| Message ID | 1406630950-32432-3-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On Tue, 2014-07-29 at 12:49 +0200, Ard Biesheuvel wrote: > The static memory footprint of a kernel Image at boot is larger than the > Image file itself. Things like .bss data and initial page tables are allocated > statically but populated dynamically so their content is not contained in the > Image file. > > However, if EFI (or GRUB) has loaded the Image at precisely the desired offset > of base of DRAM + TEXT_OFFSET, the Image will be booted in place, and we have > to make sure that the allocation done by the PE/COFF loader is large enough. > > Fix this by growing the PE/COFF .text section to cover the entire static > memory footprint. The part of the section that is not covered by the payload > will be zero initialised by the PE/COFF loader. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm64/kernel/head.S | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) Acked-by: Mark Salter <msalter@redhat.com> > > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 69dafe9621fd..dafc4f2c1ade 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -148,7 +148,7 @@ optional_header: > .short 0x20b // PE32+ format > .byte 0x02 // MajorLinkerVersion > .byte 0x14 // MinorLinkerVersion > - .long _edata - stext // SizeOfCode > + .long _end - stext // SizeOfCode > .long 0 // SizeOfInitializedData > .long 0 // SizeOfUninitializedData > .long efi_stub_entry - efi_head // AddressOfEntryPoint > @@ -166,7 +166,7 @@ extra_header_fields: > .short 0 // MinorSubsystemVersion > .long 0 // Win32VersionValue > > - .long _edata - efi_head // SizeOfImage > + .long _end - efi_head // SizeOfImage > > // Everything before the kernel image is considered part of the header > .long stext - efi_head // SizeOfHeaders > @@ -213,7 +213,7 @@ section_table: > .byte 0 > .byte 0 > .byte 0 // end of 0 padding of section name > - .long _edata - stext // VirtualSize > + .long _end - stext // VirtualSize > .long stext - efi_head // VirtualAddress > .long _edata - stext // SizeOfRawData > .long stext - efi_head // PointerToRawData
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 69dafe9621fd..dafc4f2c1ade 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -148,7 +148,7 @@ optional_header: .short 0x20b // PE32+ format .byte 0x02 // MajorLinkerVersion .byte 0x14 // MinorLinkerVersion - .long _edata - stext // SizeOfCode + .long _end - stext // SizeOfCode .long 0 // SizeOfInitializedData .long 0 // SizeOfUninitializedData .long efi_stub_entry - efi_head // AddressOfEntryPoint @@ -166,7 +166,7 @@ extra_header_fields: .short 0 // MinorSubsystemVersion .long 0 // Win32VersionValue - .long _edata - efi_head // SizeOfImage + .long _end - efi_head // SizeOfImage // Everything before the kernel image is considered part of the header .long stext - efi_head // SizeOfHeaders @@ -213,7 +213,7 @@ section_table: .byte 0 .byte 0 .byte 0 // end of 0 padding of section name - .long _edata - stext // VirtualSize + .long _end - stext // VirtualSize .long stext - efi_head // VirtualAddress .long _edata - stext // SizeOfRawData .long stext - efi_head // PointerToRawData
The static memory footprint of a kernel Image at boot is larger than the Image file itself. Things like .bss data and initial page tables are allocated statically but populated dynamically so their content is not contained in the Image file. However, if EFI (or GRUB) has loaded the Image at precisely the desired offset of base of DRAM + TEXT_OFFSET, the Image will be booted in place, and we have to make sure that the allocation done by the PE/COFF loader is large enough. Fix this by growing the PE/COFF .text section to cover the entire static memory footprint. The part of the section that is not covered by the payload will be zero initialised by the PE/COFF loader. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm64/kernel/head.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)