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Date: Tue, 14 Mar 2023 23:31:43 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: Huacai Chen <chenhuacai@...ngson.cn>
Cc: Huacai Chen <chenhuacai@...nel.org>, linux-efi@...r.kernel.org,
loongarch@...ts.linux.dev, Xuefeng Li <lixuefeng@...ngson.cn>,
Xuerui Wang <kernel@...0n.name>, linux-kernel@...r.kernel.org,
loongson-kernel@...ts.loongnix.cn
Subject: Re: [PATCH V2] efi/libstub: Call setup_graphics() before handle_kernel_image()
On Fri, 10 Mar 2023 at 03:18, Huacai Chen <chenhuacai@...ngson.cn> wrote:
>
> 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@...ngson.cn>
Please drop this patch from the loonarch tree - it is causing a
conflict in linux-next.
> ---
> V2: Use static declaration for setup_graphics() to avoid build warnings.
>
> 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"
>
> +static 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
>
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