Hi,
This patch is missing the Description and SoB line
John
On 09/08/12 19:16, Akhilesh Kumar wrote:
> yes Zhangin
>
> please find the complete patch
> ====================================================================
> diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
> index 7955409..df72738 100644
> --- a/arch/mips/kernel/process.c
> +++ b/arch/mips/kernel/process.c
> @@ -290,12 +290,45 @@ static inline int is_sp_move_ins(union
> mips_instruction *ip)
> return 0;
> }
>
> +#ifdef CONFIG_DYNAMIC_FTRACE
> +/*
> + * To create the jal <> instruction from mcount.
> + * taken from:
> + * - arch/mips/kernel/ftrace.c
> + */
> +#define ADDR_MASK 0x03ffffff /* op_code|addr : 31...26|25 ....0 */
> +#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */
> +#define INSN_JAL(addr) \
> + ((unsigned int)(JAL | (((addr) >> 2) & ADDR_MASK)))
> +
> +/*
> + * We assume jal <mcount>/<ftrace_caller> to be present in
> + * first JAL_MAX_OFFSET instructions.
> + * Increment this, if its otherwise
> + */
> +#define JAL_MAX_OFFSET 16U
> +#define MCOUNT_STACK_INST 0x27bdfff8 /* addiu sp,sp,-8 */
> +
> +/*
> + * If Dynamic Ftrace is enabled, ftrace_caller is the trace function.
> + * Otherwise its - mcount
> + */
> +extern void ftrace_caller(void);
> +#endif /* CONFIG_DYNAMIC_FTRACE */
> +
> static int get_frame_info(struct mips_frame_info *info)
> {
> union mips_instruction *ip = info->func;
> unsigned max_insns = info->func_size / sizeof(union mips_instruction);
> unsigned i;
>
> +#ifdef CONFIG_DYNAMIC_FTRACE
> + unsigned max_prolog_inst = max_insns;
> + int jal_found = 0;
> + /* instruction corresponding to jal <_mcount>/<ftrace_caller> */
> + int jal_mcount = 0;
> +#endif
> +
> info->pc_offset = -1;
> info->frame_size = 0;
>
> @@ -306,6 +339,28 @@ static int get_frame_info(struct mips_frame_info *info)
> max_insns = 128U; /* unknown function size */
> max_insns = min(128U, max_insns);
>
> +#ifdef CONFIG_DYNAMIC_FTRACE
> + max_prolog_inst = min(JAL_MAX_OFFSET, max_prolog_inst);
> + jal_mcount = INSN_JAL((unsigned)&ftrace_caller);
> +
> + for (i = 0; i < max_prolog_inst; i++, ip++) {
> + if ((*(int *)ip == jal_mcount) ||
> + /*
> + * for dyn ftrace, the code initially has 0.
> + * so we check whether the next instruction is
> + * addiu sp,sp,-8
> + */
> + (!(*(int *)ip) &&
> + (*(int *)(ip + 1) == MCOUNT_STACK_INST))
> + ) {
> + jal_found = 1;
> + break;
> + }
> + }
> + /* restore the ip to start of function */
> + ip = info->func;
> +#endif
> +
> for (i = 0; i < max_insns; i++, ip++) {
>
> if (is_jal_jalr_jr_ins(ip))
> @@ -321,6 +376,18 @@ static int get_frame_info(struct mips_frame_info *info)
> break;
> }
> }
> +#ifdef CONFIG_DYNAMIC_FTRACE
> + /*
> + * to offset the effect of:
> + * addiu sp,sp,-8
> + */
> + if (jal_found) {
> + if (info->frame_size)
> + info->frame_size += 8;
> + if (info->pc_offset >= 0)
> + info->pc_offset += 8 / sizeof(long);
> + }
> +#endif
> if (info->frame_size && info->pc_offset >= 0) /* nested */
> return 0;
> if (info->pc_offset < 0) /* leaf */
> --
> 1.7.8.4
>
> ====================================================================
>
> On Thu, Aug 9, 2012 at 9:41 PM, Wu Zhangjin <wuzhangjin@xxxxxxxxx
> <mailto:wuzhangjin@xxxxxxxxx>> wrote:
>
> Hi, Akhilesh
>
> Thanks very much for your work.
>
> Seems this patch has lost something, can you send a full one?
>
> Best Regards,
> Wu Zhangjin
>
> On Thu, Aug 9, 2012 at 9:53 PM, Akhilesh Kumar
> <akhilesh.lxr@xxxxxxxxx <mailto:akhilesh.lxr@xxxxxxxxx>> wrote:
> > Hi Ralf,
> >
> >
> > Sub:- Bug unable to retrive backtrace when HAVE_FUNCTION_TRACER
> is enable.
> > I send this bug and bug fix long back, I am resending this patch
> again for
> > review.
> >
> > Please review below patch if you agree I will regenerate this
> patch and with
> > you.
> >
> > ====[ backtrace testing ]===========
> > Testing a backtrace from process context.
> > The following trace is a kernel self test and not a bug!
> > Testing a backtrace.
> > The following trace is a kernel self test and not a bug!
> > Call Trace:
> > [<80295134>] dump_stack+0x8/0x34
> > [<c0946060>] backtrace_regression_test+0x60/0x94 [sisc_backtrcae]
> > [<800004f0>] do_one_initcall+0xf0/0x1d0
> > [<80060954>] sys_init_module+0x19c8/0x1c60
> > [<8000a418>] stack_done+0x20/0x40
> > output befor patch when HAVE_FUNCTION_TRACER is enable
> > ---------------------------------------------------------------------
> > #> insmod backtrace.ko
> > ====[ backtrace testing ]===========
> > Testing a backtrace from process context.
> > The following trace is a kernel self test and not a bug!
> > Testing a backtrace.
> > The following trace is a kernel self test and not a bug!
> > Call Trace:
> > [<802e5164>] dump_stack+0x1c/0x50
> > [<802e5164>] dump_stack+0x1c/0x50
> > ====[ end of backtrace testing ]====
> > ------------------------------------------------------
> > above shows the wrong back trcae
> > output after patch when HAVE_FUNCTION_TRACER is enable
> > ----------------------------------------------------------------------
> > ====[ backtrace testing ]===========
> > Testing a backtrace from process context.
> > The following trace is a kernel self test and not a bug!
> > Testing a backtrace.
> > The following trace is a kernel self test and not a bug!
> > Call Trace:
> > [<802eb1a4>] dump_stack+0x20/0x54
> > [<c003405c>] backtrace_test_timer+0x5c/0x74 [sisc_backtrcae]
> > [<c00340dc>] init_module+0x68/0xa0 [sisc_backtrcae]
> > [<80000508>] do_one_initcall+0x108/0x1f0
> > [<8006d4c4>] sys_init_module+0x1a10/0x1c74
> > [<8000b038>] stack_done+0x20/0x40
> > ------------------------------------------------------------------
> > get_frame_info() is used to fetch the frame information from the
> > function.
> > However,
> > 1. this function just considers the first stack adjustment for frame
> > size.
> > 2. On finding the save_lr instruction, it returns.
> > It doesn't handle the ftrace condition.
> > If Dynamic Frace "CONFIG_DYNAMIC_FTRACE" is enabled, the
> instrumentation
> > code is:
> > - jal <ftrace_caller>
> > - addiu sp,sp,-8
> > Thus, the current Frame Size of function is increased by 8 for Ftrace.
> > Signed-off-by: Akhilesh Kumar <akhilesh.lxr@xxxxxxxxx
> <mailto:akhilesh.lxr@xxxxxxxxx>>
> > ---
> > arch/mips/kernel/process.c | 67
> > ++++++++++++++++++++++++++++++++++++++++++++
> > 1 files changed, 67 insertions(+), 0 deletions(-)
> > diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
> > index 7955409..df72738 100644
> > --- a/arch/mips/kernel/process.c
> > +++ b/arch/mips/kernel/process.c
> > @@ -290,12 +290,45 @@ static inline int is_sp_move_ins(union
> > mips_instruction *ip)
> > return 0;
> > }
> > +#ifdef CONFIG_DYNAMIC_FTRACE
> > +/*
> > + * To create the jal <> instruction from mcount.
> > + * taken from:
> > + * - arch/mips/kernel/ftrace.c
> > + */
> > +#define ADDR_MASK 0x03ffffff /* op_code|addr : 31...26|25
> ....0 */
> > +#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to
> target */
> > +#define INSN_JAL(addr) \
> > + ((unsigned int)(JAL | (((addr) >> 2) & ADDR_MASK)))
> > +
> > +/*
> > + * We assume jal <mcount>/<ftrace_caller> to be present in
> > + * first JAL_MAX_OFFSET instructions.
> > + * Increment this, if its otherwise
> > + */
> > +#define JAL_MAX_OFFSET 16U
> > +#define MCOUNT_STACK_INST 0x27bdfff8 /* addiu sp,sp,-8 */
> > +
> > +/*
> > + * If Dynamic Ftrace is enabled, ftrace_caller is the trace function.
> > + * Otherwise its - mcount
> > + */
> > +extern void ftrace_caller(void);
> > +#endif /* CONFIG_DYNAMIC_FTRACE */
> > +
> > static int get_frame_info(struct mips_frame_info *info)
> > {
> > union mips_instruction *ip = info->func;
> > unsigned max_insns = info->func_size / sizeof(union
> mips_instruction);
> > unsigned i;
> > +#ifdef CONFIG_DYNAMIC_FTRACE
> > + unsigned max_prolog_inst = max_insns;
> > + int jal_found = 0;
> > + /* instruction corresponding to jal <_mcount>/<ftrace_caller> */
> > + int jal_mcount = 0;
> > +#endif
> > +
> > info->pc_offset = -1;
> > info->frame_size = 0;
>
>
