Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2. During CPU reset the CPU must be brought to the exception level it had on entry to the kernel. The HVC_CALL_FUNC hcall will provide the mechanism needed for this exception level switch. Signed-off-by: Geoff Levand <geoff at infradead.org> --- arch/arm64/include/asm/virt.h | 13 +++++++++++++ arch/arm64/kernel/hyp-stub.S | 10 ++++++++++ 2 files changed, 23 insertions(+) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index 894fe53..cc4250c 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -41,6 +41,19 @@ #define HVC_KVM_CALL_HYP 3 +/* + * HVC_CALL_FUNC - Execute a function at EL2. + * + * @x0: Physical address of the funtion 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. + */ + +#define HVC_CALL_FUNC 4 + #ifndef __ASSEMBLY__ /* diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 9ab5f70..27d786d 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -75,7 +75,17 @@ el1_sync: 1: cmp x10, #HVC_SET_VECTORS b.ne 1f msr vbar_el2, x0 + b 2f +1: cmp x10, #HVC_CALL_FUNC + b.ne 1f + mov x18, lr + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + mov lr, x18 1: 2: eret ENDPROC(el1_sync) -- 1.9.1
