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Date: Wed, 15 Mar 2023 08:22:55 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Ard Biesheuvel <ardb@...nel.org>
Cc: Huacai Chen <chenhuacai@...ngson.cn>, 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 Wed, Mar 15, 2023 at 6:31 AM Ard Biesheuvel <ardb@...nel.org> wrote:
>
> 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.
OK, will do.
Huacai
>
>
> > ---
> > 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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