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[V3,15/17] riscv: compat: Add UXL_32 support in start_thread

Message ID 20220120073911.99857-16-guoren@kernel.org
State New
Headers show
Series riscv: compat: Add COMPAT mode support for rv64 | expand

Commit Message

Guo Ren Jan. 20, 2022, 7:39 a.m. UTC 
From: Guo Ren <guoren@linux.alibaba.com>

If the current task is in COMPAT mode, set SR_UXL_32 in status for
returning userspace.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/riscv/kernel/process.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Arnd Bergmann Jan. 20, 2022, 9:39 a.m. UTC | #1 
On Thu, Jan 20, 2022 at 8:39 AM <guoren@kernel.org> wrote:
> +
> +#ifdef CONFIG_COMPAT
> +       if (is_compat_task())
> +               regs->status |= SR_UXL_32;
> +#endif


You should not need that #ifdef, as the is_compat_task() definition is
meant to drop the code at compile time, unless the SR_UXL_32
definition is not visible here.

         Arnd
Guo Ren Jan. 20, 2022, 1:43 p.m. UTC | #2 
On Thu, Jan 20, 2022 at 9:39 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Thu, Jan 20, 2022 at 8:39 AM <guoren@kernel.org> wrote:
> > +
> > +#ifdef CONFIG_COMPAT
> > +       if (is_compat_task())
> > +               regs->status |= SR_UXL_32;
> > +#endif
>
>
> You should not need that #ifdef, as the is_compat_task() definition is
> meant to drop the code at compile time, unless the SR_UXL_32
> definition is not visible here.
I almost put CONFIG_COMPAT in every compat related code, because I
hope the next arch that wants to support COMPAT could easily find
where to be modified.

>
>          Arnd
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Patch

diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 03ac3aa611f5..1a666ad299b4 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -97,6 +97,11 @@  void start_thread(struct pt_regs *regs, unsigned long pc,
 	}
 	regs->epc = pc;
 	regs->sp = sp;
+
+#ifdef CONFIG_COMPAT
+	if (is_compat_task())
+		regs->status |= SR_UXL_32;
+#endif
 }
 
 void flush_thread(void)