Hi Alex,
On 2020-07-16 16:07, Alex Bee wrote:
Along with commit commit 74d06efb9c2f ("ARM: 8932/1: Add clock_gettime64
entry point") clock_gettime64 was added for ARM platform to solve the
y2k38 problem on 32-bit platforms. glibc from version 2.31 onwards
started using this vdso-call on ARM platforms.
However it was (probably) forgotten to "nullpatch" this call, when no
reliable timer source is available, for example when
"arm,cpu-registers-not-fw-configured" is defined in devicetree for
"arm,armv7-timer".
This results in erratic time jumps whenever "gettimeofday" gets called,
since the (non-working) vdso-call will be used instead of a syscall.
This patch adds clock_gettime64 to get nullpatched as well. It has been
verified to work and solve this issue on Rockchip RK322x, RK3288 and
RPi4 (32-bit kernel build) platforms.
FYI, a version of this patch was already submitted, and is just waiting
for Russell to apply it:
https://www.armlinux.org.uk/developer/patches/viewpatch.php?id=8987/1
Robin.
Signed-off-by: Alex Bee <knaerzche@xxxxxxxxx>
---
arch/arm/kernel/vdso.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 6bfdca4769a7..fddd08a6e063 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -184,6 +184,7 @@ static void __init patch_vdso(void *ehdr)
if (!cntvct_ok) {
vdso_nullpatch_one(&einfo, "__vdso_gettimeofday");
vdso_nullpatch_one(&einfo, "__vdso_clock_gettime");
+ vdso_nullpatch_one(&einfo, "__vdso_clock_gettime64");
}
}
