* [PATCH] Fix BPF check for kernels < 3.20
@ 2016-08-30 21:38 Julian Ospald
0 siblings, 0 replies; 5+ messages in thread
From: Julian Ospald @ 2016-08-30 21:38 UTC (permalink / raw)
To: elfutils-devel
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Signed-off-by: Julian Ospald <hasufell@posteo.de>
---
configure.ac | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/configure.ac b/configure.ac
index e5503f1..a69e2dd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -331,9 +331,20 @@ else
fi
AC_SUBST([argp_LDADD])
-dnl Check if we have <linux/bpf.h> for EM_BPF disassembly.
-AC_CHECK_HEADERS(linux/bpf.h)
-AM_CONDITIONAL(HAVE_LINUX_BPF_H, [test "x$ac_cv_header_linux_bpf_h" = "xyes"])
+dnl Check if we have <linux/bpf.h> for EM_BPF disassembly and it has the required defines
+AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [#include <linux/bpf.h>],
+ [int foo=BPF_PSEUDO_MAP_FD; return 0;]
+ )],
+ [have_bpf="true"],
+ [have_bpf="false"]
+)
+
+if test "$have_bpf" = "true" ; then
+ AC_DEFINE([HAVE_LINUX_BPF_H], [1], [if we have <linux/bpf.h> for EM_BPF disassembly])
+fi
+AM_CONDITIONAL(HAVE_LINUX_BPF_H, [test "$have_bpf" = "true"])
dnl The directories with content.
--
2.9.3
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix BPF check for kernels < 3.20
@ 2016-08-31 14:21 Mark Wielaard
0 siblings, 0 replies; 5+ messages in thread
From: Mark Wielaard @ 2016-08-31 14:21 UTC (permalink / raw)
To: elfutils-devel
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On Tue, 2016-08-30 at 23:38 +0200, Julian Ospald wrote:
> -dnl Check if we have <linux/bpf.h> for EM_BPF disassembly.
> -AC_CHECK_HEADERS(linux/bpf.h)
> -AM_CONDITIONAL(HAVE_LINUX_BPF_H, [test "x$ac_cv_header_linux_bpf_h" = "xyes"])
> +dnl Check if we have <linux/bpf.h> for EM_BPF disassembly and it has the required defines
> +AC_COMPILE_IFELSE(
> + [AC_LANG_PROGRAM(
> + [#include <linux/bpf.h>],
> + [int foo=BPF_PSEUDO_MAP_FD; return 0;]
> + )],
> + [have_bpf="true"],
> + [have_bpf="false"]
> +)
> +
> +if test "$have_bpf" = "true" ; then
> + AC_DEFINE([HAVE_LINUX_BPF_H], [1], [if we have <linux/bpf.h> for EM_BPF disassembly])
> +fi
> +AM_CONDITIONAL(HAVE_LINUX_BPF_H, [test "$have_bpf" = "true"])
Thanks, that does look like the correct configure check.
But it seems that BPF_PSEUDO_MAP_FD is the only missing constant
introduced since 3.18 (when linux/bpf.h was added) that we use.
So maybe we could simply define it ourselves when not found. So we can
build against any linux/bpf.h out there.
What do people think of the following?
diff --git a/libcpu/bpf_disasm.c b/libcpu/bpf_disasm.c
index 153dba9..e4bbae4 100644
--- a/libcpu/bpf_disasm.c
+++ b/libcpu/bpf_disasm.c
@@ -40,6 +40,10 @@
#include "../libelf/common.h"
#include "../libebl/libeblP.h"
+/* BPF_PSEUDO_MAP_FD was only introduced in linux 3.20. */
+#ifndef BPF_PSEUDO_MAP_FD
+ #define BPF_PSEUDO_MAP_FD 1
+#endif
static const char class_string[8][8] = {
[BPF_LD] = "ld",
Thanks,
Mark
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix BPF check for kernels < 3.20
@ 2016-09-05 9:21 Mark Wielaard
0 siblings, 0 replies; 5+ messages in thread
From: Mark Wielaard @ 2016-09-05 9:21 UTC (permalink / raw)
To: elfutils-devel
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On Wed, 2016-08-31 at 16:21 +0200, Mark Wielaard wrote:
> Thanks, that does look like the correct configure check.
>
> But it seems that BPF_PSEUDO_MAP_FD is the only missing constant
> introduced since 3.18 (when linux/bpf.h was added) that we use.
> So maybe we could simply define it ourselves when not found. So we can
> build against any linux/bpf.h out there.
>
> What do people think of the following?
I tested it against the latest stable kernel and headers from the 3.18
kernel and it seems to work fine. Any objections to commit the attached?
Thanks,
Mark
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-libcpu-Fix-build-of-bpf_disasm.c-for-kernels-3.20.patch --]
[-- Type: text/x-patch, Size: 1272 bytes --]
From 4f7b5ba9624489b5a2f714569c29ef865d4dcd6f Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mjw@redhat.com>
Date: Mon, 5 Sep 2016 11:15:50 +0200
Subject: [PATCH] libcpu: Fix build of bpf_disasm.c for kernels < 3.20.
Before linux 3.20 the BPF_PSEUDO_MAP_FD constant wasn't defined.
Reported-by: Julian Ospald <hasufell@posteo.de>
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
libcpu/ChangeLog | 4 ++++
libcpu/bpf_disasm.c | 4 ++++
2 files changed, 8 insertions(+)
diff --git a/libcpu/ChangeLog b/libcpu/ChangeLog
index 9f3566c..9cce4e7 100644
--- a/libcpu/ChangeLog
+++ b/libcpu/ChangeLog
@@ -1,3 +1,7 @@
+2016-09-05 Mark Wielaard <mjw@redhat.com>
+
+ * bpf_disasm.c: Define BPF_PSEUDO_MAP_FD if undefined.
+
2016-08-10 Richard Henderson <rth@redhat.com>
* bpf_disasm.c (bpf_disasm): Rearrange the printing of instructions
diff --git a/libcpu/bpf_disasm.c b/libcpu/bpf_disasm.c
index 153dba9..e4bbae4 100644
--- a/libcpu/bpf_disasm.c
+++ b/libcpu/bpf_disasm.c
@@ -40,6 +40,10 @@
#include "../libelf/common.h"
#include "../libebl/libeblP.h"
+/* BPF_PSEUDO_MAP_FD was only introduced in linux 3.20. */
+#ifndef BPF_PSEUDO_MAP_FD
+ #define BPF_PSEUDO_MAP_FD 1
+#endif
static const char class_string[8][8] = {
[BPF_LD] = "ld",
--
1.8.3.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix BPF check for kernels < 3.20
@ 2016-09-06 17:00 Richard Henderson
0 siblings, 0 replies; 5+ messages in thread
From: Richard Henderson @ 2016-09-06 17:00 UTC (permalink / raw)
To: elfutils-devel
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On 09/05/2016 02:21 AM, Mark Wielaard wrote:
> On Wed, 2016-08-31 at 16:21 +0200, Mark Wielaard wrote:
>> > Thanks, that does look like the correct configure check.
>> >
>> > But it seems that BPF_PSEUDO_MAP_FD is the only missing constant
>> > introduced since 3.18 (when linux/bpf.h was added) that we use.
>> > So maybe we could simply define it ourselves when not found. So we can
>> > build against any linux/bpf.h out there.
>> >
>> > What do people think of the following?
> I tested it against the latest stable kernel and headers from the 3.18
> kernel and it seems to work fine. Any objections to commit the attached?
None.
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix BPF check for kernels < 3.20
@ 2016-09-07 10:13 Mark Wielaard
0 siblings, 0 replies; 5+ messages in thread
From: Mark Wielaard @ 2016-09-07 10:13 UTC (permalink / raw)
To: elfutils-devel
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On Tue, 2016-09-06 at 10:00 -0700, Richard Henderson wrote:
> On 09/05/2016 02:21 AM, Mark Wielaard wrote:
> > On Wed, 2016-08-31 at 16:21 +0200, Mark Wielaard wrote:
> >> > Thanks, that does look like the correct configure check.
> >> >
> >> > But it seems that BPF_PSEUDO_MAP_FD is the only missing constant
> >> > introduced since 3.18 (when linux/bpf.h was added) that we use.
> >> > So maybe we could simply define it ourselves when not found. So we can
> >> > build against any linux/bpf.h out there.
> >> >
> >> > What do people think of the following?
> > I tested it against the latest stable kernel and headers from the 3.18
> > kernel and it seems to work fine. Any objections to commit the attached?
>
> None.
Thanks. Pushed to master.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-09-07 10:13 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2016-09-06 17:00 Richard Henderson
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