arm: Disable HVC PSCI calls by default

All systems that are running on armv8 are running bare metal with firmware
that implements PSCI running in EL3. That means we don't really need to expose
the hypercall variants of them.

This patch leaves the code in, but makes the code explicit enough to have the
compiler optimize it out. With this we don't need to worry about hvc vs smc
calling convention when calling psci helper functions.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/arm/cpu/armv8/fwcall.c b/arch/arm/cpu/armv8/fwcall.c
index 079e250cbe995d4f09de60f394e3a3d73e7492bf..6bb68f2ed3368453b48b64743fb616c807227574 100644 (file)
--- a/arch/arm/cpu/armv8/fwcall.c
+++ b/arch/arm/cpu/armv8/fwcall.c
@@ -17,7 +17,7 @@
  * x0~x7: input arguments
  * x0~x3: output arguments
  */
-void hvc_call(struct pt_regs *args)
+static void hvc_call(struct pt_regs *args)
 {
        asm volatile(
                "ldr x0, %0\n"
@@ -75,13 +75,21 @@ void smc_call(struct pt_regs *args)
                  "x16", "x17");
 }
 
-void __noreturn psci_system_reset(bool conduit_smc)
+/*
+ * For now, all systems we support run at least in EL2 and thus
+ * trigger PSCI calls to EL3 using SMC. If anyone ever wants to
+ * use PSCI on U-Boot running below a hypervisor, please detect
+ * this and set the flag accordingly.
+ */
+static const bool use_smc_for_psci = true;
+
+void __noreturn psci_system_reset(void)
 {
        struct pt_regs regs;
 
        regs.regs[0] = ARM_PSCI_0_2_FN_SYSTEM_RESET;
 
-       if (conduit_smc)
+       if (use_smc_for_psci)
                smc_call(&regs);
        else
                hvc_call(&regs);

diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index c18e1e3a10ee156fa6774da14d827740ebf2ff02..5166c653f342500515ea037d3369b6db869aa729 100644 (file)
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -106,15 +106,6 @@ void smp_kick_all_cpus(void);
 
 void flush_l3_cache(void);
 
-/*
- *Issue a hypervisor call in accordance with ARM "SMC Calling convention",
- * DEN0028A
- *
- * @args: input and output arguments
- *
- */
-void hvc_call(struct pt_regs *args);
-
 /*
  *Issue a secure monitor call in accordance with ARM "SMC Calling convention",
  * DEN0028A
@@ -124,7 +115,7 @@ void hvc_call(struct pt_regs *args);
  */
 void smc_call(struct pt_regs *args);
 
-void __noreturn psci_system_reset(bool smc);
+void __noreturn psci_system_reset(void);
 
 #endif /* __ASSEMBLY__ */
 

diff --git a/arch/arm/mach-meson/board.c b/arch/arm/mach-meson/board.c
index 1dd53e2313f31b278e52f814f492914758b3def1..f159cbf849f75ab046e6f3a025bbc97c0bcfd59d 100644 (file)
--- a/arch/arm/mach-meson/board.c
+++ b/arch/arm/mach-meson/board.c
@@ -43,7 +43,7 @@ void dram_init_banksize(void)
 
 void reset_cpu(ulong addr)
 {
-       psci_system_reset(true);
+       psci_system_reset();
 }
 
 static struct mm_region gxbb_mem_map[] = {

diff --git a/board/xilinx/zynqmp/zynqmp.c b/board/xilinx/zynqmp/zynqmp.c
index 566b5e8d2afa4915bb13b6754ef43b323a1240d5..94132f809fb09c29ddf4c46b5ee442f673a1878d 100644 (file)
--- a/board/xilinx/zynqmp/zynqmp.c
+++ b/board/xilinx/zynqmp/zynqmp.c
@@ -430,5 +430,5 @@ int board_usb_cleanup(int index, enum usb_init_type init)
 
 void reset_misc(void)
 {
-       psci_system_reset(true);
+       psci_system_reset();
 }