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Commit 7daf5930 authored by Michal Suchanek's avatar Michal Suchanek Committed by Michael Ellerman
Browse files

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: e1368d0c ("powerpc/xmon: Setup debugger hooks when first break-point is set")
Signed-off-by: default avatarMichal Suchanek <msuchanek@suse.de>
Reviewed-by: default avatarVaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent e4ccb1da

arch/powerpc/xmon/xmon.c

+11 −10
Original line number Diff line number Diff line
@@ -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"