linux_dsm_epyc7002/arch/powerpc/platforms
Gustavo A. R. Silva 0f6be41c60 powerpc: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200507185749.GA14994@embeddedor
2020-05-15 11:58:54 +10:00
..
4xx powerpc: remove the ppc44x ocm.c file 2019-08-27 13:03:33 +10:00
8xx powerpc: Replace setup_irq() by request_irq() 2020-03-25 12:07:57 +11:00
40x powerpc updates for 5.3 2019-07-13 16:08:36 -07:00
44x powerpc/32: drop unused ISA_DMA_THRESHOLD 2020-04-01 14:30:50 +11:00
52xx powerpc/32: drop unused ISA_DMA_THRESHOLD 2020-04-01 14:30:50 +11:00
82xx treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
83xx powerpc/83xx: Add some error handling in 'quirk_mpc8360e_qe_enet10()' 2020-03-04 22:44:25 +11:00
85xx powerpc: Replace setup_irq() by request_irq() 2020-03-25 12:07:57 +11:00
86xx powerpc/sysdev: drop simple gpio 2019-11-21 15:41:34 +11:00
512x powerpc/512x: Use dma_request_chan() instead dma_request_slave_channel() 2020-01-06 16:25:29 +11:00
amigaone powerpc/32: drop unused ISA_DMA_THRESHOLD 2020-04-01 14:30:50 +11:00
cell powerpc: Replace _ALIGN_UP() by ALIGN() 2020-05-11 23:15:15 +10:00
chrp powerpc/32: drop unused ISA_DMA_THRESHOLD 2020-04-01 14:30:50 +11:00
embedded6xx treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
maple powerpc/maple: Fix declaration made after definition 2020-03-25 12:09:48 +11:00
pasemi arch/powerpc/setup: Drop dummy_con initialization 2020-01-14 15:29:17 +01:00
powermac powerpc: Replace zero-length array with flexible-array 2020-05-15 11:58:54 +10:00
powernv powerpc: Replace _ALIGN_UP() by ALIGN() 2020-05-11 23:15:15 +10:00
ps3 powerpc: Replace _ALIGN_UP() by ALIGN() 2020-05-11 23:15:15 +10:00
pseries powerpc: Replace _ALIGN_DOWN() by ALIGN_DOWN() 2020-05-11 23:15:15 +10:00
fsl_uli1575.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
Kconfig powerpc/64s: Reimplement power4_idle code in C 2020-01-16 14:59:37 +10:00
Kconfig.cputype powerpc/kuap: PPC_KUAP_DEBUG should depend on PPC_KUAP 2020-03-20 13:10:22 +11:00
Makefile powerpc: Add -Werror at arch/powerpc level 2018-10-19 00:56:17 +11:00