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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-05-19 17:06:44 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-06-01 11:30:26 +0100
commit02b4e2756e01c623cc4dbceae4b07be75252db5b (patch)
tree2dfe7bc32d8ac07075eb6a3d057f92b15039932e /arch/arm/mach-shmobile/platsmp-apmu.c
parent6a53bc750004fdab11494e9e6c864b4a425fc1a1 (diff)
ARM: v7 setup function should invalidate L1 cache
All ARMv5 and older CPUs invalidate their caches in the early assembly setup function, prior to enabling the MMU. This is because the L1 cache should not contain any data relevant to the execution of the kernel at this point; all data should have been flushed out to memory. This requirement should also be true for ARMv6 and ARMv7 CPUs - indeed, these typically do not search their caches when caching is disabled (as it needs to be when the MMU is disabled) so this change should be safe. ARMv7 allows there to be CPUs which search their caches while caching is disabled, and it's permitted that the cache is uninitialised at boot; for these, the architecture reference manual requires that an implementation specific code sequence is used immediately after reset to ensure that the cache is placed into a sane state. Such functionality is definitely outside the remit of the Linux kernel, and must be done by the SoC's firmware before _any_ CPU gets to the Linux kernel. Changing the data cache clean+invalidate to a mere invalidate allows us to get rid of a lot of platform specific hacks around this issue for their secondary CPU bringup paths - some of which were buggy. Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Tested-by: Florian Fainelli <f.fainelli@gmail.com> Tested-by: Heiko Stuebner <heiko@sntech.de> Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com> Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Acked-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Thierry Reding <treding@nvidia.com> Acked-by: Thierry Reding <treding@nvidia.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Michal Simek <michal.simek@xilinx.com> Tested-by: Wei Xu <xuwei5@hisilicon.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-shmobile/platsmp-apmu.c')
-rw-r--r--arch/arm/mach-shmobile/platsmp-apmu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/mach-shmobile/platsmp-apmu.c b/arch/arm/mach-shmobile/platsmp-apmu.c
index f483b560b066..b0790fc32282 100644
--- a/arch/arm/mach-shmobile/platsmp-apmu.c
+++ b/arch/arm/mach-shmobile/platsmp-apmu.c
@@ -133,7 +133,7 @@ void __init shmobile_smp_apmu_prepare_cpus(unsigned int max_cpus,
int shmobile_smp_apmu_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
/* For this particular CPU register boot vector */
- shmobile_smp_hook(cpu, virt_to_phys(shmobile_invalidate_start), 0);
+ shmobile_smp_hook(cpu, virt_to_phys(secondary_startup), 0);
return apmu_wrap(cpu, apmu_power_on);
}