/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Split from ftrace_64.S
*/
#include <linux/export.h>
#include <linux/magic.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/ftrace.h>
#include <asm/ppc-opcode.h>
#include <asm/thread_info.h>
#include <asm/bug.h>
#include <asm/ptrace.h>
/*
*
* ftrace_caller()/ftrace_regs_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.
*/
.macro ftrace_regs_entry allregs
/* Create a minimal stack frame for representing B */
PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1)
/* Create our stack frame + pt_regs */
PPC_STLU r1,-SWITCH_FRAME_SIZE(r1)
.if \allregs == 1
SAVE_GPRS(11, 12, r1)
.endif
/* Get the _mcount() call site out of LR */
mflr r11
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/* Load the ftrace_op */
PPC_LL r12, -(MCOUNT_INSN_SIZE*2 + SZL)(r11)
/* Load direct_call from the ftrace_op */
PPC_LL r12, FTRACE_OPS_DIRECT_CALL(r12)
PPC_LCMPI r12, 0
.if \allregs == 1
bne .Lftrace_direct_call_regs
.else
bne .Lftrace_direct_call
.endif
#endif
/* Save the previous LR in pt_regs->link */
PPC_STL r0, _LINK(r1)
/* Also save it in A's stack frame */
PPC_STL r0, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE+LRSAVE(r1)
/* Save all gprs to pt_regs */
SAVE_GPR(0, r1)
SAVE_GPRS(3, 10, r1)
#ifdef CONFIG_PPC64
/* Ok to continue? */
lbz r3, PACA_FTRACE_ENABLED(r13)
cmpdi r3, 0
beq ftrace_no_trace
#endif
.if \allregs == 1
SAVE_GPR(2, r1)
SAVE_GPRS(13, 31, r1)
.else
#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
SAVE_GPR(14, r1)
#endif
.endif
/* Save previous stack pointer (r1) */
addi r8, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
PPC_STL r8, GPR1(r1)
.if \allregs == 1
/* Load special regs for save below */
mfcr r7
mfmsr r8
mfctr r9
mfxer r10
.else
/* Clear MSR to flag as ftrace_caller versus frace_regs_caller */
li r8, 0
.endif
#ifdef CONFIG_PPC64
/* Save callee's TOC in the ABI compliant location */
std r2, STK_GOT(r1)
LOAD_PACA_TOC()
/* get kernel TOC in r2 */
#endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
/* r11 points to the instruction following the call to ftrace */
PPC_LL r5, -(MCOUNT_INSN_SIZE*2 + SZL)(r11)
PPC_LL r12, FTRACE_OPS_FUNC(r5)
mtctr r12
#else
/* !CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS */
#ifdef CONFIG_PPC64
LOAD_REG_ADDR(r3, function_trace_op)
ld r5,0(r3)
#else
lis r3,function_trace_op@ha
lwz r5,function_trace_op@l(r3)
#endif
#endif
/* Save special regs */
PPC_STL r8, _MSR(r1)
.if \allregs == 1
PPC_STL r7, _CCR(r1)
PPC_STL r9, _CTR(r1)
PPC_STL r10, _XER(r1)
.endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/* Clear orig_gpr3 to later detect ftrace_direct call */
li r7, 0
PPC_STL r7, ORIG_GPR3(r1)
#endif
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
/* Save our real return address in nvr for return */
.if \allregs == 0
SAVE_GPR(15, r1)
.endif
mr r15, r11
/*
* We want the ftrace location in the function, but our lr (in r11)
* points at the 'mtlr r0' instruction in the out of line stub. To
* recover the ftrace location, we read the branch instruction in the
* stub, and adjust our lr by the branch offset.
*
* See ftrace_init_ool_stub() for the profile sequence.
*/
lwz r8, MCOUNT_INSN_SIZE(r11)
slwi r8, r8, 6
srawi r8, r8, 6
add r3, r11, r8
/*
* Override our nip to point past the branch in the original function.
* This allows reliable stack trace and the ftrace stack tracer to work as-is.
*/
addi r11, r3, MCOUNT_INSN_SIZE
#else
/* Calculate ip from nip-4 into r3 for call below */
subi r3, r11, MCOUNT_INSN_SIZE
#endif
/* Save NIP as pt_regs->nip */
PPC_STL r11, _NIP(r1)
/* Also save it in B's stackframe header for proper unwind */
PPC_STL r11, LRSAVE+SWITCH_FRAME_SIZE(r1)
#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
mr r14, r11
/* remember old NIP */
#endif
/* Put the original return address in r4 as parent_ip */
mr r4, r0
/* Load &pt_regs in r6 for call below */
addi r6, r1, STACK_INT_FRAME_REGS
.endm
.macro ftrace_regs_exit allregs
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/* Check orig_gpr3 to detect ftrace_direct call */
PPC_LL r3, ORIG_GPR3(r1)
PPC_LCMPI cr1, r3, 0
mtctr r3
#endif
/* Restore possibly modified LR */
PPC_LL r0, _LINK(r1)
#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE
/* Load ctr with the possibly modified NIP */
PPC_LL r3, _NIP(r1)
#ifdef CONFIG_LIVEPATCH_64
cmpd r14, r3
/* has NIP been altered? */
#endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
beq cr1,2f
mtlr r3
b 3f
#endif
2: mtctr r3
mtlr r0
3:
#else
/* !CONFIG_PPC_FTRACE_OUT_OF_LINE */
/* Load LR with the possibly modified NIP */
PPC_LL r3, _NIP(r1)
cmpd r14, r3
/* has NIP been altered? */
bne- 1f
mr r3, r15
1: mtlr r3
.if \allregs == 0
REST_GPR(15, r1)
.endif
#endif
/* Restore gprs */
.if \allregs == 1
REST_GPRS(2, 31, r1)
.else
REST_GPRS(3, 10, r1)
#if defined(CONFIG_LIVEPATCH_64) || defined(CONFIG_PPC_FTRACE_OUT_OF_LINE)
REST_GPR(14, r1)
#endif
.endif
#ifdef CONFIG_PPC64
/* Restore callee's TOC */
ld r2, STK_GOT(r1)
#endif
/* Pop our stack frame */
addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
#ifdef CONFIG_LIVEPATCH_64
/* Based on the cmpd above, if the NIP was altered handle livepatch */
bne- livepatch_handler
#endif
/* jump after _mcount site */
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
bnectr cr1
#endif
/*
* Return with blr to keep the link stack balanced. The function profiling sequence
* uses 'mtlr r0' to restore LR.
*/
blr
#else
bctr
#endif
.endm
.macro ftrace_regs_func allregs
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
bctrl
#else
.if \allregs == 1
.globl ftrace_regs_call
ftrace_regs_call:
.else
.globl ftrace_call
ftrace_call:
.endif
/* ftrace_call(r3, r4, r5, r6) */
bl ftrace_stub
#endif
.endm
_
GLOBAL(ftrace_regs_caller)
ftrace_regs_entry 1
ftrace_regs_func 1
ftrace_regs_exit 1
_
GLOBAL(ftrace_caller)
ftrace_regs_entry 0
ftrace_regs_func 0
ftrace_regs_exit 0
_
GLOBAL(ftrace_stub)
blr
#ifdef CONFIG_PPC64
ftrace_no_trace:
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
REST_GPR(3, r1)
addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
blr
#else
mflr r3
mtctr r3
REST_GPR(3, r1)
addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
mtlr r0
bctr
#endif
#endif
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
.Lftrace_direct_call_regs:
mtctr r12
REST_GPRS(11, 12, r1)
addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
bctr
.Lftrace_direct_call:
mtctr r12
addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE
bctr
SYM_FUNC_START(ftrace_stub_direct_tramp)
blr
SYM_FUNC_END(ftrace_stub_direct_tramp)
#endif
#ifdef CONFIG_LIVEPATCH_64
/*
* 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.
*
* With PPC_FTRACE_OUT_OF_LINE=n, on entry:
* - LR points back to the original caller (in A)
* - CTR holds the new NIP in C
* - r0, r11 & r12 are free
*
* With PPC_FTRACE_OUT_OF_LINE=y, on entry:
* - r0 points back to the original caller (in A)
* - LR holds the new NIP in C
* - r11 & r12 are free
*/
livepatch_handler:
ld r12, PACA_THREAD_INFO(r13)
/* Allocate 3 x 8 bytes */
ld r11, TI_livepatch_sp(r12)
addi r11, r11, 24
std r11, TI_livepatch_sp(r12)
/* Store stack end marker */
lis r12, STACK_END_MAGIC@h
ori r12, r12, STACK_END_MAGIC@l
std r12, -8(r11)
/* Save toc & real LR on livepatch stack */
std r2, -24(r11)
#ifndef CONFIG_PPC_FTRACE_OUT_OF_LINE
mflr r12
std r12, -16(r11)
mfctr r12
#else
std r0, -16(r11)
mflr r12
/* Put ctr in r12 for global entry and branch there */
mtctr r12
#endif
bctrl
/*
* Now we are returning from the patched function to the original
* caller A. We are free to use r11, r12 and we can use r2 until we
* restore it.
*/
ld r12, PACA_THREAD_INFO(r13)
ld r11, 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(r11)
1: tdne r12, r2
EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0
/* Restore LR & toc from livepatch stack */
ld r12, -16(r11)
mtlr r12
ld r2, -24(r11)
/* Pop livepatch stack frame */
ld r12, PACA_THREAD_INFO(r13)
subi r11, r11, 24
std r11, TI_livepatch_sp(r12)
/* Return to original caller of live patched function */
blr
#endif
/* CONFIG_LIVEPATCH */
#ifndef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY
_
GLOBAL(mcount)
_
GLOBAL(_mcount)
EXPORT_SYMBOL(_mcount)
mflr r12
mtctr r12
mtlr r0
bctr
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
_
GLOBAL(return_to_handler)
/* need to save return values */
#ifdef CONFIG_PPC64
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.
*/
LOAD_PACA_TOC()
#else
stwu r1, -16(r1)
stw r3, 8(r1)
stw r4, 12(r1)
#endif
bl ftrace_return_to_handler
nop
/* return value has real return address */
mtlr r3
#ifdef CONFIG_PPC64
ld r1, 0(r1)
ld r4, -32(r1)
ld r3, -24(r1)
ld r2, -16(r1)
ld r31, -8(r1)
#else
lwz r3, 8(r1)
lwz r4, 12(r1)
addi r1, r1, 16
#endif
/* Jump back to real return address */
blr
#endif
/* CONFIG_FUNCTION_GRAPH_TRACER */
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
SYM_DATA(ftrace_ool_stub_text_count, .long CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESER
VE)
SYM_START(ftrace_ool_stub_text, SYM_L_GLOBAL, .balign SZL)
.space CONFIG_PPC_FTRACE_OUT_OF_LINE_NUM_RESERVE * FTRACE_OOL_STUB_SIZE
SYM_CODE_END(ftrace_ool_stub_text)
#endif
.pushsection ".tramp.ftrace.text","aw",@progbits;
.globl ftrace_tramp_text
ftrace_tramp_text:
.space 32
.popsection
.pushsection ".tramp.ftrace.init","aw",@progbits;
.globl ftrace_tramp_init
ftrace_tramp_init:
.space 32
.popsection
