kernel_optimize_test/arch
Linus Torvalds 6ec4476ac8 Raise gcc version requirement to 4.9
I realize that we fairly recently raised it to 4.8, but the fact is, 4.9
is a much better minimum version to target.

We have a number of workarounds for actual bugs in pre-4.9 gcc versions
(including things like internal compiler errors on ARM), but we also
have some syntactic workarounds for lacking features.

In particular, raising the minimum to 4.9 means that we can now just
assume _Generic() exists, which is likely the much better replacement
for a lot of very convoluted built-time magic with conditionals on
sizeof and/or __builtin_choose_expr() with same_type() etc.

Using _Generic also means that you will need to have a very recent
version of 'sparse', but thats easy to build yourself, and much less of
a hassle than some old gcc version can be.

The latest (in a long string) of reasons for minimum compiler version
upgrades was commit 5435f73d5c ("efi/x86: Fix build with gcc 4").

Ard points out that RHEL 7 uses gcc-4.8, but the people who stay back on
old RHEL versions persumably also don't build their own kernels anyway.
And maybe they should cross-built or just have a little side affair with
a newer compiler?

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-08 10:48:35 -07:00
..
alpha Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
arc ARCv2: support loop buffer (LPB) disabling 2020-06-18 13:07:24 -07:00
arm Raise gcc version requirement to 4.9 2020-07-08 10:48:35 -07:00
arm64 Bugfixes and a one-liner patch to silence sparse. 2020-07-06 12:48:04 -07:00
c6x
csky maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
h8300
hexagon treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
ia64 Merge branch 'hch' (maccess patches from Christoph Hellwig) 2020-06-18 12:35:51 -07:00
m68k m68k: mm: fix node memblock init 2020-06-29 23:58:05 +10:00
microblaze
mips Raise gcc version requirement to 4.9 2020-07-08 10:48:35 -07:00
nds32 maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
nios2 nios2 update for v5.8-rc1 2020-06-12 11:55:11 -07:00
openrisc openrisc: fix boot oops when DEBUG_VM is enabled 2020-06-26 00:27:36 -07:00
parisc maccess: make get_kernel_nofault() check for minimal type compatibility 2020-06-18 12:10:37 -07:00
powerpc powerpc/mm/pkeys: Make pkey access check work on execute_only_key 2020-06-29 16:17:02 +10:00
riscv riscv: Fixup __vdso_gettimeofday broke dynamic ftrace 2020-06-25 15:38:39 -07:00
s390 Bugfixes and a one-liner patch to silence sparse. 2020-07-06 12:48:04 -07:00
sh maccess: rename probe_kernel_address to get_kernel_nofault 2020-06-18 11:14:40 -07:00
sparc treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
um maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
unicore32
x86 Bugfixes and a one-liner patch to silence sparse. 2020-07-06 12:48:04 -07:00
xtensa
.gitignore
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00