[U-Boot] [RFC] efi_loader: support for CONFIG_ARMV7_NONSEC

[Alexander Graf]

On 06.04.18 07:43, Heinrich Schuchardt wrote:
> Booting with SMP fails on the Allwinner A20 CPU.
> https://gist.github.com/xypron/2524ba898d6905d959c744c2b05da196
> 
> When executing bootefi we need to
> * copy the Power State Coordination Interface (PSCI) code to its
>   destination address
> * switch between our hypervisor mode (HYP) and the supervisor mode (SVC)
>   of the payload (http://linux-sunxi.org/PSCI)
> 
> This patch is incomplete. It is just meant to indicate where we could
> change the entry point.
> 
> With the patch iPXE cannot get a network address.
> 
> Possibly a better moment for switching to SVC is ExitBootServices.
> 
> We also have to consider switching modes at EFI_ENTRY and EFI_EXIT.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

Well, I think it makes perfect sense to switch to HYP mode. We do the
same on AArch64 when we're in EL3 (MON). The fact that iPXE can not get
a network address then sounds weird - HYP should have the same privilege
level as Linux does eventually and there network probably works for you.

Maybe we also need to do the dcache flushing dance? See efi_run_in_el2().

Either way, here's a slightly more clean (untested!) version of your
patch. Because Thunderbird is very good at mangling patches, I'll also
give you a pastebin link[1].


Alex

[1] http://paste.opensuse.org/view/raw/69476551


diff --git a/cmd/bootefi.c b/cmd/bootefi.c
index 5a2a81005f..8107ada52c 100644
--- a/cmd/bootefi.c
+++ b/cmd/bootefi.c
@@ -20,6 +20,11 @@
 #include <asm-generic/sections.h>
 #include <linux/linkage.h>

+#ifdef CONFIG_ARM
+#include <asm/armv7.h>
+#include <asm/secure.h>
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;

 #define OBJ_LIST_NOT_INITIALIZED 1
@@ -178,6 +183,15 @@ static efi_status_t efi_run_in_el2(EFIAPI
efi_status_t (*entry)(
 }
 #endif

+#ifdef CONFIG_ARMV7_NONSEC
+static efi_status_t efi_run_in_hyp(EFIAPI efi_status_t (*entry)(
+			efi_handle_t image_handle, struct efi_system_table *st),
+			efi_handle_t image_handle, struct efi_system_table *st)
+{
+	return efi_do_enter(image_handle, st, entry);
+}
+#endif
+
 /* Carve out DT reserved memory ranges */
 static efi_status_t efi_carve_out_dt_rsv(void *fdt)
 {
@@ -327,6 +341,19 @@ static efi_status_t do_bootefi_exec(void *efi,
 	}
 #endif

+#ifdef CONFIG_ARMV7_NONSEC
+	if (armv7_boot_nonsec()) {
+		armv7_init_nonsec();
+		secure_ram_addr(_do_nonsec_entry)(efi_run_in_hyp,
+				(uintptr_t)entry,
+				(uintptr_t)&loaded_image_info_obj.handle,
+				(uintptr_t)&systab);
+
+		/* Should never reach here, efi exits with longjmp */
+		while (1) { }
+	}
+#endif
+
 	ret = efi_do_enter(loaded_image_info_obj.handle, &systab, entry);

 exit: