---
b/arch/x86/include/asm/processor.h | 7 ++++++-
b/arch/x86/kernel/fpu/core.c | 11 +++--------
b/arch/x86/kernel/fpu/init.c | 2 +-
3 files changed, 10 insertions(+), 10 deletions(-)
diff -puN arch/x86/kernel/fpu/core.c~debug-32bit-fpregs arch/x86/kernel/fpu/core.c
--- a/arch/x86/kernel/fpu/core.c~debug-32bit-fpregs 2024-06-13 10:39:30.819589794 -0700
+++ b/arch/x86/kernel/fpu/core.c 2024-06-13 12:37:46.166450575 -0700
@@ -57,7 +57,7 @@ struct fpu *x86_task_fpu(struct task_str
if (WARN_ON_ONCE(task->flags & PF_KTHREAD))
return NULL;
- return (void *)task + sizeof(*task);
+ return __x86_task_fpu(task);
}
#endif
@@ -594,13 +594,8 @@ static int update_fpu_shstk(struct task_
int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
unsigned long ssp)
{
- /*
- * We allocate the new FPU structure right after the end of the task struct.
- * task allocation size already took this into account.
- *
- * This is safe because task_struct size is a multiple of cacheline size.
- */
- struct fpu *dst_fpu = (void *)dst + sizeof(*dst);
+ /* 'dst' is partially built, disable debugging: */
+ struct fpu *dst_fpu = __x86_task_fpu(dst);
BUILD_BUG_ON(sizeof(*dst) % SMP_CACHE_BYTES != 0);
diff -puN arch/x86/include/asm/processor.h~debug-32bit-fpregs arch/x86/include/asm/processor.h
--- a/arch/x86/include/asm/processor.h~debug-32bit-fpregs 2024-06-13 11:09:19.508181013 -0700
+++ b/arch/x86/include/asm/processor.h 2024-06-13 12:36:24.480086965 -0700
@@ -504,10 +504,15 @@ struct thread_struct {
#endif
};
+/* XSAVE requrires 64-byte alignment: */
+#define fpu_align(x) ALIGN(x, 64)
+
+#define __x86_task_fpu(task) ((struct fpu *)((void *)(task) + fpu_align(sizeof(*(task)))))
+
#ifdef CONFIG_X86_DEBUG_FPU
extern struct fpu *x86_task_fpu(struct task_struct *task);
#else
-# define x86_task_fpu(task) ((struct fpu *)((void *)(task) + sizeof(*(task))))
+#define x86_task_fpu(task) __x86_task_fpu(task)
#endif
/*
diff -puN arch/x86/kernel/fpu/init.c~debug-32bit-fpregs arch/x86/kernel/fpu/init.c
--- a/arch/x86/kernel/fpu/init.c~debug-32bit-fpregs 2024-06-13 11:55:22.597114454 -0700
+++ b/arch/x86/kernel/fpu/init.c 2024-06-13 12:39:15.924492560 -0700
@@ -158,7 +158,7 @@ static void __init fpu__init_task_struct
{
int task_size = sizeof(struct task_struct);
- task_size += sizeof(struct fpu);
+ task_size += fpu_align(sizeof(struct fpu));
/*
* Subtract off the static size of the register state.
_