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? > + */ > + > +#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? > + 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). -- Catalin
