[PATCH 0/3] selftests/powerpc: Transactional Memory

[PATCH 0/3] selftests/powerpc: Transactional Memory

[Rashmica Gupta]

This is reliant on the following patch series:
- selftests/powerpc by Michael Ellerman 
- selftests/powerpc by Michael Neuling 
- powerpc/tm by Michael Neuling 

Rashmica Gupta (3):
  selftests/powerpc: Standardise TM calls
  selftests/powerpc: Add test for forking inside transaction
  selftests/powerpc: Add in check for TM

 tools/testing/selftests/powerpc/tm/.gitignore      |  1 +
 tools/testing/selftests/powerpc/tm/Makefile        |  2 +-
 tools/testing/selftests/powerpc/tm/tm-fork.c       | 41 ++++++++++++++++++++++
 .../testing/selftests/powerpc/tm/tm-resched-dscr.c | 18 +++++-----
 .../testing/selftests/powerpc/tm/tm-signal-stack.c |  4 +--
 5 files changed, 53 insertions(+), 13 deletions(-)
 create mode 100644 tools/testing/selftests/powerpc/tm/tm-fork.c

-- 
2.5.0

[PATCH 1/3] selftests/powerpc: Standardise TM calls

[Rashmica Gupta]

Currently tbegin, tend etc are written as opcodes or asm instructions. So
standardise these to asm instructions.

Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
---
 tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 16 ++++++----------
 tools/testing/selftests/powerpc/tm/tm-signal-stack.c |  4 ++--
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
index 42d4c8caad81..88c46481e59b 100644
--- a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
+++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
@@ -29,12 +29,8 @@
 #include <asm/tm.h>
 
 #include "utils.h"
+#include "tm.h"
 
-#define TBEGIN          ".long 0x7C00051D ;"
-#define TEND            ".long 0x7C00055D ;"
-#define TCHECK          ".long 0x7C00059C ;"
-#define TSUSPEND        ".long 0x7C0005DD ;"
-#define TRESUME         ".long 0x7C2005DD ;"
 #define SPRN_TEXASR     0x82
 #define SPRN_DSCR       0x03
 
@@ -52,13 +48,13 @@ int test_body(void)
 			"mtspr   %[sprn_dscr], 3;"
 
 			/* start and suspend a transaction */
-			TBEGIN
+			"tbegin.;"
 			"beq     1f;"
-			TSUSPEND
+			"tsuspend.;"
 
 			/* hard loop until the transaction becomes doomed */
 			"2: ;"
-			TCHECK
+			"tcheck 0;"
 			"bc      4, 0, 2b;"
 
 			/* record DSCR and TEXASR */
@@ -67,8 +63,8 @@ int test_body(void)
 			"mfspr   3, %[sprn_texasr];"
 			"std     3, %[texasr];"
 
-			TRESUME
-			TEND
+			"tresume.;"
+			"tend.;"
 			"li      %[rv], 0;"
 			"1: ;"
 			: [rv]"=r"(rv), [dscr2]"=m"(dscr2), [texasr]"=m"(texasr)
diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-stack.c b/tools/testing/selftests/powerpc/tm/tm-signal-stack.c
index 82c29cb222dc..8ffd5cee7271 100644
--- a/tools/testing/selftests/powerpc/tm/tm-signal-stack.c
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-stack.c
@@ -60,9 +60,9 @@ int tm_signal_stack()
 		exit(1);
 	asm volatile("li 1, 0 ;"		/* stack ptr == NULL */
 		     "1:"
-		     ".long 0x7C00051D ;"	/* tbegin */
+		     "tbegin.;"
 		     "beq 1b ;"			/* retry forever */
-		     ".long 0x7C0005DD ; ;"	/* tsuspend */
+		     "tsuspend.;"	
 		     "ld 2, 0(1) ;"		/* trigger segv" */
 		     : : : "memory");
 
-- 
2.5.0

Re: [PATCH 1/3] selftests/powerpc: Standardise TM calls

[Anshuman Khandual]

On 12/01/2015 10:38 AM, Rashmica Gupta wrote:
> Currently tbegin, tend etc are written as opcodes or asm instructions. So
> standardise these to asm instructions.

I think the asm instructions can be used with only newer versions of GCC.
But not sure, does it work with the older gcc as well ?

Re: [PATCH 1/3] selftests/powerpc: Standardise TM calls

[Michael Ellerman]

On Tue, 2015-12-01 at 13:38 +0530, Anshuman Khandual wrote:
> On 12/01/2015 10:38 AM, Rashmica Gupta wrote:
> > Currently tbegin, tend etc are written as opcodes or asm instructions. So
> > standardise these to asm instructions.
> 
> I think the asm instructions can be used with only newer versions of GCC.
> But not sure, does it work with the older gcc as well ?

No they don't work with all versions of GCC.

The HTM instructions were added in 4.9 AFAICS, but also backported to 4.8. That
seems old enough to me.

Also we have another test (tm-syscall) which is already using the tbegin
instruction, and no one has complained, so I don't think anyone is trying to
build the selftests with really old compilers.

cheers

Re: [PATCH 1/3] selftests/powerpc: Standardise TM calls

[Anshuman Khandual]

On 12/02/2015 09:10 AM, Michael Ellerman wrote:
> On Tue, 2015-12-01 at 13:38 +0530, Anshuman Khandual wrote:
>> > On 12/01/2015 10:38 AM, Rashmica Gupta wrote:
>>> > > Currently tbegin, tend etc are written as opcodes or asm instructions. So
>>> > > standardise these to asm instructions.
>> > 
>> > I think the asm instructions can be used with only newer versions of GCC.
>> > But not sure, does it work with the older gcc as well ?
> No they don't work with all versions of GCC.
> 
> The HTM instructions were added in 4.9 AFAICS, but also backported to 4.8. That
> seems old enough to me.
> 
> Also we have another test (tm-syscall) which is already using the tbegin
> instruction, and no one has complained, so I don't think anyone is trying to
> build the selftests with really old compilers.

Its only a concern if you try to build these self tests on some older distro.
But then some other self tests dont build there because of lack of newer
compiler options. Its generic problem not something specific to this test.

[PATCH 2/3] selftests/powerpc: Add test for forking inside transaction

[Rashmica Gupta]

This test does a fork syscall inside a transaction. Basic sniff test to see
if we can enter the kernel during a transaction.

Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
---
 tools/testing/selftests/powerpc/tm/.gitignore |  1 +
 tools/testing/selftests/powerpc/tm/Makefile   |  2 +-
 tools/testing/selftests/powerpc/tm/tm-fork.c  | 41 +++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/powerpc/tm/tm-fork.c

diff --git a/tools/testing/selftests/powerpc/tm/.gitignore b/tools/testing/selftests/powerpc/tm/.gitignore
index e6668217ccd0..d0c7c97e9b13 100644
--- a/tools/testing/selftests/powerpc/tm/.gitignore
+++ b/tools/testing/selftests/powerpc/tm/.gitignore
@@ -2,3 +2,4 @@ tm-resched-dscr
 tm-syscall
 tm-signal-msr-resv
 tm-signal-stack
+tm-fork
diff --git a/tools/testing/selftests/powerpc/tm/Makefile b/tools/testing/selftests/powerpc/tm/Makefile
index 578572a3700a..f7d4727662aa 100644
--- a/tools/testing/selftests/powerpc/tm/Makefile
+++ b/tools/testing/selftests/powerpc/tm/Makefile
@@ -1,4 +1,4 @@
-TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack
+TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack tm-fork
 
 all: $(TEST_PROGS)
 
diff --git a/tools/testing/selftests/powerpc/tm/tm-fork.c b/tools/testing/selftests/powerpc/tm/tm-fork.c
new file mode 100644
index 000000000000..f571a48a59a0
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-fork.c
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2015, Michael Neuling, IBM Corp.
+ * Licensed under GPLv2.
+ *
+ * Edited: Rashmica Gupta, Nov 2015
+ *
+ * Fork inside a transaction
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "utils.h"
+#include "tm.h"
+
+int test_fork(void)
+{
+	SKIP_IF(!have_htm());
+
+	asm __volatile__(
+		"tbegin.;"
+		"blt    1f; "
+		"li     0, 2;"  /* fork syscall */
+		"sc  ;"
+		"tend.;"
+		"1: ;"
+		: : : "memory", "r0");
+	/* If we reach here, we've passed.  Otherwise we've probably crashed
+	 * the kernel */
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	return test_harness(test_fork, "tm_fork");
+}
-- 
2.5.0

Re: [PATCH 2/3] selftests/powerpc: Add test for forking inside transaction

[Anshuman Khandual]

On 12/01/2015 10:38 AM, Rashmica Gupta wrote:
> +int test_fork(void)
> +{
> +	SKIP_IF(!have_htm());
> +
> +	asm __volatile__(
> +		"tbegin.;"
> +		"blt    1f; "
> +		"li     0, 2;"  /* fork syscall */
> +		"sc  ;"
> +		"tend.;"
> +		"1: ;"
> +		: : : "memory", "r0");
> +	/* If we reach here, we've passed.  Otherwise we've probably crashed
> +	 * the kernel */

The transaction inside the parent process will abort. What
is expected inside the child process ? Why should the kernel
crash ?

Re: [PATCH 2/3] selftests/powerpc: Add test for forking inside transaction

[Rashmica]

As far as I'm aware, the kernel used to crash when forking inside a 
transaction (see powerpc/tm: Fix crash when forking inside a 
transaction). So this is to check that the transaction aborts rather 
than your whole kernel crashing.

On 01/12/15 19:11, Anshuman Khandual wrote:
> On 12/01/2015 10:38 AM, Rashmica Gupta wrote:
>> +int test_fork(void)
>> +{
>> +	SKIP_IF(!have_htm());
>> +
>> +	asm __volatile__(
>> +		"tbegin.;"
>> +		"blt    1f; "
>> +		"li     0, 2;"  /* fork syscall */
>> +		"sc  ;"
>> +		"tend.;"
>> +		"1: ;"
>> +		: : : "memory", "r0");
>> +	/* If we reach here, we've passed.  Otherwise we've probably crashed
>> +	 * the kernel */
> The transaction inside the parent process will abort. What
> is expected inside the child process ? Why should the kernel
> crash ?
>

Re: [PATCH 2/3] selftests/powerpc: Add test for forking inside transaction

[Michael Neuling]

On Tue, 2015-12-01 at 16:08 +1100, Rashmica Gupta wrote:
> This test does a fork syscall inside a transaction. Basic sniff test
> to see
> if we can enter the kernel during a transaction.

Can you add this description to the top of the test case as well?

Mikey

>=20
> Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
> ---
>  tools/testing/selftests/powerpc/tm/.gitignore |  1 +
>  tools/testing/selftests/powerpc/tm/Makefile   |  2 +-
>  tools/testing/selftests/powerpc/tm/tm-fork.c  | 41
> +++++++++++++++++++++++++++
>  3 files changed, 43 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/powerpc/tm/tm-fork.c
>=20
> diff --git a/tools/testing/selftests/powerpc/tm/.gitignore
> b/tools/testing/selftests/powerpc/tm/.gitignore
> index e6668217ccd0..d0c7c97e9b13 100644
> --- a/tools/testing/selftests/powerpc/tm/.gitignore
> +++ b/tools/testing/selftests/powerpc/tm/.gitignore
> @@ -2,3 +2,4 @@ tm-resched-dscr
>  tm-syscall
>  tm-signal-msr-resv
>  tm-signal-stack
> +tm-fork
> diff --git a/tools/testing/selftests/powerpc/tm/Makefile
> b/tools/testing/selftests/powerpc/tm/Makefile
> index 578572a3700a..f7d4727662aa 100644
> --- a/tools/testing/selftests/powerpc/tm/Makefile
> +++ b/tools/testing/selftests/powerpc/tm/Makefile
> @@ -1,4 +1,4 @@
> -TEST_PROGS :=3D tm-resched-dscr tm-syscall tm-signal-msr-resv tm
> -signal-stack
> +TEST_PROGS :=3D tm-resched-dscr tm-syscall tm-signal-msr-resv tm
> -signal-stack tm-fork
> =20
>  all: $(TEST_PROGS)
> =20
> diff --git a/tools/testing/selftests/powerpc/tm/tm-fork.c
> b/tools/testing/selftests/powerpc/tm/tm-fork.c
> new file mode 100644
> index 000000000000..f571a48a59a0
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/tm/tm-fork.c
> @@ -0,0 +1,41 @@
> +/*
> + * Copyright 2015, Michael Neuling, IBM Corp.
> + * Licensed under GPLv2.
> + *
> + * Edited: Rashmica Gupta, Nov 2015
> + *
> + * Fork inside a transaction
> + */
> +
> +#include <errno.h>
> +#include <inttypes.h>
> +#include <pthread.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +
> +#include "utils.h"
> +#include "tm.h"
> +
> +int test_fork(void)
> +{
> +	SKIP_IF(!have_htm());
> +
> +	asm __volatile__(
> +		"tbegin.;"
> +		"blt    1f; "
> +		"li     0, 2;"  /* fork syscall */
> +		"sc  ;"
> +		"tend.;"
> +		"1: ;"
> +		: : : "memory", "r0");
> +	/* If we reach here, we've passed.  Otherwise we've probably
> crashed
> +	 * the kernel */
> +
> +	return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	return test_harness(test_fork, "tm_fork");
> +}

[PATCH 3/3] selftests/powerpc: Add in check for TM

[Rashmica Gupta]

The resched-dscr test does not currently check for TM, so add in check.

Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
---
 tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
index 88c46481e59b..8243558aac6c 100644
--- a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
+++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
@@ -38,6 +38,8 @@ int test_body(void)
 {
 	uint64_t rv, dscr1 = 1, dscr2, texasr;
 
+	SKIP_IF(!have_htm());
+
 	printf("Check DSCR TM context switch: ");
 	fflush(stdout);
 	for (;;) {
-- 
2.5.0

Re: [PATCH 0/3] selftests/powerpc: Transactional Memory

[Andrew Donnellan]

On 01/12/15 16:08, Rashmica Gupta wrote:
> This is reliant on the following patch series:
> - selftests/powerpc by Michael Ellerman
> - selftests/powerpc by Michael Neuling
> - powerpc/tm by Michael Neuling

Could you provide the full titles of the patch series? (Links to 
patchwork.ozlabs.org are good too.)


Andrew

-- 
Andrew Donnellan              Software Engineer, OzLabs
andrew.donnellan@au1.ibm.com  Australia Development Lab, Canberra
+61 2 6201 8874 (work)        IBM Australia Limited