2020-07-23 16:37:42

by Emil Renner Berthing

Subject: [PATCH] riscv: Grab text_mutex before patching jump-labels

Like other arch's we use patch_text_nosync or equivalent
to patch the jump-labels, but also like other arch's we
need to hold the text_mutex before calling that.

Signed-off-by: Emil Renner Berthing <[email protected]>
---

Fixes: b6e0878a4ec8 ("riscv: Add jump-label implementation")
..that is already in riscv/for-next.

Palmer: Sorry, I didn't notice this before. Feel free to
squash this into the commit above if you like.
---
arch/riscv/kernel/jump_label.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/jump_label.c b/arch/riscv/kernel/jump_label.c
index 1bab1abc1aa5..20e09056d141 100644
--- a/arch/riscv/kernel/jump_label.c
+++ b/arch/riscv/kernel/jump_label.c
@@ -4,8 +4,10 @@
*
* Based on arch/arm64/kernel/jump_label.c
*/
-#include <linux/kernel.h>
#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mutex.h>
#include <asm/bug.h>
#include <asm/patch.h>

@@ -33,7 +35,9 @@ void arch_jump_label_transform(struct jump_entry *entry,
insn = RISCV_INSN_NOP;
}

+ mutex_lock(&text_mutex);
patch_text_nosync(addr, &insn, sizeof(insn));
+ mutex_unlock(&text_mutex);
}

void arch_jump_label_transform_static(struct jump_entry *entry,
--
2.27.0

2020-07-27 20:20:23

by Palmer Dabbelt

Subject: Re: [PATCH] riscv: Grab text_mutex before patching jump-labels

On Thu, 23 Jul 2020 09:36:28 PDT (-0700), [email protected] wrote:
> Like other arch's we use patch_text_nosync or equivalent
> to patch the jump-labels, but also like other arch's we
> need to hold the text_mutex before calling that.
>
> Signed-off-by: Emil Renner Berthing <[email protected]>
> ---
>
> Fixes: b6e0878a4ec8 ("riscv: Add jump-label implementation")
> ..that is already in riscv/for-next.
>
> Palmer: Sorry, I didn't notice this before. Feel free to
> squash this into the commit above if you like.
> ---
> arch/riscv/kernel/jump_label.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/jump_label.c b/arch/riscv/kernel/jump_label.c
> index 1bab1abc1aa5..20e09056d141 100644
> --- a/arch/riscv/kernel/jump_label.c
> +++ b/arch/riscv/kernel/jump_label.c
> @@ -4,8 +4,10 @@
> *
> * Based on arch/arm64/kernel/jump_label.c
> */
> -#include <linux/kernel.h>
> #include <linux/jump_label.h>
> +#include <linux/kernel.h>
> +#include <linux/memory.h>
> +#include <linux/mutex.h>
> #include <asm/bug.h>
> #include <asm/patch.h>
>
> @@ -33,7 +35,9 @@ void arch_jump_label_transform(struct jump_entry *entry,
> insn = RISCV_INSN_NOP;
> }
>
> + mutex_lock(&text_mutex);
> patch_text_nosync(addr, &insn, sizeof(insn));
> + mutex_unlock(&text_mutex);
> }
>
> void arch_jump_label_transform_static(struct jump_entry *entry,

I've just put this on for-next as is. I generally try to avoid rebasing stuff,
but I think I saw a message today about a patch I put there prematurely so I
might have to rewrite history anyway. If I do I'll squash it and a few other
small fixes.

Thanks!