by David Miller

[permalink] [raw]

Subject: Re: [PATCH 05/14] all-archs: consolidate .data section definition in asm-generic

From: Sam Ravnborg <[email protected]>
Date: Fri, 18 May 2007 11:42:31 +0200

> On Fri, May 18, 2007 at 12:16:04AM -0700, David Miller wrote:
> >
> > Looking at these patches reminds me of a quirk in the generic
> > RODATA definition:
> >
> > > #define RODATA \
> > > . = ALIGN(4096); \
> > > .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
> >
> > It uses ALIGN(4096) which is likely supposed to be something
> > like ALIGN(PAGE_SIZE). Perhaps we should handle this by
> > definiting a LD_PAGE_SIZE at the top of vmlinux.ld.S files
> > that need a value other than 4096, and define the default of
> > 4096 in asm-generic/vmlinux.lds.h?
>
> I would much rather use PAGE_SIZE direct since we have access to that symbol.

I completely agree, that seems to be what platforms which have
a configurable page size such as powerpc, ia64, etc. are already
using in their vmlinux.lds.S files, and I'll likely follow suit on
sparc64. :-)

> > If you could take care of this I'd really appreciate it.
> Will do.
> And may expend the effort a bit further when attacking the .lds files.
>
> It will be a week or two before I get at it.

Thanks a lot.

2007-05-18 10:42:16

by Sam Ravnborg

[permalink] [raw]

Subject: Re: [PATCH 05/14] all-archs: consolidate .data section definition in asm-generic

On Fri, May 18, 2007 at 03:21:26AM -0700, David Miller wrote:
> From: Sam Ravnborg <[email protected]>
> Date: Fri, 18 May 2007 11:42:31 +0200
>
> > On Fri, May 18, 2007 at 12:16:04AM -0700, David Miller wrote:
> > >
> > > Looking at these patches reminds me of a quirk in the generic
> > > RODATA definition:
> > >
> > > > #define RODATA \
> > > > . = ALIGN(4096); \
> > > > .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
> > >
> > > It uses ALIGN(4096) which is likely supposed to be something
> > > like ALIGN(PAGE_SIZE). Perhaps we should handle this by
> > > definiting a LD_PAGE_SIZE at the top of vmlinux.ld.S files
> > > that need a value other than 4096, and define the default of
> > > 4096 in asm-generic/vmlinux.lds.h?
> >
> > I would much rather use PAGE_SIZE direct since we have access to that symbol.
>
> I completely agree, that seems to be what platforms which have
> a configurable page size such as powerpc, ia64, etc. are already
> using in their vmlinux.lds.S files, and I'll likely follow suit on
> sparc64. :-)

If you hold of a bit I would like to use sparc64 as template for
a bit more consolidation.
Most likely I will try to consolidate vmlinux.lds for sparc64 and ARM
at the same time and then take the other arch's one by one.

In the process the vmlinux.lds will start to use a consistent
indenting like the following.

Sample diff only on top of -linus.
I will redo it when I have my current patch-set applied.

Sam

diff --git a/arch/sparc64/kernel/vmlinux.lds.S b/arch/sparc64/kernel/vmlinux.lds.S
index 13fa2a2..e9469ea 100644
--- a/arch/sparc64/kernel/vmlinux.lds.S
+++ b/arch/sparc64/kernel/vmlinux.lds.S
@@ -9,105 +9,149 @@ ENTRY(_start)
jiffies = jiffies_64;
SECTIONS
{
- swapper_low_pmd_dir = 0x0000000000402000;
- . = 0x4000;
- .text 0x0000000000404000 :
- {
- _text = .;
- *(.text)
- SCHED_TEXT
- LOCK_TEXT
- KPROBES_TEXT
- *(.gnu.warning)
- } =0
- _etext = .;
- PROVIDE (etext = .);
-
- RODATA
-
- .data :
- {
- *(.data)
- CONSTRUCTORS
- }
- .data1 : { *(.data1) }
- . = ALIGN(64);
- .data.cacheline_aligned : { *(.data.cacheline_aligned) }
- . = ALIGN(64);
- .data.read_mostly : { *(.data.read_mostly) }
- _edata = .;
- PROVIDE (edata = .);
- .fixup : { *(.fixup) }
-
- . = ALIGN(16);
- __start___ex_table = .;
- __ex_table : { *(__ex_table) }
- __stop___ex_table = .;
-
- . = ALIGN(8192);
- __init_begin = .;
- .init.text : {
- _sinittext = .;
- *(.init.text)
- _einittext = .;
- }
- .init.data : { *(.init.data) }
- . = ALIGN(16);
- __setup_start = .;
- .init.setup : { *(.init.setup) }
- __setup_end = .;
- __initcall_start = .;
- .initcall.init : {
- INITCALLS
- }
- __initcall_end = .;
- __con_initcall_start = .;
- .con_initcall.init : { *(.con_initcall.init) }
- __con_initcall_end = .;
- SECURITY_INIT
- . = ALIGN(4);
- __tsb_ldquad_phys_patch = .;
- .tsb_ldquad_phys_patch : { *(.tsb_ldquad_phys_patch) }
- __tsb_ldquad_phys_patch_end = .;
- __tsb_phys_patch = .;
- .tsb_phys_patch : { *(.tsb_phys_patch) }
- __tsb_phys_patch_end = .;
- __cpuid_patch = .;
- .cpuid_patch : { *(.cpuid_patch) }
- __cpuid_patch_end = .;
- __sun4v_1insn_patch = .;
- .sun4v_1insn_patch : { *(.sun4v_1insn_patch) }
- __sun4v_1insn_patch_end = .;
- __sun4v_2insn_patch = .;
- .sun4v_2insn_patch : { *(.sun4v_2insn_patch) }
- __sun4v_2insn_patch_end = .;
+ swapper_low_pmd_dir = 0x0000000000402000;
+ . = 0x4000;
+ .text 0x0000000000404000 : {
+ _text = .;
+ *(.text)
+ SCHED_TEXT
+ LOCK_TEXT
+ KPROBES_TEXT
+ *(.gnu.warning)
+ } =0
+ _etext = .;
+ PROVIDE (etext = .);
+
+ RODATA
+
+ .data : {
+ *(.data)
+ CONSTRUCTORS
+ }
+ .data1 : {
+ *(.data1)
+ }
+
+ . = ALIGN(64);
+ .data.cacheline_aligned : {
+ *(.data.cacheline_aligned)
+ }
+
+ . = ALIGN(64);
+ .data.read_mostly : {
+ *(.data.read_mostly)
+ }
+ _edata = .;
+ PROVIDE (edata = .);
+ .fixup : {
+ *(.fixup)
+ }
+
+ . = ALIGN(16);
+ __start___ex_table = .;
+ __ex_table : {
+ *(__ex_table)
+ }
+ __stop___ex_table = .;
+
+ . = ALIGN(8192);
+ __init_begin = .;
+ .init.text : {
+ _sinittext = .;
+ *(.init.text)
+ _einittext = .;
+ }
+
+ .init.data : {
+ *(.init.data)
+ }
+
+ . = ALIGN(16);
+ __setup_start = .;
+ .init.setup : {
+ *(.init.setup)
+ }
+ __setup_end = .;
+
+ __initcall_start = .;
+ .initcall.init : {
+ INITCALLS
+ }
+ __initcall_end = .;
+
+ __con_initcall_start = .;
+ .con_initcall.init : {
+ *(.con_initcall.init)
+ }
+ __con_initcall_end = .;
+ SECURITY_INIT
+
+ . = ALIGN(4);
+ __tsb_ldquad_phys_patch = .;
+ .tsb_ldquad_phys_patch : {
+ *(.tsb_ldquad_phys_patch)
+ }
+ __tsb_ldquad_phys_patch_end = .;
+
+ __tsb_phys_patch = .;
+ .tsb_phys_patch : {
+ *(.tsb_phys_patch)
+ }
+ __tsb_phys_patch_end = .;
+
+ __cpuid_patch = .;
+ .cpuid_patch : {
+ *(.cpuid_patch)
+ }
+ __cpuid_patch_end = .;
+
+ __sun4v_1insn_patch = .;
+ .sun4v_1insn_patch : {
+ *(.sun4v_1insn_patch)
+ }
+ __sun4v_1insn_patch_end = .;
+ __sun4v_2insn_patch = .;
+ .sun4v_2insn_patch : {
+ *(.sun4v_2insn_patch)
+ }
+ __sun4v_2insn_patch_end = .;

#ifdef CONFIG_BLK_DEV_INITRD
- . = ALIGN(8192);
- __initramfs_start = .;
- .init.ramfs : { *(.init.ramfs) }
- __initramfs_end = .;
+ . = ALIGN(8192);
+ __initramfs_start = .;
+ .init.ramfs : {
+ *(.init.ramfs)
+ }
+ __initramfs_end = .;
#endif

- . = ALIGN(8192);
- __per_cpu_start = .;
- .data.percpu : { *(.data.percpu) }
- __per_cpu_end = .;
- . = ALIGN(8192);
- __init_end = .;
- __bss_start = .;
- .sbss : { *(.sbss) *(.scommon) }
- .bss :
- {
- *(.dynbss)
- *(.bss)
- *(COMMON)
- }
- _end = . ;
- PROVIDE (end = .);
- /DISCARD/ : { *(.exit.text) *(.exit.data) *(.exitcall.exit) }
-
- STABS_DEBUG
-
- DWARF_DEBUG
+ . = ALIGN(8192);
+ __per_cpu_start = .;
+ .data.percpu : {
+ *(.data.percpu)
+ }
+ __per_cpu_end = .;
+ . = ALIGN(8192);
+ __init_end = .;
+ __bss_start = .;
+ .sbss : {
+ *(.sbss)
+ *(.scommon)
+ }
+ .bss : {
+ *(.dynbss)
+ *(.bss)
+ *(COMMON)
+ }
+ _end = . ;
+ PROVIDE (end = .);
+
+ /DISCARD/ : {
+ *(.exit.text)
+ *(.exit.data)
+ *(.exitcall.exit)
+ }
+
+ STABS_DEBUG
+ DWARF_DEBUG
}