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| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-12-13 17:02:48 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2019-02-02 01:05:23 +0300 |
| commit | 6213f70e7c10fd4a01b65bad3826648fc78df8a8 (patch) | |
| tree | c1296d53776c9668057f570485285754c2424ab5 /arch/arm/mach-exynos/headsmp.S | |
| parent | 70678554c4c40f2cf8de5e7cd53fdd2c73387e51 (diff) | |
| download | linux-6213f70e7c10fd4a01b65bad3826648fc78df8a8.tar.xz | |
ARM: smp: remove arch-provided "pen_release"
Consolidating the "pen_release" stuff amongst the various SoC
implementations gives credence to having a CPU holding pen for
secondary CPUs. However, this is far from the truth.
Many SoC implementations cargo-cult copied various bits of the pen
release implementation from the initial Realview/Versatile Express
implementation without understanding what it was or why it existed.
The reason it existed is because these are _development_ platforms,
and some board firmware is unable to individually control the
startup of secondary CPUs. Moreover, they do not have a way to
power down or reset secondary CPUs for hot-unplug. Hence, the
pen_release implementation was designed for ARM Ltd's development
platforms to provide a working implementation, even though it is
very far from what is required.
It was decided a while back to reduce the duplication by consolidating
the "pen_release" variable, but this only made the situation worse -
we have ended up with several implementations that read this variable
but do not write it - again, showing the cargo-cult mentality at work,
lack of proper review of new code, and in some cases a lack of testing.
While it would be preferable to remove pen_release entirely from the
kernel, this is not possible without help from the SoC maintainers,
which seems to be lacking. However, I want to remove pen_release from
arch code to remove the credence that having it gives.
This patch removes pen_release from the arch code entirely, adding
private per-SoC definitions for it instead, and explicitly stating
that write_pen_release() is cargo-cult copied and should not be
copied any further. Rename write_pen_release() in a similar fashion
as well.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/mach-exynos/headsmp.S')
| -rw-r--r-- | arch/arm/mach-exynos/headsmp.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/mach-exynos/headsmp.S b/arch/arm/mach-exynos/headsmp.S index 005695c9bf40..0ac2cb9a7355 100644 --- a/arch/arm/mach-exynos/headsmp.S +++ b/arch/arm/mach-exynos/headsmp.S @@ -36,4 +36,4 @@ ENDPROC(exynos4_secondary_startup) .align 2 1: .long . - .long pen_release + .long exynos_pen_release |