Commit 22821671 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/ftrace: Refactor ftrace_{regs_}caller 



ftrace_caller() and frace_regs_caller() have now a lot in common.

Refactor them using GAS macros.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9d7df9e4fc98a86051489f61d3c9bc67f92f7e27.1645099283.git.christophe.leroy@csgroup.eu
parent 9bdb2eec

arch/powerpc/kernel/trace/ftrace_mprofile.S

+45 −102
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ 
 * 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_regs_caller)

.macro	ftrace_regs_entry allregs

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

#ifdef CONFIG_MPROFILE_KERNEL

	PPC_STL	r0,LRSAVE(r1)
@@ -43,7 +43,7 @@ _GLOBAL(ftrace_regs_caller) 


	/* Save all gprs to pt_regs */

	SAVE_GPR(0, r1)

	SAVE_GPRS(2, 11, r1)

	SAVE_GPRS(3, 10, r1)



#ifdef CONFIG_PPC64

	/* Ok to continue? */
@@ -52,17 +52,29 @@ _GLOBAL(ftrace_regs_caller) 
	beq	ftrace_no_trace

#endif



	SAVE_GPRS(12, 31, r1)

	.if \allregs == 1

	SAVE_GPR(2, r1)

	SAVE_GPRS(11, 31, r1)

	.else

#ifdef CONFIG_LIVEPATCH_64

	SAVE_GPR(14, r1)

#endif

	.endif



	/* Save previous stack pointer (r1) */

	addi	r8, r1, SWITCH_FRAME_SIZE

	PPC_STL	r8, GPR1(r1)



	.if \allregs == 1

	/* Load special regs for save below */

	mfmsr   r8

	mfctr   r9

	mfxer   r10

	mfcr	r11

	.else

	/* Clear MSR to flag as ftrace_caller versus frace_regs_caller */

	li	r8, 0

	.endif



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

	mflr	r7
@@ -96,19 +108,17 @@ _GLOBAL(ftrace_regs_caller) 


	/* Save special regs */

	PPC_STL	r8, _MSR(r1)

	.if \allregs == 1

	PPC_STL	r9, _CTR(r1)

	PPC_STL	r10, _XER(r1)

	PPC_STL	r11, _CCR(r1)

	.endif



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

	addi    r6, r1, STACK_FRAME_OVERHEAD

.endm



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

.globl ftrace_regs_call

ftrace_regs_call:

	bl	ftrace_stub

	nop



.macro	ftrace_regs_exit allregs

	/* Load ctr with the possibly modified NIP */

	PPC_LL	r3, _NIP(r1)

	mtctr	r3
@@ -118,7 +128,14 @@ ftrace_regs_call: 
#endif



	/* Restore gprs */

	.if \allregs == 1

	REST_GPRS(2, 31, r1)

	.else

	REST_GPRS(3, 10, r1)

#ifdef CONFIG_LIVEPATCH_64

	REST_GPR(14, r1)

#endif

	.endif



	/* Restore possibly modified LR */

	PPC_LL	r0, _LINK(r1)
@@ -137,113 +154,39 @@ ftrace_regs_call: 
	bne-	livepatch_handler

#endif

	bctr			/* jump after _mcount site */

.endm



_GLOBAL(ftrace_stub)

	blr



#ifdef CONFIG_PPC64

ftrace_no_trace:

	mflr	r3

	mtctr	r3

	REST_GPR(3, r1)

	addi	r1, r1, SWITCH_FRAME_SIZE

	mtlr	r0

	bctr

#endif

_GLOBAL(ftrace_regs_caller)

	ftrace_regs_entry 1

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

.globl ftrace_regs_call

ftrace_regs_call:

	bl	ftrace_stub

	nop

	ftrace_regs_exit 1



_GLOBAL(ftrace_caller)

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

#ifdef CONFIG_MPROFILE_KERNEL

	PPC_STL	r0, LRSAVE(r1)

#endif



	/* Create our stack frame + pt_regs */

	PPC_STLU	r1, -SWITCH_FRAME_SIZE(r1)



	/* Save all gprs to pt_regs */

	SAVE_GPRS(3, 10, r1)



#ifdef CONFIG_PPC64

	lbz	r3, PACA_FTRACE_ENABLED(r13)

	cmpdi	r3, 0

	beq	ftrace_no_trace

#endif



	/* Save previous stack pointer (r1) */

	addi	r8, r1, SWITCH_FRAME_SIZE

	PPC_STL	r8, GPR1(r1)



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

	mflr	r7

	PPC_STL     r7, _NIP(r1)



#ifdef CONFIG_PPC64

	/* 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)

#else

	lis	r3,function_trace_op@ha

	lwz	r5,function_trace_op@l(r3)

#endif



#ifdef CONFIG_LIVEPATCH_64

	SAVE_GPR(14, r1)

	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 */

	PPC_STL	r0, _LINK(r1)

	mr	r4, r0



	/* Clear MSR to flag as ftrace_caller versus frace_regs_caller */

	li	r8, 0

	PPC_STL	r8, _MSR(r1)



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

	addi    r6, r1, STACK_FRAME_OVERHEAD



	ftrace_regs_entry 0

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

.globl ftrace_call

ftrace_call:

	bl	ftrace_stub

	nop

	ftrace_regs_exit 0



	PPC_LL	r3, _NIP(r1)

	mtctr	r3



#ifdef CONFIG_LIVEPATCH_64

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

	REST_GPR(14, r1)

#endif



	/* Restore gprs */

	REST_GPRS(3, 10, r1)

_GLOBAL(ftrace_stub)

	blr



#ifdef CONFIG_PPC64

	/* Restore callee's TOC */

	ld	r2, 24(r1)

#endif



	/* Restore possibly modified LR */

	PPC_LL	r0, _LINK(r1)

	mtlr	r0



	/* Pop our stack frame */

ftrace_no_trace:

	mflr	r3

	mtctr	r3

	REST_GPR(3, r1)

	addi	r1, r1, SWITCH_FRAME_SIZE



#ifdef CONFIG_LIVEPATCH_64

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

	bne-	livepatch_handler

	mtlr	r0

	bctr

#endif



	bctr			/* jump after _mcount site */



#ifdef CONFIG_LIVEPATCH_64

	/*

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