EFI_STUB fails to boot non-EFI on arm64

[Catalin Marinas]

I forgot about this thread. I think we need it sorted in some way.

On Fri, May 23, 2014 at 04:03:31PM +0100, Leif Lindholm wrote:
> On Fri, May 23, 2014 at 02:47:20PM +0100, Catalin Marinas wrote:
> > Can we add another of detecting whether it's an EFI application and
> > avoid calling efi_init()? I can see x86 sets some efi_loader_signature
> > string in exit_boot() and checks against it later when calling
> > efi_init().

So, to be in line with 32-bit arm, the only way to tell the uncompressed
kernel image that it was started as an EFI application is via FDT.

> My view is that this should be fixed in fdt_find_uefi_params(). A
> single info message that we can't find evidence of UEFI should be
> printed in the non-error case.
[...]
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index cd36deb..4bb42e1e 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -366,11 +366,8 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
>  
>  	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
>  		prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
> -		if (!prop) {
> -			pr_err("Can't find %s in device tree!\n",
> -			       dt_params[i].name);
> -			return 0;
> -		}
> +		if (!prop)
> +			goto fail;
>  		dest = info->params + dt_params[i].offset;
>  
>  		val = of_read_number(prop, len / sizeof(u32));
> @@ -385,6 +382,14 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
>  				dt_params[i].size * 2, val);
>  	}
>  	return 1;
> +
> +	fail:
> +	if (i == 0)
> +		pr_info("  UEFI not found.\n");
> +	else
> +		pr_err("Can't find %s in device tree!\n", dt_params[i].name);
> +
> +	return 0;

I'm ok with the idea but I don't particularly like the implementation.
Does this look any better (functionally the same as yours)?

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index eff1a2f22f09..dc79346689e6 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -346,6 +346,7 @@ static __initdata struct {
 
 struct param_info {
 	int verbose;
+	int found;
 	void *params;
 };
 
@@ -362,16 +363,12 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
 	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen at 0") != 0))
 		return 0;
 
-	pr_info("Getting parameters from FDT:\n");
-
 	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
 		prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
-		if (!prop) {
-			pr_err("Can't find %s in device tree!\n",
-			       dt_params[i].name);
+		if (!prop)
 			return 0;
-		}
 		dest = info->params + dt_params[i].offset;
+		info->found++;
 
 		val = of_read_number(prop, len / sizeof(u32));
 
@@ -390,10 +387,21 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
 int __init efi_get_fdt_params(struct efi_fdt_params *params, int verbose)
 {
 	struct param_info info;
+	int ret;
+
+	pr_info("Getting EFI parameters from FDT:\n");
 
 	info.verbose = verbose;
+	info.found = 0;
 	info.params = params;
 
-	return of_scan_flat_dt(fdt_find_uefi_params, &info);
+	ret = of_scan_flat_dt(fdt_find_uefi_params, &info);
+	if (!info.found)
+		pr_info("UEFI not found.\n");
+	else if (!ret)
+		pr_err("Can't find '%s' in device tree!\n",
+		       dt_params[info.found].name);
+
+	return ret;
 }
 #endif /* CONFIG_EFI_PARAMS_FROM_FDT */