When CPU1 is brought out of reset, it's MMU is not turned on yet, so it will
only be able to use physical addresses. For systems with that have the
MMU page configured for 0xC0000000, 0x80000000, or 0x40000000
"BIC 0x40000000" will work just fine, as it was just converting the
virtual address of &cpu1start_addr into a physical address, ie. 0xC0000000
became 0x80000000. So for systems where the SDRAM controller was able to do a
wrap-around access, this was working fine, as it was just dropping the MSB,
but for systems where out of bounds memory access is not allowed, this would
not allow CPU1 to correctly fetch &cpu1start_addr.
This patch fixes the secondary_trampoline code to correctly fetch the
physical address of cpu1start_addr directly. The patch will subtract the
correct PAGE_OFFSET from &cpu1start_addr. And since on this platform, the
physical memory will always start at 0x0, subtracting PAGE_OFFSET from
&cpu1start_addr will allow CPU1 to correctly fetch the value of cpu1start_addr.
While at it, change the name of cpu1start_addr to socfpga_cpu1start_addr
to avoid any future naming collisions for multiplatform image.
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
---
v4: Updated commit log to correctly lay out the usage of PAGE_OFFSET and
add comments to the same effect.
v3: Used PAGE_OFFSET to get the physical address
v2: Correctly get the physical address instead of just a BIC hack.
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings. In any case, they are temporary and harmless.
This removes all the ARM uses of the __cpuinit macros from C code,
and all __CPUINIT from assembly code. It also had two ".previous"
section statements that were paired off against __CPUINIT
(aka .section ".cpuinit.text") that also get removed here.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Because the CPU1 start address is different for socfpga-vt and
socfpga-cyclone5, we add code to use the correct CPU1 start addr.
Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Signed-off-by: Pavel Machek <pavel@denx.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Olof Johansson <olof@lixom.net>
The socfpga_boot_secondary is correctly marked as __cpuinit but references
secondary_trampoline, which was introduced into the init section, causing
this build warning:
WARNING: vmlinux.o(.cpuinit.text+0xf90): Section mismatch in reference from the function socfpga_boot_secondary() to the variable .init.text:secondary_trampoline
The function __cpuinit socfpga_boot_secondary() references
a variable __init secondary_trampoline.
If secondary_trampoline is only used by socfpga_boot_secondary then
annotate secondary_trampoline with a matching annotation.
The solution is to mark secondary_trampoline as cpuinit as well.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Building a multiplatform kernel with combined armv7 and armv6
kernel does not work with the socfpga smp code, which contains
v7-only instructions. Since this code never runs on armv6,
we can annotate the assmebly with .arch armv7-a, as suggested
by Russell King.
[arnd: reword commit message]
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
