--- /dev/null
- std r0, LRSAVE+SWITCH_FRAME_SIZE(r1)
+ /* 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)
+
+ /* Save all gprs to pt_regs */
+ SAVE_GPR(0, r1)
+ SAVE_GPRS(3, 10, r1)
+
+ #ifdef CONFIG_PPC64
+ /* Save the original return address in A's stack frame */
- addi r1, r1, SWITCH_FRAME_SIZE
++ std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1)
+ /* 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(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
+ /* Save it as pt_regs->nip */
+ PPC_STL r7, _NIP(r1)
++ /* Also save it in B's stackframe header for proper unwind */
++ PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1)
+ /* Save the read LR in pt_regs->link */
+ PPC_STL r0, _LINK(r1)
+
+ #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 */
+ 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
+
+ #ifdef CONFIG_LIVEPATCH_64
+ 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 */
+ 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_INT_FRAME_REGS
+ .endm
+
+ .macro ftrace_regs_exit allregs
+ /* Load ctr with the possibly modified NIP */
+ PPC_LL r3, _NIP(r1)
+ mtctr r3
+
+ #ifdef CONFIG_LIVEPATCH_64
+ cmpd r14, r3 /* has NIP been altered? */
+ #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)
+ mtlr r0
+
+ #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
+ bctr /* jump after _mcount site */
+ .endm
+
+ _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)
+ ftrace_regs_entry 0
+ /* ftrace_call(r3, r4, r5, r6) */
+ .globl ftrace_call
+ ftrace_call:
+ bl ftrace_stub
+ nop
+ ftrace_regs_exit 0
+
+ _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
+
+ #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
+ * - LR points back to the original caller (in A)
+ * - CTR holds the new NIP in C
+ * - r0, 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)
+
+ /* Save toc & real LR on livepatch stack */
+ std r2, -24(r11)
+ mflr r12
+ std r12, -16(r11)
+
+ /* Store stack end marker */
+ lis r12, STACK_END_MAGIC@h
+ ori r12, r12, STACK_END_MAGIC@l
+ std r12, -8(r11)
+
+ /* 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 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 */
+
+ .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
projects / linux-block.git / commitdiff