linux/arch/powerpc
Christophe Leroy fdacae8a84 powerpc: Activate CONFIG_STRICT_KERNEL_RWX by default
CONFIG_STRICT_KERNEL_RWX should be set by default on every
architectures (See https://github.com/KSPP/linux/issues/4)

On PPC32 we have to find a compromise between performance and/or
memory wasting and selection of strict_kernel_rwx, because it implies
either smaller memory chunks or larger alignment between RO memory
and RW memory.

For instance the 8xx maps memory with 8M pages. So either the limit
between RO and RW must be 8M aligned or it falls back or 512k pages
which implies more pressure on the TLB.

book3s/32 maps memory with BATs as much as possible. BATS can have
any power-of-two size between 128k and 256M but we have only 4 to 8
BATs so the alignment must be good enough to allow efficient use of
the BATs and avoid falling back on standard page mapping which would
kill performance.

So let's go one step forward and make it the default but still allow
users to unset it when wanted.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/057c40164084bfc7d77c0b2ff78d95dbf6a2a21b.1632503622.git.christophe.leroy@csgroup.eu
2021-10-22 15:22:05 +11:00
..
boot powerpc/5200: dts: fix memory node unit name 2021-10-22 15:22:04 +11:00
configs powerpc/configs/microwatt: Enable options for systemd 2021-08-27 00:56:53 +10:00
crypto crypto: powepc/sha1 - remove unneeded semicolon 2021-03-07 15:13:14 +11:00
include powerpc/8xx: Simplify TLB handling 2021-10-22 15:22:05 +11:00
kernel powerpc: warn on emulation of dcbz instruction in kernel mode 2021-10-22 15:22:05 +11:00
kexec powerpc/machdep: Remove stale functions from ppc_md structure 2021-10-22 15:22:05 +11:00
kvm powerpc/asm: Remove UPD_CONSTR after GCC 4.9 removal 2021-10-09 00:15:59 +11:00
lib powerpc/lib/sstep: Don't use __{get/put}_user() on kernel addresses 2021-10-22 15:22:05 +11:00
math-emu powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
mm powerpc/8xx: Simplify TLB handling 2021-10-22 15:22:05 +11:00
net bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-07-29 00:20:56 +02:00
perf powerpc/perf: Fix cycles/instructions as PM_CYC/PM_INST_CMPL in power10 2021-10-14 21:46:45 +11:00
platforms powerpc/vas: Fix potential NULL pointer dereference 2021-10-22 15:22:04 +11:00
purgatory powerpc/kexec: Don't use .machine ppc64 in trampoline_64.S 2021-04-08 21:17:43 +10:00
sysdev powerpc/xics: Set the IRQ chip data for the ICS native backend 2021-09-15 22:05:53 +10:00
tools powerpc/head_check: Fix shellcheck errors 2021-08-17 22:52:02 +10:00
xmon powerpc: Refactor verification of MSR_RI 2021-08-26 21:21:07 +10:00
Kbuild
Kconfig powerpc: Activate CONFIG_STRICT_KERNEL_RWX by default 2021-10-22 15:22:05 +11:00
Kconfig.debug powerpc/ptdump: Convert powerpc to GENERIC_PTDUMP 2021-08-25 13:35:48 +10:00
Makefile powerpc: Add "-z notext" flag to disable diagnostic 2021-08-15 13:49:39 +10:00
Makefile.postlink powerpc: unrel_branch_check.sh: use nm to find symbol value 2020-09-02 11:00:22 +10:00