Commit 67787b68 authored by AKASHI Takahiro's avatar AKASHI Takahiro Committed by Catalin Marinas
Browse files

arm64: kgdb: handle read-only text / modules 



Handle read-only cases when CONFIG_DEBUG_RODATA (4.0) or
CONFIG_DEBUG_SET_MODULE_RONX (3.18) are enabled by using
aarch64_insn_write() instead of probe_kernel_write() as introduced by
commit 2f896d58 ("arm64: use fixmap for text patching") in 4.0.

Fixes: 11d91a77 ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support")
Signed-off-by: default avatarAKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent c18df0ad

arch/arm64/include/asm/debug-monitors.h

+0 −2
Original line number Diff line number Diff line
@@ -61,8 +61,6 @@ 


#define AARCH64_BREAK_KGDB_DYN_DBG	\

	(AARCH64_BREAK_MON | (KGDB_DYN_DBG_BRK_IMM << 5))

#define KGDB_DYN_BRK_INS_BYTE(x)	\

	((AARCH64_BREAK_KGDB_DYN_DBG >> (8 * (x))) & 0xff)



#define CACHE_FLUSH_IS_SAFE		1

arch/arm64/kernel/kgdb.c

+24 −12
Original line number Diff line number Diff line
@@ -19,10 +19,13 @@ 
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/bug.h>

#include <linux/irq.h>

#include <linux/kdebug.h>

#include <linux/kgdb.h>

#include <linux/kprobes.h>

#include <asm/debug-monitors.h>

#include <asm/insn.h>

#include <asm/traps.h>



struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
@@ -338,15 +341,24 @@ void kgdb_arch_exit(void) 
	unregister_die_notifier(&kgdb_notifier);

}



/*

 * ARM instructions are always in LE.

 * Break instruction is encoded in LE format

 */

struct kgdb_arch arch_kgdb_ops = {

	.gdb_bpt_instr = {

		KGDB_DYN_BRK_INS_BYTE(0),

		KGDB_DYN_BRK_INS_BYTE(1),

		KGDB_DYN_BRK_INS_BYTE(2),

		KGDB_DYN_BRK_INS_BYTE(3),

struct kgdb_arch arch_kgdb_ops;



int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)

{

	int err;



	BUILD_BUG_ON(AARCH64_INSN_SIZE != BREAK_INSTR_SIZE);



	err = aarch64_insn_read((void *)bpt->bpt_addr, (u32 *)bpt->saved_instr);

	if (err)

		return err;



	return aarch64_insn_write((void *)bpt->bpt_addr,

			(u32)AARCH64_BREAK_KGDB_DYN_DBG);

}



int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)

{

	return aarch64_insn_write((void *)bpt->bpt_addr,

			*(u32 *)bpt->saved_instr);

}
 
};

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