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f3a0c23f25
Commit 883bbbffa5 ("ftrace,kcfi: Separate ftrace_stub() and
ftrace_stub_graph()") added a separate ftrace_stub_graph function for
CFI_CLANG. Add the stub to fix FUNCTION_GRAPH_TRACER compatibility
with CFI.
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230710183544.999540-11-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
132 lines
2.8 KiB
ArmAsm
132 lines
2.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (C) 2017 Andes Technology Corporation */
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <linux/cfi_types.h>
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#include <asm/asm.h>
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#include <asm/csr.h>
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#include <asm/unistd.h>
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#include <asm/thread_info.h>
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#include <asm/asm-offsets.h>
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#include <asm-generic/export.h>
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#include <asm/ftrace.h>
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.text
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.macro SAVE_ABI_STATE
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addi sp, sp, -16
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REG_S s0, 0*SZREG(sp)
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REG_S ra, 1*SZREG(sp)
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addi s0, sp, 16
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.endm
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/*
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* The call to ftrace_return_to_handler would overwrite the return
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* register if a0 was not saved.
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*/
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.macro SAVE_RET_ABI_STATE
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addi sp, sp, -4*SZREG
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REG_S s0, 2*SZREG(sp)
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REG_S ra, 3*SZREG(sp)
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REG_S a0, 1*SZREG(sp)
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REG_S a1, 0*SZREG(sp)
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addi s0, sp, 4*SZREG
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.endm
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.macro RESTORE_ABI_STATE
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REG_L ra, 1*SZREG(sp)
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REG_L s0, 0*SZREG(sp)
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addi sp, sp, 16
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.endm
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.macro RESTORE_RET_ABI_STATE
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REG_L ra, 3*SZREG(sp)
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REG_L s0, 2*SZREG(sp)
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REG_L a0, 1*SZREG(sp)
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REG_L a1, 0*SZREG(sp)
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addi sp, sp, 4*SZREG
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.endm
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SYM_TYPED_FUNC_START(ftrace_stub)
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#ifdef CONFIG_DYNAMIC_FTRACE
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.global MCOUNT_NAME
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.set MCOUNT_NAME, ftrace_stub
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#endif
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ret
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SYM_FUNC_END(ftrace_stub)
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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SYM_TYPED_FUNC_START(ftrace_stub_graph)
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ret
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SYM_FUNC_END(ftrace_stub_graph)
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ENTRY(return_to_handler)
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/*
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* On implementing the frame point test, the ideal way is to compare the
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* s0 (frame pointer, if enabled) on entry and the sp (stack pointer) on return.
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* However, the psABI of variable-length-argument functions does not allow this.
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*
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* So alternatively we check the *old* frame pointer position, that is, the
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* value stored in -16(s0) on entry, and the s0 on return.
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*/
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SAVE_RET_ABI_STATE
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mv a0, sp
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call ftrace_return_to_handler
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mv a2, a0
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RESTORE_RET_ABI_STATE
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jalr a2
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ENDPROC(return_to_handler)
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#endif
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#ifndef CONFIG_DYNAMIC_FTRACE
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ENTRY(MCOUNT_NAME)
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la t4, ftrace_stub
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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la t0, ftrace_graph_return
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REG_L t1, 0(t0)
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bne t1, t4, do_ftrace_graph_caller
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la t3, ftrace_graph_entry
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REG_L t2, 0(t3)
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la t6, ftrace_graph_entry_stub
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bne t2, t6, do_ftrace_graph_caller
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#endif
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la t3, ftrace_trace_function
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REG_L t5, 0(t3)
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bne t5, t4, do_trace
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ret
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* A pseudo representation for the function graph tracer:
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* prepare_to_return(&ra_to_caller_of_caller, ra_to_caller)
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*/
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do_ftrace_graph_caller:
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addi a0, s0, -SZREG
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mv a1, ra
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#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
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REG_L a2, -2*SZREG(s0)
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#endif
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SAVE_ABI_STATE
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call prepare_ftrace_return
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RESTORE_ABI_STATE
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ret
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#endif
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/*
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* A pseudo representation for the function tracer:
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* (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller)
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*/
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do_trace:
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REG_L a1, -SZREG(s0)
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mv a0, ra
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SAVE_ABI_STATE
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jalr t5
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RESTORE_ABI_STATE
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ret
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ENDPROC(MCOUNT_NAME)
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#endif
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EXPORT_SYMBOL(MCOUNT_NAME)
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