Commit 6cbe5e95 authored by Jonas Bonn's avatar Jonas Bonn
Browse files

openrisc: sanitize use of orig_gpr11 



The pt_regs struct had both a 'syscallno' field and an 'orig_gpr11' field
and it wasn't really clear how these were supposed to be used.  This patch
removes the syscallno field altogether and makes orig_gpr11 work more
like other architectures: keep track of syscall number in progress or
hold -1 for non-syscall exceptions.

Signed-off-by: default avatarJonas Bonn <jonas@southpole.se>
parent 2f099a28

arch/openrisc/include/asm/ptrace.h

+5 −1
Original line number Diff line number Diff line
@@ -73,9 +73,13 @@ struct pt_regs { 
		};

	};

	long  pc;

	/* For restarting system calls:

	 * Set to syscall number for syscall exceptions,

	 * -1 for all other exceptions.

	 */

	long  orig_gpr11;	/* For restarting system calls */

	long  syscallno;	/* Syscall number (used by strace) */

	long dummy;		/* Cheap alignment fix */

	long dummy2;		/* Cheap alignment fix */

};



/* TODO: Rename this to REDZONE because that's what it is */

arch/openrisc/include/asm/syscall.h

+2 −5
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ 
static inline int

syscall_get_nr(struct task_struct *task, struct pt_regs *regs)

{

	return regs->syscallno ? regs->syscallno : -1;

	return regs->orig_gpr11;

}



static inline void
@@ -50,10 +50,7 @@ static inline void 
syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,

			 int error, long val)

{

	if (error)

		regs->gpr[11] = -error;

	else

		regs->gpr[11] = val;

	regs->gpr[11] = (long) error ?: val;

}



static inline void

arch/openrisc/kernel/entry.S

+8 −8
Original line number Diff line number Diff line
@@ -95,7 +95,6 @@ handler: ;\ 
	/* r1, EPCR, ESR a already saved */			;\

	l.sw	PT_GPR2(r1),r2					;\

	l.sw    PT_GPR3(r1),r3					;\

	l.sw    PT_ORIG_GPR11(r1),r11				;\

	/* r4 already save */					;\

	l.sw    PT_GPR5(r1),r5					;\

	l.sw    PT_GPR6(r1),r6					;\
@@ -125,7 +124,9 @@ handler: ;\ 
	/* r30 already save */					;\

/*        l.sw    PT_GPR30(r1),r30*/					;\

	l.sw    PT_GPR31(r1),r31					;\

	l.sw    PT_SYSCALLNO(r1),r0

	/* Store -1 in orig_gpr11 for non-syscall exceptions */	;\

	l.addi	r30,r0,-1					;\

	l.sw	PT_ORIG_GPR11(r1),r30



#define UNHANDLED_EXCEPTION(handler,vector)			\

	.global	handler						;\
@@ -133,7 +134,6 @@ handler: ;\ 
	/* r1, EPCR, ESR already saved */			;\

	l.sw    PT_GPR2(r1),r2					;\

	l.sw    PT_GPR3(r1),r3					;\

	l.sw    PT_ORIG_GPR11(r1),r11				;\

	l.sw    PT_GPR5(r1),r5					;\

	l.sw    PT_GPR6(r1),r6					;\

	l.sw    PT_GPR7(r1),r7					;\
@@ -162,7 +162,9 @@ handler: ;\ 
	/* r31 already saved */					;\

	l.sw    PT_GPR30(r1),r30					;\

/*        l.sw    PT_GPR31(r1),r31	*/				;\

	l.sw    PT_SYSCALLNO(r1),r0				;\

	/* Store -1 in orig_gpr11 for non-syscall exceptions */	;\

	l.addi	r30,r0,-1					;\

	l.sw	PT_ORIG_GPR11(r1),r30				;\

	l.addi	r3,r1,0						;\

	/* r4 is exception EA */				;\

	l.addi	r5,r0,vector					;\
@@ -554,6 +556,7 @@ ENTRY(_sys_call_handler) 
	l.sw    PT_GPR9(r1),r9

	/* r10 already saved */

	l.sw    PT_GPR11(r1),r11

	/* orig_gpr11 must be set for syscalls */

	l.sw    PT_ORIG_GPR11(r1),r11

	/* r12,r13 already saved */
@@ -567,9 +570,6 @@ ENTRY(_sys_call_handler) 
	/* r30 is the only register we clobber in the fast path */

	/* r30 already saved */

/*	l.sw    PT_GPR30(r1),r30 */

	/* This is used by do_signal to determine whether to check for

	 * syscall restart or not */

	l.sw    PT_SYSCALLNO(r1),r11



_syscall_check_trace_enter:

	/* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */
@@ -731,7 +731,7 @@ _syscall_trace_enter: 
	 * so that we can do the syscall for real and return to the syscall

	 * hot path.

	 */

	l.lwz	r11,PT_SYSCALLNO(r1)

	l.lwz	r11,PT_GPR11(r1)

	l.lwz	r3,PT_GPR3(r1)

	l.lwz	r4,PT_GPR4(r1)

	l.lwz	r5,PT_GPR5(r1)

arch/openrisc/kernel/ptrace.c

+2 −2
Original line number Diff line number Diff line
@@ -188,11 +188,11 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 
		 */

		ret = -1L;



	audit_syscall_entry(audit_arch(), regs->syscallno,

	audit_syscall_entry(audit_arch(), regs->gpr[11],

			    regs->gpr[3], regs->gpr[4],

			    regs->gpr[5], regs->gpr[6]);



	return ret ? : regs->syscallno;

	return ret ? : regs->gpr[11];

}



asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)

arch/openrisc/kernel/signal.c

+1 −1
Original line number Diff line number Diff line
@@ -305,7 +305,7 @@ void do_signal(struct pt_regs *regs) 
	 * below mean that the syscall executed to completion and no

	 * restart is necessary.

	 */

	if (regs->syscallno) {

	if (regs->orig_gpr11) {

		int restart = 0;



		switch (regs->gpr[11]) {