On Sun, 12 Mar 2023 at 23:58, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > In some cases, we expose the kernel's struct screen_info to the EFI stub > directly, so it gets populated before even entering the kernel. This > means the early console is available as soon as the early param parsing > happens, which is nice. It also means we need two different ways to pass > this information, as this trick only works if the EFI stub is baked into > the core kernel image, which is not always the case. > > Huacai reports that the preparatory refactoring that was needed to > implement this alternative method for zboot resulted in a non-functional > efifb earlycon for other cases as well, due to the reordering of the > kernel image relocation with the population of the screen_info struct, > and the latter now takes place after copying the image to its new > location, which means we copy the old, uninitialized state. > > To fix this and simplify things at the same time, let's just always use > the config table method. > > Cc: loongarch@xxxxxxxxxxxxxxx > Cc: Xuefeng Li <lixuefeng@xxxxxxxxxxx> > Cc: Xuerui Wang <kernel@xxxxxxxxxx> > Cc: loongson-kernel@xxxxxxxxxxxxxxxxx > Reported-by: Huacai Chen <chenhuacai@xxxxxxxxxxx> > Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@xxxxxxxxxxx/ > Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file") > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Please disregard - I think I can simplify this without losing the very early earlycon. > --- > arch/arm64/kernel/image-vars.h | 1 - > arch/loongarch/kernel/image-vars.h | 1 - > arch/riscv/kernel/image-vars.h | 1 - > drivers/firmware/efi/libstub/efi-stub.c | 9 --------- > drivers/firmware/efi/libstub/screen_info.c | 19 ------------------- > 5 files changed, 31 deletions(-) > > diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h > index 8309197c0ebd4a8e..01382bd99d0addea 100644 > --- a/arch/arm64/kernel/image-vars.h > +++ b/arch/arm64/kernel/image-vars.h > @@ -27,7 +27,6 @@ PROVIDE(__efistub__text = _text); > PROVIDE(__efistub__end = _end); > PROVIDE(__efistub___inittext_end = __inittext_end); > PROVIDE(__efistub__edata = _edata); > -PROVIDE(__efistub_screen_info = screen_info); > PROVIDE(__efistub__ctype = _ctype); > > PROVIDE(__pi___memcpy = __pi_memcpy); > diff --git a/arch/loongarch/kernel/image-vars.h b/arch/loongarch/kernel/image-vars.h > index e561989d02de93c5..110cdc32cba5f28b 100644 > --- a/arch/loongarch/kernel/image-vars.h > +++ b/arch/loongarch/kernel/image-vars.h > @@ -12,7 +12,6 @@ __efistub_kernel_entry = kernel_entry; > __efistub_kernel_asize = kernel_asize; > __efistub_kernel_fsize = kernel_fsize; > __efistub_kernel_offset = kernel_offset; > -__efistub_screen_info = screen_info; > > #endif > > diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h > index 7e2962ef73f92e95..5e2515fa013495cb 100644 > --- a/arch/riscv/kernel/image-vars.h > +++ b/arch/riscv/kernel/image-vars.h > @@ -29,7 +29,6 @@ __efistub__start = _start; > __efistub__start_kernel = _start_kernel; > __efistub__end = _end; > __efistub__edata = _edata; > -__efistub_screen_info = screen_info; > > #endif > > diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c > index 2955c1ac6a36ee00..c4b9eccad0f103dc 100644 > --- a/drivers/firmware/efi/libstub/efi-stub.c > +++ b/drivers/firmware/efi/libstub/efi-stub.c > @@ -47,15 +47,6 @@ > static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; > static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0); > > -struct screen_info * __weak alloc_screen_info(void) > -{ > - return &screen_info; > -} > - > -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; > diff --git a/drivers/firmware/efi/libstub/screen_info.c b/drivers/firmware/efi/libstub/screen_info.c > index 8e76a8b384ba142d..7b791541a1ad1b48 100644 > --- a/drivers/firmware/efi/libstub/screen_info.c > +++ b/drivers/firmware/efi/libstub/screen_info.c > @@ -5,25 +5,6 @@ > > #include "efistub.h" > > -/* > - * There are two ways of populating the core kernel's struct screen_info via the stub: > - * - using a configuration table, like below, which relies on the EFI init code > - * to locate the table and copy the contents; > - * - by linking directly to the core kernel's copy of the global symbol. > - * > - * The latter is preferred because it makes the EFIFB earlycon available very > - * early, but it only works if the EFI stub is part of the core kernel image > - * itself. The zboot decompressor can only use the configuration table > - * approach. > - * > - * In order to support both methods from the same build of the EFI stub > - * library, provide this dummy global definition of struct screen_info. If it > - * is required to satisfy a link dependency, it means we need to override the > - * __weak alloc and free methods with the ones below, and those will be pulled > - * in as well. > - */ > -struct screen_info screen_info; > - > static efi_guid_t screen_info_guid = LINUX_EFI_SCREEN_INFO_TABLE_GUID; > > struct screen_info *alloc_screen_info(void) > -- > 2.39.2 >
