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| author | Nathan Lynch <nathanl@linux.ibm.com> | 2023-03-06 15:33:40 -0600 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-03-30 23:36:34 +1100 |
| commit | f40b0f6c5c27de167fdd10e541e0a4b5f2bc772b (patch) | |
| tree | 09aed2ec1ed30fd3813d44c17dcfa2db38e4bf6b | |
| parent | 05dce4ba125336875cd3eed3c1503fa81cd2f691 (diff) | |
| download | linux-stable-f40b0f6c5c27de167fdd10e541e0a4b5f2bc772b.tar.gz linux-stable-f40b0f6c5c27de167fdd10e541e0a4b5f2bc772b.tar.bz2 linux-stable-f40b0f6c5c27de167fdd10e541e0a4b5f2bc772b.zip | |
powerpc/rtas: ensure 8-byte alignment for struct rtas_args
CHRP and PAPR agree: "In order to make an RTAS call, the operating
system must construct an argument call buffer aligned on an eight byte
boundary in physically contiguous real memory [...]." (7.2.7 Calling
Mechanism and Conventions).
struct rtas_args is the type used for this argument call buffer. The
unarchitected 'rets' member happens to produce 8-byte alignment for
the struct on 64-bit targets in practice. But without an alignment
directive the structure will have only 4-byte alignment on 32-bit
targets:
$ nm b/{before,after}/chrp32/vmlinux | grep rtas_args
c096881c b rtas_args
c0968820 b rtas_args
Add an alignment directive to the struct rtas_args declaration so all
instances have the alignment required by the specs. rtas-types.h no
longer refers to any spinlock types, so drop the spinlock_types.h
inclusion while we're here.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230220-rtas-queue-for-6-4-v1-1-010e4416f13f@linux.ibm.com
| -rw-r--r-- | arch/powerpc/include/asm/rtas-types.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/rtas-types.h b/arch/powerpc/include/asm/rtas-types.h index f2ad4a96cbc5..9d5b16803cbb 100644 --- a/arch/powerpc/include/asm/rtas-types.h +++ b/arch/powerpc/include/asm/rtas-types.h @@ -2,7 +2,7 @@ #ifndef _ASM_POWERPC_RTAS_TYPES_H #define _ASM_POWERPC_RTAS_TYPES_H -#include <linux/spinlock_types.h> +#include <linux/compiler_attributes.h> typedef __be32 rtas_arg_t; @@ -12,7 +12,7 @@ struct rtas_args { __be32 nret; rtas_arg_t args[16]; rtas_arg_t *rets; /* Pointer to return values in args[]. */ -}; +} __aligned(8); struct rtas_t { unsigned long entry; /* physical address pointer */ |