| Message ID | 20230312225838.3702574-1-ardb@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | efi: libstub: Always pass screen_info via config table | expand |
On Sun, 12 Mar 2023 at 23:58, Ard Biesheuvel <ardb@kernel.org> 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@lists.linux.dev > Cc: Xuefeng Li <lixuefeng@loongson.cn> > Cc: Xuerui Wang <kernel@xen0n.name> > Cc: loongson-kernel@lists.loongnix.cn > Reported-by: Huacai Chen <chenhuacai@loongson.cn> > Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ > Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file") > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 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 >
Hi, On 2023/3/13 06:58, Ard Biesheuvel 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@lists.linux.dev > Cc: Xuefeng Li <lixuefeng@loongson.cn> > Cc: Xuerui Wang <kernel@xen0n.name> > Cc: loongson-kernel@lists.loongnix.cn > Reported-by: Huacai Chen <chenhuacai@loongson.cn> > Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ > Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file") > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > --- > 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(-) > The cleanup looks good to me, thanks! I'm currently unable to verify though, because my loongarch box currently has an RX 6400 plugged in which won't get initialized by the firmware (likely related to newer x86 emulation capability required by the card's VBIOS) so I can't see the efifb. I'll swap that card out maybe this week to test this (and the other "Reprobe after parsing config tables" patch) though!
Hi, Ard, I'm a bit confused, It seems this patch cannot solve the problem reported in [1] for LoongArch. [1] https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ Huacai On Mon, Mar 13, 2023 at 3:45 PM Ard Biesheuvel <ardb@kernel.org> wrote: > > On Sun, 12 Mar 2023 at 23:58, Ard Biesheuvel <ardb@kernel.org> 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@lists.linux.dev > > Cc: Xuefeng Li <lixuefeng@loongson.cn> > > Cc: Xuerui Wang <kernel@xen0n.name> > > Cc: loongson-kernel@lists.loongnix.cn > > Reported-by: Huacai Chen <chenhuacai@loongson.cn> > > Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ > > Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file") > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > 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 > > >
On Mon, 13 Mar 2023 at 08:56, Huacai Chen <chenhuacai@kernel.org> wrote: > > Hi, Ard, > > I'm a bit confused, It seems this patch cannot solve the problem > reported in [1] for LoongArch. > [1] https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ > The intent was to always pass the screen_info contents via the configuration table, so I am surprised that this does not work. However, I am preparing a v2 that preserves the old behavior - I'll send it out in a minute. > > On Mon, Mar 13, 2023 at 3:45 PM Ard Biesheuvel <ardb@kernel.org> wrote: > > > > On Sun, 12 Mar 2023 at 23:58, Ard Biesheuvel <ardb@kernel.org> 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@lists.linux.dev > > > Cc: Xuefeng Li <lixuefeng@loongson.cn> > > > Cc: Xuerui Wang <kernel@xen0n.name> > > > Cc: loongson-kernel@lists.loongnix.cn > > > Reported-by: Huacai Chen <chenhuacai@loongson.cn> > > > Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ > > > Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file") > > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > > > 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 > > > > >
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)
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@lists.linux.dev Cc: Xuefeng Li <lixuefeng@loongson.cn> Cc: Xuerui Wang <kernel@xen0n.name> Cc: loongson-kernel@lists.loongnix.cn Reported-by: Huacai Chen <chenhuacai@loongson.cn> Link: https://lore.kernel.org/linux-efi/20230310021749.921041-1-chenhuacai@loongson.cn/ Fixes: 42c8ea3dca094ab8 ("efi: libstub: Factor out EFI stub entrypoint into separate file") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- 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(-)