From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Message-ID: <1422654751.21823.35.camel@infradead.org> Subject: Re: [PATCH 3/8] arm64: Add new hcall HVC_CALL_FUNC From: Geoff Levand Date: Fri, 30 Jan 2015 13:52:31 -0800 In-Reply-To: <20150127173947.GJ3226@e104818-lin.cambridge.arm.com> References: <3f1795bc1dad1d0510a9d24a168ecd5d83666507.1421449714.git.geoff@infradead.org> <20150127173947.GJ3226@e104818-lin.cambridge.arm.com> Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Catalin Marinas Cc: Marc Zyngier , "kexec@lists.infradead.org" , Will Deacon , "linux-arm-kernel@lists.infradead.org" , "grant.likely@linaro.org" , "christoffer.dall@linaro.org" Hi Catalin, On Tue, 2015-01-27 at 17:39 +0000, Catalin Marinas wrote: > On Sat, Jan 17, 2015 at 12:23:34AM +0000, Geoff Levand wrote: > > diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h > > index 99c319c..4f23a48 100644 > > --- a/arch/arm64/include/asm/virt.h > > +++ b/arch/arm64/include/asm/virt.h > > @@ -41,6 +41,19 @@ > > > > #define HVC_CALL_HYP 3 > > > > +/* > > + * HVC_CALL_FUNC - Execute a function at EL2. > > + * > > + * @x0: Physical address of the function to be executed. > > + * @x1: Passed as the first argument to the function. > > + * @x2: Passed as the second argument to the function. > > + * @x3: Passed as the third argument to the function. > > + * > > + * The called function must preserve the contents of register x18. > > Can you pick a register that's normally callee saved? Mark covered this in his reply. > > + */ > > + > > +#define HVC_CALL_FUNC 4 > > + > > #ifndef __ASSEMBLY__ > > > > /* > > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S > > index e3db3fd..b5d36e7 100644 > > --- a/arch/arm64/kernel/hyp-stub.S > > +++ b/arch/arm64/kernel/hyp-stub.S > > @@ -66,9 +66,20 @@ el1_sync: > > mrs x0, vbar_el2 > > b 2f > > > > -1: cmp x18, #HVC_SET_VECTORS > > - b.ne 2f > > - msr vbar_el2, x0 > > +1: cmp x18, #HVC_SET_VECTORS > > This line doesn't seem to have any change, apart from some whitespace. > Or did you want to drop the label? Some whitespace problems got in there from so many rebases. I went through the series and cleaned them up. > > + b.ne 1f > > + msr vbar_el2, x0 > > + b 2f > > + > > +1: cmp x18, #HVC_CALL_FUNC > > + b.ne 2f > > + mov x18, lr > > + mov lr, x0 > > + mov x0, x1 > > + mov x1, x2 > > + mov x2, x3 > > + blr lr > > + mov lr, x18 > > > > 2: eret > > ENDPROC(el1_sync) > > What is the calling convention for this HVC? You mentioned x18 above but > what about other registers that the called function may corrupt (x18 is > a temporary register, so it's not expected to be callee saved). Again, Mark covered this in his reply. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec