Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 256 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/trace/ftrace_mprofile.S b/arch/powerpc/kernel/trace/ftrace_mprofile.S
new file mode 100644
index 000000000..f4a72b384
--- /dev/null
+++ b/arch/powerpc/kernel/trace/ftrace_mprofile.S
@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Split from ftrace_64.S
+ */
+
+#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>
+#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 */
+	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+STACK_FRAME_MIN_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_FRAME_OVERHEAD
+.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+STACK_FRAME_MIN_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 */