[boot-wrapper PATCH] Allow --enable-psci to choose between smc and hvc
Qi Feng
qi.feng at arm.com
Thu Jun 17 20:22:45 PDT 2021
According to Armv8-R AArch64 manual [1], Armv8-R AArch64 does not
support smc:
- Pseudocode for AArch64.CheckForSMCUndefOrTrap has this snippet:
if !HaveEL(EL3) || PSTATE.EL == EL0 then
UNDEFINED;
And Armv8-R AArch64 does not have EL3.
- In the document of HCR_EL2 TSC bit:
If EL3 is not implemented and HCR_EL2.NV is 0, it is IMPLEMENTATION
DEFINED whether this bit is:
- RES0.
- Implemented with the functionality as described in HCR_EL2.TSC.
So hvc is needed in this situation. And due to the lack of libfdt, the
psci method cannot be modified at runtime.
To use smc, use --enable-psci or --enable-psci=smc.
To use hvc, use --enable-psci=hvc.
[1]: https://developer.arm.com/documentation/ddi0600/latest/
Signed-off-by: Qi Feng <qi.feng at arm.com>
---
Makefile.am | 2 +-
configure.ac | 14 +++++++++-----
2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/Makefile.am b/Makefile.am
index ef6b793..a9ddd16 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -47,7 +47,7 @@ BOOTMETHOD := psci.o
OFILES += psci.o
PSCI_NODE := psci { \
compatible = \"arm,psci\"; \
- method = \"smc\"; \
+ method = \"$(PSCI_METHOD)\"; \
cpu_on = <$(PSCI_CPU_ON)>; \
cpu_off = <$(PSCI_CPU_OFF)>; \
};
diff --git a/configure.ac b/configure.ac
index 6914eb4..9aab4a1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -83,13 +83,17 @@ AS_IF([test "x$X_IMAGE" != "x"],
# Allow a user to pass --enable-psci
AC_ARG_ENABLE([psci],
AS_HELP_STRING([--enable-psci], [enable the psci boot method]),
- [USE_PSCI=$enableval])
-AM_CONDITIONAL([PSCI], [test "x$USE_PSCI" = "xyes"])
-AS_IF([test "x$USE_PSCI" = "xyes"], [], [USE_PSCI=no])
-
-AS_IF([test "x$USE_PSCI" != "xyes" -a "x$KERNEL_ES" = "x32"],
+ [case "${enableval}" in
+ yes|smc) USE_PSCI=smc ;;
+ hvc) USE_PSCI=hvc ;;
+ *) AC_MSG_ERROR([Bad value "${enableval}" for --enable-psci. Use "smc" or "hvc"]) ;;
+ esac])
+AM_CONDITIONAL([PSCI], [test "x$USE_PSCI" = "xyes" -o "x$USE_PSCI" = "xsmc" -o "x$USE_PSCI" = "xhvc"])
+
+AS_IF([test "x$USE_PSCI" = "xno" -a "x$KERNEL_ES" = "x32"],
[AC_MSG_ERROR([With an AArch32 kernel, boot method must be PSCI.])]
)
+AC_SUBST([PSCI_METHOD], [$USE_PSCI])
# Allow a user to pass --with-initrd
AC_ARG_WITH([initrd],
--
2.25.1
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