Currently, the documented kernel entry requirements are not
explicit about whether the kernel should be entered in ARM or
Thumb, leading to an ambiguitity about how to enter Thumb-2
kernels. As a result, the kernel is reliant on the zImage
decompressor to enter the kernel proper in the correct instruction
set state.
This patch changes the boot entry protocol for head.S and Image to
be the same as for zImage: in all cases, the kernel is now entered
in ARM.
Documentation/arm/Booting is updated to reflect this new policy.
A different rule will be needed for Cortex-M class CPUs as and when
support for those lands in mainline, since these CPUs don't support
the ARM instruction set at all: a note is added to the effect that
the kernel must be entered in Thumb on such systems.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since the debug macros no longer depend on the machine type information,
the machine type lookup can be deferred to setup_arch() in setup.c which
simplifies the code somewhat.
We also move the __error_a functionality into setup.c for displaying a
message when a bad machine ID is passed to the kernel via the LL debug
code. We also log this into the kernel ring buffer which makes it
possible to retrieve the message via a debugger.
Original idea from Grant Likely.
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
nommu can jump directly to __mmap_switched without the absolute
address branching which the mmuful kernel does.
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This has the consequence of changing the section name used for head
code from ".text.head" to ".head.text". Since this commit changes all
users in the architecture, this change should be harmless.
The .text.head output section is eliminated and the head text code is
included at the start of the .init output section.
Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The patch removes the "mrc" instruction in head-nommu.S overriding the
r0 register containing the value to be written in the CP15 system
control register.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This declaration specifies the "function" type and size for various
assembly functions, mainly needed for generating the correct branch
instructions in Thumb-2.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There are 43 includes of asm/mach-types.h by files that don't
reference anything from that file. Remove these unnecessary
includes.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit 86c0baf123 highlighted that we
may end up with the head text placed elsewhere in the kernel image.
Introduce a new .text.head section to contain the initial kernel
startup code, and always place this section at the beginning of the
kernel image.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
These files want to provide/access ELF hwcap information, so should
be including asm/elf.h rather than asm/procinfo.h
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
In nommu mode, the exception vector location depends on the platforms.
Some of the implementations may have some special exception control
forwarding method in their ROM/flash and for some of them has its own
re-mapping mechanism by the h/w.
This patch introduces a special configuration CONFIG_CPU_HIGH_VECTOR which
turns on the CR_V bit in nommu mode. The CR_V bit is turned off by default.
This feature depends on CP15 and does not supported by ARM740.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
All the current CP15 access codes in ARM arch can be categorized and
conditioned by the defines as follows:
Related operation Safe condition
a. any CP15 access !CPU_CP15
b. alignment trap CPU_CP15_MMU
c. D-cache(C-bit) CPU_CP15
d. I-cache CPU_CP15 && !( CPU_ARM610 || CPU_ARM710 ||
CPU_ARM720 || CPU_ARM740 ||
CPU_XSCALE || CPU_XSC3 )
e. alternate vector CPU_CP15 && !CPU_ARM740
f. TTB CPU_CP15_MMU
g. Domain CPU_CP15_MMU
h. FSR/FAR CPU_CP15_MMU
For example, alternate vector is supported if and only if
"CPU_CP15 && !CPU_ARM740" is satisfied.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
DEFAULT_FIQ was entirely unused. MODE_* are just redefinitions
of *_MODE. Use *_MODE instead.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Uwe Zeisberger
added the following constants:
- MACHINFO_TYPE
- MACHINFO_NAME
- MACHINFO_PHYSIO
- MACHINFO_PGOFFIO
- PROCINFO_INITFUNC
- PROCINFO_MMUFLAGS
and removed their definition from head.S and head-nommu.S
Signed-off-by: Uwe Zeisberger <Uwe_Zeisberger@digi.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch fix compilation problem of start-up codes.
(head-nommu.S, arch/arm/kernel/Makefile)
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds nommu version start-up code head-nommu.S.
The common part of the start-up codes is moved to head-common.S.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Dave Martin