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.
