Commit-ID: 7b32aeadbc95d4a41402c1c0da6aa3ab51af4c10 Gitweb: http://git.kernel.org/tip/7b32aeadbc95d4a41402c1c0da6aa3ab51af4c10 Author: Brian Gerst <brge...@gmail.com> AuthorDate: Sat, 13 Aug 2016 12:38:18 -0400 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 24 Aug 2016 12:27:41 +0200
sched/x86: Add 'struct inactive_task_frame' to better document the sleeping task stack frame 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 <brge...@gmail.com> Reviewed-by: Josh Poimboeuf <jpoim...@redhat.com> Cc: Andy Lutomirski <l...@kernel.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/1471106302-10159-4-git-send-email-brge...@gmail.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- 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 0944218..7646fb2 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 14e4b20..ec689c6 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -30,6 +30,11 @@ static inline void prepare_switch_to(struct task_struct *prev, #endif } +/* 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 62c0b0e..0115a4a 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -32,6 +32,7 @@ #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, @@ -556,7 +557,7 @@ 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;
