7875bc9b07
PPC32 mcount() caller already saves LR on stack, no need to save it again. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/eadcfc770b4f1e35535ffb85e28e858a2c31dec4.1640017960.git.christophe.leroy@csgroup.eu
185 lines
3.5 KiB
ArmAsm
185 lines
3.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Split from entry_32.S
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*/
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#include <linux/magic.h>
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#include <asm/reg.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/ftrace.h>
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#include <asm/export.h>
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#include <asm/ptrace.h>
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_GLOBAL(mcount)
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_GLOBAL(_mcount)
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/*
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* It is required that _mcount on PPC32 must preserve the
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* link register. But we have r12 to play with. We use r12
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* to push the return address back to the caller of mcount
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* into the ctr register, restore the link register and
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* then jump back using the ctr register.
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*/
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mflr r12
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mtctr r12
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mtlr r0
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bctr
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EXPORT_SYMBOL(_mcount)
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_GLOBAL(ftrace_caller)
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MCOUNT_SAVE_FRAME
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/* r3 ends up with link register */
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subi r3, r3, MCOUNT_INSN_SIZE
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lis r5,function_trace_op@ha
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lwz r5,function_trace_op@l(r5)
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li r6, 0
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.globl ftrace_call
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ftrace_call:
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bl ftrace_stub
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nop
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MCOUNT_RESTORE_FRAME
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ftrace_caller_common:
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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.globl ftrace_graph_call
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ftrace_graph_call:
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b ftrace_graph_stub
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_GLOBAL(ftrace_graph_stub)
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#endif
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/* old link register ends up in ctr reg */
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bctr
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_GLOBAL(ftrace_stub)
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blr
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_GLOBAL(ftrace_regs_caller)
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/* Create our stack frame + pt_regs */
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stwu r1,-INT_FRAME_SIZE(r1)
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/* Save all gprs to pt_regs */
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stw r0, GPR0(r1)
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stmw r2, GPR2(r1)
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/* Save previous stack pointer (r1) */
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addi r8, r1, INT_FRAME_SIZE
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stw r8, GPR1(r1)
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/* Load special regs for save below */
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mfmsr r8
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mfctr r9
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mfxer r10
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mfcr r11
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/* Get the _mcount() call site out of LR */
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mflr r7
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/* Save it as pt_regs->nip */
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stw r7, _NIP(r1)
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/* Save the read LR in pt_regs->link */
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stw r0, _LINK(r1)
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lis r3,function_trace_op@ha
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lwz r5,function_trace_op@l(r3)
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/* Calculate ip from nip-4 into r3 for call below */
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subi r3, r7, MCOUNT_INSN_SIZE
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/* Put the original return address in r4 as parent_ip */
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mr r4, r0
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/* Save special regs */
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stw r8, _MSR(r1)
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stw r9, _CTR(r1)
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stw r10, _XER(r1)
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stw r11, _CCR(r1)
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/* Load &pt_regs in r6 for call below */
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addi r6, r1, STACK_FRAME_OVERHEAD
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/* ftrace_call(r3, r4, r5, r6) */
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.globl ftrace_regs_call
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ftrace_regs_call:
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bl ftrace_stub
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nop
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/* Load ctr with the possibly modified NIP */
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lwz r3, _NIP(r1)
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mtctr r3
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/* Restore gprs */
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lmw r2, GPR2(r1)
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/* Restore possibly modified LR */
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lwz r0, _LINK(r1)
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mtlr r0
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/* Pop our stack frame */
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addi r1, r1, INT_FRAME_SIZE
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b ftrace_caller_common
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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_GLOBAL(ftrace_graph_caller)
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stwu r1,-48(r1)
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stw r3, 12(r1)
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stw r4, 16(r1)
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stw r5, 20(r1)
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stw r6, 24(r1)
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stw r7, 28(r1)
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stw r8, 32(r1)
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stw r9, 36(r1)
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stw r10,40(r1)
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addi r5, r1, 48
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mfctr r4 /* ftrace_caller has moved local addr here */
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stw r4, 44(r1)
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mflr r3 /* ftrace_caller has restored LR from stack */
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subi r4, r4, MCOUNT_INSN_SIZE
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bl prepare_ftrace_return
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nop
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/*
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* prepare_ftrace_return gives us the address we divert to.
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* Change the LR in the callers stack frame to this.
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*/
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stw r3,52(r1)
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mtlr r3
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lwz r0,44(r1)
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mtctr r0
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lwz r3, 12(r1)
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lwz r4, 16(r1)
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lwz r5, 20(r1)
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lwz r6, 24(r1)
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lwz r7, 28(r1)
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lwz r8, 32(r1)
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lwz r9, 36(r1)
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lwz r10,40(r1)
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addi r1, r1, 48
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bctr
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_GLOBAL(return_to_handler)
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/* need to save return values */
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stwu r1, -32(r1)
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stw r3, 20(r1)
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stw r4, 16(r1)
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stw r31, 12(r1)
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mr r31, r1
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bl ftrace_return_to_handler
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nop
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/* return value has real return address */
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mtlr r3
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lwz r3, 20(r1)
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lwz r4, 16(r1)
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lwz r31,12(r1)
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lwz r1, 0(r1)
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/* Jump back to real return address */
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blr
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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