/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright IBM Corp. 2008, 2009
 *
 */

#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/ftrace.h>
#include <asm/nospec-insn.h>
#include <asm/ptrace.h>
#include <asm/march.h>

#define STACK_FRAME_SIZE_PTREGS         (STACK_FRAME_OVERHEAD + __PT_SIZE)
#define STACK_PTREGS                    (STACK_FRAME_OVERHEAD)
#define STACK_PTREGS_GPRS               (STACK_PTREGS + __PT_GPRS)
#define STACK_PTREGS_PSW                (STACK_PTREGS + __PT_PSW)

#define STACK_FRAME_SIZE_FREGS          (STACK_FRAME_OVERHEAD + __FTRACE_REGS_SIZE)
#define STACK_FREGS                     (STACK_FRAME_OVERHEAD)
#define STACK_FREGS_PTREGS              (STACK_FRAME_OVERHEAD + __FTRACE_REGS_PT_REGS)
#define STACK_FREGS_PTREGS_GPRS         (STACK_FREGS_PTREGS + __PT_GPRS)
#define STACK_FREGS_PTREGS_PSW          (STACK_FREGS_PTREGS + __PT_PSW)
#define STACK_FREGS_PTREGS_ORIG_GPR2    (STACK_FREGS_PTREGS + __PT_ORIG_GPR2)
#define STACK_FREGS_PTREGS_FLAGS        (STACK_FREGS_PTREGS + __PT_FLAGS)

/* packed stack: allocate just enough for r14, r15 and backchain */
#define TRACED_FUNC_FRAME_SIZE  24

#ifdef CONFIG_FUNCTION_TRACER

        GEN_BR_THUNK %r1
        GEN_BR_THUNK %r14

        .section .kprobes.text, "ax"

SYM_FUNC_START(ftrace_stub)
        BR_EX   %r14
SYM_FUNC_END(ftrace_stub)

SYM_CODE_START(ftrace_stub_direct_tramp)
        lgr     %r1, %r0
        BR_EX   %r1
SYM_CODE_END(ftrace_stub_direct_tramp)

        .macro  ftrace_regs_entry, allregs=0
        stg     %r14,(__SF_GPRS+8*8)(%r15)      # save traced function caller

        .if \allregs == 1
        # save psw mask
        # don't put any instructions clobbering CC before this point
        epsw    %r1,%r14
        risbg   %r14,%r1,0,31,32
        .endif

        lgr     %r1,%r15
        # allocate stack frame for ftrace_caller to contain traced function
        aghi    %r15,-TRACED_FUNC_FRAME_SIZE
        stg     %r1,__SF_BACKCHAIN(%r15)
        stg     %r0,(__SF_GPRS+8*8)(%r15)
        stg     %r15,(__SF_GPRS+9*8)(%r15)
        # allocate ftrace_regs and stack frame for ftrace_trace_function
        aghi    %r15,-STACK_FRAME_SIZE_FREGS
        stg     %r1,(STACK_FREGS_PTREGS_GPRS+15*8)(%r15)
        xc      STACK_FREGS_PTREGS_ORIG_GPR2(8,%r15),STACK_FREGS_PTREGS_ORIG_GPR2(%r15)

        .if \allregs == 1
        stg     %r14,(STACK_FREGS_PTREGS_PSW)(%r15)
        mvghi   STACK_FREGS_PTREGS_FLAGS(%r15),_PIF_FTRACE_FULL_REGS
        .else
        xc      STACK_FREGS_PTREGS_FLAGS(8,%r15),STACK_FREGS_PTREGS_FLAGS(%r15)
        .endif

        lg      %r14,(__SF_GPRS+8*8)(%r1)       # restore original return address
        aghi    %r1,-TRACED_FUNC_FRAME_SIZE
        stg     %r1,__SF_BACKCHAIN(%r15)
        stg     %r0,(STACK_FREGS_PTREGS_PSW+8)(%r15)
        stmg    %r2,%r14,(STACK_FREGS_PTREGS_GPRS+2*8)(%r15)
        .endm

SYM_CODE_START(ftrace_regs_caller)
        ftrace_regs_entry       1
        j       ftrace_common
SYM_CODE_END(ftrace_regs_caller)

SYM_CODE_START(ftrace_caller)
        ftrace_regs_entry       0
        j       ftrace_common
SYM_CODE_END(ftrace_caller)

SYM_CODE_START(ftrace_common)
#ifdef MARCH_HAS_Z196_FEATURES
        aghik   %r2,%r0,-MCOUNT_INSN_SIZE
        lgrl    %r4,function_trace_op
        lgrl    %r1,ftrace_func
#else
        lgr     %r2,%r0
        aghi    %r2,-MCOUNT_INSN_SIZE
        larl    %r4,function_trace_op
        lg      %r4,0(%r4)
        larl    %r1,ftrace_func
        lg      %r1,0(%r1)
#endif
        lgr     %r3,%r14
        la      %r5,STACK_FREGS(%r15)
        BASR_EX %r14,%r1
        lg      %r0,(STACK_FREGS_PTREGS_PSW+8)(%r15)
#ifdef MARCH_HAS_Z196_FEATURES
        ltg     %r1,STACK_FREGS_PTREGS_ORIG_GPR2(%r15)
        locgrz  %r1,%r0
#else
        lg      %r1,STACK_FREGS_PTREGS_ORIG_GPR2(%r15)
        ltgr    %r1,%r1
        jnz     0f
        lgr     %r1,%r0
#endif
0:      lmg     %r2,%r15,(STACK_FREGS_PTREGS_GPRS+2*8)(%r15)
        BR_EX   %r1
SYM_CODE_END(ftrace_common)

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

SYM_FUNC_START(return_to_handler)
        stmg    %r2,%r5,32(%r15)
        lgr     %r1,%r15
        # allocate ftrace_regs and stack frame for ftrace_return_to_handler
        aghi    %r15,-STACK_FRAME_SIZE_FREGS
        stg     %r1,__SF_BACKCHAIN(%r15)
        stg     %r2,(STACK_FREGS_PTREGS_GPRS+2*8)(%r15)
        stg     %r1,(STACK_FREGS_PTREGS_GPRS+15*8)(%r15)
        la      %r2,STACK_FRAME_OVERHEAD(%r15)
        brasl   %r14,ftrace_return_to_handler
        aghi    %r15,STACK_FRAME_SIZE_FREGS
        lgr     %r14,%r2
        lmg     %r2,%r5,32(%r15)
        BR_EX   %r14
SYM_FUNC_END(return_to_handler)

#endif
#endif /* CONFIG_FUNCTION_TRACER */

SYM_CODE_START(ftrace_shared_hotpatch_trampoline_br)
        lmg     %r0,%r1,2(%r1)
        br      %r1
SYM_INNER_LABEL(ftrace_shared_hotpatch_trampoline_br_end, SYM_L_GLOBAL)
SYM_CODE_END(ftrace_shared_hotpatch_trampoline_br)

#ifdef CONFIG_EXPOLINE
SYM_CODE_START(ftrace_shared_hotpatch_trampoline_exrl)
        lmg     %r0,%r1,2(%r1)
        exrl    %r0,0f
        j       .
0:      br      %r1
SYM_INNER_LABEL(ftrace_shared_hotpatch_trampoline_exrl_end, SYM_L_GLOBAL)
SYM_CODE_END(ftrace_shared_hotpatch_trampoline_exrl)
#endif /* CONFIG_EXPOLINE */

#ifdef CONFIG_RETHOOK

SYM_CODE_START(arch_rethook_trampoline)
        stg     %r14,(__SF_GPRS+8*8)(%r15)
        lay     %r15,-STACK_FRAME_SIZE_PTREGS(%r15)
        stmg    %r0,%r14,STACK_PTREGS_GPRS(%r15)

        # store original stack pointer in backchain and pt_regs
        lay     %r7,STACK_FRAME_SIZE_PTREGS(%r15)
        stg     %r7,__SF_BACKCHAIN(%r15)
        stg     %r7,STACK_PTREGS_GPRS+(15*8)(%r15)

        # store full psw
        epsw    %r2,%r3
        risbg   %r3,%r2,0,31,32
        stg     %r3,STACK_PTREGS_PSW(%r15)
        larl    %r1,arch_rethook_trampoline
        stg     %r1,STACK_PTREGS_PSW+8(%r15)

        lay     %r2,STACK_PTREGS(%r15)
        brasl   %r14,arch_rethook_trampoline_callback

        mvc     __SF_EMPTY(16,%r7),STACK_PTREGS_PSW(%r15)
        lmg     %r0,%r15,STACK_PTREGS_GPRS(%r15)
        lpswe   __SF_EMPTY(%r15)
SYM_CODE_END(arch_rethook_trampoline)

#endif /* CONFIG_RETHOOK */