[PATCH] efi/libstub: Call setup_graphics() before handle_kernel_image()

From: Huacai Chen
Date: Thu Mar 09 2023 - 01:00:31 EST


Commit 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint
into separate file") moves setup_graphics() into efi_stub_common() which
is after handle_kernel_image(). This causes efifb no longer work because
handle_kernel_image() may move the core kernel to its preferred address,
which means the screen_info filled by the efistub will not be the same
as the one accessed by the core kernel. So let us call setup_graphics()
before handle_kernel_image() which restores the old behavior.

The side effect is zboot will not call setup_graphics(), but I think
zboot doesn't need it either.

Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file")
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
drivers/firmware/efi/libstub/efi-stub-entry.c | 29 +++++++++++++++++++
drivers/firmware/efi/libstub/efi-stub.c | 27 -----------------
2 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/drivers/firmware/efi/libstub/efi-stub-entry.c b/drivers/firmware/efi/libstub/efi-stub-entry.c
index 5245c4f031c0..f971fd25a4eb 100644
--- a/drivers/firmware/efi/libstub/efi-stub-entry.c
+++ b/drivers/firmware/efi/libstub/efi-stub-entry.c
@@ -5,6 +5,30 @@

#include "efistub.h"

+struct screen_info *setup_graphics(void)
+{
+ unsigned long size;
+ efi_status_t status;
+ efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
+ void **gop_handle = NULL;
+ struct screen_info *si = NULL;
+
+ size = 0;
+ status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
+ &gop_proto, NULL, &size, gop_handle);
+ if (status == EFI_BUFFER_TOO_SMALL) {
+ si = alloc_screen_info();
+ if (!si)
+ return NULL;
+ status = efi_setup_gop(si, &gop_proto, size);
+ if (status != EFI_SUCCESS) {
+ free_screen_info(si);
+ return NULL;
+ }
+ }
+ return si;
+}
+
/*
* EFI entry point for the generic EFI stub used by ARM, arm64, RISC-V and
* LoongArch. This is the entrypoint that is described in the PE/COFF header
@@ -22,6 +46,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
unsigned long reserve_addr = 0;
unsigned long reserve_size = 0;
+ struct screen_info *si;

WRITE_ONCE(efi_system_table, systab);

@@ -47,6 +72,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,

efi_info("Booting Linux Kernel...\n");

+ si = setup_graphics();
+
status = handle_kernel_image(&image_addr, &image_size,
&reserve_addr,
&reserve_size,
@@ -58,6 +85,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,

status = efi_stub_common(handle, image, image_addr, cmdline_ptr);

+ free_screen_info(si);
+
efi_free(image_size, image_addr);
efi_free(reserve_size, reserve_addr);

diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
index 2955c1ac6a36..bc67af721412 100644
--- a/drivers/firmware/efi/libstub/efi-stub.c
+++ b/drivers/firmware/efi/libstub/efi-stub.c
@@ -56,30 +56,6 @@ void __weak free_screen_info(struct screen_info *si)
{
}

-static struct screen_info *setup_graphics(void)
-{
- efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
- efi_status_t status;
- unsigned long size;
- void **gop_handle = NULL;
- struct screen_info *si = NULL;
-
- size = 0;
- status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
- &gop_proto, NULL, &size, gop_handle);
- if (status == EFI_BUFFER_TOO_SMALL) {
- si = alloc_screen_info();
- if (!si)
- return NULL;
- status = efi_setup_gop(si, &gop_proto, size);
- if (status != EFI_SUCCESS) {
- free_screen_info(si);
- return NULL;
- }
- }
- return si;
-}
-
static void install_memreserve_table(void)
{
struct linux_efi_memreserve *rsv;
@@ -163,14 +139,12 @@ efi_status_t efi_stub_common(efi_handle_t handle,
unsigned long image_addr,
char *cmdline_ptr)
{
- struct screen_info *si;
efi_status_t status;

status = check_platform_features();
if (status != EFI_SUCCESS)
return status;

- si = setup_graphics();

efi_retrieve_tpm2_eventlog();

@@ -190,7 +164,6 @@ efi_status_t efi_stub_common(efi_handle_t handle,

status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr);

- free_screen_info(si);
return status;
}

--
2.39.1