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Commit cf7d6fb0 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc/64s: Blacklist system_call() and system_call_common() from kprobes 



Convert some of the symbols into private symbols and blacklist
system_call_common() and system_call() from kprobes. We can't take a
trap at parts of these functions as either MSR_RI is unset or the
kernel stack pointer is not yet setup.

Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Don't convert system_call_common to _GLOBAL()]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 9d6c4523

arch/powerpc/kernel/entry_64.S

+14 −12
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ system_call_common: 
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

BEGIN_FTR_SECTION

	extrdi.	r10, r12, 1, (63-MSR_TS_T_LG) /* transaction active? */

	bne	tabort_syscall

	bne	.Ltabort_syscall

END_FTR_SECTION_IFSET(CPU_FTR_TM)

#endif

	andi.	r10,r12,MSR_PR
@@ -152,9 +152,9 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR) 
	CURRENT_THREAD_INFO(r11, r1)

	ld	r10,TI_FLAGS(r11)

	andi.	r11,r10,_TIF_SYSCALL_DOTRACE

	bne	syscall_dotrace		/* does not return */

	bne	.Lsyscall_dotrace		/* does not return */

	cmpldi	0,r0,NR_syscalls

	bge-	syscall_enosys

	bge-	.Lsyscall_enosys



system_call:			/* label this so stack traces look sane */

/*
@@ -208,7 +208,7 @@ system_call: /* label this so stack traces look sane */ 
	ld	r9,TI_FLAGS(r12)

	li	r11,-MAX_ERRNO

	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)

	bne-	syscall_exit_work

	bne-	.Lsyscall_exit_work



	/* If MSR_FP and MSR_VEC are set in user msr, then no need to restore */

	li	r7,MSR_FP
@@ -217,12 +217,12 @@ system_call: /* label this so stack traces look sane */ 
#endif

	and	r0,r8,r7

	cmpd	r0,r7

	bne	syscall_restore_math

	bne	.Lsyscall_restore_math

.Lsyscall_restore_math_cont:



	cmpld	r3,r11

	ld	r5,_CCR(r1)

	bge-	syscall_error

	bge-	.Lsyscall_error

.Lsyscall_error_cont:

	ld	r7,_NIP(r1)

BEGIN_FTR_SECTION
@@ -248,13 +248,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) 
	RFI

	b	.	/* prevent speculative execution */



syscall_error:	

.Lsyscall_error:

	oris	r5,r5,0x1000	/* Set SO bit in CR */

	neg	r3,r3

	std	r5,_CCR(r1)

	b	.Lsyscall_error_cont



syscall_restore_math:

.Lsyscall_restore_math:

	/*

	 * Some initial tests from restore_math to avoid the heavyweight

	 * C code entry and MSR manipulations.
@@ -289,7 +289,7 @@ syscall_restore_math: 
	b	.Lsyscall_restore_math_cont



/* Traced system call support */

syscall_dotrace:

.Lsyscall_dotrace:

	bl	save_nvgprs

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	do_syscall_trace_enter
@@ -322,11 +322,11 @@ syscall_dotrace: 
	b	.Lsyscall_exit





syscall_enosys:

.Lsyscall_enosys:

	li	r3,-ENOSYS

	b	.Lsyscall_exit

	

syscall_exit_work:

.Lsyscall_exit_work:

#ifdef CONFIG_PPC_BOOK3S

	li	r10,MSR_RI

	mtmsrd	r10,1		/* Restore RI */
@@ -386,7 +386,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) 
	b	ret_from_except



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

tabort_syscall:

.Ltabort_syscall:

	/* Firstly we need to enable TM in the kernel */

	mfmsr	r10

	li	r9, 1
@@ -412,6 +412,8 @@ tabort_syscall: 
	rfid

	b	.	/* prevent speculative execution */

#endif

_ASM_NOKPROBE_SYMBOL(system_call_common);

_ASM_NOKPROBE_SYMBOL(system_call);



/* Save non-volatile GPRs, if not already saved. */

_GLOBAL(save_nvgprs)