linux/arch/arm/kernel
Nicolas Pitre ca8b5d97d6 ARM: XIP kernel: store .data compressed in ROM
The .data segment stored in ROM is only copied to RAM once at boot time
and never referenced afterwards. This is arguably a suboptimal usage of
ROM resources.

This patch allows for compressing the .data segment before storing it
into ROM and decompressing it to RAM rather than simply copying it,
saving on precious ROM space.

Because global data is not available yet (obviously) we must allocate
decompressor workspace memory on the stack. The .bss area is used as a
stack area for that purpose before it is cleared. The required stack
frame is 9568 bytes for __inflate_kernel_data() alone, so make sure
the .bss is large enough to cope with that plus extra room for called
functions or fail the build.

Those numbers were picked arbitrarily based on the above 9568 byte
stack frame:

10240 (2.5 * PAGE_SIZE): used to override -Wframe-larger-than whose
default value is 1024.
12288 (3 * PAGE_SIZE): minimum .bss size to contain the stack.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Chris Brandt <Chris.Brandt@renesas.com>
2017-09-10 19:34:53 -04:00
..
.gitignore
arch_timer.c
armksyms.c arm: kernel: Add SMC structure parameter 2017-02-03 18:46:33 +00:00
asm-offsets.c ARM: save and reset the address limit when entering an exception 2016-07-07 16:01:01 +01:00
atags_compat.c
atags_parse.c ARM: fix rd_size declaration 2017-07-10 16:32:34 -07:00
atags_proc.c
atags.h
bios32.c ARM/PCI: Fix pcibios_init_resource() struct pci_host_bridge leak 2017-07-10 09:33:14 -05:00
cpuidle.c ARM: 8595/2: apply more __ro_after_init 2016-08-12 16:47:06 +01:00
crash_dump.c
debug.S
devtree.c ARM: 8616/1: dt: Respect property size when parsing CPUs 2016-09-29 16:57:43 +01:00
dma-isa.c
dma.c
early_printk.c
efi.c
elf.c
entry-armv.S ARM: Prepare for randomized task_struct 2017-06-30 12:00:50 -07:00
entry-common.S ARM: convert to generated system call tables 2016-10-18 21:34:06 +01:00
entry-ftrace.S ARM: 8678/1: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS 2017-06-18 22:25:16 +01:00
entry-header.S ARM: save and reset the address limit when entering an exception 2016-07-07 16:01:01 +01:00
entry-v7m.S
fiq.c
fiqasm.S
ftrace.c ARM: 8678/1: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS 2017-06-18 22:25:16 +01:00
head-common.S ARM: XIP kernel: store .data compressed in ROM 2017-09-10 19:34:53 -04:00
head-inflate-data.c ARM: XIP kernel: store .data compressed in ROM 2017-09-10 19:34:53 -04:00
head-nommu.S ARM: 8649/2: nommu: remove Hivecs configuration is asm 2017-02-28 11:06:15 +00:00
head.S Revert "arm: move exports to definitions" 2016-11-23 10:00:03 +00:00
hibernate.c
hw_breakpoint.c ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init 2017-06-20 12:25:22 +02:00
hyp-stub.S ARM: hyp-stub: Fix Thumb-2 compilation 2017-04-20 12:58:53 +02:00
insn.c
io.c
irq.c
isa.c
iwmmxt.S
jump_label.c
kgdb.c scripts/spelling.txt: add regsiter -> register spelling mistake 2017-05-08 17:15:13 -07:00
machine_kexec.c ARM: kexec: fix failure to boot crash kernel 2017-07-20 11:37:42 +01:00
Makefile ARM: XIP kernel: store .data compressed in ROM 2017-09-10 19:34:53 -04:00
module-plts.c ARM: 8662/1: module: split core and init PLT sections 2017-03-17 10:01:28 +00:00
module.c ARM: Silence first allocation with CONFIG_ARM_MODULE_PLTS=y 2017-05-11 14:43:31 +01:00
module.lds ARM: 8662/1: module: split core and init PLT sections 2017-03-17 10:01:28 +00:00
opcodes.c
paravirt.c
patch.c arm: Prevent hotplug rwsem recursion 2017-05-26 10:10:46 +02:00
perf_callchain.c
perf_event_v6.c arm: perf: make of_device_ids const 2017-06-15 11:07:34 +01:00
perf_event_v7.c arm: perf: use builtin_platform_driver 2017-02-03 18:46:42 +00:00
perf_event_xscale.c arm: perf: use builtin_platform_driver 2017-02-03 18:46:42 +00:00
perf_regs.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
pj4-cp0.c
process.c ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO 2017-06-21 13:02:58 +01:00
psci_smp.c
ptrace.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
reboot.c ARM: soft-reboot into same mode that we entered the kernel 2017-04-09 07:49:24 -07:00
reboot.h
relocate_kernel.S
return_address.c
setup.c ARM: kexec: avoid allocating crashkernel region outside lowmem 2017-07-20 11:37:15 +01:00
signal.c ARM: 8687/1: signal: Fix unparseable iwmmxt_sigframe in uc_regspace[] 2017-07-24 14:26:55 +01:00
sigreturn_codes.S
sleep.S
smccc-call.S arm: kernel: Add SMC structure parameter 2017-02-03 18:46:33 +00:00
smp_scu.c
smp_tlb.c ARM: 8613/1: Fix the uaccess crash on PB11MPCore 2017-01-16 17:30:46 +00:00
smp_twd.c clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLARE 2017-06-14 11:58:45 +02:00
smp.c arm: Adjust system_state check 2017-05-23 10:01:35 +02:00
stacktrace.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
suspend.c sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-02 08:42:37 +01:00
swp_emulate.c sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-02 08:42:37 +01:00
sys_arm.c
sys_oabi-compat.c sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
tcm.c
thumbee.c
time.c clocksource/drivers: Rename clocksource_probe to timer_probe 2017-06-14 11:59:16 +02:00
topology.c arm,arm64,drivers: add a prefix to drivers arch_topology interfaces 2017-06-03 19:10:09 +09:00
traps.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> 2017-03-02 08:42:36 +01:00
unwind.c
v7m.c
vdso.c ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO 2017-06-21 13:02:58 +01:00
vmlinux-xip.lds.S ARM: XIP kernel: store .data compressed in ROM 2017-09-10 19:34:53 -04:00
vmlinux.lds.S ARM: vmlinux.lds.S: replace open coded .data sections with generic macros 2017-09-10 19:34:52 -04:00
xscale-cp0.c