[v2] compel/ppc64le: make task size detection more robust

Submitted by Mike Rapoport on Sept. 3, 2017, 7:27 a.m.

Details

Message ID 1504423672-30288-1-git-send-email-rppt@linux.vnet.ibm.com
State New
Series "compel/ppc64le: make task size detection more robust"
Headers show

Commit Message

Mike Rapoport Sept. 3, 2017, 7:27 a.m.
The recent changes to user address space limits in the Linux kernel break
the assumption that TASK_SIZE is 128TB. For now, the maximal task size on
ppc64le is 512TB and we need to detect it in runtime for compatibility with
older kernels.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
v2: fix off-by-one

 compel/arch/ppc64/src/lib/infect.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

Patch hide | download patch | download mbox

diff --git a/compel/arch/ppc64/src/lib/infect.c b/compel/arch/ppc64/src/lib/infect.c
index 8112588..1f1195e 100644
--- a/compel/arch/ppc64/src/lib/infect.c
+++ b/compel/arch/ppc64/src/lib/infect.c
@@ -2,6 +2,7 @@ 
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <sys/user.h>
+#include <sys/mman.h>
 #include <stdint.h>
 #include <errno.h>
 #include <compel/plugins/std/syscall-codes.h>
@@ -9,6 +10,7 @@ 
 #include "errno.h"
 #include "log.h"
 #include "common/bug.h"
+#include "common/page.h"
 #include "infect.h"
 #include "infect-priv.h"
 
@@ -458,7 +460,19 @@  int arch_fetch_sas(struct parasite_ctl *ctl, struct rt_sigframe *s)
  *
  * NOTE: 32bit tasks are not supported.
  */
-#define TASK_SIZE_USER64	(0x0000400000000000UL)
-#define TASK_SIZE		TASK_SIZE_USER64
+#define TASK_SIZE_64TB  (0x0000400000000000UL)
+#define TASK_SIZE_128TB (0x0000800000000000UL)
+#define TASK_SIZE_512TB (0x0002000000000000UL)
 
-unsigned long compel_task_size(void) { return TASK_SIZE; }
+#define TASK_SIZE_MIN TASK_SIZE_64TB
+#define TASK_SIZE_MAX TASK_SIZE_512TB
+
+unsigned long compel_task_size(void)
+{
+	unsigned long task_size;
+
+	for (task_size = TASK_SIZE_MIN; task_size < TASK_SIZE_MAX; task_size <<= 1)
+		if (munmap((void *)task_size, page_size()))
+			break;
+	return task_size;
+}

Comments

Laurent Dufour Sept. 4, 2017, 6:55 a.m.
On 03/09/2017 09:27, Mike Rapoport wrote:
> The recent changes to user address space limits in the Linux kernel break
> the assumption that TASK_SIZE is 128TB. For now, the maximal task size on
> ppc64le is 512TB and we need to detect it in runtime for compatibility with
> older kernels.
> 
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> ---
> v2: fix off-by-one
> 
>  compel/arch/ppc64/src/lib/infect.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/compel/arch/ppc64/src/lib/infect.c b/compel/arch/ppc64/src/lib/infect.c
> index 8112588..1f1195e 100644
> --- a/compel/arch/ppc64/src/lib/infect.c
> +++ b/compel/arch/ppc64/src/lib/infect.c
> @@ -2,6 +2,7 @@
>  #include <sys/types.h>
>  #include <sys/uio.h>
>  #include <sys/user.h>
> +#include <sys/mman.h>
>  #include <stdint.h>
>  #include <errno.h>
>  #include <compel/plugins/std/syscall-codes.h>
> @@ -9,6 +10,7 @@
>  #include "errno.h"
>  #include "log.h"
>  #include "common/bug.h"
> +#include "common/page.h"
>  #include "infect.h"
>  #include "infect-priv.h"
> 
> @@ -458,7 +460,19 @@ int arch_fetch_sas(struct parasite_ctl *ctl, struct rt_sigframe *s)
>   *
>   * NOTE: 32bit tasks are not supported.
>   */
> -#define TASK_SIZE_USER64	(0x0000400000000000UL)
> -#define TASK_SIZE		TASK_SIZE_USER64
> +#define TASK_SIZE_64TB  (0x0000400000000000UL)
> +#define TASK_SIZE_128TB (0x0000800000000000UL)

Hi Mike,
What's the need for defining TASK_SIZE_128TB ?

> +#define TASK_SIZE_512TB (0x0002000000000000UL)
> 
> -unsigned long compel_task_size(void) { return TASK_SIZE; }
> +#define TASK_SIZE_MIN TASK_SIZE_64TB
> +#define TASK_SIZE_MAX TASK_SIZE_512TB
> +
> +unsigned long compel_task_size(void)
> +{
> +	unsigned long task_size;
> +
> +	for (task_size = TASK_SIZE_MIN; task_size < TASK_SIZE_MAX; task_size <<= 1)
> +		if (munmap((void *)task_size, page_size()))
> +			break;
> +	return task_size;
> +}
> 

Except for minor TASK_SIZE_128TB's remarks:

Acked-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Mike Rapoport Sept. 4, 2017, 7:29 a.m.
On Mon, Sep 04, 2017 at 08:55:39AM +0200, Laurent Dufour wrote:
> On 03/09/2017 09:27, Mike Rapoport wrote:
> > The recent changes to user address space limits in the Linux kernel break
> > the assumption that TASK_SIZE is 128TB. For now, the maximal task size on
> > ppc64le is 512TB and we need to detect it in runtime for compatibility with
> > older kernels.
> > 
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> > ---
> > v2: fix off-by-one
> > 
> >  compel/arch/ppc64/src/lib/infect.c | 20 +++++++++++++++++---
> >  1 file changed, 17 insertions(+), 3 deletions(-)
> > 
> > diff --git a/compel/arch/ppc64/src/lib/infect.c b/compel/arch/ppc64/src/lib/infect.c
> > index 8112588..1f1195e 100644
> > --- a/compel/arch/ppc64/src/lib/infect.c
> > +++ b/compel/arch/ppc64/src/lib/infect.c
> > @@ -2,6 +2,7 @@
> >  #include <sys/types.h>
> >  #include <sys/uio.h>
> >  #include <sys/user.h>
> > +#include <sys/mman.h>
> >  #include <stdint.h>
> >  #include <errno.h>
> >  #include <compel/plugins/std/syscall-codes.h>
> > @@ -9,6 +10,7 @@
> >  #include "errno.h"
> >  #include "log.h"
> >  #include "common/bug.h"
> > +#include "common/page.h"
> >  #include "infect.h"
> >  #include "infect-priv.h"
> > 
> > @@ -458,7 +460,19 @@ int arch_fetch_sas(struct parasite_ctl *ctl, struct rt_sigframe *s)
> >   *
> >   * NOTE: 32bit tasks are not supported.
> >   */
> > -#define TASK_SIZE_USER64	(0x0000400000000000UL)
> > -#define TASK_SIZE		TASK_SIZE_USER64
> > +#define TASK_SIZE_64TB  (0x0000400000000000UL)
> > +#define TASK_SIZE_128TB (0x0000800000000000UL)
> 
> Hi Mike,
> What's the need for defining TASK_SIZE_128TB ?
 
I've just copied the entire chunk from arch/powerpc/include/asm/processor.h :)

> > +#define TASK_SIZE_512TB (0x0002000000000000UL)
> > 
> > -unsigned long compel_task_size(void) { return TASK_SIZE; }
> > +#define TASK_SIZE_MIN TASK_SIZE_64TB
> > +#define TASK_SIZE_MAX TASK_SIZE_512TB
> > +
> > +unsigned long compel_task_size(void)
> > +{
> > +	unsigned long task_size;
> > +
> > +	for (task_size = TASK_SIZE_MIN; task_size < TASK_SIZE_MAX; task_size <<= 1)
> > +		if (munmap((void *)task_size, page_size()))
> > +			break;
> > +	return task_size;
> > +}
> > 
> 
> Except for minor TASK_SIZE_128TB's remarks:
> 
> Acked-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>