Well, there's a bug I noticed in this patch, $1 is restored from the wrong location. I'm not sure $1 ($at) needs to be restored at all, really. I guess make this a RFC.
-corey On 09/16/2014 04:45 PM, [email protected] wrote: > From: Corey Minyard <[email protected]> > > The MIPS frame save code was just saving a few registers, enough to > do a backtrace if every function set up a frame. However, this is > not working if you are using DWARF unwinding, because most of the > registers are wrong. This was causing kdump backtraces to be short > or bogus. > > So save all the registers. > > Signed-off-by: Corey Minyard <[email protected]> > --- > arch/mips/include/asm/stacktrace.h | 64 > +++++++++++++++++++++++++++++--------- > 1 file changed, 50 insertions(+), 14 deletions(-) > > diff --git a/arch/mips/include/asm/stacktrace.h > b/arch/mips/include/asm/stacktrace.h > index 780ee2c..05a2195 100644 > --- a/arch/mips/include/asm/stacktrace.h > +++ b/arch/mips/include/asm/stacktrace.h > @@ -2,6 +2,8 @@ > #define _ASM_STACKTRACE_H > > #include <asm/ptrace.h> > +#include <asm/asm.h> > +#include <linux/stringify.h> > > #ifdef CONFIG_KALLSYMS > extern int raw_show_trace; > @@ -20,6 +22,14 @@ static inline unsigned long unwind_stack(struct > task_struct *task, > } > #endif > > +#define STR_PTR_LA __stringify(PTR_LA) > +#define STR_LONG_S __stringify(LONG_S) > +#define STR_LONG_L __stringify(LONG_L) > +#define STR_LONGSIZE __stringify(LONGSIZE) > + > +#define STORE_ONE_REG(r) \ > + STR_LONG_S " $" > __stringify(r)",("STR_LONGSIZE"*"__stringify(r)")(%1)\n\t" > + > static __always_inline void prepare_frametrace(struct pt_regs *regs) > { > #ifndef CONFIG_KALLSYMS > @@ -32,21 +42,47 @@ static __always_inline void prepare_frametrace(struct > pt_regs *regs) > __asm__ __volatile__( > ".set push\n\t" > ".set noat\n\t" > -#ifdef CONFIG_64BIT > - "1: dla $1, 1b\n\t" > - "sd $1, %0\n\t" > - "sd $29, %1\n\t" > - "sd $31, %2\n\t" > -#else > - "1: la $1, 1b\n\t" > - "sw $1, %0\n\t" > - "sw $29, %1\n\t" > - "sw $31, %2\n\t" > -#endif > + /* Store $1 so we can use it */ > + STR_LONG_S " $1,"STR_LONGSIZE"(%1)\n\t" > + /* Store the PC */ > + "1: " STR_PTR_LA " $1, 1b\n\t" > + STR_LONG_S " $1,%0\n\t" > + STORE_ONE_REG(2) > + STORE_ONE_REG(3) > + STORE_ONE_REG(4) > + STORE_ONE_REG(5) > + STORE_ONE_REG(6) > + STORE_ONE_REG(7) > + STORE_ONE_REG(8) > + STORE_ONE_REG(9) > + STORE_ONE_REG(10) > + STORE_ONE_REG(11) > + STORE_ONE_REG(12) > + STORE_ONE_REG(13) > + STORE_ONE_REG(14) > + STORE_ONE_REG(15) > + STORE_ONE_REG(16) > + STORE_ONE_REG(17) > + STORE_ONE_REG(18) > + STORE_ONE_REG(19) > + STORE_ONE_REG(20) > + STORE_ONE_REG(21) > + STORE_ONE_REG(22) > + STORE_ONE_REG(23) > + STORE_ONE_REG(24) > + STORE_ONE_REG(25) > + STORE_ONE_REG(26) > + STORE_ONE_REG(27) > + STORE_ONE_REG(28) > + STORE_ONE_REG(29) > + STORE_ONE_REG(30) > + STORE_ONE_REG(31) > + /* Restore $1 */ > + STR_LONG_L " $1,(%1)\n\t" > ".set pop\n\t" > - : "=m" (regs->cp0_epc), > - "=m" (regs->regs[29]), "=m" (regs->regs[31]) > - : : "memory"); > + : "=m" (regs->cp0_epc) > + : "r" (regs->regs) > + : "memory"); > } > > #endif /* _ASM_STACKTRACE_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
