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-rw-r--r--arch/arm64/kernel/probes/kprobes_trampoline.S86
1 files changed, 86 insertions, 0 deletions
diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S
new file mode 100644
index 000000000..9a6499bed
--- /dev/null
+++ b/arch/arm64/kernel/probes/kprobes_trampoline.S
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * trampoline entry and return code for kretprobes.
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/assembler.h>
+
+ .text
+
+ .macro save_all_base_regs
+ stp x0, x1, [sp, #S_X0]
+ stp x2, x3, [sp, #S_X2]
+ stp x4, x5, [sp, #S_X4]
+ stp x6, x7, [sp, #S_X6]
+ stp x8, x9, [sp, #S_X8]
+ stp x10, x11, [sp, #S_X10]
+ stp x12, x13, [sp, #S_X12]
+ stp x14, x15, [sp, #S_X14]
+ stp x16, x17, [sp, #S_X16]
+ stp x18, x19, [sp, #S_X18]
+ stp x20, x21, [sp, #S_X20]
+ stp x22, x23, [sp, #S_X22]
+ stp x24, x25, [sp, #S_X24]
+ stp x26, x27, [sp, #S_X26]
+ stp x28, x29, [sp, #S_X28]
+ add x0, sp, #PT_REGS_SIZE
+ stp lr, x0, [sp, #S_LR]
+ /*
+ * Construct a useful saved PSTATE
+ */
+ mrs x0, nzcv
+ mrs x1, daif
+ orr x0, x0, x1
+ mrs x1, CurrentEL
+ orr x0, x0, x1
+ mrs x1, SPSel
+ orr x0, x0, x1
+ stp xzr, x0, [sp, #S_PC]
+ .endm
+
+ .macro restore_all_base_regs
+ ldr x0, [sp, #S_PSTATE]
+ and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
+ msr nzcv, x0
+ ldp x0, x1, [sp, #S_X0]
+ ldp x2, x3, [sp, #S_X2]
+ ldp x4, x5, [sp, #S_X4]
+ ldp x6, x7, [sp, #S_X6]
+ ldp x8, x9, [sp, #S_X8]
+ ldp x10, x11, [sp, #S_X10]
+ ldp x12, x13, [sp, #S_X12]
+ ldp x14, x15, [sp, #S_X14]
+ ldp x16, x17, [sp, #S_X16]
+ ldp x18, x19, [sp, #S_X18]
+ ldp x20, x21, [sp, #S_X20]
+ ldp x22, x23, [sp, #S_X22]
+ ldp x24, x25, [sp, #S_X24]
+ ldp x26, x27, [sp, #S_X26]
+ ldp x28, x29, [sp, #S_X28]
+ .endm
+
+SYM_CODE_START(__kretprobe_trampoline)
+ sub sp, sp, #PT_REGS_SIZE
+
+ save_all_base_regs
+
+ /* Setup a frame pointer. */
+ add x29, sp, #S_FP
+
+ mov x0, sp
+ bl trampoline_probe_handler
+ /*
+ * Replace trampoline address in lr with actual orig_ret_addr return
+ * address.
+ */
+ mov lr, x0
+
+ /* The frame pointer (x29) is restored with other registers. */
+ restore_all_base_regs
+
+ add sp, sp, #PT_REGS_SIZE
+ ret
+
+SYM_CODE_END(__kretprobe_trampoline)