[PATCH 5.19 26/38] parisc: Allow CONFIG_64BIT with ARCH=parisc

Greg Kroah-Hartman
2022-09-21T15:51:09Z

From: Helge Deller <deller@gmx.de>

commit 805ce8614958c925877ba6b6dc26cdf9f8800474 upstream.

The previous patch triggered a build failure for the debian kernel,
which has CONFIG_64BIT enabled, uses the CROSS_COMPILER environment
variable and uses ARCH=parisc to configure the kernel for 64-bit
support.

This patch weakens the previous patch while keeping the recommended way
to configure the kernel with:
ARCH=parisc -> build 32-bit kernel
ARCH=parisc64 -> build 64-bit kernel
while adding the possibility for debian to configure a 64-bit kernel
even if ARCH=parisc is set (PA8X00 CPU has to be selected and
CONFIG_64BIT needs to be enabled).

The downside of this patch is, that we now have a small window open
again where people may get it wrong: if they enable CONFIG_64BIT and try
to compile with a 32-bit compiler.

Fixes: 3dcfb729b5f4 ("parisc: Make CONFIG_64BIT available for ARCH=parisc64 only")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # 5.15+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/parisc/Kconfig | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -225,8 +225,18 @@ config MLONGCALLS
Enabling this option will probably slow down your kernel.

config 64BIT
- def_bool "$(ARCH)" = "parisc64"
+ def_bool y if "$(ARCH)" = "parisc64"
+ bool "64-bit kernel" if "$(ARCH)" = "parisc"
depends on PA8X00
+ help
+ Enable this if you want to support 64bit kernel on PA-RISC platform.
+
+ At the moment, only people willing to use more than 2GB of RAM,
+ or having a 64bit-only capable PA-RISC machine should say Y here.
+
+ Since there is no 64bit userland on PA-RISC, there is no point to
+ enable this option otherwise. The 64bit kernel is significantly bigger
+ and slower than the 32bit one.

choice
prompt "Kernel page size"