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fac23fe4be
linux/arch/powerpc/kernel
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Michael Ellerman fac23fe4be powerpc: Introduce infrastructure for feature sections with alternatives 
The current feature section logic only supports nop'ing out code, this means
if you want to choose at runtime between instruction sequences, one or both
cases will have to execute the nop'ed out contents of the other section, eg:

BEGIN_FTR_SECTION
	or	1,1,1
END_FTR_SECTION_IFSET(FOO)
BEGIN_FTR_SECTION
	or	2,2,2
END_FTR_SECTION_IFCLR(FOO)

and the resulting code will be either,

	or	1,1,1
	nop

or,
	nop
	or	2,2,2

For small code segments this is fine, but for larger code blocks and in
performance criticial code segments, it would be nice to avoid the nops.
This commit starts to implement logic to allow the following:

BEGIN_FTR_SECTION
	or	1,1,1
FTR_SECTION_ELSE
	or	2,2,2
ALT_FTR_SECTION_END_IFSET(FOO)

and the resulting code will be:

	or	1,1,1
or,
	or	2,2,2

We achieve this by extending the existing FTR macros. The current feature
section semantic just becomes a special case, ie. if the else case is empty
we nop out the default case.

The key limitation is that the size of the else case must be less than or
equal to the size of the default case. If the else case is smaller the
remainder of the section is nop'ed.

We let the linker put the else case code in with the rest of the text,
so that relative branches from the else case are more likley to link,
this has the disadvantage that we can't free the unused else cases.

This commit introduces the required macro and linker script changes, but
does not enable the patching of the alternative sections.

We also need to update two hand-made section entries in reg.h and timex.h

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01 11:28:28 +10:00
..
vdso32 powerpc: Introduce infrastructure for feature sections with alternatives 2008-07-01 11:28:28 +10:00
vdso64 powerpc: Introduce infrastructure for feature sections with alternatives 2008-07-01 11:28:28 +10:00
align.c
asm-offsets.c [POWERPC] 40x/Book-E: Save/restore volatile exception registers 2008-06-02 14:56:35 -05:00
audit.c
btext.c [POWERPC] Remove duplicate #include 2008-05-09 20:22:58 +10:00
clock.c
compat_audit.c
cpu_setup_6xx.S [POWERPC] ppc32: Fix errata for 603 CPUs 2008-04-21 15:00:32 -05:00
cpu_setup_44x.S Revert "[POWERPC] 4xx: Fix 460GT support to not enable FPU" 2008-06-11 07:52:40 -04:00
cpu_setup_pa6t.S
cpu_setup_ppc970.S
cputable.c powerpc: Split out do_feature_fixups() from cputable.c 2008-07-01 11:28:24 +10:00
crash_dump.c powerpc: Add PPC_NOP_INSTR, a hash define for the preferred nop instruction 2008-07-01 11:28:23 +10:00
crash.c powerpc: Increase CRASH_HANDLER_MAX 2008-06-30 22:31:00 +10:00
dma_64.c iommu sg: powerpc: convert iommu to use the IOMMU helper 2008-02-05 09:44:11 -08:00
entry_32.S powerpc/85xx: add DOZE/NAP support for e500 core 2008-06-26 01:48:56 -05:00
entry_64.S [POWERPC] irqtrace support for 64-bit powerpc 2008-04-18 15:38:47 +10:00
firmware.c
fpu.S
head_8xx.S [POWERPC] 8xx: fix swap 2008-03-07 08:42:28 -06:00
head_32.S [POWERPC] Move stackframe definitions to common header 2008-04-18 15:37:18 +10:00
head_40x.S [POWERPC] 40x/Book-E: Save/restore volatile exception registers 2008-06-02 14:56:35 -05:00
head_44x.S Merge branch 'linux-2.6' 2008-06-30 10:16:50 +10:00
head_64.S [POWERPC] Fix bogus paca->_current initialization 2008-05-09 20:22:58 +10:00
head_booke.h powerpc/booke: Add support for new e500mc core 2008-06-18 16:17:56 -05:00
head_fsl_booke.S powerpc/85xx: add DOZE/NAP support for e500 core 2008-06-26 01:48:56 -05:00
ibmebus.c [POWERPC] Replace remaining __FUNCTION__ occurrences 2008-04-01 20:43:09 +11:00
idle_6xx.S powerpc/85xx: add DOZE/NAP support for e500 core 2008-06-26 01:48:56 -05:00
idle_e500.S powerpc/e500mc: flush L2 on NAP for e500mc 2008-06-26 01:49:03 -05:00
idle_power4.S
idle.c
init_task.c [PATCH] take init_files to fs/file.c 2008-05-16 17:22:20 -04:00
io.c
iomap.c
iommu.c [POWERPC] Replace remaining __FUNCTION__ occurrences 2008-04-01 20:43:09 +11:00
irq.c Merge branch 'linux-2.6' 2008-06-30 10:16:50 +10:00
isa-bridge.c [POWERPC] Remove leftover printk in isa-bridge.c 2008-05-09 20:22:59 +10:00
kprobes.c powerpc/booke: Add kprobes support for booke style processors 2008-06-26 03:35:46 -05:00
l2cr_6xx.S
legacy_serial.c [POWERPC] Fix legacy serial search for opb bus ports 2008-02-06 16:30:00 +11:00
lparcfg.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
machine_kexec_32.c
machine_kexec_64.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
machine_kexec.c [POWERPC] Fix crashkernel= handling when no crashkernel= specified 2008-04-30 19:49:48 +10:00
Makefile powerpc: Move common module code into its own file 2008-07-01 11:28:05 +10:00
misc_32.S powerpc/kprobes: Some minor fixes 2008-06-26 03:35:33 -05:00
misc_64.S [POWERPC] Clean up misc_64.S 2008-04-24 20:58:03 +10:00
misc.S powerpc: Add cputable entry for POWER7 2008-06-30 22:31:11 +10:00
module_32.c powerpc: Move common module code into its own file 2008-07-01 11:28:05 +10:00
module_64.c powerpc: Add PPC_NOP_INSTR, a hash define for the preferred nop instruction 2008-07-01 11:28:23 +10:00
module.c powerpc: Move common module code into its own file 2008-07-01 11:28:05 +10:00
msi.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
nvram_64.c
of_device.c [POWERPC] Move of_device_get_modalias to drivers/of 2008-05-16 23:22:28 +10:00
of_platform.c [POWERPC] cell: Generalize io-workarounds code 2008-04-24 21:08:12 +10:00
paca.c [POWERPC] Raise the upper limit of NR_CPUS and move the pacas into the BSS 2008-04-24 20:58:04 +10:00
pci_32.c
pci_64.c [POWERPC] Use dev_set_name in pci_64.c 2008-06-09 11:32:40 +10:00
pci_dn.c
pci-common.c PCI: powerpc: use generic pci_enable_resources() 2008-04-20 21:47:05 -07:00
pmc.c [POWERPC] Made FSL Book-E PMC support more generic 2008-02-05 23:34:14 -06:00
ppc32.h Revert "[POWERPC] Add compat handler for PTRACE_GETSIGINFO" 2008-04-24 14:05:15 +10:00
ppc_ksyms.c [POWERPC] Remove ppc32's export of console_drivers 2008-06-16 15:00:56 +10:00
proc_ppc64.c powerpc: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
process.c [POWERPC] Add IRQSTACKS support on ppc32 2008-04-29 15:57:34 +10:00
prom_init_check.sh [POWERPC] Fix -Os kernel builds with newer gcc versions 2008-06-16 15:00:54 +10:00
prom_init.c powerpc: Tell firmware we support architecture V2.06 2008-07-01 11:28:00 +10:00
prom_parse.c
prom.c [POWERPC] 85xx: Add support for relocatable kernel (and booting at non-zero) 2008-04-24 20:58:01 +10:00
ptrace32.c Revert "[POWERPC] Add compat handler for PTRACE_GETSIGINFO" 2008-04-24 14:05:15 +10:00
ptrace.c [POWERPC] user_regset PTRACE_SETREGS regression fix 2008-03-20 10:10:56 +11:00
rtas_flash.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
rtas_pci.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
rtas-proc.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
rtas-rtc.c
rtas.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
setup_32.c powerpc/85xx: add DOZE/NAP support for e500 core 2008-06-26 01:48:56 -05:00
setup_64.c [POWERPC] Initialize lockdep earlier 2008-05-09 20:22:58 +10:00
setup-common.c powerpc: Add the PC speaker only when requested 2008-06-09 13:42:30 +10:00
setup.h
signal_32.c [POWERPC] Define and use TLF_RESTORE_SIGMASK 2008-05-14 22:31:33 +10:00
signal_64.c [POWERPC] Fix incorrect enabling of VMX when building signal or user context 2008-06-09 11:32:36 +10:00
signal.c [POWERPC] Define and use TLF_RESTORE_SIGMASK 2008-05-14 22:31:33 +10:00
signal.h
smp-tbsync.c
smp.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
softemu8xx.c
stacktrace.c [POWERPC] Fix new warnings arising from stacktrace patch 2008-04-24 20:58:02 +10:00
suspend.c
swsusp_32.S
swsusp_64.c
swsusp_asm64.S
swsusp.c
sys_ppc32.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-04-21 15:50:49 -07:00
syscalls.c unified (weak) sys_pipe implementation 2008-05-03 13:50:33 -07:00
sysfs.c remove __attribute_used__ 2008-01-28 23:21:18 +01:00
systbl_chk.c
systbl_chk.sh
systbl.S
tau_6xx.c
time.c [POWERPC] Fix sparse warnings in arch/powerpc/kernel 2008-05-14 22:31:59 +10:00
traps.c powerpc/booke: Add kprobes support for booke style processors 2008-06-26 03:35:46 -05:00
udbg_16550.c
udbg.c [POWERPC] Mark udbg console as CON_ANYTIME, ie. callable early in boot 2008-04-24 21:08:11 +10:00
vdso.c Reinstate ZERO_PAGE optimization in 'get_user_pages()' and fix XIP 2008-06-20 11:18:25 -07:00
vecemu.c
vector.S
vio.c [POWERPC] Replace remaining __FUNCTION__ occurrences 2008-04-01 20:43:09 +11:00
vmlinux.lds.S powerpc: Introduce infrastructure for feature sections with alternatives 2008-07-01 11:28:28 +10:00