| Message ID | 1486676573-19237-1-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/2] efi: arm-stub: Correct FDT and initrd allocation rules for arm64 | expand |
On 2/9/2017 2:42 PM, Ard Biesheuvel wrote: > On arm64, we have made some changes over the past year to the way the > kernel itself is allocated and to how it deals with the initrd and FDT. > This patch brings the allocation logic in the EFI stub in line with that, > which is necessary because the introduction of KASLR has created the > possibility for the initrd to be allocated in a place where the kernel > may not be able to map it. (This is mostly a theoretical scenario, since > it only affects systems where the physical memory footprint exceeds the > size of the linear mapping.) > > Since we know the kernel itself will be covered by the linear mapping, > choose a suitably sized window (i.e., based on the size of the linear > region) covering the kernel when allocating memory for the initrd. > > The FDT may be anywhere in memory on arm64 now that we map it via the > fixmap, so we can lift the address restriction there completely. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm/include/asm/efi.h | 14 +++++++++++++- > arch/arm64/include/asm/efi.h | 18 +++++++++++++++++- > drivers/firmware/efi/libstub/arm-stub.c | 7 ++++--- > 3 files changed, 34 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h > index 0b06f5341b45..2de0195dfd1e 100644 > --- a/arch/arm/include/asm/efi.h > +++ b/arch/arm/include/asm/efi.h > @@ -84,6 +84,18 @@ static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt) > */ > #define ZIMAGE_OFFSET_LIMIT SZ_128M > #define MIN_ZIMAGE_OFFSET MAX_UNCOMP_KERNEL_SIZE > -#define MAX_FDT_OFFSET ZIMAGE_OFFSET_LIMIT > + > +/* on ARM, the FDT should be located in the first 128 MB of RAM */ > +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) > +{ > + return dram_base + ZIMAGE_OFFSET_LIMIT; > +} > + > +/* on ARM, the initrd should be loaded in a lowmem region */ > +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, > + unsigned long image_addr) > +{ > + return dram_base + SZ_512M; > +} > > #endif /* _ASM_ARM_EFI_H */ > diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h > index 0b6b1633017f..342e90d6d204 100644 > --- a/arch/arm64/include/asm/efi.h > +++ b/arch/arm64/include/asm/efi.h > @@ -46,7 +46,23 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); > * 2MiB so we know it won't cross a 2MiB boundary. > */ > #define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */ > -#define MAX_FDT_OFFSET SZ_512M > + > +/* on arm64, the FDT may be located anywhere in system RAM */ > +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) > +{ > + return ULONG_MAX; > +} > + > +/* > + * On arm64, we have to ensure that the initrd ends up in the linear region, > + * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is > + * guaranteed to cover the kernel Image. > + */ > +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, > + unsigned long image_addr) > +{ > + return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1)); > +} > Please update booting.txt which specifies a window of 32G for ARM64 > #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) > #define __efi_call_early(f, ...) f(__VA_ARGS__) > diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c > index b4f7d78f9e8b..557281fe375f 100644 > --- a/drivers/firmware/efi/libstub/arm-stub.c > +++ b/drivers/firmware/efi/libstub/arm-stub.c > @@ -333,8 +333,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, > if (!fdt_addr) > pr_efi(sys_table, "Generating empty DTB\n"); > > - status = handle_cmdline_files(sys_table, image, cmdline_ptr, > - "initrd=", dram_base + SZ_512M, > + status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=", > + efi_get_max_initrd_addr(dram_base, > + *image_addr), > (unsigned long *)&initrd_addr, > (unsigned long *)&initrd_size); > if (status != EFI_SUCCESS) > @@ -344,7 +345,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, > > new_fdt_addr = fdt_addr; > status = allocate_new_fdt_and_exit_boot(sys_table, handle, > - &new_fdt_addr, dram_base + MAX_FDT_OFFSET, > + &new_fdt_addr, efi_get_max_fdt_addr(dram_base), > initrd_addr, initrd_size, cmdline_ptr, > fdt_addr, fdt_size); > -- Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> On 10 Feb 2017, at 00:42, Ruigrok, Richard <rruigrok@codeaurora.org> wrote: > > > >> On 2/9/2017 2:42 PM, Ard Biesheuvel wrote: >> On arm64, we have made some changes over the past year to the way the >> kernel itself is allocated and to how it deals with the initrd and FDT. >> This patch brings the allocation logic in the EFI stub in line with that, >> which is necessary because the introduction of KASLR has created the >> possibility for the initrd to be allocated in a place where the kernel >> may not be able to map it. (This is mostly a theoretical scenario, since >> it only affects systems where the physical memory footprint exceeds the >> size of the linear mapping.) >> >> Since we know the kernel itself will be covered by the linear mapping, >> choose a suitably sized window (i.e., based on the size of the linear >> region) covering the kernel when allocating memory for the initrd. >> >> The FDT may be anywhere in memory on arm64 now that we map it via the >> fixmap, so we can lift the address restriction there completely. >> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> --- >> arch/arm/include/asm/efi.h | 14 +++++++++++++- >> arch/arm64/include/asm/efi.h | 18 +++++++++++++++++- >> drivers/firmware/efi/libstub/arm-stub.c | 7 ++++--- >> 3 files changed, 34 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h >> index 0b06f5341b45..2de0195dfd1e 100644 >> --- a/arch/arm/include/asm/efi.h >> +++ b/arch/arm/include/asm/efi.h >> @@ -84,6 +84,18 @@ static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt) >> */ >> #define ZIMAGE_OFFSET_LIMIT SZ_128M >> #define MIN_ZIMAGE_OFFSET MAX_UNCOMP_KERNEL_SIZE >> -#define MAX_FDT_OFFSET ZIMAGE_OFFSET_LIMIT >> + >> +/* on ARM, the FDT should be located in the first 128 MB of RAM */ >> +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) >> +{ >> + return dram_base + ZIMAGE_OFFSET_LIMIT; >> +} >> + >> +/* on ARM, the initrd should be loaded in a lowmem region */ >> +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, >> + unsigned long image_addr) >> +{ >> + return dram_base + SZ_512M; >> +} >> >> #endif /* _ASM_ARM_EFI_H */ >> diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h >> index 0b6b1633017f..342e90d6d204 100644 >> --- a/arch/arm64/include/asm/efi.h >> +++ b/arch/arm64/include/asm/efi.h >> @@ -46,7 +46,23 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); >> * 2MiB so we know it won't cross a 2MiB boundary. >> */ >> #define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */ >> -#define MAX_FDT_OFFSET SZ_512M >> + >> +/* on arm64, the FDT may be located anywhere in system RAM */ >> +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) >> +{ >> + return ULONG_MAX; >> +} >> + >> +/* >> + * On arm64, we have to ensure that the initrd ends up in the linear region, >> + * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is >> + * guaranteed to cover the kernel Image. >> + */ >> +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, >> + unsigned long image_addr) >> +{ >> + return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1)); >> +} >> > Please update booting.txt which specifies a window of 32G for ARM64 > No. The efi stub is built into the kernel, so there we can be lax about these things. For boot loaders, 32GB remains a reasonable limit because some configurations require it >> #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) >> #define __efi_call_early(f, ...) f(__VA_ARGS__) >> diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c >> index b4f7d78f9e8b..557281fe375f 100644 >> --- a/drivers/firmware/efi/libstub/arm-stub.c >> +++ b/drivers/firmware/efi/libstub/arm-stub.c >> @@ -333,8 +333,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, >> if (!fdt_addr) >> pr_efi(sys_table, "Generating empty DTB\n"); >> >> - status = handle_cmdline_files(sys_table, image, cmdline_ptr, >> - "initrd=", dram_base + SZ_512M, >> + status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=", >> + efi_get_max_initrd_addr(dram_base, >> + *image_addr), >> (unsigned long *)&initrd_addr, >> (unsigned long *)&initrd_size); >> if (status != EFI_SUCCESS) >> @@ -344,7 +345,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, >> >> new_fdt_addr = fdt_addr; >> status = allocate_new_fdt_and_exit_boot(sys_table, handle, >> - &new_fdt_addr, dram_base + MAX_FDT_OFFSET, >> + &new_fdt_addr, efi_get_max_fdt_addr(dram_base), >> initrd_addr, initrd_size, cmdline_ptr, >> fdt_addr, fdt_size); >> > > -- > Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc. > Qualcomm Technologies, Inc. is a member of the > Code Aurora Forum, a Linux Foundation Collaborative Project. > -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Feb 10, 2017 at 06:38:11AM +0000, Ard Biesheuvel wrote: > > On 10 Feb 2017, at 00:42, Ruigrok, Richard <rruigrok@codeaurora.org> wrote: > >> On 2/9/2017 2:42 PM, Ard Biesheuvel wrote: > >> diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h > >> index 0b6b1633017f..342e90d6d204 100644 > >> --- a/arch/arm64/include/asm/efi.h > >> +++ b/arch/arm64/include/asm/efi.h > >> @@ -46,7 +46,23 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); > >> * 2MiB so we know it won't cross a 2MiB boundary. > >> */ > >> #define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */ > >> -#define MAX_FDT_OFFSET SZ_512M > >> + > >> +/* on arm64, the FDT may be located anywhere in system RAM */ > >> +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) > >> +{ > >> + return ULONG_MAX; > >> +} > >> + > >> +/* > >> + * On arm64, we have to ensure that the initrd ends up in the linear region, > >> + * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is > >> + * guaranteed to cover the kernel Image. > >> + */ > >> +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, > >> + unsigned long image_addr) > >> +{ > >> + return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1)); > >> +} > >> > > Please update booting.txt which specifies a window of 32G for ARM64 > > > > No. The efi stub is built into the kernel, so there we can be lax > about these things. Sure. Given this is a source of confusion, can we drop a comment here as to how this is deliberate? e.g. /* * On arm64, we have to ensure that the initrd ends up in the linear region, * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is * guaranteed to cover the kernel Image. * * Since the EFI stub is part of the kernel Image, we can relax than the * usual requirements in Documentation/arm64/booting.txt, which still * apply to other bootloaders, and are required for some kernel * configurations. */ Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10 February 2017 at 10:05, Mark Rutland <mark.rutland@arm.com> wrote: > On Fri, Feb 10, 2017 at 06:38:11AM +0000, Ard Biesheuvel wrote: >> > On 10 Feb 2017, at 00:42, Ruigrok, Richard <rruigrok@codeaurora.org> wrote: >> >> On 2/9/2017 2:42 PM, Ard Biesheuvel wrote: > >> >> diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h >> >> index 0b6b1633017f..342e90d6d204 100644 >> >> --- a/arch/arm64/include/asm/efi.h >> >> +++ b/arch/arm64/include/asm/efi.h >> >> @@ -46,7 +46,23 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); >> >> * 2MiB so we know it won't cross a 2MiB boundary. >> >> */ >> >> #define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */ >> >> -#define MAX_FDT_OFFSET SZ_512M >> >> + >> >> +/* on arm64, the FDT may be located anywhere in system RAM */ >> >> +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) >> >> +{ >> >> + return ULONG_MAX; >> >> +} >> >> + >> >> +/* >> >> + * On arm64, we have to ensure that the initrd ends up in the linear region, >> >> + * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is >> >> + * guaranteed to cover the kernel Image. >> >> + */ >> >> +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, >> >> + unsigned long image_addr) >> >> +{ >> >> + return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1)); >> >> +} >> >> >> > Please update booting.txt which specifies a window of 32G for ARM64 >> > >> >> No. The efi stub is built into the kernel, so there we can be lax >> about these things. > > Sure. > > Given this is a source of confusion, can we drop a comment here as to > how this is deliberate? e.g. > > /* > * On arm64, we have to ensure that the initrd ends up in the linear region, > * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is > * guaranteed to cover the kernel Image. > * > * Since the EFI stub is part of the kernel Image, we can relax than the > * usual requirements in Documentation/arm64/booting.txt, which still > * apply to other bootloaders, and are required for some kernel > * configurations. > */ > Absolutely -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2/9/2017 2:42 PM, Ard Biesheuvel wrote: > On arm64, we have made some changes over the past year to the way the > kernel itself is allocated and to how it deals with the initrd and FDT. > This patch brings the allocation logic in the EFI stub in line with that, > which is necessary because the introduction of KASLR has created the > possibility for the initrd to be allocated in a place where the kernel > may not be able to map it. (This is mostly a theoretical scenario, since > it only affects systems where the physical memory footprint exceeds the > size of the linear mapping.) > > Since we know the kernel itself will be covered by the linear mapping, > choose a suitably sized window (i.e., based on the size of the linear > region) covering the kernel when allocating memory for the initrd. > > The FDT may be anywhere in memory on arm64 now that we map it via the > fixmap, so we can lift the address restriction there completely. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- Reviewed-By: Jeffrey Hugo <jhugo@codeaurora.org> > arch/arm/include/asm/efi.h | 14 +++++++++++++- > arch/arm64/include/asm/efi.h | 18 +++++++++++++++++- > drivers/firmware/efi/libstub/arm-stub.c | 7 ++++--- > 3 files changed, 34 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h > index 0b06f5341b45..2de0195dfd1e 100644 > --- a/arch/arm/include/asm/efi.h > +++ b/arch/arm/include/asm/efi.h > @@ -84,6 +84,18 @@ static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt) > */ > #define ZIMAGE_OFFSET_LIMIT SZ_128M > #define MIN_ZIMAGE_OFFSET MAX_UNCOMP_KERNEL_SIZE > -#define MAX_FDT_OFFSET ZIMAGE_OFFSET_LIMIT > + > +/* on ARM, the FDT should be located in the first 128 MB of RAM */ > +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) > +{ > + return dram_base + ZIMAGE_OFFSET_LIMIT; > +} > + > +/* on ARM, the initrd should be loaded in a lowmem region */ > +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, > + unsigned long image_addr) > +{ > + return dram_base + SZ_512M; > +} > > #endif /* _ASM_ARM_EFI_H */ > diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h > index 0b6b1633017f..342e90d6d204 100644 > --- a/arch/arm64/include/asm/efi.h > +++ b/arch/arm64/include/asm/efi.h > @@ -46,7 +46,23 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); > * 2MiB so we know it won't cross a 2MiB boundary. > */ > #define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */ > -#define MAX_FDT_OFFSET SZ_512M > + > +/* on arm64, the FDT may be located anywhere in system RAM */ > +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) > +{ > + return ULONG_MAX; > +} > + > +/* > + * On arm64, we have to ensure that the initrd ends up in the linear region, > + * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is > + * guaranteed to cover the kernel Image. > + */ > +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, > + unsigned long image_addr) > +{ > + return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1)); > +} > > #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) > #define __efi_call_early(f, ...) f(__VA_ARGS__) > diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c > index b4f7d78f9e8b..557281fe375f 100644 > --- a/drivers/firmware/efi/libstub/arm-stub.c > +++ b/drivers/firmware/efi/libstub/arm-stub.c > @@ -333,8 +333,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, > if (!fdt_addr) > pr_efi(sys_table, "Generating empty DTB\n"); > > - status = handle_cmdline_files(sys_table, image, cmdline_ptr, > - "initrd=", dram_base + SZ_512M, > + status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=", > + efi_get_max_initrd_addr(dram_base, > + *image_addr), > (unsigned long *)&initrd_addr, > (unsigned long *)&initrd_size); > if (status != EFI_SUCCESS) > @@ -344,7 +345,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, > > new_fdt_addr = fdt_addr; > status = allocate_new_fdt_and_exit_boot(sys_table, handle, > - &new_fdt_addr, dram_base + MAX_FDT_OFFSET, > + &new_fdt_addr, efi_get_max_fdt_addr(dram_base), > initrd_addr, initrd_size, cmdline_ptr, > fdt_addr, fdt_size); > > -- Jeffrey Hugo Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h index 0b06f5341b45..2de0195dfd1e 100644 --- a/arch/arm/include/asm/efi.h +++ b/arch/arm/include/asm/efi.h @@ -84,6 +84,18 @@ static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt) */ #define ZIMAGE_OFFSET_LIMIT SZ_128M #define MIN_ZIMAGE_OFFSET MAX_UNCOMP_KERNEL_SIZE -#define MAX_FDT_OFFSET ZIMAGE_OFFSET_LIMIT + +/* on ARM, the FDT should be located in the first 128 MB of RAM */ +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) +{ + return dram_base + ZIMAGE_OFFSET_LIMIT; +} + +/* on ARM, the initrd should be loaded in a lowmem region */ +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, + unsigned long image_addr) +{ + return dram_base + SZ_512M; +} #endif /* _ASM_ARM_EFI_H */ diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index 0b6b1633017f..342e90d6d204 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -46,7 +46,23 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); * 2MiB so we know it won't cross a 2MiB boundary. */ #define EFI_FDT_ALIGN SZ_2M /* used by allocate_new_fdt_and_exit_boot() */ -#define MAX_FDT_OFFSET SZ_512M + +/* on arm64, the FDT may be located anywhere in system RAM */ +static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base) +{ + return ULONG_MAX; +} + +/* + * On arm64, we have to ensure that the initrd ends up in the linear region, + * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is + * guaranteed to cover the kernel Image. + */ +static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base, + unsigned long image_addr) +{ + return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1)); +} #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) #define __efi_call_early(f, ...) f(__VA_ARGS__) diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index b4f7d78f9e8b..557281fe375f 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -333,8 +333,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, if (!fdt_addr) pr_efi(sys_table, "Generating empty DTB\n"); - status = handle_cmdline_files(sys_table, image, cmdline_ptr, - "initrd=", dram_base + SZ_512M, + status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=", + efi_get_max_initrd_addr(dram_base, + *image_addr), (unsigned long *)&initrd_addr, (unsigned long *)&initrd_size); if (status != EFI_SUCCESS) @@ -344,7 +345,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, new_fdt_addr = fdt_addr; status = allocate_new_fdt_and_exit_boot(sys_table, handle, - &new_fdt_addr, dram_base + MAX_FDT_OFFSET, + &new_fdt_addr, efi_get_max_fdt_addr(dram_base), initrd_addr, initrd_size, cmdline_ptr, fdt_addr, fdt_size);
On arm64, we have made some changes over the past year to the way the kernel itself is allocated and to how it deals with the initrd and FDT. This patch brings the allocation logic in the EFI stub in line with that, which is necessary because the introduction of KASLR has created the possibility for the initrd to be allocated in a place where the kernel may not be able to map it. (This is mostly a theoretical scenario, since it only affects systems where the physical memory footprint exceeds the size of the linear mapping.) Since we know the kernel itself will be covered by the linear mapping, choose a suitably sized window (i.e., based on the size of the linear region) covering the kernel when allocating memory for the initrd. The FDT may be anywhere in memory on arm64 now that we map it via the fixmap, so we can lift the address restriction there completely. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm/include/asm/efi.h | 14 +++++++++++++- arch/arm64/include/asm/efi.h | 18 +++++++++++++++++- drivers/firmware/efi/libstub/arm-stub.c | 7 ++++--- 3 files changed, 34 insertions(+), 5 deletions(-) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html