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Make a frame pointer (make the x29 register points the address of pt_regs->regs[29]) on __kretprobe_trampoline. This frame pointer will be used by the stacktracer when it is called from the kretprobe handlers. In this case, the stack tracer will unwind stack to trampoline_probe_handler() and find the next frame pointer in the stack frame of the __kretprobe_trampoline(). Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
87 lines
1.8 KiB
ArmAsm
87 lines
1.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* trampoline entry and return code for kretprobes.
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*/
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#include <linux/linkage.h>
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#include <asm/asm-offsets.h>
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#include <asm/assembler.h>
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.text
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.macro save_all_base_regs
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stp x0, x1, [sp, #S_X0]
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stp x2, x3, [sp, #S_X2]
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stp x4, x5, [sp, #S_X4]
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stp x6, x7, [sp, #S_X6]
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stp x8, x9, [sp, #S_X8]
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stp x10, x11, [sp, #S_X10]
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stp x12, x13, [sp, #S_X12]
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stp x14, x15, [sp, #S_X14]
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stp x16, x17, [sp, #S_X16]
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stp x18, x19, [sp, #S_X18]
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stp x20, x21, [sp, #S_X20]
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stp x22, x23, [sp, #S_X22]
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stp x24, x25, [sp, #S_X24]
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stp x26, x27, [sp, #S_X26]
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stp x28, x29, [sp, #S_X28]
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add x0, sp, #PT_REGS_SIZE
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stp lr, x0, [sp, #S_LR]
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/*
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* Construct a useful saved PSTATE
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*/
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mrs x0, nzcv
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mrs x1, daif
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orr x0, x0, x1
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mrs x1, CurrentEL
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orr x0, x0, x1
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mrs x1, SPSel
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orr x0, x0, x1
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stp xzr, x0, [sp, #S_PC]
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.endm
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.macro restore_all_base_regs
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ldr x0, [sp, #S_PSTATE]
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and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
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msr nzcv, x0
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ldp x0, x1, [sp, #S_X0]
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ldp x2, x3, [sp, #S_X2]
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ldp x4, x5, [sp, #S_X4]
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ldp x6, x7, [sp, #S_X6]
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ldp x8, x9, [sp, #S_X8]
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ldp x10, x11, [sp, #S_X10]
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ldp x12, x13, [sp, #S_X12]
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ldp x14, x15, [sp, #S_X14]
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ldp x16, x17, [sp, #S_X16]
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ldp x18, x19, [sp, #S_X18]
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ldp x20, x21, [sp, #S_X20]
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ldp x22, x23, [sp, #S_X22]
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ldp x24, x25, [sp, #S_X24]
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ldp x26, x27, [sp, #S_X26]
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ldp x28, x29, [sp, #S_X28]
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.endm
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SYM_CODE_START(__kretprobe_trampoline)
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sub sp, sp, #PT_REGS_SIZE
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save_all_base_regs
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/* Setup a frame pointer. */
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add x29, sp, #S_FP
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mov x0, sp
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bl trampoline_probe_handler
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/*
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* Replace trampoline address in lr with actual orig_ret_addr return
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* address.
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*/
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mov lr, x0
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/* The frame pointer (x29) is restored with other registers. */
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restore_all_base_regs
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add sp, sp, #PT_REGS_SIZE
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ret
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SYM_CODE_END(__kretprobe_trampoline)
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