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

diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
index 76dab07..630b2de 100644 (file)
--- a/arch/powerpc/kernel/trace/ftrace_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -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