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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-imx
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-imx')
-rw-r--r--arch/arm/mach-imx/headsmp.S1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/arm/mach-imx/headsmp.S b/arch/arm/mach-imx/headsmp.S
index de5047c8a6c8..b5e976816b63 100644
--- a/arch/arm/mach-imx/headsmp.S
+++ b/arch/arm/mach-imx/headsmp.S
@@ -25,7 +25,6 @@ diag_reg_offset:
.endm
ENTRY(v7_secondary_startup)
- bl v7_invalidate_l1
set_diag_reg
b secondary_startup
ENDPROC(v7_secondary_startup)