Thread (92 messages) 92 messages, 7 authors, 2021-08-11

Re: [PATCH 03/32] vdso.7: Remove outdated limitation for powerpc

From: Alejandro Colomar (man-pages) <hidden>
Date: 2021-08-08 00:21:22

Hello Michael,

On 8/8/21 2:17 AM, Michael Kerrisk (man-pages) wrote:
Hello Alex,

On 7/28/21 10:19 PM, Alejandro Colomar wrote:
quoted
Christophe Leroy via Bugzilla:
For the commit message, it would be good to have a URL for 
the bug. (I could not find the bug.)
That's right.  <https://bugzilla.kernel.org/show_bug.cgi?id=213419>
quoted
[
https://man7.org/linux/man-pages/man7/vdso.7.html
(as of today, flagged 2021-03-22)

ppc/32 and ppc/64 sections both have the following note:

       The CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE clocks
       are not supported by the __kernel_clock_getres and
       __kernel_clock_gettime interfaces; the kernel falls back to
       the real system call

This note has been wrong from quite some time now,
since commit 654abc69ef2e
("powerpc/vdso32: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE")
and commit 5c929885f1bb
("powerpc/vdso64: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE")
]

Reported-by: Christophe Leroy <redacted>
Signed-off-by: Alejandro Colomar <redacted>
In cases such as this, I prefer not to drop the historical info.
See below.
And also right.
quoted hunk ↗ jump to hunk
quoted
---
 man7/vdso.7 | 26 --------------------------
 1 file changed, 26 deletions(-)
diff --git a/man7/vdso.7 b/man7/vdso.7
index ef6bef5bd..1d527c38e 100644
--- a/man7/vdso.7
+++ b/man7/vdso.7
@@ -385,19 +385,6 @@ __kernel_sync_dicache_p5	LINUX_2.6.15
 .in
 .ft P
 \}
-.PP
-The
-.B CLOCK_REALTIME_COARSE
-and
-.B CLOCK_MONOTONIC_COARSE
-clocks are
-.I not
-supported by the
-.I __kernel_clock_getres
-and
-.I __kernel_clock_gettime
-interfaces;
-the kernel falls back to the real system call.
 .SS ppc/64 functions
 .\" See linux/arch/powerpc/kernel/vdso64/vdso64.lds.S
 The table below lists the symbols exported by the vDSO.
@@ -423,19 +410,6 @@ __kernel_sync_dicache_p5	LINUX_2.6.15
 .in
 .ft P
 \}
-.PP
-The
-.B CLOCK_REALTIME_COARSE
-and
-.B CLOCK_MONOTONIC_COARSE
-clocks are
-.I not
-supported by the
-.I __kernel_clock_getres
-and
-.I __kernel_clock_gettime
-interfaces;
-the kernel falls back to the real system call.
 .SS riscv functions
 .\" See linux/arch/riscv/kernel/vdso/vdso.lds.S
 The table below lists the symbols exported by the vDSO.
I instead applied the patch below.

Cheers,

Michael

diff --git a/man7/vdso.7 b/man7/vdso.7
index ef6bef5bd..39d6dc4ad 100644
--- a/man7/vdso.7
+++ b/man7/vdso.7
@@ -386,7 +386,9 @@ __kernel_sync_dicache_p5    LINUX_2.6.15
 .ft P
 \}
 .PP
-The
+In kernel versions before Linux 5.6,
+.\" commit 654abc69ef2e69712e6d4e8a6cb9292b97a4aa39
+the
 .B CLOCK_REALTIME_COARSE
 and
 .B CLOCK_MONOTONIC_COARSE
@@ -424,7 +426,9 @@ __kernel_sync_dicache_p5    LINUX_2.6.15
 .ft P
 \}
 .PP
-The
+In kernel versions before Linux 4.16,
+.\" commit 5c929885f1bb4b77f85b1769c49405a0e0f154a1
+the
Much better!

Thanks,

Alex
 .B CLOCK_REALTIME_COARSE
 and
 .B CLOCK_MONOTONIC_COARSE

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/
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