From: Ralf Baechle <ralf@linux-mips.org>
To: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org, David Daney <ddaney.cavm@gmail.com>,
James Hogan <james.hogan@imgtec.com>,
kvm@vger.kernel.org, David Daney <david.daney@cavium.com>
Subject: Re: [PATCH v2 09/13] MIPS: Add functions for hypervisor call
Date: Tue, 3 Jun 2014 10:30:31 +0200 [thread overview]
Message-ID: <20140603083031.GP17197@linux-mips.org> (raw)
In-Reply-To: <1401313936-11867-10-git-send-email-andreas.herrmann@caviumnetworks.com>
On Wed, May 28, 2014 at 11:52:12PM +0200, Andreas Herrmann wrote:
> +/*
> + * Hypercalls for KVM.
> + *
> + * Hypercall number is passed in v0.
> + * Return value will be placed in v0.
> + * Up to 3 arguments are passed in a0, a1, and a2.
> + */
> +static inline unsigned long kvm_hypercall0(unsigned long num)
> +{
> + register unsigned long n asm("v0");
> + register unsigned long r asm("v0");
Btw, is it safe to put two variables in the same register?
The syscall wrappers that used to be in <asm/unistd.h> were occasionally
hitting problems which eventually forced me to stop forcing variables
into particular registers instead using a MOVE instruction to shove
each variable into the right place.
Of course they were being used from non-PIC and PIC code, kernel and userland
so GCC had a much better chance to do evil than in the hypercall wrapper
case - but it made me paranoid ...
Ralf
next prev parent reply other threads:[~2014-06-03 8:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-28 21:52 [PATCH v2 00/13] MIPS: Add mips_paravirt Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 01/13] MIPS: OCTEON: Enable use of FPU Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 02/13] MIPS: Move system level config items from CPU_CAVIUM_OCTEON to CAVIUM_OCTEON_SOC Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 03/13] MIPS: OCTEON: Move CAVIUM_OCTEON_CVMSEG_SIZE to CPU_CAVIUM_OCTEON Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 04/13] MIPS: Don't use RI/XI with 32-bit kernels on 64-bit CPUs Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 05/13] MIPS: Don't build fast TLB refill handler with 32-bit kernels Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 06/13] MIPS: Add minimal support for OCTEON3 to c-r4k.c Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 07/13] MIPS: Add function get_ebase_cpunum Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 08/13] MIPS: OCTEON: Add OCTEON3 to __get_cpu_type Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 09/13] MIPS: Add functions for hypervisor call Andreas Herrmann
2014-06-03 8:30 ` Ralf Baechle [this message]
2014-06-03 15:03 ` Andreas Herrmann
2014-06-03 16:40 ` David Daney
2014-06-03 16:45 ` Pinski, Andrew
2014-05-28 21:52 ` [PATCH v2 10/13] MIPS: Add code for new system 'paravirt' Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 11/13] MIPS: paravirt: Add pci controller for virtio Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 12/13] MIPS: Enable build for new system 'paravirt' Andreas Herrmann
2014-05-28 21:52 ` [PATCH v2 13/13] MIPS: Add minimal defconfig for mips_paravirt Andreas Herrmann
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