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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /arch/powerpc/kernel/optprobes_head.S
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
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Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/powerpc/kernel/optprobes_head.S')
-rw-r--r--arch/powerpc/kernel/optprobes_head.S133
1 files changed, 133 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S
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+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Code to prepare detour buffer for optprobes in Kernel.
+ *
+ * Copyright 2017, Anju T, IBM Corp.
+ */
+
+#include <asm/ppc_asm.h>
+#include <asm/ptrace.h>
+#include <asm/asm-offsets.h>
+
+#define OPT_SLOT_SIZE 65536
+
+ .balign 4
+
+ /*
+ * Reserve an area to allocate slots for detour buffer.
+ * This is part of .text section (rather than vmalloc area)
+ * as this needs to be within 32MB of the probed address.
+ */
+ .global optinsn_slot
+optinsn_slot:
+ .space OPT_SLOT_SIZE
+
+ /*
+ * Optprobe template:
+ * This template gets copied into one of the slots in optinsn_slot
+ * and gets fixed up with real optprobe structures et al.
+ */
+ .global optprobe_template_entry
+optprobe_template_entry:
+ /* Create an in-memory pt_regs */
+ stdu r1,-INT_FRAME_SIZE(r1)
+ SAVE_GPR(0,r1)
+ /* Save the previous SP into stack */
+ addi r0,r1,INT_FRAME_SIZE
+ std r0,GPR1(r1)
+ SAVE_10GPRS(2,r1)
+ SAVE_10GPRS(12,r1)
+ SAVE_10GPRS(22,r1)
+ /* Save SPRS */
+ mfmsr r5
+ std r5,_MSR(r1)
+ li r5,0x700
+ std r5,_TRAP(r1)
+ li r5,0
+ std r5,ORIG_GPR3(r1)
+ std r5,RESULT(r1)
+ mfctr r5
+ std r5,_CTR(r1)
+ mflr r5
+ std r5,_LINK(r1)
+ mfspr r5,SPRN_XER
+ std r5,_XER(r1)
+ mfcr r5
+ std r5,_CCR(r1)
+ lbz r5,PACAIRQSOFTMASK(r13)
+ std r5,SOFTE(r1)
+
+ /*
+ * We may get here from a module, so load the kernel TOC in r2.
+ * The original TOC gets restored when pt_regs is restored
+ * further below.
+ */
+ ld r2,PACATOC(r13)
+
+ .global optprobe_template_op_address
+optprobe_template_op_address:
+ /*
+ * Parameters to optimized_callback():
+ * 1. optimized_kprobe structure in r3
+ */
+ nop
+ nop
+ nop
+ nop
+ nop
+ /* 2. pt_regs pointer in r4 */
+ addi r4,r1,STACK_FRAME_OVERHEAD
+
+ .global optprobe_template_call_handler
+optprobe_template_call_handler:
+ /* Branch to optimized_callback() */
+ nop
+
+ /*
+ * Parameters for instruction emulation:
+ * 1. Pass SP in register r3.
+ */
+ addi r3,r1,STACK_FRAME_OVERHEAD
+
+ .global optprobe_template_insn
+optprobe_template_insn:
+ /* 2, Pass instruction to be emulated in r4 */
+ nop
+ nop
+ nop
+ nop
+ nop
+
+ .global optprobe_template_call_emulate
+optprobe_template_call_emulate:
+ /* Branch to emulate_step() */
+ nop
+
+ /*
+ * All done.
+ * Now, restore the registers...
+ */
+ ld r5,_MSR(r1)
+ mtmsr r5
+ ld r5,_CTR(r1)
+ mtctr r5
+ ld r5,_LINK(r1)
+ mtlr r5
+ ld r5,_XER(r1)
+ mtxer r5
+ ld r5,_CCR(r1)
+ mtcr r5
+ REST_GPR(0,r1)
+ REST_10GPRS(2,r1)
+ REST_10GPRS(12,r1)
+ REST_10GPRS(22,r1)
+ /* Restore the previous SP */
+ addi r1,r1,INT_FRAME_SIZE
+
+ .global optprobe_template_ret
+optprobe_template_ret:
+ /* ... and jump back from trampoline */
+ nop
+
+ .global optprobe_template_end
+optprobe_template_end: