Subject: [PATCH 2/4] arch: arm/xen: add putc() for debugging
This new function, xen_debug_putc(), is intended to be used to enable CONFIG_DEBUG_UART on xen guest.
Please note that the underlying functionality in Xen is available only when Xen is configured with !NDEBUG but is much simpler than a generic HYPERVISOR_console_io().
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org
arch/arm/include/asm/xen/hypercall.h | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/arm/include/asm/xen/hypercall.h b/arch/arm/include/asm/xen/hypercall.h index a4fd077079a9..121ccfcc608f 100644 --- a/arch/arm/include/asm/xen/hypercall.h +++ b/arch/arm/include/asm/xen/hypercall.h @@ -19,4 +19,10 @@ int HYPERVISOR_sched_op(int cmd, void *arg); int HYPERVISOR_event_channel_op(int cmd, void *arg); unsigned long HYPERVISOR_hvm_op(int op, void *arg); int HYPERVISOR_memory_op(unsigned int cmd, void *arg);
+static inline void xen_debug_putc(int c) {
- register int v __asm__ ("x0") = c;
- __asm__ __volatile__("hvc 0xfffe" : "=r" (v) : "0" (v)); }
#endif /* _ASM_ARM_XEN_HYPERCALL_H */
Reviewed-by: Peng Fan peng.fan@nxp.com
-- 2.28.0