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authorHauke Mehrtens <hauke@hauke-m.de>2016-01-25 23:26:19 +0000
committerHauke Mehrtens <hauke@hauke-m.de>2016-01-25 23:26:19 +0000
commit998f8bd02c128e0c0dcc6a8228ae5aabfec05468 (patch)
tree9f43e9af445eb474a92788dee1f454a4e63604f0 /toolchain
parent0b55a7904b835c97518aeaf5a1d368cb3d38eeb5 (diff)
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musl: fix mips vdso handling
mips returns -ENOSYS in case it can not handle the vdso call and wants the libc to call the original syscall in such a case. This fixes the patch to add such handling. I hope this fixes the random reboots I got. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> SVN-Revision: 48501
Diffstat (limited to 'toolchain')
-rw-r--r--toolchain/musl/patches/030-mips-add-vdso-support.patch57
1 files changed, 54 insertions, 3 deletions
diff --git a/toolchain/musl/patches/030-mips-add-vdso-support.patch b/toolchain/musl/patches/030-mips-add-vdso-support.patch
index e4a15e323b..537a1ca0b4 100644
--- a/toolchain/musl/patches/030-mips-add-vdso-support.patch
+++ b/toolchain/musl/patches/030-mips-add-vdso-support.patch
@@ -1,4 +1,4 @@
-From c29a29c3334344e0f3cfdec6130a6261514507a0 Mon Sep 17 00:00:00 2001
+From 93332ebdcd54b0e0c0e86bced537cc96247bc1f1 Mon Sep 17 00:00:00 2001
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Sat, 23 Jan 2016 16:23:09 +0100
Subject: [PATCH 2/2] mips: add vdso support
@@ -7,10 +7,32 @@ vdso support is available on mips starting with kernel 4.4, see kernel
commit a7f4df4e21 "MIPS: VDSO: Add implementations of gettimeofday()
and clock_gettime()" for details.
+In Linux kernel 4.4.0 the mips code returns -ENOSYS in case it can not
+handle the vdso call and assumes the libc will call the original
+syscall in this case. Handle this case in musl. Currently Linux kernel
+4.4.0 handles the following types: CLOCK_REALTIME_COARSE,
+CLOCK_MONOTONIC_COARSE, CLOCK_REALTIME and CLOCK_MONOTONIC.
+
+These are some measurements of calling clock_gettime(CLOCK_MONOTONIC,
+&tp); 1.000.000 times.
+
+without vdso:
+root@OpenWrt:/# time ./vdso-test
+real 0m 0.95s
+user 0m 0.24s
+sys 0m 0.70s
+
+with vdso:
+root@OpenWrt:/# time /usr/bin/vdso-test
+real 0m 0.35s
+user 0m 0.34s
+sys 0m 0.00s
+
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---
- arch/mips/syscall_arch.h | 4 ++++
- 1 file changed, 4 insertions(+)
+ arch/mips/syscall_arch.h | 4 ++++
+ src/time/clock_gettime.c | 12 +++++++++++-
+ 2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/mips/syscall_arch.h b/arch/mips/syscall_arch.h
index e74e0ad..39c0ea3 100644
@@ -24,6 +46,35 @@ index e74e0ad..39c0ea3 100644
+#define VDSO_USEFUL
+#define VDSO_CGT_SYM "__vdso_clock_gettime"
+#define VDSO_CGT_VER "LINUX_2.6"
+diff --git a/src/time/clock_gettime.c b/src/time/clock_gettime.c
+index 1572de0..dba99ff 100644
+--- a/src/time/clock_gettime.c
++++ b/src/time/clock_gettime.c
+@@ -26,13 +26,23 @@ void *__vdsosym(const char *, const char *);
+ int __clock_gettime(clockid_t clk, struct timespec *ts)
+ {
+ #ifdef VDSO_CGT_SYM
++ int ret;
+ static int (*volatile cgt)(clockid_t, struct timespec *);
+ if (!cgt) {
+ void *f = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
+ if (!f) f = (void *)sc_clock_gettime;
+ a_cas_p(&cgt, 0, f);
+ }
+- return cgt(clk, ts);
++ ret = cgt(clk, ts);
++
++ /*
++ * mips in linux kernel 4.4.0 returns -ENOSYS if it can not
++ * handle the syscall in vdso, the original syscall should be
++ * called by the libc in such a case.
++ */
++ if (ret == -ENOSYS)
++ return sc_clock_gettime(clk, ts);
++ return ret;
+ #else
+ return sc_clock_gettime(clk, ts);
+ #endif
--
2.7.0.rc3