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powerpc/xmon: Also setup debugger hooks when single-stepping 

When single-stepping kernel code from xmon without a debug hook
enabled the kernel crashes. This can happen when kernel starts with
xmon on crash disabled but xmon is entered using sysrq.

Call force_enable_xmon when single-stepping in xmon to install the
xmon debug hooks.

Fixes: e1368d0c9e ("powerpc/xmon: Setup debugger hooks when first break-point is set")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michal Suchanek 2018-05-23 20:00:54 +02:00 committed by Michael Ellerman
parent e4ccb1dae6
commit 7daf593009
1 changed files with 11 additions and 10 deletions
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21
arch/powerpc/xmon/xmon.c
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@ -778,6 +778,16 @@ static int xmon_fault_handler(struct pt_regs *regs)
return 0;
}
/* 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 struct bpt *at_breakpoint(unsigned long pc)
{
int i;
@ -1094,6 +1104,7 @@ static int do_step(struct pt_regs *regs)
unsigned int instr;
int stepped;
force_enable_xmon();
/* check we are in 64-bit kernel mode, translation enabled */
if ((regs->msr & (MSR_64BIT|MSR_PR|MSR_IR)) == (MSR_64BIT|MSR_IR)) {
if (mread(regs->nip, &instr, 4) == 4) {
@ -1268,16 +1279,6 @@ 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"