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Commit 9f6b3c2c authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

hw-breakpoints: Fix broken a.out format dump 



Fix the broken a.out format dump. For now we only dump the ptrace
breakpoints.

TODO: Dump every perf breakpoints for the current thread, not only
ptrace based ones.

Reported-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
parent 676c0dbe

arch/x86/include/asm/a.out-core.h

+2 −8
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


#include <linux/user.h>

#include <linux/elfcore.h>

#include <asm/debugreg.h>



/*

 * fill in the user structure for an a.out core dump
@@ -32,14 +33,7 @@ static inline void aout_dump_thread(struct pt_regs *regs, struct user *dump) 
			>> PAGE_SHIFT;

	dump->u_dsize -= dump->u_tsize;

	dump->u_ssize = 0;

	dump->u_debugreg[0] = current->thread.debugreg[0];

	dump->u_debugreg[1] = current->thread.debugreg[1];

	dump->u_debugreg[2] = current->thread.debugreg[2];

	dump->u_debugreg[3] = current->thread.debugreg[3];

	dump->u_debugreg[4] = 0;

	dump->u_debugreg[5] = 0;

	dump->u_debugreg[6] = current->thread.debugreg6;

	dump->u_debugreg[7] = current->thread.debugreg7;

	aout_dump_debugregs(dump);



	if (dump->start_stack < TASK_SIZE)

		dump->u_ssize = ((unsigned long)(TASK_SIZE - dump->start_stack))

arch/x86/include/asm/debugreg.h

+2 −0
Original line number Diff line number Diff line
@@ -89,6 +89,8 @@ static inline void hw_breakpoint_disable(void) 
	set_debugreg(0UL, 3);

}



extern void aout_dump_debugregs(struct user *dump);



#ifdef CONFIG_KVM

extern void hw_breakpoint_restore(void);

#endif

arch/x86/kernel/hw_breakpoint.c

+35 −0
Original line number Diff line number Diff line
@@ -375,6 +375,41 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp, 
	return 0;

}



/*

 * Dump the debug register contents to the user.

 * We can't dump our per cpu values because it

 * may contain cpu wide breakpoint, something that

 * doesn't belong to the current task.

 *

 * TODO: include non-ptrace user breakpoints (perf)

 */

void aout_dump_debugregs(struct user *dump)

{

	int i;

	int dr7 = 0;

	struct perf_event *bp;

	struct arch_hw_breakpoint *info;

	struct thread_struct *thread = &current->thread;



	for (i = 0; i < HBP_NUM; i++) {

		bp = thread->ptrace_bps[i];



		if (bp && !bp->attr.disabled) {

			dump->u_debugreg[i] = bp->attr.bp_addr;

			info = counter_arch_bp(bp);

			dr7 |= encode_dr7(i, info->len, info->type);

		} else {

			dump->u_debugreg[i] = 0;

		}

	}



	dump->u_debugreg[4] = 0;

	dump->u_debugreg[5] = 0;

	dump->u_debugreg[6] = current->thread.debugreg6;



	dump->u_debugreg[7] = dr7;

}



/*

 * Release the user breakpoints used by ptrace

 */