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| author | Vaibhav Jain <vaibhav@linux.vnet.ibm.com> | 2018-03-04 23:00:25 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-03-13 15:10:16 +1100 |
| commit | e1368d0c9edbc366e45216e7295fd61ae55c2b12 (patch) | |
| tree | 8d19dcb1040d221eec0234781cfb12b567a76397 /arch/powerpc/xmon | |
| parent | b395e55b49ecd56ea28dc629f4ca4c6239fc07c3 (diff) | |
| download | linux-e1368d0c9edbc366e45216e7295fd61ae55c2b12.tar.gz linux-e1368d0c9edbc366e45216e7295fd61ae55c2b12.tar.bz2 linux-e1368d0c9edbc366e45216e7295fd61ae55c2b12.zip | |
powerpc/xmon: Setup debugger hooks when first break-point is set
Presently sysrq key for xmon('x') is registered during kernel init
irrespective of the value of kernel param 'xmon'. Thus xmon is enabled
even if 'xmon=off' is passed on the kernel command line. However this
doesn't enable the kernel debugger hooks needed for instruction or
data breakpoints. Thus when a break-point is hit with xmon=off a
kernel oops of the form below is reported:
Oops: Exception in kernel mode, sig: 5 [#1]
< snip >
Trace/breakpoint trap
To fix this the patch checks and enables debugger hooks when an
instruction or data break-point is set via xmon console.
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Just printf directly, no need for static const char[]]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/xmon')
| -rw-r--r-- | arch/powerpc/xmon/xmon.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 82e1a3ee6e0f..ee4b6071007d 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -1273,6 +1273,16 @@ static long check_bp_loc(unsigned long addr) return 1; } +/* Force enable xmon if not already enabled */ +static inline void force_enable_xmon(void) +{ + /* Enable xmon hooks if needed */ + if (!xmon_on) { + printf("xmon: Enabling debugger hooks\n"); + xmon_on = 1; + } +} + static char *breakpoint_help_string = "Breakpoint command usage:\n" "b show breakpoints\n" @@ -1315,6 +1325,8 @@ bpt_cmds(void) dabr.address &= ~HW_BRK_TYPE_DABR; dabr.enabled = mode | BP_DABR; } + + force_enable_xmon(); break; case 'i': /* bi - hardware instr breakpoint */ @@ -1335,6 +1347,7 @@ bpt_cmds(void) if (bp != NULL) { bp->enabled |= BP_CIABR; iabr = bp; + force_enable_xmon(); } break; #endif @@ -1399,8 +1412,10 @@ bpt_cmds(void) if (!check_bp_loc(a)) break; bp = new_breakpoint(a); - if (bp != NULL) + if (bp != NULL) { bp->enabled |= BP_TRAP; + force_enable_xmon(); + } break; } } |