This is a note to let you know that I've just added the patch titled
Revert "arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD"
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-arm64-fpsimd-implement-lazy-restore-for-kerne.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b6fb5d8556512e9b817e4aa1fc270749c13feea4
Author: Will Deacon <will@xxxxxxxxxx>
Date: Fri May 17 12:55:55 2024 +0100
Revert "arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD"
[ Upstream commit b8995a18417088bb53f87c49d200ec72a9dd4ec1 ]
This reverts commit 2632e25217696712681dd1f3ecc0d71624ea3b23.
Johannes (and others) report data corruption with dm-crypt on Apple M1
which has been bisected to this change. Revert the offending commit
while we figure out what's going on.
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Johannes Nixdorf <mixi@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/D1B7GPIR9K1E.5JFV37G0YTIF@xxxxxxxxxxxxx/
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 5b0a04810b236..ce6eebd6c08bd 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -169,7 +169,6 @@ struct thread_struct {
struct debug_info debug; /* debugging */
struct user_fpsimd_state kernel_fpsimd_state;
- unsigned int kernel_fpsimd_cpu;
#ifdef CONFIG_ARM64_PTR_AUTH
struct ptrauth_keys_user keys_user;
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 92cb6dd1cfc1a..aa695057c93dd 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1552,30 +1552,12 @@ void do_fpsimd_exc(unsigned long esr, struct pt_regs *regs)
static void fpsimd_load_kernel_state(struct task_struct *task)
{
- struct cpu_fp_state *last = this_cpu_ptr(&fpsimd_last_state);
-
- /*
- * Elide the load if this CPU holds the most recent kernel mode
- * FPSIMD context of the current task.
- */
- if (last->st == &task->thread.kernel_fpsimd_state &&
- task->thread.kernel_fpsimd_cpu == smp_processor_id())
- return;
-
fpsimd_load_state(&task->thread.kernel_fpsimd_state);
}
static void fpsimd_save_kernel_state(struct task_struct *task)
{
- struct cpu_fp_state cpu_fp_state = {
- .st = &task->thread.kernel_fpsimd_state,
- .to_save = FP_STATE_FPSIMD,
- };
-
fpsimd_save_state(&task->thread.kernel_fpsimd_state);
- fpsimd_bind_state_to_cpu(&cpu_fp_state);
-
- task->thread.kernel_fpsimd_cpu = smp_processor_id();
}
void fpsimd_thread_switch(struct task_struct *next)
