertions(+)

diff --git a/include/vtv-change-permission.h b/include/vtv-change-permission.h
index 70bdad92bca..64e419c29d5 100644
--- a/include/vtv-change-permission.h
+++ b/include/vtv-change-permission.h
@@ -48,6 +48,10 @@ extern void __VLTChangePermission (int);
 #else 
 #if defined(__sun__) && defined(__svr4__) && defined(__sparc__)
 #define VTV_PAGE_SIZE 8192
+/* LoongArch architecture 64-bit system supports 4k,16k and 64k
+   page size, which is set to the maximum value here.  */
+#elif defined(__loongarch_lp64)
+#define VTV_PAGE_SIZE 65536
 #else
 #define VTV_PAGE_SIZE 4096
 #endif
diff --git a/libvtv/configure.tgt b/libvtv/configure.tgt
index aa2a3f675b8..6cdd1e97ab1 100644
--- a/libvtv/configure.tgt
+++ b/libvtv/configure.tgt
@@ -50,6 +50,9 @@ case "${target}" in
 	;;
   x86_64-*-darwin[1]* | i?86-*-darwin[1]*)
 	;;
+  loongarch*-*-linux*)
+	VTV_SUPPORTED=yes
+	;;
   *)
 	;;
 esac
diff --git a/libvtv/vtv_malloc.cc b/libvtv/vtv_malloc.cc
index 67c5de6d4e9..45804b8d7f8 100644
--- a/libvtv/vtv_malloc.cc
+++ b/libvtv/vtv_malloc.cc
@@ -212,6 +212,11 @@ __vtv_malloc_init (void)
 
 #if defined (__CYGWIN__) || defined (__MINGW32__)
   if (VTV_PAGE_SIZE != sysconf_SC_PAGE_SIZE())
+#elif defined (__loongarch_lp64)
+  /* I think that under the LoongArch 64-bit system, VTV_PAGE_SIZE is set
+     to the maximum value of 64K supported by the system, so there is no
+     need to judge here.  */
+  if (false)
 #else
   if (VTV_PAGE_SIZE != sysconf (_SC_PAGE_SIZE))
 #endif
-- 
2.31.1

Re: [PATCH v2] LoongArch: Libvtv add loongarch support.

[Xi Ruoyao]

On Tue, 2022-09-27 at 15:49 +0800, Lulu Cheng wrote:
>  #if defined (__CYGWIN__) || defined (__MINGW32__)
>    if (VTV_PAGE_SIZE != sysconf_SC_PAGE_SIZE())
> +#elif defined (__loongarch_lp64)
> +  /* I think that under the LoongArch 64-bit system, VTV_PAGE_SIZE is set
> +     to the maximum value of 64K supported by the system, so there is no
> +     need to judge here.  */
> +  if (false)

I think "if (false)" can trigger some compiler warnings...

Still not sure if the maximum value is always correct (+ Caroline for a
confirmation).  If it's correct I'd suggest...

>  #else
>    if (VTV_PAGE_SIZE != sysconf (_SC_PAGE_SIZE))

if (VTV_PAGE_SIZE % sysconf (_SC_PAGE_SIZE) != 0)

>  #endif

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

Re: [PATCH v2] LoongArch: Libvtv add loongarch support.

[Lulu Cheng]

在 2022/9/27 下午7:44, Xi Ruoyao 写道:
> On Tue, 2022-09-27 at 15:49 +0800, Lulu Cheng wrote:
>>   #if defined (__CYGWIN__) || defined (__MINGW32__)
>>     if (VTV_PAGE_SIZE != sysconf_SC_PAGE_SIZE())
>> +#elif defined (__loongarch_lp64)
>> +  /* I think that under the LoongArch 64-bit system, VTV_PAGE_SIZE is set
>> +     to the maximum value of 64K supported by the system, so there is no
>> +     need to judge here.  */
>> +  if (false)
> I think "if (false)" can trigger some compiler warnings...
>
> Still not sure if the maximum value is always correct (+ Caroline for a
> confirmation).  If it's correct I'd suggest...
>
>>   #else
>>     if (VTV_PAGE_SIZE != sysconf (_SC_PAGE_SIZE))
> if (VTV_PAGE_SIZE % sysconf (_SC_PAGE_SIZE) != 0)


If the setting to the maximum value is correct,

I also think it is better to achieve this.

>
>>   #endif

Re: [PATCH v2] LoongArch: Libvtv add loongarch support.

[Xi Ruoyao]

On Mon, 2022-10-10 at 10:49 -0700, Caroline Tice via Gcc-patches wrote:
> Is "if (VTV_PAGE_SIZE != sysconf (_SC_PAGE_SIZE))" going to fail for
> loongarch?

Because LoongArch systems may have 4KB, 16KB, or 64KB pages.

> If not, why do you need to insert anything here at all?  If so,
> perhaps you could write something similar to sysconf_SC_PAGE_SIZE for
> loongarch (as was done for __CYGWIN__ & __MINGW32__)?

I'd like to ask a question: if we set VTV_PAGE_SIZE to 64KB and make the
special case, will libvtv work for 4KB and 16KB pages?  (If I read code
correctly, setting VTV_PAGE_SIZE to 4KB will obviously break 16KB or
64KB configuration.)

If VTV_PAGE_SIZE == sysconf (_SC_PAGE_SIZE) is strictly required for
libvtv we'll have to keep the check as-is and then we'll only support
16KB page configuration (which is the default in Linux kernel
configuration for LoongArch).

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University