From 062b1c19b879e7831cbceb599ab1d758f87eda40 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Tue, 27 Jan 2015 01:15:10 +0300 Subject: xtensa: clean up access to spilled registers locations Define macros SPILL_SLOT* that return a reference to the stack location of the spill slot for specific register and use them instead of opencoded address calculations. Signed-off-by: Max Filippov --- arch/xtensa/kernel/stacktrace.c | 35 ++++++++--------------------------- 1 file changed, 8 insertions(+), 27 deletions(-) (limited to 'arch/xtensa/kernel/stacktrace.c') diff --git a/arch/xtensa/kernel/stacktrace.c b/arch/xtensa/kernel/stacktrace.c index e7d30ee0fd48..0df4080fa20f 100644 --- a/arch/xtensa/kernel/stacktrace.c +++ b/arch/xtensa/kernel/stacktrace.c @@ -23,14 +23,6 @@ */ extern int common_exception_return; -/* A struct that maps to the part of the frame containing the a0 and - * a1 registers. - */ -struct frame_start { - unsigned long a0; - unsigned long a1; -}; - void xtensa_backtrace_user(struct pt_regs *regs, unsigned int depth, int (*ufn)(struct stackframe *frame, void *data), void *data) @@ -96,26 +88,16 @@ void xtensa_backtrace_user(struct pt_regs *regs, unsigned int depth, /* Start from the a1 register. */ /* a1 = regs->areg[1]; */ while (a0 != 0 && depth--) { - struct frame_start frame_start; - /* Get the location for a1, a0 for the - * previous frame from the current a1. - */ - unsigned long *psp = (unsigned long *)a1; - - psp -= 4; + pc = MAKE_PC_FROM_RA(a0, pc); /* Check if the region is OK to access. */ - if (!access_ok(VERIFY_READ, psp, sizeof(frame_start))) + if (!access_ok(VERIFY_READ, &SPILL_SLOT(a1, 0), 8)) return; /* Copy a1, a0 from user space stack frame. */ - if (__copy_from_user_inatomic(&frame_start, psp, - sizeof(frame_start))) + if (__get_user(a0, &SPILL_SLOT(a1, 0)) || + __get_user(a1, &SPILL_SLOT(a1, 1))) return; - pc = MAKE_PC_FROM_RA(a0, pc); - a0 = frame_start.a0; - a1 = frame_start.a1; - frame.pc = pc; frame.sp = a1; @@ -147,7 +129,6 @@ void xtensa_backtrace_kernel(struct pt_regs *regs, unsigned int depth, */ while (a1 > sp_start && a1 < sp_end && depth--) { struct stackframe frame; - unsigned long *psp = (unsigned long *)a1; frame.pc = pc; frame.sp = a1; @@ -171,8 +152,8 @@ void xtensa_backtrace_kernel(struct pt_regs *regs, unsigned int depth, sp_start = a1; pc = MAKE_PC_FROM_RA(a0, pc); - a0 = *(psp - 4); - a1 = *(psp - 3); + a0 = SPILL_SLOT(a1, 0); + a1 = SPILL_SLOT(a1, 1); } } EXPORT_SYMBOL(xtensa_backtrace_kernel); @@ -196,8 +177,8 @@ void walk_stackframe(unsigned long *sp, sp = (unsigned long *)a1; - a0 = *(sp - 4); - a1 = *(sp - 3); + a0 = SPILL_SLOT(a1, 0); + a1 = SPILL_SLOT(a1, 1); if (a1 <= (unsigned long)sp) break; -- cgit