https://github.com/torvalds/linux
Revision 47ce8527fbba145a7723685bc9a27d9855e06491 authored by Martin Fäcknitz on 05 July 2021, 00:03:54 UTC, committed by Thomas Bogendoerfer on 09 July 2021, 13:29:06 UTC
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>
1 parent 97e4880
Tip revision: 47ce8527fbba145a7723685bc9a27d9855e06491 authored by Martin Fäcknitz on 05 July 2021, 00:03:54 UTC
MIPS: vdso: Invalid GIC access through VDSO
MIPS: vdso: Invalid GIC access through VDSO
Tip revision: 47ce852
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