On Thu, Apr 19, 2018 at 08:23:41PM +0800, Wei Li wrote:
> From: Wei Li <liwei1...@163.com>
>
> In kdb, as the frontend for kgdb, cmd "ss" does not work well. It can only
> take effects once and the single step exception is reported as oops after a
> breakpoint triggered in kdb. Then the cmd "go" does not work well either due
> to this. Refer to the DDI0487C_a_armv8_arm.pdf (D2.12), i set the SPSR.SS=1
> every time. It has been verified in qemu.
>
> Signed-off-by: Wei Li <liwei1...@163.com>
> ---
> include/asm/debug-monitors.h | 3 +++
> kernel/debug-monitors.c | 4 ++--
> kernel/kgdb.c | 3 ++-
This contains many similar changes to a patch from earlier with the same
Subject. It is a v2? If so the subject should reflect that (and a
changelog would be nice).
Daniel.
> 3 files changed, 7 insertions(+), 3 deletions(-)
>
> diff -uprN linux-4.16.2_org/arch/arm64/include/asm/debug-monitors.h
> linux-4.16.2_mod/arch/arm64/include/asm/debug-monitors.h
> --- linux-4.16.2_org/arch/arm64/include/asm/debug-monitors.h 2018-04-12
> 18:30:01.000000000 +0800
> +++ linux-4.16.2_mod/arch/arm64/include/asm/debug-monitors.h 2018-04-19
> 00:19:10.134999268 +0800
> @@ -135,6 +135,9 @@ static inline int reinstall_suspended_bp
>
> int aarch32_break_handler(struct pt_regs *regs);
>
> +void set_regs_spsr_ss(struct pt_regs *regs);
> +void clear_regs_spsr_ss(struct pt_regs *regs);
> +
> #endif /* __ASSEMBLY */
> #endif /* __KERNEL__ */
> #endif /* __ASM_DEBUG_MONITORS_H */
> diff -uprN linux-4.16.2_org/arch/arm64/kernel/debug-monitors.c
> linux-4.16.2_mod/arch/arm64/kernel/debug-monitors.c
> --- linux-4.16.2_org/arch/arm64/kernel/debug-monitors.c 2018-04-12
> 18:30:01.000000000 +0800
> +++ linux-4.16.2_mod/arch/arm64/kernel/debug-monitors.c 2018-04-19
> 00:19:19.435189356 +0800
> @@ -150,13 +150,13 @@ postcore_initcall(debug_monitors_init);
> /*
> * Single step API and exception handling.
> */
> -static void set_regs_spsr_ss(struct pt_regs *regs)
> +void set_regs_spsr_ss(struct pt_regs *regs)
> {
> regs->pstate |= DBG_SPSR_SS;
> }
> NOKPROBE_SYMBOL(set_regs_spsr_ss);
>
> -static void clear_regs_spsr_ss(struct pt_regs *regs)
> +void clear_regs_spsr_ss(struct pt_regs *regs)
> {
> regs->pstate &= ~DBG_SPSR_SS;
> }
> diff -uprN linux-4.16.2_org/arch/arm64/kernel/kgdb.c
> linux-4.16.2_mod/arch/arm64/kernel/kgdb.c
> --- linux-4.16.2_org/arch/arm64/kernel/kgdb.c 2018-04-12
> 18:30:01.000000000 +0800
> +++ linux-4.16.2_mod/arch/arm64/kernel/kgdb.c 2018-04-19
> 00:19:40.892911795 +0800
> @@ -221,6 +221,7 @@ int kgdb_arch_handle_exception(int excep
> /*
> * Enable single step handling
> */
> + set_regs_spsr_ss(linux_regs);
> if (!kernel_active_single_step())
> kernel_enable_single_step(linux_regs);
> err = 0;
> @@ -252,7 +253,7 @@ static int kgdb_step_brk_fn(struct pt_re
> if (!kgdb_single_step)
> return DBG_HOOK_ERROR;
>
> - kgdb_handle_exception(1, SIGTRAP, 0, regs);
> + kgdb_handle_exception(0, SIGTRAP, 0, regs);
> return 0;
> }
> NOKPROBE_SYMBOL(kgdb_step_brk_fn);
>
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