Commit 7853f9c0 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc: Split ftrace bits into a separate file 



entry_*.S now includes a lot more than just kernel entry/exit code. As a
first step at cleaning this up, let's split out the ftrace bits into
separate files. Also move all related tracing code into a new trace/
subdirectory.

No functional changes.

Suggested-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 2505820f

arch/powerpc/kernel/Makefile

+1 −8
Original line number Diff line number Diff line
@@ -25,8 +25,6 @@ CFLAGS_REMOVE_cputable.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) 
CFLAGS_REMOVE_prom_init.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_btext.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_prom.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

# do not trace tracer code

CFLAGS_REMOVE_ftrace.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

# timers used by tracing

CFLAGS_REMOVE_time.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

endif
@@ -119,10 +117,7 @@ obj64-$(CONFIG_AUDIT) += compat_audit.o 


obj-$(CONFIG_PPC_IO_WORKAROUNDS)	+= io-workarounds.o



obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o

obj-$(CONFIG_FTRACE_SYSCALLS)	+= ftrace.o

obj-$(CONFIG_TRACING)		+= trace_clock.o

obj-y				+= trace/



ifneq ($(CONFIG_PPC_INDIRECT_PIO),y)

obj-y				+= iomap.o
@@ -143,8 +138,6 @@ obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o 
# Disable GCOV & sanitizers in odd or sensitive code

GCOV_PROFILE_prom_init.o := n

UBSAN_SANITIZE_prom_init.o := n

GCOV_PROFILE_ftrace.o := n

UBSAN_SANITIZE_ftrace.o := n

GCOV_PROFILE_machine_kexec_64.o := n

UBSAN_SANITIZE_machine_kexec_64.o := n

GCOV_PROFILE_machine_kexec_32.o := n

arch/powerpc/kernel/entry_32.S

+0 −107
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ 
#include <asm/ppc_asm.h>

#include <asm/asm-offsets.h>

#include <asm/unistd.h>

#include <asm/ftrace.h>

#include <asm/ptrace.h>

#include <asm/export.h>
@@ -1315,109 +1314,3 @@ machine_check_in_rtas: 
	/* XXX load up BATs and panic */



#endif /* CONFIG_PPC_RTAS */
 


#ifdef CONFIG_FUNCTION_TRACER

#ifdef CONFIG_DYNAMIC_FTRACE

_GLOBAL(mcount)

_GLOBAL(_mcount)

	/*

	 * It is required that _mcount on PPC32 must preserve the

	 * link register. But we have r0 to play with. We use r0

	 * to push the return address back to the caller of mcount

	 * into the ctr register, restore the link register and

	 * then jump back using the ctr register.

	 */

	mflr	r0

	mtctr	r0

	lwz	r0, 4(r1)

	mtlr	r0

	bctr



_GLOBAL(ftrace_caller)

	MCOUNT_SAVE_FRAME

	/* r3 ends up with link register */

	subi	r3, r3, MCOUNT_INSN_SIZE

.globl ftrace_call

ftrace_call:

	bl	ftrace_stub

	nop

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

.globl ftrace_graph_call

ftrace_graph_call:

	b	ftrace_graph_stub

_GLOBAL(ftrace_graph_stub)

#endif

	MCOUNT_RESTORE_FRAME

	/* old link register ends up in ctr reg */

	bctr

#else

_GLOBAL(mcount)

_GLOBAL(_mcount)



	MCOUNT_SAVE_FRAME



	subi	r3, r3, MCOUNT_INSN_SIZE

	LOAD_REG_ADDR(r5, ftrace_trace_function)

	lwz	r5,0(r5)



	mtctr	r5

	bctrl

	nop



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	b	ftrace_graph_caller

#endif

	MCOUNT_RESTORE_FRAME

	bctr

#endif

EXPORT_SYMBOL(_mcount)



_GLOBAL(ftrace_stub)

	blr



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

_GLOBAL(ftrace_graph_caller)

	/* load r4 with local address */

	lwz	r4, 44(r1)

	subi	r4, r4, MCOUNT_INSN_SIZE



	/* Grab the LR out of the caller stack frame */

	lwz	r3,52(r1)



	bl	prepare_ftrace_return

	nop



        /*

         * prepare_ftrace_return gives us the address we divert to.

         * Change the LR in the callers stack frame to this.

         */

	stw	r3,52(r1)



	MCOUNT_RESTORE_FRAME

	/* old link register ends up in ctr reg */

	bctr



_GLOBAL(return_to_handler)

	/* need to save return values */

	stwu	r1, -32(r1)

	stw	r3, 20(r1)

	stw	r4, 16(r1)

	stw	r31, 12(r1)

	mr	r31, r1



	bl	ftrace_return_to_handler

	nop



	/* return value has real return address */

	mtlr	r3



	lwz	r3, 20(r1)

	lwz	r4, 16(r1)

	lwz	r31,12(r1)

	lwz	r1, 0(r1)



	/* Jump back to real return address */

	blr

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */



#endif /* CONFIG_FUNCTION_TRACER */

arch/powerpc/kernel/entry_64.S

+0 −378
Original line number Diff line number Diff line
@@ -20,7 +20,6 @@ 


#include <linux/errno.h>

#include <linux/err.h>

#include <linux/magic.h>

#include <asm/unistd.h>

#include <asm/processor.h>

#include <asm/page.h>
@@ -33,7 +32,6 @@ 
#include <asm/bug.h>

#include <asm/ptrace.h>

#include <asm/irqflags.h>

#include <asm/ftrace.h>

#include <asm/hw_irq.h>

#include <asm/context_tracking.h>

#include <asm/tm.h>
@@ -1173,379 +1171,3 @@ _GLOBAL(enter_prom) 
	ld	r0,16(r1)

	mtlr    r0

        blr
 


#ifdef CONFIG_FUNCTION_TRACER

#ifdef CONFIG_DYNAMIC_FTRACE

_GLOBAL(mcount)

_GLOBAL(_mcount)

EXPORT_SYMBOL(_mcount)

	mflr	r12

	mtctr	r12

	mtlr	r0

	bctr



#ifndef CC_USING_MPROFILE_KERNEL

_GLOBAL_TOC(ftrace_caller)

	/* Taken from output of objdump from lib64/glibc */

	mflr	r3

	ld	r11, 0(r1)

	stdu	r1, -112(r1)

	std	r3, 128(r1)

	ld	r4, 16(r11)

	subi	r3, r3, MCOUNT_INSN_SIZE

.globl ftrace_call

ftrace_call:

	bl	ftrace_stub

	nop

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

.globl ftrace_graph_call

ftrace_graph_call:

	b	ftrace_graph_stub

_GLOBAL(ftrace_graph_stub)

#endif

	ld	r0, 128(r1)

	mtlr	r0

	addi	r1, r1, 112



#else /* CC_USING_MPROFILE_KERNEL */

/*

 *

 * ftrace_caller() is the function that replaces _mcount() when ftrace is

 * active.

 *

 * We arrive here after a function A calls function B, and we are the trace

 * function for B. When we enter r1 points to A's stack frame, B has not yet

 * had a chance to allocate one yet.

 *

 * Additionally r2 may point either to the TOC for A, or B, depending on

 * whether B did a TOC setup sequence before calling us.

 *

 * On entry the LR points back to the _mcount() call site, and r0 holds the

 * saved LR as it was on entry to B, ie. the original return address at the

 * call site in A.

 *

 * Our job is to save the register state into a struct pt_regs (on the stack)

 * and then arrange for the ftrace function to be called.

 */

_GLOBAL(ftrace_caller)

	/* Save the original return address in A's stack frame */

	std	r0,LRSAVE(r1)



	/* Create our stack frame + pt_regs */

	stdu	r1,-SWITCH_FRAME_SIZE(r1)



	/* Save all gprs to pt_regs */

	SAVE_8GPRS(0,r1)

	SAVE_8GPRS(8,r1)

	SAVE_8GPRS(16,r1)

	SAVE_8GPRS(24,r1)



	/* Load special regs for save below */

	mfmsr   r8

	mfctr   r9

	mfxer   r10

	mfcr	r11



	/* Get the _mcount() call site out of LR */

	mflr	r7

	/* Save it as pt_regs->nip */

	std     r7, _NIP(r1)

	/* Save the read LR in pt_regs->link */

	std     r0, _LINK(r1)



	/* Save callee's TOC in the ABI compliant location */

	std	r2, 24(r1)

	ld	r2,PACATOC(r13)	/* get kernel TOC in r2 */



	addis	r3,r2,function_trace_op@toc@ha

	addi	r3,r3,function_trace_op@toc@l

	ld	r5,0(r3)



#ifdef CONFIG_LIVEPATCH

	mr	r14,r7		/* remember old NIP */

#endif

	/* Calculate ip from nip-4 into r3 for call below */

	subi    r3, r7, MCOUNT_INSN_SIZE



	/* Put the original return address in r4 as parent_ip */

	mr	r4, r0



	/* Save special regs */

	std     r8, _MSR(r1)

	std     r9, _CTR(r1)

	std     r10, _XER(r1)

	std     r11, _CCR(r1)



	/* Load &pt_regs in r6 for call below */

	addi    r6, r1 ,STACK_FRAME_OVERHEAD



	/* ftrace_call(r3, r4, r5, r6) */

.globl ftrace_call

ftrace_call:

	bl	ftrace_stub

	nop



	/* Load ctr with the possibly modified NIP */

	ld	r3, _NIP(r1)

	mtctr	r3

#ifdef CONFIG_LIVEPATCH

	cmpd	r14,r3		/* has NIP been altered? */

#endif



	/* Restore gprs */

	REST_8GPRS(0,r1)

	REST_8GPRS(8,r1)

	REST_8GPRS(16,r1)

	REST_8GPRS(24,r1)



	/* Restore possibly modified LR */

	ld	r0, _LINK(r1)

	mtlr	r0



	/* Restore callee's TOC */

	ld	r2, 24(r1)



	/* Pop our stack frame */

	addi r1, r1, SWITCH_FRAME_SIZE



#ifdef CONFIG_LIVEPATCH

        /* Based on the cmpd above, if the NIP was altered handle livepatch */

	bne-	livepatch_handler

#endif



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

.globl ftrace_graph_call

ftrace_graph_call:

	b	ftrace_graph_stub

_GLOBAL(ftrace_graph_stub)

#endif



	bctr			/* jump after _mcount site */

#endif /* CC_USING_MPROFILE_KERNEL */



_GLOBAL(ftrace_stub)

	blr



#ifdef CONFIG_LIVEPATCH

	/*

	 * This function runs in the mcount context, between two functions. As

	 * such it can only clobber registers which are volatile and used in

	 * function linkage.

	 *

	 * We get here when a function A, calls another function B, but B has

	 * been live patched with a new function C.

	 *

	 * On entry:

	 *  - we have no stack frame and can not allocate one

	 *  - LR points back to the original caller (in A)

	 *  - CTR holds the new NIP in C

	 *  - r0 & r12 are free

	 *

	 * r0 can't be used as the base register for a DS-form load or store, so

	 * we temporarily shuffle r1 (stack pointer) into r0 and then put it back.

	 */

livepatch_handler:

	CURRENT_THREAD_INFO(r12, r1)



	/* Save stack pointer into r0 */

	mr	r0, r1



	/* Allocate 3 x 8 bytes */

	ld	r1, TI_livepatch_sp(r12)

	addi	r1, r1, 24

	std	r1, TI_livepatch_sp(r12)



	/* Save toc & real LR on livepatch stack */

	std	r2,  -24(r1)

	mflr	r12

	std	r12, -16(r1)



	/* Store stack end marker */

	lis     r12, STACK_END_MAGIC@h

	ori     r12, r12, STACK_END_MAGIC@l

	std	r12, -8(r1)



	/* Restore real stack pointer */

	mr	r1, r0



	/* Put ctr in r12 for global entry and branch there */

	mfctr	r12

	bctrl



	/*

	 * Now we are returning from the patched function to the original

	 * caller A. We are free to use r0 and r12, and we can use r2 until we

	 * restore it.

	 */



	CURRENT_THREAD_INFO(r12, r1)



	/* Save stack pointer into r0 */

	mr	r0, r1



	ld	r1, TI_livepatch_sp(r12)



	/* Check stack marker hasn't been trashed */

	lis     r2,  STACK_END_MAGIC@h

	ori     r2,  r2, STACK_END_MAGIC@l

	ld	r12, -8(r1)

1:	tdne	r12, r2

	EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0



	/* Restore LR & toc from livepatch stack */

	ld	r12, -16(r1)

	mtlr	r12

	ld	r2,  -24(r1)



	/* Pop livepatch stack frame */

	CURRENT_THREAD_INFO(r12, r0)

	subi	r1, r1, 24

	std	r1, TI_livepatch_sp(r12)



	/* Restore real stack pointer */

	mr	r1, r0



	/* Return to original caller of live patched function */

	blr

#endif





#else

_GLOBAL_TOC(_mcount)

EXPORT_SYMBOL(_mcount)

	/* Taken from output of objdump from lib64/glibc */

	mflr	r3

	ld	r11, 0(r1)

	stdu	r1, -112(r1)

	std	r3, 128(r1)

	ld	r4, 16(r11)



	subi	r3, r3, MCOUNT_INSN_SIZE

	LOAD_REG_ADDR(r5,ftrace_trace_function)

	ld	r5,0(r5)

	ld	r5,0(r5)

	mtctr	r5

	bctrl

	nop





#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	b	ftrace_graph_caller

#endif

	ld	r0, 128(r1)

	mtlr	r0

	addi	r1, r1, 112

_GLOBAL(ftrace_stub)

	blr



#endif /* CONFIG_DYNAMIC_FTRACE */



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

#ifndef CC_USING_MPROFILE_KERNEL

_GLOBAL(ftrace_graph_caller)

	/* load r4 with local address */

	ld	r4, 128(r1)

	subi	r4, r4, MCOUNT_INSN_SIZE



	/* Grab the LR out of the caller stack frame */

	ld	r11, 112(r1)

	ld	r3, 16(r11)



	bl	prepare_ftrace_return

	nop



	/*

	 * prepare_ftrace_return gives us the address we divert to.

	 * Change the LR in the callers stack frame to this.

	 */

	ld	r11, 112(r1)

	std	r3, 16(r11)



	ld	r0, 128(r1)

	mtlr	r0

	addi	r1, r1, 112

	blr



#else /* CC_USING_MPROFILE_KERNEL */

_GLOBAL(ftrace_graph_caller)

	stdu	r1, -112(r1)

	/* with -mprofile-kernel, parameter regs are still alive at _mcount */

	std	r10, 104(r1)

	std	r9, 96(r1)

	std	r8, 88(r1)

	std	r7, 80(r1)

	std	r6, 72(r1)

	std	r5, 64(r1)

	std	r4, 56(r1)

	std	r3, 48(r1)



	/* Save callee's TOC in the ABI compliant location */

	std	r2, 24(r1)

	ld	r2, PACATOC(r13)	/* get kernel TOC in r2 */



	mfctr	r4		/* ftrace_caller has moved local addr here */

	std	r4, 40(r1)

	mflr	r3		/* ftrace_caller has restored LR from stack */

	subi	r4, r4, MCOUNT_INSN_SIZE



	bl	prepare_ftrace_return

	nop



	/*

	 * prepare_ftrace_return gives us the address we divert to.

	 * Change the LR to this.

	 */

	mtlr	r3



	ld	r0, 40(r1)

	mtctr	r0

	ld	r10, 104(r1)

	ld	r9, 96(r1)

	ld	r8, 88(r1)

	ld	r7, 80(r1)

	ld	r6, 72(r1)

	ld	r5, 64(r1)

	ld	r4, 56(r1)

	ld	r3, 48(r1)



	/* Restore callee's TOC */

	ld	r2, 24(r1)



	addi	r1, r1, 112

	mflr	r0

	std	r0, LRSAVE(r1)

	bctr

#endif /* CC_USING_MPROFILE_KERNEL */



_GLOBAL(return_to_handler)

	/* need to save return values */

	std	r4,  -32(r1)

	std	r3,  -24(r1)

	/* save TOC */

	std	r2,  -16(r1)

	std	r31, -8(r1)

	mr	r31, r1

	stdu	r1, -112(r1)



	/*

	 * We might be called from a module.

	 * Switch to our TOC to run inside the core kernel.

	 */

	ld	r2, PACATOC(r13)



	bl	ftrace_return_to_handler

	nop



	/* return value has real return address */

	mtlr	r3



	ld	r1, 0(r1)

	ld	r4,  -32(r1)

	ld	r3,  -24(r1)

	ld	r2,  -16(r1)

	ld	r31, -8(r1)



	/* Jump back to real return address */

	blr

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

#endif /* CONFIG_FUNCTION_TRACER */

arch/powerpc/kernel/trace/Makefile

0 → 100644
+24 −0
Original line number Diff line number Diff line 
#

# Makefile for the powerpc trace subsystem

#



subdir-ccflags-$(CONFIG_PPC_WERROR)	:= -Werror



ifdef CONFIG_FUNCTION_TRACER

# do not trace tracer code

CFLAGS_REMOVE_ftrace.o = -mno-sched-epilog $(CC_FLAGS_FTRACE)

endif



obj32-$(CONFIG_FUNCTION_TRACER)		+= ftrace_32.o

obj64-$(CONFIG_FUNCTION_TRACER)		+= ftrace_64.o

obj-$(CONFIG_DYNAMIC_FTRACE)		+= ftrace.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o

obj-$(CONFIG_FTRACE_SYSCALLS)		+= ftrace.o

obj-$(CONFIG_TRACING)			+= trace_clock.o



obj-$(CONFIG_PPC64)			+= $(obj64-y)

obj-$(CONFIG_PPC32)			+= $(obj32-y)



# Disable GCOV & sanitizers in odd or sensitive code

GCOV_PROFILE_ftrace.o := n

UBSAN_SANITIZE_ftrace.o := n

CRA Git | Maintained and supported by SUSTech CRA and CCSE