Hi Huang.
A few comments..
> Init BSS sections are added for uninitialized init DATA sections to
> reduce kernel image size.
- If this is relevant for more than just x86 then the definition
of the section should be in include/asm-generic/vmlinux.lds.h
- Please add a comment along the definitions in the .lds file
explaning the use of the section.
- Same goes for init.h
- Is this concept restricted to __init or is it
relevant for __devinit etc (I hope we can avoid that)
- Can we do any kind of build time check to catch
accidental misuse?
Sam
>
> Signed-off-by: Huang Ying <[EMAIL PROTECTED]>
>
> ---
> arch/x86/kernel/head64.c | 2 ++
> arch/x86/kernel/head_32.S | 5 +++++
> arch/x86/kernel/vmlinux_32.lds.S | 9 +++++++--
> arch/x86/kernel/vmlinux_64.lds.S | 24 ++++++++++++++----------
> include/asm-generic/sections.h | 1 +
> include/linux/init.h | 1 +
> 6 files changed, 30 insertions(+), 12 deletions(-)
>
> --- a/arch/x86/kernel/vmlinux_32.lds.S
> +++ b/arch/x86/kernel/vmlinux_32.lds.S
> @@ -189,10 +189,15 @@ SECTIONS
> __per_cpu_end = .;
> }
> . = ALIGN(PAGE_SIZE);
Do we really need to aling this to PAGE_SIZE - I
assume we free everything in one go - or?
> - /* freed after init ends here */
>
> .bss : AT(ADDR(.bss) - LOAD_OFFSET) {
> - __init_end = .;
> + __init_bss_start = .;
> + *(.bss.init.page_aligned)
I do not see this section used anywhere. At least init.h does not
define it.
> + *(.bss.init)
> + . = ALIGN(4);
> + __init_bss_stop = .;
> + . = ALIGN(PAGE_SIZE);
Why do we have these two ALIGN() following each other?
The latter should be enough.
> + __init_end = .; /* freed after init ends here */
> __bss_start = .; /* BSS */
> *(.bss.page_aligned)
> *(.bss)
> --- a/arch/x86/kernel/vmlinux_64.lds.S
> +++ b/arch/x86/kernel/vmlinux_64.lds.S
> @@ -150,6 +150,12 @@ SECTIONS
> . = ALIGN(PAGE_SIZE);
> __smp_alt_end = .;
>
> + . = ALIGN(PAGE_SIZE);
> + __nosave_begin = .;
> + .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { *(.data.nosave) }
> + . = ALIGN(PAGE_SIZE);
> + __nosave_end = .;
> +
This change looks unrelated - it is not in the changelog.
Or is it just diff that fools me?
> . = ALIGN(PAGE_SIZE); /* Init code and data */
> __init_begin = .;
> .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
> @@ -219,17 +225,15 @@ SECTIONS
>
> PERCPU(PAGE_SIZE)
>
> - . = ALIGN(PAGE_SIZE);
> - __init_end = .;
> -
> - . = ALIGN(PAGE_SIZE);
> - __nosave_begin = .;
> - .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { *(.data.nosave) }
> - . = ALIGN(PAGE_SIZE);
> - __nosave_end = .;
> -
> - __bss_start = .; /* BSS */
> + . = ALIGN(PAGE_SIZE); /* BSS */
> .bss : AT(ADDR(.bss) - LOAD_OFFSET) {
> + __init_bss_start = .;
> + *(.bss.init.page_aligned)
> + *(.bss.init)
> + __init_bss_stop = .;
> + . = ALIGN(PAGE_SIZE);
> + __init_end = .;
> + __bss_start = .;
> *(.bss.page_aligned)
> *(.bss)
> }
> --- a/arch/x86/kernel/head_32.S
> +++ b/arch/x86/kernel/head_32.S
> @@ -105,6 +105,11 @@ ENTRY(startup_32)
> */
> cld
> xorl %eax,%eax
> + movl $pa(__init_bss_start),%edi
> + movl $pa(__init_bss_stop), %ecx
> + subl %edi,%ecx
> + shrl $2,%ecx
> + rep ; stosl
> movl $pa(__bss_start),%edi
> movl $pa(__bss_stop),%ecx
> subl %edi,%ecx
How about introducing head32.c and do this in a similar
way that 64 bit does?
Then we could later move more stuff to said file.
Sam
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