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-rw-r--r--arch/powerpc/kernel/trace/ftrace_64.S389
1 files changed, 389 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/trace/ftrace_64.S b/arch/powerpc/kernel/trace/ftrace_64.S
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index 000000000000..587e7b5c0aff
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+++ b/arch/powerpc/kernel/trace/ftrace_64.S
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+/*
+ * Split from entry_64.S
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#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/export.h>
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+_GLOBAL(mcount)
+_GLOBAL(_mcount)
+EXPORT_SYMBOL(_mcount)
+ mflr r12
+ mtctr r12
+ mtlr r0
+ bctr
+
+#ifndef CC_USING_MPROFILE_KERNEL
+_GLOBAL_TOC(ftrace_caller)
+ /* Taken from output of objdump from lib64/glibc */
+ mflr r3
+ ld r11, 0(r1)
+ stdu r1, -112(r1)
+ std r3, 128(r1)
+ ld r4, 16(r11)
+ subi r3, r3, MCOUNT_INSN_SIZE
+.globl ftrace_call
+ftrace_call:
+ bl ftrace_stub
+ nop
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+.globl ftrace_graph_call
+ftrace_graph_call:
+ b ftrace_graph_stub
+_GLOBAL(ftrace_graph_stub)
+#endif
+ ld r0, 128(r1)
+ mtlr r0
+ addi r1, r1, 112
+
+#else /* CC_USING_MPROFILE_KERNEL */
+/*
+ *
+ * ftrace_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.
+ */
+_GLOBAL(ftrace_caller)
+ /* Save the original return address in A's stack frame */
+ std r0,LRSAVE(r1)
+
+ /* Create our stack frame + pt_regs */
+ stdu r1,-SWITCH_FRAME_SIZE(r1)
+
+ /* Save all gprs to pt_regs */
+ SAVE_8GPRS(0,r1)
+ SAVE_8GPRS(8,r1)
+ SAVE_8GPRS(16,r1)
+ SAVE_8GPRS(24,r1)
+
+ /* Load special regs for save below */
+ mfmsr r8
+ mfctr r9
+ mfxer r10
+ mfcr r11
+
+ /* Get the _mcount() call site out of LR */
+ mflr r7
+ /* Save it as pt_regs->nip */
+ std r7, _NIP(r1)
+ /* Save the read LR in pt_regs->link */
+ std r0, _LINK(r1)
+
+ /* 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)
+
+#ifdef CONFIG_LIVEPATCH
+ 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 */
+ mr r4, r0
+
+ /* Save special regs */
+ std r8, _MSR(r1)
+ std r9, _CTR(r1)
+ std r10, _XER(r1)
+ std r11, _CCR(r1)
+
+ /* Load &pt_regs in r6 for call below */
+ addi r6, r1 ,STACK_FRAME_OVERHEAD
+
+ /* ftrace_call(r3, r4, r5, r6) */
+.globl ftrace_call
+ftrace_call:
+ bl ftrace_stub
+ nop
+
+ /* Load ctr with the possibly modified NIP */
+ ld r3, _NIP(r1)
+ mtctr r3
+#ifdef CONFIG_LIVEPATCH
+ cmpd r14,r3 /* has NIP been altered? */
+#endif
+
+ /* Restore gprs */
+ REST_8GPRS(0,r1)
+ REST_8GPRS(8,r1)
+ REST_8GPRS(16,r1)
+ REST_8GPRS(24,r1)
+
+ /* Restore possibly modified LR */
+ ld r0, _LINK(r1)
+ mtlr r0
+
+ /* Restore callee's TOC */
+ ld r2, 24(r1)
+
+ /* Pop our stack frame */
+ addi r1, r1, SWITCH_FRAME_SIZE
+
+#ifdef CONFIG_LIVEPATCH
+ /* Based on the cmpd above, if the NIP was altered handle livepatch */
+ bne- livepatch_handler
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+.globl ftrace_graph_call
+ftrace_graph_call:
+ b ftrace_graph_stub
+_GLOBAL(ftrace_graph_stub)
+#endif
+
+ bctr /* jump after _mcount site */
+#endif /* CC_USING_MPROFILE_KERNEL */
+
+_GLOBAL(ftrace_stub)
+ blr
+
+#ifdef CONFIG_LIVEPATCH
+ /*
+ * 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
+ * - LR points back to the original caller (in A)
+ * - CTR holds the new NIP in C
+ * - r0 & r12 are free
+ *
+ * r0 can't be used as the base register for a DS-form load or store, so
+ * we temporarily shuffle r1 (stack pointer) into r0 and then put it back.
+ */
+livepatch_handler:
+ CURRENT_THREAD_INFO(r12, r1)
+
+ /* Save stack pointer into r0 */
+ mr r0, r1
+
+ /* Allocate 3 x 8 bytes */
+ ld r1, TI_livepatch_sp(r12)
+ addi r1, r1, 24
+ std r1, TI_livepatch_sp(r12)
+
+ /* Save toc & real LR on livepatch stack */
+ std r2, -24(r1)
+ mflr r12
+ std r12, -16(r1)
+
+ /* Store stack end marker */
+ lis r12, STACK_END_MAGIC@h
+ ori r12, r12, STACK_END_MAGIC@l
+ std r12, -8(r1)
+
+ /* Restore real stack pointer */
+ mr r1, r0
+
+ /* Put ctr in r12 for global entry and branch there */
+ mfctr r12
+ bctrl
+
+ /*
+ * Now we are returning from the patched function to the original
+ * caller A. We are free to use r0 and r12, and we can use r2 until we
+ * restore it.
+ */
+
+ CURRENT_THREAD_INFO(r12, r1)
+
+ /* Save stack pointer into r0 */
+ mr r0, r1
+
+ ld r1, 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(r1)
+1: tdne r12, r2
+ EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0
+
+ /* Restore LR & toc from livepatch stack */
+ ld r12, -16(r1)
+ mtlr r12
+ ld r2, -24(r1)
+
+ /* Pop livepatch stack frame */
+ CURRENT_THREAD_INFO(r12, r0)
+ subi r1, r1, 24
+ std r1, TI_livepatch_sp(r12)
+
+ /* Restore real stack pointer */
+ mr r1, r0
+
+ /* Return to original caller of live patched function */
+ blr
+#endif
+
+
+#else
+_GLOBAL_TOC(_mcount)
+EXPORT_SYMBOL(_mcount)
+ /* Taken from output of objdump from lib64/glibc */
+ mflr r3
+ ld r11, 0(r1)
+ stdu r1, -112(r1)
+ std r3, 128(r1)
+ ld r4, 16(r11)
+
+ subi r3, r3, MCOUNT_INSN_SIZE
+ LOAD_REG_ADDR(r5,ftrace_trace_function)
+ ld r5,0(r5)
+ ld r5,0(r5)
+ mtctr r5
+ bctrl
+ nop
+
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ b ftrace_graph_caller
+#endif
+ ld r0, 128(r1)
+ mtlr r0
+ addi r1, r1, 112
+_GLOBAL(ftrace_stub)
+ blr
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#ifndef CC_USING_MPROFILE_KERNEL
+_GLOBAL(ftrace_graph_caller)
+ /* load r4 with local address */
+ ld r4, 128(r1)
+ subi r4, r4, MCOUNT_INSN_SIZE
+
+ /* Grab the LR out of the caller stack frame */
+ ld r11, 112(r1)
+ ld r3, 16(r11)
+
+ bl prepare_ftrace_return
+ nop
+
+ /*
+ * prepare_ftrace_return gives us the address we divert to.
+ * Change the LR in the callers stack frame to this.
+ */
+ ld r11, 112(r1)
+ std r3, 16(r11)
+
+ ld r0, 128(r1)
+ mtlr r0
+ addi r1, r1, 112
+ blr
+
+#else /* CC_USING_MPROFILE_KERNEL */
+_GLOBAL(ftrace_graph_caller)
+ stdu r1, -112(r1)
+ /* with -mprofile-kernel, parameter regs are still alive at _mcount */
+ std r10, 104(r1)
+ std r9, 96(r1)
+ std r8, 88(r1)
+ std r7, 80(r1)
+ std r6, 72(r1)
+ std r5, 64(r1)
+ std r4, 56(r1)
+ std r3, 48(r1)
+
+ /* Save callee's TOC in the ABI compliant location */
+ std r2, 24(r1)
+ ld r2, PACATOC(r13) /* get kernel TOC in r2 */
+
+ mfctr r4 /* ftrace_caller has moved local addr here */
+ std r4, 40(r1)
+ mflr r3 /* ftrace_caller has restored LR from stack */
+ subi r4, r4, MCOUNT_INSN_SIZE
+
+ bl prepare_ftrace_return
+ nop
+
+ /*
+ * prepare_ftrace_return gives us the address we divert to.
+ * Change the LR to this.
+ */
+ mtlr r3
+
+ ld r0, 40(r1)
+ mtctr r0
+ ld r10, 104(r1)
+ ld r9, 96(r1)
+ ld r8, 88(r1)
+ ld r7, 80(r1)
+ ld r6, 72(r1)
+ ld r5, 64(r1)
+ ld r4, 56(r1)
+ ld r3, 48(r1)
+
+ /* Restore callee's TOC */
+ ld r2, 24(r1)
+
+ addi r1, r1, 112
+ mflr r0
+ std r0, LRSAVE(r1)
+ bctr
+#endif /* CC_USING_MPROFILE_KERNEL */
+
+_GLOBAL(return_to_handler)
+ /* need to save return values */
+ 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.
+ */
+ ld r2, PACATOC(r13)
+
+ bl ftrace_return_to_handler
+ nop
+
+ /* return value has real return address */
+ mtlr r3
+
+ ld r1, 0(r1)
+ ld r4, -32(r1)
+ ld r3, -24(r1)
+ ld r2, -16(r1)
+ ld r31, -8(r1)
+
+ /* Jump back to real return address */
+ blr
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */