[PATCH v6 03/28] powerpc/xmon: Move breakpoints to text section
Christophe Leroy
christophe.leroy at c-s.fr
Tue Apr 28 15:19:55 AEST 2020
Le 28/04/2020 à 03:57, Jordan Niethe a écrit :
> The instructions for xmon's breakpoint are stored bpt_table[] which is in
> the data section. This is problematic as the data section may be marked
> as no execute. Move bpt_table[] to the text section.
>
> Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
> ---
> v6: - New to series. Was part of the previous patch.
> - Make BPT_SIZE available in assembly
> ---
> arch/powerpc/kernel/asm-offsets.c | 8 ++++++++
> arch/powerpc/xmon/Makefile | 2 +-
> arch/powerpc/xmon/xmon.c | 6 +-----
> arch/powerpc/xmon/xmon_bpts.S | 9 +++++++++
> arch/powerpc/xmon/xmon_bpts.h | 14 ++++++++++++++
> 5 files changed, 33 insertions(+), 6 deletions(-)
> create mode 100644 arch/powerpc/xmon/xmon_bpts.S
> create mode 100644 arch/powerpc/xmon/xmon_bpts.h
>
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index c25e562f1cd9..2401f415f423 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -70,6 +70,10 @@
> #include <asm/fixmap.h>
> #endif
>
> +#ifdef CONFIG_XMON
> +#include "../xmon/xmon_bpts.h"
> +#endif
> +
> #define STACK_PT_REGS_OFFSET(sym, val) \
> DEFINE(sym, STACK_FRAME_OVERHEAD + offsetof(struct pt_regs, val))
>
> @@ -783,5 +787,9 @@ int main(void)
> DEFINE(VIRT_IMMR_BASE, (u64)__fix_to_virt(FIX_IMMR_BASE));
> #endif
>
> +#ifdef CONFIG_XMON
> + DEFINE(BPT_SIZE, BPT_SIZE);
> +#endif
> +
> return 0;
> }
> diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
> index c3842dbeb1b7..515a13ea6f28 100644
> --- a/arch/powerpc/xmon/Makefile
> +++ b/arch/powerpc/xmon/Makefile
> @@ -21,7 +21,7 @@ endif
>
> ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
>
> -obj-y += xmon.o nonstdio.o spr_access.o
> +obj-y += xmon.o nonstdio.o spr_access.o xmon_bpts.o
>
> ifdef CONFIG_XMON_DISASSEMBLY
> obj-y += ppc-dis.o ppc-opc.o
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index a064392df1b8..f7ce3ea8694c 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -62,6 +62,7 @@
>
> #include "nonstdio.h"
> #include "dis-asm.h"
> +#include "xmon_bpts.h"
>
> #ifdef CONFIG_SMP
> static cpumask_t cpus_in_xmon = CPU_MASK_NONE;
> @@ -108,7 +109,6 @@ struct bpt {
> #define BP_TRAP 2
> #define BP_DABR 4
>
> -#define NBPTS 256
> static struct bpt bpts[NBPTS];
> static struct bpt dabr;
> static struct bpt *iabr;
> @@ -116,10 +116,6 @@ static unsigned bpinstr = 0x7fe00008; /* trap */
>
> #define BP_NUM(bp) ((bp) - bpts + 1)
>
> -#define BPT_SIZE (sizeof(unsigned int) * 2)
> -#define BPT_WORDS (BPT_SIZE / sizeof(unsigned int))
> -static unsigned int bpt_table[NBPTS * BPT_WORDS];
> -
> /* Prototypes */
> static int cmds(struct pt_regs *);
> static int mread(unsigned long, void *, int);
> diff --git a/arch/powerpc/xmon/xmon_bpts.S b/arch/powerpc/xmon/xmon_bpts.S
> new file mode 100644
> index 000000000000..f3ad0ab50854
> --- /dev/null
> +++ b/arch/powerpc/xmon/xmon_bpts.S
> @@ -0,0 +1,9 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#include <asm/ppc_asm.h>
> +#include <asm/asm-compat.h>
> +#include <asm/asm-offsets.h>
> +#include "xmon_bpts.h"
> +
> +.global bpt_table
> +bpt_table:
> + .space NBPTS * BPT_SIZE
No alignment required ? Standard alignment (probably 4 bytes ?) is
acceptable ?
> diff --git a/arch/powerpc/xmon/xmon_bpts.h b/arch/powerpc/xmon/xmon_bpts.h
> new file mode 100644
> index 000000000000..b7e94375db86
> --- /dev/null
> +++ b/arch/powerpc/xmon/xmon_bpts.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef XMON_BPTS_H
> +#define XMON_BPTS_H
> +
> +#define NBPTS 256
> +#ifndef __ASSEMBLY__
> +#define BPT_SIZE (sizeof(unsigned int) * 2)
> +#define BPT_WORDS (BPT_SIZE / sizeof(unsigned int))
> +
> +extern unsigned int bpt_table[NBPTS * BPT_WORDS];
> +
> +#endif /* __ASSEMBLY__ */
> +
> +#endif /* XMON_BPTS_H */
>
Christophe
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