Messages in this thread Patch in this message | | | From | Brian Gerst <> | Subject | [PATCH v2 3/6] x86: Add struct inactive_task_frame | Date | Sat, 18 Jun 2016 16:56:15 -0400 |
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Add struct inactive_task_frame, which defines the layout of the stack for a sleeping process. For now, the only defined field is the BP register (frame pointer).
Signed-off-by: Brian Gerst <brgerst@gmail.com> --- arch/x86/include/asm/stacktrace.h | 4 ++-- arch/x86/include/asm/switch_to.h | 5 +++++ arch/x86/kernel/kgdb.c | 3 ++- arch/x86/kernel/process.c | 3 ++- 4 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h index 7c247e7..fb4a078 100644 --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -8,6 +8,7 @@ #include <linux/uaccess.h> #include <linux/ptrace.h> +#include <asm/switch_to.h> extern int kstack_depth_to_print; @@ -70,8 +71,7 @@ stack_frame(struct task_struct *task, struct pt_regs *regs) return bp; } - /* bp is the last reg pushed by switch_to */ - return *(unsigned long *)task->thread.sp; + return ((struct inactive_task_frame *)task->thread.sp)->bp; } #else static inline unsigned long diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index 8f321a1..02de86e 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -8,6 +8,11 @@ struct tss_struct; void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, struct tss_struct *tss); +/* data that is pointed to by thread.sp */ +struct inactive_task_frame { + unsigned long bp; +}; + #ifdef CONFIG_X86_32 #ifdef CONFIG_CC_STACKPROTECTOR diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 5e3f294..8e36f24 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -50,6 +50,7 @@ #include <asm/apicdef.h> #include <asm/apic.h> #include <asm/nmi.h> +#include <asm/switch_to.h> struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { @@ -166,7 +167,7 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) gdb_regs[GDB_DX] = 0; gdb_regs[GDB_SI] = 0; gdb_regs[GDB_DI] = 0; - gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; + gdb_regs[GDB_BP] = ((struct inactive_task_frame *)p->thread.sp)->bp; #ifdef CONFIG_X86_32 gdb_regs[GDB_DS] = __KERNEL_DS; gdb_regs[GDB_ES] = __KERNEL_DS; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 96becbb..00ebab0 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -31,6 +31,7 @@ #include <asm/tlbflush.h> #include <asm/mce.h> #include <asm/vm86.h> +#include <asm/switch_to.h> /* * per-CPU TSS segments. Threads are completely 'soft' on Linux, @@ -555,7 +556,7 @@ unsigned long get_wchan(struct task_struct *p) if (sp < bottom || sp > top) return 0; - fp = READ_ONCE_NOCHECK(*(unsigned long *)sp); + fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp); do { if (fp < bottom || fp > top) return 0; -- 2.5.5
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