[PATCH 1/2] efi/gop: Fix return value of setup_gop32/64

From: Arvind Sankar <nivedita@alum.mit.edu>
To: Ard Biesheuvel <ardb@kernel.org>, linux-efi@vger.kernel.org
Subject: [PATCH 1/2] efi/gop: Fix return value of setup_gop32/64
Date: Tue,  3 Dec 2019 16:47:27 -0500	[thread overview]
Message-ID: <20191203214728.19264-1-nivedita@alum.mit.edu> (raw)

There are two ways the status return of setup_gop32/64 could be
incorrect.

1. If we don't find a usable GOP because none of them have a framebuffer
(i.e. they were all PIXEL_BLT_ONLY), but all the efi calls succeeded, we
will return EFI_SUCCESS even though we didn't find a usable GOP. Return
EFI_NOT_FOUND instead, allowing the caller to probe for UGA instead.

2. If we do find a usable GOP, but one of the subsequent ones fails in
an EFI call while checking if any support console output, we may return
an EFI error code even though we found a usable GOP. Fix this by always
returning EFI_SUCCESS if we got a usable GOP.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
 drivers/firmware/efi/libstub/gop.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/firmware/efi/libstub/gop.c b/drivers/firmware/efi/libstub/gop.c
index 0101ca4c13b1..235a98797105 100644
--- a/drivers/firmware/efi/libstub/gop.c
+++ b/drivers/firmware/efi/libstub/gop.c
@@ -119,7 +119,6 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 	u64 fb_base;
 	struct efi_pixel_bitmask pixel_info;
 	int pixel_format;
-	efi_status_t status = EFI_NOT_FOUND;
 	u32 *handles = (u32 *)(unsigned long)gop_handle;
 	int i;
 
@@ -134,6 +133,7 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 		void *dummy = NULL;
 		efi_handle_t h = (efi_handle_t)(unsigned long)handles[i];
 		u64 current_fb_base;
+		efi_status_t status;
 
 		status = efi_call_early(handle_protocol, h,
 					proto, (void **)&gop32);
@@ -175,7 +175,7 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 
 	/* Did we find any GOPs? */
 	if (!first_gop)
-		goto out;
+		return EFI_NOT_FOUND;
 
 	/* EFI framebuffer */
 	si->orig_video_isVGA = VIDEO_TYPE_EFI;
@@ -197,8 +197,8 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 	si->lfb_size = si->lfb_linelength * si->lfb_height;
 
 	si->capabilities |= VIDEO_CAPABILITY_SKIP_QUIRKS;
-out:
-	return status;
+
+	return EFI_SUCCESS;
 }
 
 static efi_status_t
@@ -237,7 +237,6 @@ setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 	u64 fb_base;
 	struct efi_pixel_bitmask pixel_info;
 	int pixel_format;
-	efi_status_t status = EFI_NOT_FOUND;
 	u64 *handles = (u64 *)(unsigned long)gop_handle;
 	int i;
 
@@ -252,6 +251,7 @@ setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 		void *dummy = NULL;
 		efi_handle_t h = (efi_handle_t)(unsigned long)handles[i];
 		u64 current_fb_base;
+		efi_status_t status;
 
 		status = efi_call_early(handle_protocol, h,
 					proto, (void **)&gop64);
@@ -293,7 +293,7 @@ setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 
 	/* Did we find any GOPs? */
 	if (!first_gop)
-		goto out;
+		return EFI_NOT_FOUND;
 
 	/* EFI framebuffer */
 	si->orig_video_isVGA = VIDEO_TYPE_EFI;
@@ -315,8 +315,8 @@ setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 	si->lfb_size = si->lfb_linelength * si->lfb_height;
 
 	si->capabilities |= VIDEO_CAPABILITY_SKIP_QUIRKS;
-out:
-	return status;
+
+	return EFI_SUCCESS;
 }
 
 /*
-- 
2.23.0

