Commit 37cddff8 authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle

MIPS: 16 byte align MSA vector context

The MSA specification upon first read appears to suggest that it is safe
to perform vector loads & stores with arbitrary alignment. However it
leaves provision for "address-dependent exceptions"... Align the vector
context to a 16 byte boundary to ensure that the kernel cannot cause any
such exceptions.

Note that the fpu field of struct thread_struct was already at a 16 byte
boundary within the struct, the introduction of FPU_ALIGN simply makes
the requirement explicit. The only part of this impacting the generated
kernel binary is ARCH_MIN_TASKALIGN.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7308/Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 762a1f43
...@@ -238,7 +238,13 @@ typedef struct { ...@@ -238,7 +238,13 @@ typedef struct {
unsigned long seg; unsigned long seg;
} mm_segment_t; } mm_segment_t;
#define ARCH_MIN_TASKALIGN 8 #ifdef CONFIG_CPU_HAS_MSA
# define ARCH_MIN_TASKALIGN 16
# define FPU_ALIGN __aligned(16)
#else
# define ARCH_MIN_TASKALIGN 8
# define FPU_ALIGN
#endif
struct mips_abi; struct mips_abi;
...@@ -255,7 +261,7 @@ struct thread_struct { ...@@ -255,7 +261,7 @@ struct thread_struct {
unsigned long cp0_status; unsigned long cp0_status;
/* Saved fpu/fpu emulator stuff. */ /* Saved fpu/fpu emulator stuff. */
struct mips_fpu_struct fpu; struct mips_fpu_struct fpu FPU_ALIGN;
#ifdef CONFIG_MIPS_MT_FPAFF #ifdef CONFIG_MIPS_MT_FPAFF
/* Emulated instruction count */ /* Emulated instruction count */
unsigned long emulated_fp; unsigned long emulated_fp;
......
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