2021-08-10 16:46:11

by Christophe Leroy

Subject: [PATCH] powerpc/interrupt: Do not call single_step_exception() from other exceptions

single_step_exception() is called by emulate_single_step() which
is called from (at least) alignment exception() handler and
program_check_exception() handler.

Redefine it as a regular __single_step_exception() which is called
by both single_step_exception() handler and emulate_single_step()
function.

Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers")
Cc: [email protected]
Cc: Stan Johnson <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Finn Thain <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/traps.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index dfbce527c98e..d56254f05e17 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1104,7 +1104,7 @@ DEFINE_INTERRUPT_HANDLER(RunModeException)
_exception(SIGTRAP, regs, TRAP_UNK, 0);
}

-DEFINE_INTERRUPT_HANDLER(single_step_exception)
+static void __single_step_exception(struct pt_regs *regs)
{
clear_single_step(regs);
clear_br_trace(regs);
@@ -1121,6 +1121,11 @@ DEFINE_INTERRUPT_HANDLER(single_step_exception)
_exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
}

+DEFINE_INTERRUPT_HANDLER(single_step_exception)
+{
+ __single_step_exception(regs);
+}
+
/*
* After we have successfully emulated an instruction, we have to
* check if the instruction was being single-stepped, and if so,
@@ -1130,7 +1135,7 @@ DEFINE_INTERRUPT_HANDLER(single_step_exception)
static void emulate_single_step(struct pt_regs *regs)
{
if (single_stepping(regs))
- single_step_exception(regs);
+ __single_step_exception(regs);
}

static inline int __parse_fpscr(unsigned long fpscr)
--
2.25.0

2021-08-12 12:13:52

by Nicholas Piggin

Subject: Re: [PATCH] powerpc/interrupt: Do not call single_step_exception() from other exceptions

Excerpts from Christophe Leroy's message of August 11, 2021 2:13 am:
> single_step_exception() is called by emulate_single_step() which
> is called from (at least) alignment exception() handler and
> program_check_exception() handler.
>
> Redefine it as a regular __single_step_exception() which is called
> by both single_step_exception() handler and emulate_single_step()
> function.
>

Reviewed-by: Nicholas Piggin <[email protected]>

> Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers")
> Cc: [email protected]
> Cc: Stan Johnson <[email protected]>
> Cc: Nicholas Piggin <[email protected]>
> Cc: Finn Thain <[email protected]>
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> arch/powerpc/kernel/traps.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index dfbce527c98e..d56254f05e17 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -1104,7 +1104,7 @@ DEFINE_INTERRUPT_HANDLER(RunModeException)
> _exception(SIGTRAP, regs, TRAP_UNK, 0);
> }
>
> -DEFINE_INTERRUPT_HANDLER(single_step_exception)
> +static void __single_step_exception(struct pt_regs *regs)
> {
> clear_single_step(regs);
> clear_br_trace(regs);
> @@ -1121,6 +1121,11 @@ DEFINE_INTERRUPT_HANDLER(single_step_exception)
> _exception(SIGTRAP, regs, TRAP_TRACE, regs->nip);
> }
>
> +DEFINE_INTERRUPT_HANDLER(single_step_exception)
> +{
> + __single_step_exception(regs);
> +}
> +
> /*
> * After we have successfully emulated an instruction, we have to
> * check if the instruction was being single-stepped, and if so,
> @@ -1130,7 +1135,7 @@ DEFINE_INTERRUPT_HANDLER(single_step_exception)
> static void emulate_single_step(struct pt_regs *regs)
> {
> if (single_stepping(regs))
> - single_step_exception(regs);
> + __single_step_exception(regs);
> }
>
> static inline int __parse_fpscr(unsigned long fpscr)
> --
> 2.25.0
>
>

2021-08-13 17:00:57

by Michael Ellerman

Subject: Re: [PATCH] powerpc/interrupt: Do not call single_step_exception() from other exceptions

On Tue, 10 Aug 2021 16:13:17 +0000 (UTC), Christophe Leroy wrote:
> single_step_exception() is called by emulate_single_step() which
> is called from (at least) alignment exception() handler and
> program_check_exception() handler.
>
> Redefine it as a regular __single_step_exception() which is called
> by both single_step_exception() handler and emulate_single_step()
> function.

Applied to powerpc/fixes.

[1/1] powerpc/interrupt: Do not call single_step_exception() from other exceptions
https://git.kernel.org/powerpc/c/01fcac8e4dfc112f420dcaeb70056a74e326cacf

cheers