Date: Thu, 02 Sep 2021 15:48:48 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-arm@FreeBSD.org Subject: [Bug 258217] Kernel GICv3 ITS driver: potentially unsupported 32-bit read of 64-bit register GICR_TYPER Message-ID: <bug-258217-7@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=258217 Bug ID: 258217 Summary: Kernel GICv3 ITS driver: potentially unsupported 32-bit read of 64-bit register GICR_TYPER Product: Base System Version: CURRENT Hardware: arm64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: arm Assignee: freebsd-arm@FreeBSD.org Reporter: olivier.delande@provenrun.com The kernel driver for the Interrupt Translation Service of ARM's Generic Interrupt Controller version 3 (sys/arm64/arm64/gicv3_its.c) reads the GICR_TYPER memory-mapped register of the redistributor in its its_init_cpu() function: /* Check if the ITS is enabled on this CPU */ if ((gic_r_read_4(gicv3, GICR_TYPER) & GICR_TYPER_PLPIS) == 0) ... This is a 32-bit read. However, GICR_TYPER is a 64-bit register and the GICv3 specification ([1], ยง11.1.3) only requires that such accesses be supported on systems with at least one core supporting Aarch32. By contrast, 64-bit reads are always supported. I suggest extending the read to 64 bits. By the way, the main GICv3 driver (sys/arm64/arm64/gic_v3.c) also reads GICR_TYPER, and it does so with bus_read_8(). This issue showed up on a software implementation of the ITS (hypervisor) that expected a 64-bit read. [1] https://developer.arm.com/documentation/ihi0069/latest -- You are receiving this mail because: You are the assignee for the bug.help
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