From: Martin Fäcknitz faecknitz@hotsplots.de
stable inclusion from linux-4.19.198 commit 8553099bdbe95a717e974552b6e6dbb8c4dac70b
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[ Upstream commit 47ce8527fbba145a7723685bc9a27d9855e06491 ]
Accessing raw timers (currently only CLOCK_MONOTONIC_RAW) through VDSO doesn't return the correct time when using the GIC as clock source. The address of the GIC mapped page is in this case not calculated correctly. The GIC mapped page is calculated from the VDSO data by subtracting PAGE_SIZE:
void *get_gic(const struct vdso_data *data) { return (void __iomem *)data - PAGE_SIZE; }
However, the data pointer is not page aligned for raw clock sources. This is because the VDSO data for raw clock sources (CS_RAW = 1) is stored after the VDSO data for coarse clock sources (CS_HRES_COARSE = 0). Therefore, only the VDSO data for CS_HRES_COARSE is page aligned:
+--------------------+ | | | vd[CS_RAW] | ---+ | vd[CS_HRES_COARSE] | | +--------------------+ | -PAGE_SIZE | | | | GIC mapped page | <--+ | | +--------------------+
When __arch_get_hw_counter() is called with &vd[CS_RAW], get_gic returns the wrong address (somewhere inside the GIC mapped page). The GIC counter values are not returned which results in an invalid time.
Fixes: a7f4df4e21dd ("MIPS: VDSO: Add implementations of gettimeofday() and clock_gettime()") Signed-off-by: Martin Fäcknitz faecknitz@hotsplots.de Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/mips/vdso/vdso.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/vdso/vdso.h b/arch/mips/vdso/vdso.h index cfb1be441decc..921589b45bc20 100644 --- a/arch/mips/vdso/vdso.h +++ b/arch/mips/vdso/vdso.h @@ -81,7 +81,7 @@ static inline const union mips_vdso_data *get_vdso_data(void)
static inline void __iomem *get_gic(const union mips_vdso_data *data) { - return (void __iomem *)data - PAGE_SIZE; + return (void __iomem *)((unsigned long)data & PAGE_MASK) - PAGE_SIZE; }
#endif /* CONFIG_CLKSRC_MIPS_GIC */