FAILED: patch "[PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is" failed to apply to 6.4-stable tree

FAILED: patch "[PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is" failed to apply to 6.4-stable tree

[gregkh]

The patch below does not apply to the 6.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y
git checkout FETCH_HEAD
git cherry-pick -x 656f9aec07dba7c61d469727494a5d1b18d0bef4
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023082705-predator-enjoyable-15fb@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 656f9aec07dba7c61d469727494a5d1b18d0bef4 Mon Sep 17 00:00:00 2001
From: Huacai Chen <chenhuacai@kernel.org>
Date: Sat, 26 Aug 2023 22:21:57 +0800
Subject: [PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is
 up to date

This is a port of commit 379eb01c21795edb4c ("riscv: Ensure the value
of FP registers in the core dump file is up to date").

The values of FP/SIMD registers in the core dump file come from the
thread.fpu. However, kernel saves the FP/SIMD registers only before
scheduling out the process. If no process switch happens during the
exception handling, kernel will not have a chance to save the latest
values of FP/SIMD registers. So it may cause their values in the core
dump file incorrect. To solve this problem, force fpr_get()/simd_get()
to save the FP/SIMD registers into the thread.fpu if the target task
equals the current task.

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/include/asm/fpu.h b/arch/loongarch/include/asm/fpu.h
index b541f6248837..c2d8962fda00 100644
--- a/arch/loongarch/include/asm/fpu.h
+++ b/arch/loongarch/include/asm/fpu.h
@@ -173,16 +173,30 @@ static inline void restore_fp(struct task_struct *tsk)
 		_restore_fp(&tsk->thread.fpu);
 }
 
-static inline union fpureg *get_fpu_regs(struct task_struct *tsk)
+static inline void save_fpu_regs(struct task_struct *tsk)
 {
+	unsigned int euen;
+
 	if (tsk == current) {
 		preempt_disable();
-		if (is_fpu_owner())
+
+		euen = csr_read32(LOONGARCH_CSR_EUEN);
+
+#ifdef CONFIG_CPU_HAS_LASX
+		if (euen & CSR_EUEN_LASXEN)
+			_save_lasx(&current->thread.fpu);
+		else
+#endif
+#ifdef CONFIG_CPU_HAS_LSX
+		if (euen & CSR_EUEN_LSXEN)
+			_save_lsx(&current->thread.fpu);
+		else
+#endif
+		if (euen & CSR_EUEN_FPEN)
 			_save_fp(&current->thread.fpu);
+
 		preempt_enable();
 	}
-
-	return tsk->thread.fpu.fpr;
 }
 
 static inline int is_simd_owner(void)
diff --git a/arch/loongarch/kernel/ptrace.c b/arch/loongarch/kernel/ptrace.c
index a0767c3a0f0a..f72adbf530c6 100644
--- a/arch/loongarch/kernel/ptrace.c
+++ b/arch/loongarch/kernel/ptrace.c
@@ -147,6 +147,8 @@ static int fpr_get(struct task_struct *target,
 {
 	int r;
 
+	save_fpu_regs(target);
+
 	if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
 		r = gfpr_get(target, &to);
 	else
@@ -278,6 +280,8 @@ static int simd_get(struct task_struct *target,
 {
 	const unsigned int wr_size = NUM_FPU_REGS * regset->size;
 
+	save_fpu_regs(target);
+
 	if (!tsk_used_math(target)) {
 		/* The task hasn't used FP or LSX, fill with 0xff */
 		copy_pad_fprs(target, regset, &to, 0);

Re: FAILED: patch "[PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is" failed to apply to 6.4-stable tree

[Huacai Chen]

On Sun, Aug 27, 2023 at 2:45 PM <gregkh@linuxfoundation.org> wrote:
>
>
> The patch below does not apply to the 6.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
>
> To reproduce the conflict and resubmit, you may use the following commands:
>
> git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y
> git checkout FETCH_HEAD
> git cherry-pick -x 656f9aec07dba7c61d469727494a5d1b18d0bef4
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023082705-predator-enjoyable-15fb@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^..
>
> Possible dependencies:
I'm sorry, this is my mistake. 6.4 also need to cut the simd_get()
part, because simd is only supported since 6.5

Huacai

>
>
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 656f9aec07dba7c61d469727494a5d1b18d0bef4 Mon Sep 17 00:00:00 2001
> From: Huacai Chen <chenhuacai@kernel.org>
> Date: Sat, 26 Aug 2023 22:21:57 +0800
> Subject: [PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is
>  up to date
>
> This is a port of commit 379eb01c21795edb4c ("riscv: Ensure the value
> of FP registers in the core dump file is up to date").
>
> The values of FP/SIMD registers in the core dump file come from the
> thread.fpu. However, kernel saves the FP/SIMD registers only before
> scheduling out the process. If no process switch happens during the
> exception handling, kernel will not have a chance to save the latest
> values of FP/SIMD registers. So it may cause their values in the core
> dump file incorrect. To solve this problem, force fpr_get()/simd_get()
> to save the FP/SIMD registers into the thread.fpu if the target task
> equals the current task.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
>
> diff --git a/arch/loongarch/include/asm/fpu.h b/arch/loongarch/include/asm/fpu.h
> index b541f6248837..c2d8962fda00 100644
> --- a/arch/loongarch/include/asm/fpu.h
> +++ b/arch/loongarch/include/asm/fpu.h
> @@ -173,16 +173,30 @@ static inline void restore_fp(struct task_struct *tsk)
>                 _restore_fp(&tsk->thread.fpu);
>  }
>
> -static inline union fpureg *get_fpu_regs(struct task_struct *tsk)
> +static inline void save_fpu_regs(struct task_struct *tsk)
>  {
> +       unsigned int euen;
> +
>         if (tsk == current) {
>                 preempt_disable();
> -               if (is_fpu_owner())
> +
> +               euen = csr_read32(LOONGARCH_CSR_EUEN);
> +
> +#ifdef CONFIG_CPU_HAS_LASX
> +               if (euen & CSR_EUEN_LASXEN)
> +                       _save_lasx(&current->thread.fpu);
> +               else
> +#endif
> +#ifdef CONFIG_CPU_HAS_LSX
> +               if (euen & CSR_EUEN_LSXEN)
> +                       _save_lsx(&current->thread.fpu);
> +               else
> +#endif
> +               if (euen & CSR_EUEN_FPEN)
>                         _save_fp(&current->thread.fpu);
> +
>                 preempt_enable();
>         }
> -
> -       return tsk->thread.fpu.fpr;
>  }
>
>  static inline int is_simd_owner(void)
> diff --git a/arch/loongarch/kernel/ptrace.c b/arch/loongarch/kernel/ptrace.c
> index a0767c3a0f0a..f72adbf530c6 100644
> --- a/arch/loongarch/kernel/ptrace.c
> +++ b/arch/loongarch/kernel/ptrace.c
> @@ -147,6 +147,8 @@ static int fpr_get(struct task_struct *target,
>  {
>         int r;
>
> +       save_fpu_regs(target);
> +
>         if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))
>                 r = gfpr_get(target, &to);
>         else
> @@ -278,6 +280,8 @@ static int simd_get(struct task_struct *target,
>  {
>         const unsigned int wr_size = NUM_FPU_REGS * regset->size;
>
> +       save_fpu_regs(target);
> +
>         if (!tsk_used_math(target)) {
>                 /* The task hasn't used FP or LSX, fill with 0xff */
>                 copy_pad_fprs(target, regset, &to, 0);
>

Re: FAILED: patch "[PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is" failed to apply to 6.4-stable tree

[Greg KH]

On Sun, Aug 27, 2023 at 04:23:35PM +0800, Huacai Chen wrote:
> On Sun, Aug 27, 2023 at 2:45 PM <gregkh@linuxfoundation.org> wrote:
> >
> >
> > The patch below does not apply to the 6.4-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> >
> > To reproduce the conflict and resubmit, you may use the following commands:
> >
> > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y
> > git checkout FETCH_HEAD
> > git cherry-pick -x 656f9aec07dba7c61d469727494a5d1b18d0bef4
> > # <resolve conflicts, build, test, etc.>
> > git commit -s
> > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023082705-predator-enjoyable-15fb@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^..
> >
> > Possible dependencies:
> I'm sorry, this is my mistake. 6.4 also need to cut the simd_get()
> part, because simd is only supported since 6.5

I do not understand, sorry.  Is this relevant for 6.4.y?  If so, can you
provide a working backport?

thanks,

greg k-h

Re: FAILED: patch "[PATCH] LoongArch: Ensure FP/SIMD registers in the core dump file is" failed to apply to 6.4-stable tree

[Huacai Chen]

On Sun, Aug 27, 2023 at 4:38 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Sun, Aug 27, 2023 at 04:23:35PM +0800, Huacai Chen wrote:
> > On Sun, Aug 27, 2023 at 2:45 PM <gregkh@linuxfoundation.org> wrote:
> > >
> > >
> > > The patch below does not apply to the 6.4-stable tree.
> > > If someone wants it applied there, or to any other stable or longterm
> > > tree, then please email the backport, including the original git commit
> > > id to <stable@vger.kernel.org>.
> > >
> > > To reproduce the conflict and resubmit, you may use the following commands:
> > >
> > > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y
> > > git checkout FETCH_HEAD
> > > git cherry-pick -x 656f9aec07dba7c61d469727494a5d1b18d0bef4
> > > # <resolve conflicts, build, test, etc.>
> > > git commit -s
> > > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023082705-predator-enjoyable-15fb@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^..
> > >
> > > Possible dependencies:
> > I'm sorry, this is my mistake. 6.4 also need to cut the simd_get()
> > part, because simd is only supported since 6.5
>
> I do not understand, sorry.  Is this relevant for 6.4.y?  If so, can you
> provide a working backport?
Sorry to bother you. Please give up backporting this patch, I found
that there are some dependencies but they shouldn't be backported to
stable branches.
Sorry for that again.

Huacai
>
> thanks,
>
> greg k-h