kernel.git/arch/powerpc/xmon, branch linux-3.8.y

powerpc/xmon: Fallback to printk() in xmon_printf() if udbg is not setup

2012-11-15T02:00:02Z

It is possible to configure a kernel which has xmon enabled, but has no udbg backend to provide IO. This can make xmon rather confusing, as it produces no output, blocks for two seconds, and then returns. As a last resort we can instead try to printk(), which may deadlock or otherwise crash, but tries quite hard not to. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Fiddle xmon_depth_to_print logic in xmon_show_stack()

2012-11-15T01:59:59Z

Currently xmon_depth_to_print is static and global, but it's only ever used in xmon_show_stack(). At least with a modern compiler it's inlined, so there's no point in it being static, we could #define it but it's only used in one place. By reworking the logic we can drop count and just decrement the max value as a loop counter. Also switch to a while loop so we actually print no more than 64 frames as you'd expect based on the variable name. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Use STACK_FRAME_OVERHEAD in xmon_show_stack()

2012-11-15T01:59:55Z

We use STACK_FRAME_OVERHEAD in the exception vectors to establish the exception frame, so it should be good enough to use here. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Remove unused #defines

2012-11-15T01:59:52Z

Neither REGS_PER_LINE or LAST_VOLATILE are used, nor have they ever been as far back as I can see. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Remove renaming #defines of scanhex() and skipbl()

2012-11-15T01:59:49Z

We have two #defines that rename scanhex() and skipbl() to xmon_scanhex() and xmon_skipbl() - but no one ever uses those names. So the only effect is to rename the actual symbols in the generated code, and AFACIS there is no reason to do that, so drop them. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Merge start.c into nonstdio.c

2012-11-15T01:59:46Z

The routines in start.c are only ever called from nonstdio.c, so if we move them in there they can become static which is nice. I suspect the idea behind the separation was that start.c could be replaced in order to build xmon in userland. If anyone still cares about doing that we could handle that with an ifdef or two. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Make xmon_getchar() static

2012-11-15T01:59:43Z

xmon_getchar() is only called from within nonstdio.c, so make it static. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Remove empty xmon_map_scc()

2012-11-15T01:59:40Z

This has been empty since 2005, commit 51d3082 "Unify udbg (#2)". Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/xmon: Remove unused xmon_expect() & xmon_read_poll()

2012-11-15T01:59:37Z

It looks like xmon_expect() was used for doing xmon over a modem (!?), that code was dropped in 2005 in commit 51d3082 "Unify udbg (#2)". Once xmon_expect() is gone xmon_read_poll() is unused, drop it too. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc: Add an xmon command to dump one or all pacas

2012-09-18T05:02:36Z

This was originally motivated by a desire to see the mapping between logical and hardware cpu numbers. But it seemed that it made more sense to just add a command to dump (most of) the paca. With no arguments "dp" will dump the paca for the current cpu. It also takes an argument, eg. "dp 3" which is the logical cpu number in hex. This form does not check if the cpu is possible, but displays the paca regardless, as well as the cpu's state in the possible, present and online masks. Thirdly, "dpa" will display the paca for all possible cpus. If there are no possible cpus, like early in boot, it will tell you that. Sample output, number in brackets is the offset into the struct: 2:mon> dp 3 paca for cpu 0x3 @ c00000000ff20a80: possible = yes present = yes online = yes lock_token = 0x8000 (0x8) paca_index = 0x3 (0xa) kernel_toc = 0xc00000000144f990 (0x10) kernelbase = 0xc000000000000000 (0x18) kernel_msr = 0xb000000000001032 (0x20) stab_real = 0x0 (0x28) stab_addr = 0x0 (0x30) emergency_sp = 0xc00000003ffe4000 (0x38) data_offset = 0xa40000 (0x40) hw_cpu_id = 0x9 (0x50) cpu_start = 0x1 (0x52) kexec_state = 0x0 (0x53) __current = 0xc00000007e568680 (0x218) kstack = 0xc00000007e5a3e30 (0x220) stab_rr = 0x1a (0x228) saved_r1 = 0xc00000007e7cb450 (0x230) trap_save = 0x0 (0x240) soft_enabled = 0x0 (0x242) irq_happened = 0x0 (0x243) io_sync = 0x0 (0x244) irq_work_pending = 0x0 (0x245) nap_state_lost = 0x0 (0x246) Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt